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i2c: i2c-stm32f7: add driver
This patch adds initial support for the STM32F7 I2C controller. Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com> Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Pierre-Yves MORDRET
Wolfram Sang
parent
df8c847b53
commit
aeb068c572
@ -945,6 +945,16 @@ config I2C_STM32F4
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This driver can also be built as module. If so, the module
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will be called i2c-stm32f4.
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config I2C_STM32F7
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tristate "STMicroelectronics STM32F7 I2C support"
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depends on ARCH_STM32 || COMPILE_TEST
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help
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Enable this option to add support for STM32 I2C controller embedded
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in STM32F7 SoCs.
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This driver can also be built as module. If so, the module
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will be called i2c-stm32f7.
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config I2C_STU300
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tristate "ST Microelectronics DDC I2C interface"
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depends on MACH_U300
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@ -94,6 +94,7 @@ obj-$(CONFIG_I2C_SIRF) += i2c-sirf.o
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obj-$(CONFIG_I2C_SPRD) += i2c-sprd.o
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obj-$(CONFIG_I2C_ST) += i2c-st.o
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obj-$(CONFIG_I2C_STM32F4) += i2c-stm32f4.o
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obj-$(CONFIG_I2C_STM32F7) += i2c-stm32f7.o
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obj-$(CONFIG_I2C_STU300) += i2c-stu300.o
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obj-$(CONFIG_I2C_SUN6I_P2WI) += i2c-sun6i-p2wi.o
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obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o
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972
drivers/i2c/busses/i2c-stm32f7.c
Normal file
972
drivers/i2c/busses/i2c-stm32f7.c
Normal file
@ -0,0 +1,972 @@
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/*
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* Driver for STMicroelectronics STM32F7 I2C controller
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*
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* This I2C controller is described in the STM32F75xxx and STM32F74xxx Soc
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* reference manual.
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* Please see below a link to the documentation:
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* http://www.st.com/resource/en/reference_manual/dm00124865.pdf
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*
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* Copyright (C) M'boumba Cedric Madianga 2017
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* Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
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*
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* This driver is based on i2c-stm32f4.c
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*
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* License terms: GNU General Public License (GPL), version 2
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*/
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/iopoll.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/reset.h>
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#include <linux/slab.h>
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#include "i2c-stm32.h"
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/* STM32F7 I2C registers */
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#define STM32F7_I2C_CR1 0x00
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#define STM32F7_I2C_CR2 0x04
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#define STM32F7_I2C_TIMINGR 0x10
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#define STM32F7_I2C_ISR 0x18
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#define STM32F7_I2C_ICR 0x1C
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#define STM32F7_I2C_RXDR 0x24
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#define STM32F7_I2C_TXDR 0x28
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/* STM32F7 I2C control 1 */
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#define STM32F7_I2C_CR1_ANFOFF BIT(12)
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#define STM32F7_I2C_CR1_ERRIE BIT(7)
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#define STM32F7_I2C_CR1_TCIE BIT(6)
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#define STM32F7_I2C_CR1_STOPIE BIT(5)
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#define STM32F7_I2C_CR1_NACKIE BIT(4)
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#define STM32F7_I2C_CR1_ADDRIE BIT(3)
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#define STM32F7_I2C_CR1_RXIE BIT(2)
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#define STM32F7_I2C_CR1_TXIE BIT(1)
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#define STM32F7_I2C_CR1_PE BIT(0)
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#define STM32F7_I2C_ALL_IRQ_MASK (STM32F7_I2C_CR1_ERRIE \
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| STM32F7_I2C_CR1_TCIE \
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| STM32F7_I2C_CR1_STOPIE \
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| STM32F7_I2C_CR1_NACKIE \
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| STM32F7_I2C_CR1_RXIE \
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| STM32F7_I2C_CR1_TXIE)
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/* STM32F7 I2C control 2 */
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#define STM32F7_I2C_CR2_RELOAD BIT(24)
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#define STM32F7_I2C_CR2_NBYTES_MASK GENMASK(23, 16)
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#define STM32F7_I2C_CR2_NBYTES(n) (((n) & 0xff) << 16)
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#define STM32F7_I2C_CR2_NACK BIT(15)
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#define STM32F7_I2C_CR2_STOP BIT(14)
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#define STM32F7_I2C_CR2_START BIT(13)
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#define STM32F7_I2C_CR2_RD_WRN BIT(10)
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#define STM32F7_I2C_CR2_SADD7_MASK GENMASK(7, 1)
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#define STM32F7_I2C_CR2_SADD7(n) (((n) & 0x7f) << 1)
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/* STM32F7 I2C Interrupt Status */
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#define STM32F7_I2C_ISR_BUSY BIT(15)
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#define STM32F7_I2C_ISR_ARLO BIT(9)
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#define STM32F7_I2C_ISR_BERR BIT(8)
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#define STM32F7_I2C_ISR_TCR BIT(7)
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#define STM32F7_I2C_ISR_TC BIT(6)
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#define STM32F7_I2C_ISR_STOPF BIT(5)
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#define STM32F7_I2C_ISR_NACKF BIT(4)
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#define STM32F7_I2C_ISR_RXNE BIT(2)
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#define STM32F7_I2C_ISR_TXIS BIT(1)
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/* STM32F7 I2C Interrupt Clear */
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#define STM32F7_I2C_ICR_ARLOCF BIT(9)
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#define STM32F7_I2C_ICR_BERRCF BIT(8)
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#define STM32F7_I2C_ICR_STOPCF BIT(5)
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#define STM32F7_I2C_ICR_NACKCF BIT(4)
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/* STM32F7 I2C Timing */
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#define STM32F7_I2C_TIMINGR_PRESC(n) (((n) & 0xf) << 28)
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#define STM32F7_I2C_TIMINGR_SCLDEL(n) (((n) & 0xf) << 20)
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#define STM32F7_I2C_TIMINGR_SDADEL(n) (((n) & 0xf) << 16)
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#define STM32F7_I2C_TIMINGR_SCLH(n) (((n) & 0xff) << 8)
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#define STM32F7_I2C_TIMINGR_SCLL(n) ((n) & 0xff)
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#define STM32F7_I2C_MAX_LEN 0xff
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#define STM32F7_I2C_DNF_DEFAULT 0
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#define STM32F7_I2C_DNF_MAX 16
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#define STM32F7_I2C_ANALOG_FILTER_ENABLE 1
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#define STM32F7_I2C_ANALOG_FILTER_DELAY_MIN 50 /* ns */
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#define STM32F7_I2C_ANALOG_FILTER_DELAY_MAX 260 /* ns */
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#define STM32F7_I2C_RISE_TIME_DEFAULT 25 /* ns */
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#define STM32F7_I2C_FALL_TIME_DEFAULT 10 /* ns */
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#define STM32F7_PRESC_MAX BIT(4)
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#define STM32F7_SCLDEL_MAX BIT(4)
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#define STM32F7_SDADEL_MAX BIT(4)
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#define STM32F7_SCLH_MAX BIT(8)
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#define STM32F7_SCLL_MAX BIT(8)
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/**
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* struct stm32f7_i2c_spec - private i2c specification timing
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* @rate: I2C bus speed (Hz)
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* @rate_min: 80% of I2C bus speed (Hz)
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* @rate_max: 100% of I2C bus speed (Hz)
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* @fall_max: Max fall time of both SDA and SCL signals (ns)
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* @rise_max: Max rise time of both SDA and SCL signals (ns)
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* @hddat_min: Min data hold time (ns)
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* @vddat_max: Max data valid time (ns)
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* @sudat_min: Min data setup time (ns)
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* @l_min: Min low period of the SCL clock (ns)
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* @h_min: Min high period of the SCL clock (ns)
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*/
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struct stm32f7_i2c_spec {
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u32 rate;
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u32 rate_min;
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u32 rate_max;
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u32 fall_max;
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u32 rise_max;
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u32 hddat_min;
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u32 vddat_max;
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u32 sudat_min;
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u32 l_min;
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u32 h_min;
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};
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/**
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* struct stm32f7_i2c_setup - private I2C timing setup parameters
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* @speed: I2C speed mode (standard, Fast Plus)
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* @speed_freq: I2C speed frequency (Hz)
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* @clock_src: I2C clock source frequency (Hz)
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* @rise_time: Rise time (ns)
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* @fall_time: Fall time (ns)
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* @dnf: Digital filter coefficient (0-16)
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* @analog_filter: Analog filter delay (On/Off)
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*/
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struct stm32f7_i2c_setup {
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enum stm32_i2c_speed speed;
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u32 speed_freq;
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u32 clock_src;
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u32 rise_time;
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u32 fall_time;
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u8 dnf;
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bool analog_filter;
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};
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/**
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* struct stm32f7_i2c_timings - private I2C output parameters
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* @prec: Prescaler value
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* @scldel: Data setup time
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* @sdadel: Data hold time
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* @sclh: SCL high period (master mode)
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* @sclh: SCL low period (master mode)
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*/
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struct stm32f7_i2c_timings {
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struct list_head node;
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u8 presc;
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u8 scldel;
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u8 sdadel;
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u8 sclh;
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u8 scll;
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};
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/**
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* struct stm32f7_i2c_msg - client specific data
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* @addr: 8-bit slave addr, including r/w bit
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* @count: number of bytes to be transferred
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* @buf: data buffer
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* @result: result of the transfer
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* @stop: last I2C msg to be sent, i.e. STOP to be generated
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*/
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struct stm32f7_i2c_msg {
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u8 addr;
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u32 count;
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u8 *buf;
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int result;
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bool stop;
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};
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/**
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* struct stm32f7_i2c_dev - private data of the controller
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* @adap: I2C adapter for this controller
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* @dev: device for this controller
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* @base: virtual memory area
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* @complete: completion of I2C message
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* @clk: hw i2c clock
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* @speed: I2C clock frequency of the controller. Standard, Fast or Fast+
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* @msg: Pointer to data to be written
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* @msg_num: number of I2C messages to be executed
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* @msg_id: message identifiant
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* @f7_msg: customized i2c msg for driver usage
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* @setup: I2C timing input setup
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* @timing: I2C computed timings
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*/
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struct stm32f7_i2c_dev {
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struct i2c_adapter adap;
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struct device *dev;
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void __iomem *base;
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struct completion complete;
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struct clk *clk;
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int speed;
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struct i2c_msg *msg;
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unsigned int msg_num;
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unsigned int msg_id;
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struct stm32f7_i2c_msg f7_msg;
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struct stm32f7_i2c_setup *setup;
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struct stm32f7_i2c_timings timing;
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};
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/**
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* All these values are coming from I2C Specification, Version 6.0, 4th of
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* April 2014.
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*
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* Table10. Characteristics of the SDA and SCL bus lines for Standard, Fast,
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* and Fast-mode Plus I2C-bus devices
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*/
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static struct stm32f7_i2c_spec i2c_specs[] = {
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[STM32_I2C_SPEED_STANDARD] = {
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.rate = 100000,
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.rate_min = 80000,
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.rate_max = 100000,
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.fall_max = 300,
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.rise_max = 1000,
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.hddat_min = 0,
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.vddat_max = 3450,
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.sudat_min = 250,
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.l_min = 4700,
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.h_min = 4000,
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},
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[STM32_I2C_SPEED_FAST] = {
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.rate = 400000,
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.rate_min = 320000,
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.rate_max = 400000,
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.fall_max = 300,
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.rise_max = 300,
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.hddat_min = 0,
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.vddat_max = 900,
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.sudat_min = 100,
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.l_min = 1300,
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.h_min = 600,
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},
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[STM32_I2C_SPEED_FAST_PLUS] = {
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.rate = 1000000,
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.rate_min = 800000,
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.rate_max = 1000000,
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.fall_max = 100,
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.rise_max = 120,
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.hddat_min = 0,
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.vddat_max = 450,
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.sudat_min = 50,
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.l_min = 500,
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.h_min = 260,
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},
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};
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struct stm32f7_i2c_setup stm32f7_setup = {
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.rise_time = STM32F7_I2C_RISE_TIME_DEFAULT,
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.fall_time = STM32F7_I2C_FALL_TIME_DEFAULT,
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.dnf = STM32F7_I2C_DNF_DEFAULT,
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.analog_filter = STM32F7_I2C_ANALOG_FILTER_ENABLE,
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};
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static inline void stm32f7_i2c_set_bits(void __iomem *reg, u32 mask)
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{
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writel_relaxed(readl_relaxed(reg) | mask, reg);
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}
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static inline void stm32f7_i2c_clr_bits(void __iomem *reg, u32 mask)
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{
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writel_relaxed(readl_relaxed(reg) & ~mask, reg);
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}
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static int stm32f7_i2c_compute_timing(struct stm32f7_i2c_dev *i2c_dev,
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struct stm32f7_i2c_setup *setup,
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struct stm32f7_i2c_timings *output)
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{
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u32 p_prev = STM32F7_PRESC_MAX;
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u32 i2cclk = DIV_ROUND_CLOSEST(NSEC_PER_SEC,
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setup->clock_src);
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u32 i2cbus = DIV_ROUND_CLOSEST(NSEC_PER_SEC,
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setup->speed_freq);
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u32 clk_error_prev = i2cbus;
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u32 tsync;
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u32 af_delay_min, af_delay_max;
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u32 dnf_delay;
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u32 clk_min, clk_max;
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int sdadel_min, sdadel_max;
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int scldel_min;
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struct stm32f7_i2c_timings *v, *_v, *s;
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struct list_head solutions;
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u16 p, l, a, h;
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int ret = 0;
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if (setup->speed >= STM32_I2C_SPEED_END) {
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dev_err(i2c_dev->dev, "speed out of bound {%d/%d}\n",
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setup->speed, STM32_I2C_SPEED_END - 1);
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return -EINVAL;
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}
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if ((setup->rise_time > i2c_specs[setup->speed].rise_max) ||
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(setup->fall_time > i2c_specs[setup->speed].fall_max)) {
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dev_err(i2c_dev->dev,
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"timings out of bound Rise{%d>%d}/Fall{%d>%d}\n",
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setup->rise_time, i2c_specs[setup->speed].rise_max,
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setup->fall_time, i2c_specs[setup->speed].fall_max);
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return -EINVAL;
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}
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if (setup->dnf > STM32F7_I2C_DNF_MAX) {
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dev_err(i2c_dev->dev,
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"DNF out of bound %d/%d\n",
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setup->dnf, STM32F7_I2C_DNF_MAX);
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return -EINVAL;
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}
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if (setup->speed_freq > i2c_specs[setup->speed].rate) {
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dev_err(i2c_dev->dev, "ERROR: Freq {%d/%d}\n",
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setup->speed_freq, i2c_specs[setup->speed].rate);
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return -EINVAL;
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}
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/* Analog and Digital Filters */
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af_delay_min =
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(setup->analog_filter ?
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STM32F7_I2C_ANALOG_FILTER_DELAY_MIN : 0);
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af_delay_max =
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(setup->analog_filter ?
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STM32F7_I2C_ANALOG_FILTER_DELAY_MAX : 0);
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dnf_delay = setup->dnf * i2cclk;
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sdadel_min = setup->fall_time - i2c_specs[setup->speed].hddat_min -
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af_delay_min - (setup->dnf + 3) * i2cclk;
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sdadel_max = i2c_specs[setup->speed].vddat_max - setup->rise_time -
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af_delay_max - (setup->dnf + 4) * i2cclk;
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scldel_min = setup->rise_time + i2c_specs[setup->speed].sudat_min;
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if (sdadel_min < 0)
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sdadel_min = 0;
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if (sdadel_max < 0)
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sdadel_max = 0;
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dev_dbg(i2c_dev->dev, "SDADEL(min/max): %i/%i, SCLDEL(Min): %i\n",
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sdadel_min, sdadel_max, scldel_min);
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INIT_LIST_HEAD(&solutions);
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/* Compute possible values for PRESC, SCLDEL and SDADEL */
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for (p = 0; p < STM32F7_PRESC_MAX; p++) {
|
||||
for (l = 0; l < STM32F7_SCLDEL_MAX; l++) {
|
||||
u32 scldel = (l + 1) * (p + 1) * i2cclk;
|
||||
|
||||
if (scldel < scldel_min)
|
||||
continue;
|
||||
|
||||
for (a = 0; a < STM32F7_SDADEL_MAX; a++) {
|
||||
u32 sdadel = (a * (p + 1) + 1) * i2cclk;
|
||||
|
||||
if (((sdadel >= sdadel_min) &&
|
||||
(sdadel <= sdadel_max)) &&
|
||||
(p != p_prev)) {
|
||||
v = kmalloc(sizeof(*v), GFP_KERNEL);
|
||||
if (!v) {
|
||||
ret = -ENOMEM;
|
||||
goto exit;
|
||||
}
|
||||
|
||||
v->presc = p;
|
||||
v->scldel = l;
|
||||
v->sdadel = a;
|
||||
p_prev = p;
|
||||
|
||||
list_add_tail(&v->node,
|
||||
&solutions);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if (list_empty(&solutions)) {
|
||||
dev_err(i2c_dev->dev, "no Prescaler solution\n");
|
||||
ret = -EPERM;
|
||||
goto exit;
|
||||
}
|
||||
|
||||
tsync = af_delay_min + dnf_delay + (2 * i2cclk);
|
||||
s = NULL;
|
||||
clk_max = NSEC_PER_SEC / i2c_specs[setup->speed].rate_min;
|
||||
clk_min = NSEC_PER_SEC / i2c_specs[setup->speed].rate_max;
|
||||
|
||||
/*
|
||||
* Among Prescaler possibilities discovered above figures out SCL Low
|
||||
* and High Period. Provided:
|
||||
* - SCL Low Period has to be higher than SCL Clock Low Period
|
||||
* defined by I2C Specification. I2C Clock has to be lower than
|
||||
* (SCL Low Period - Analog/Digital filters) / 4.
|
||||
* - SCL High Period has to be lower than SCL Clock High Period
|
||||
* defined by I2C Specification
|
||||
* - I2C Clock has to be lower than SCL High Period
|
||||
*/
|
||||
list_for_each_entry(v, &solutions, node) {
|
||||
u32 prescaler = (v->presc + 1) * i2cclk;
|
||||
|
||||
for (l = 0; l < STM32F7_SCLL_MAX; l++) {
|
||||
u32 tscl_l = (l + 1) * prescaler + tsync;
|
||||
|
||||
if ((tscl_l < i2c_specs[setup->speed].l_min) ||
|
||||
(i2cclk >=
|
||||
((tscl_l - af_delay_min - dnf_delay) / 4))) {
|
||||
continue;
|
||||
}
|
||||
|
||||
for (h = 0; h < STM32F7_SCLH_MAX; h++) {
|
||||
u32 tscl_h = (h + 1) * prescaler + tsync;
|
||||
u32 tscl = tscl_l + tscl_h +
|
||||
setup->rise_time + setup->fall_time;
|
||||
|
||||
if ((tscl >= clk_min) && (tscl <= clk_max) &&
|
||||
(tscl_h >= i2c_specs[setup->speed].h_min) &&
|
||||
(i2cclk < tscl_h)) {
|
||||
int clk_error = tscl - i2cbus;
|
||||
|
||||
if (clk_error < 0)
|
||||
clk_error = -clk_error;
|
||||
|
||||
if (clk_error < clk_error_prev) {
|
||||
clk_error_prev = clk_error;
|
||||
v->scll = l;
|
||||
v->sclh = h;
|
||||
s = v;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if (!s) {
|
||||
dev_err(i2c_dev->dev, "no solution at all\n");
|
||||
ret = -EPERM;
|
||||
goto exit;
|
||||
}
|
||||
|
||||
output->presc = s->presc;
|
||||
output->scldel = s->scldel;
|
||||
output->sdadel = s->sdadel;
|
||||
output->scll = s->scll;
|
||||
output->sclh = s->sclh;
|
||||
|
||||
dev_dbg(i2c_dev->dev,
|
||||
"Presc: %i, scldel: %i, sdadel: %i, scll: %i, sclh: %i\n",
|
||||
output->presc,
|
||||
output->scldel, output->sdadel,
|
||||
output->scll, output->sclh);
|
||||
|
||||
exit:
|
||||
/* Release list and memory */
|
||||
list_for_each_entry_safe(v, _v, &solutions, node) {
|
||||
list_del(&v->node);
|
||||
kfree(v);
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int stm32f7_i2c_setup_timing(struct stm32f7_i2c_dev *i2c_dev,
|
||||
struct stm32f7_i2c_setup *setup)
|
||||
{
|
||||
int ret = 0;
|
||||
|
||||
setup->speed = i2c_dev->speed;
|
||||
setup->speed_freq = i2c_specs[setup->speed].rate;
|
||||
setup->clock_src = clk_get_rate(i2c_dev->clk);
|
||||
|
||||
if (!setup->clock_src) {
|
||||
dev_err(i2c_dev->dev, "clock rate is 0\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
do {
|
||||
ret = stm32f7_i2c_compute_timing(i2c_dev, setup,
|
||||
&i2c_dev->timing);
|
||||
if (ret) {
|
||||
dev_err(i2c_dev->dev,
|
||||
"failed to compute I2C timings.\n");
|
||||
if (i2c_dev->speed > STM32_I2C_SPEED_STANDARD) {
|
||||
i2c_dev->speed--;
|
||||
setup->speed = i2c_dev->speed;
|
||||
setup->speed_freq =
|
||||
i2c_specs[setup->speed].rate;
|
||||
dev_warn(i2c_dev->dev,
|
||||
"downgrade I2C Speed Freq to (%i)\n",
|
||||
i2c_specs[setup->speed].rate);
|
||||
} else {
|
||||
break;
|
||||
}
|
||||
}
|
||||
} while (ret);
|
||||
|
||||
if (ret) {
|
||||
dev_err(i2c_dev->dev, "Impossible to compute I2C timings.\n");
|
||||
return ret;
|
||||
}
|
||||
|
||||
dev_dbg(i2c_dev->dev, "I2C Speed(%i), Freq(%i), Clk Source(%i)\n",
|
||||
setup->speed, setup->speed_freq, setup->clock_src);
|
||||
dev_dbg(i2c_dev->dev, "I2C Rise(%i) and Fall(%i) Time\n",
|
||||
setup->rise_time, setup->fall_time);
|
||||
dev_dbg(i2c_dev->dev, "I2C Analog Filter(%s), DNF(%i)\n",
|
||||
(setup->analog_filter ? "On" : "Off"), setup->dnf);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void stm32f7_i2c_hw_config(struct stm32f7_i2c_dev *i2c_dev)
|
||||
{
|
||||
struct stm32f7_i2c_timings *t = &i2c_dev->timing;
|
||||
u32 timing = 0;
|
||||
|
||||
/* Timing settings */
|
||||
timing |= STM32F7_I2C_TIMINGR_PRESC(t->presc);
|
||||
timing |= STM32F7_I2C_TIMINGR_SCLDEL(t->scldel);
|
||||
timing |= STM32F7_I2C_TIMINGR_SDADEL(t->sdadel);
|
||||
timing |= STM32F7_I2C_TIMINGR_SCLH(t->sclh);
|
||||
timing |= STM32F7_I2C_TIMINGR_SCLL(t->scll);
|
||||
writel_relaxed(timing, i2c_dev->base + STM32F7_I2C_TIMINGR);
|
||||
|
||||
/* Enable I2C */
|
||||
if (i2c_dev->setup->analog_filter)
|
||||
stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1,
|
||||
STM32F7_I2C_CR1_ANFOFF);
|
||||
else
|
||||
stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1,
|
||||
STM32F7_I2C_CR1_ANFOFF);
|
||||
stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1,
|
||||
STM32F7_I2C_CR1_PE);
|
||||
}
|
||||
|
||||
static void stm32f7_i2c_write_tx_data(struct stm32f7_i2c_dev *i2c_dev)
|
||||
{
|
||||
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
|
||||
void __iomem *base = i2c_dev->base;
|
||||
|
||||
if (f7_msg->count) {
|
||||
writeb_relaxed(*f7_msg->buf++, base + STM32F7_I2C_TXDR);
|
||||
f7_msg->count--;
|
||||
}
|
||||
}
|
||||
|
||||
static void stm32f7_i2c_read_rx_data(struct stm32f7_i2c_dev *i2c_dev)
|
||||
{
|
||||
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
|
||||
void __iomem *base = i2c_dev->base;
|
||||
|
||||
if (f7_msg->count) {
|
||||
*f7_msg->buf++ = readb_relaxed(base + STM32F7_I2C_RXDR);
|
||||
f7_msg->count--;
|
||||
}
|
||||
}
|
||||
|
||||
static void stm32f7_i2c_reload(struct stm32f7_i2c_dev *i2c_dev)
|
||||
{
|
||||
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
|
||||
u32 cr2;
|
||||
|
||||
cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2);
|
||||
|
||||
cr2 &= ~STM32F7_I2C_CR2_NBYTES_MASK;
|
||||
if (f7_msg->count > STM32F7_I2C_MAX_LEN) {
|
||||
cr2 |= STM32F7_I2C_CR2_NBYTES(STM32F7_I2C_MAX_LEN);
|
||||
} else {
|
||||
cr2 &= ~STM32F7_I2C_CR2_RELOAD;
|
||||
cr2 |= STM32F7_I2C_CR2_NBYTES(f7_msg->count);
|
||||
}
|
||||
|
||||
writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2);
|
||||
}
|
||||
|
||||
static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev)
|
||||
{
|
||||
u32 status;
|
||||
int ret;
|
||||
|
||||
ret = readl_relaxed_poll_timeout(i2c_dev->base + STM32F7_I2C_ISR,
|
||||
status,
|
||||
!(status & STM32F7_I2C_ISR_BUSY),
|
||||
10, 1000);
|
||||
if (ret) {
|
||||
dev_dbg(i2c_dev->dev, "bus busy\n");
|
||||
ret = -EBUSY;
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
|
||||
struct i2c_msg *msg)
|
||||
{
|
||||
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
|
||||
void __iomem *base = i2c_dev->base;
|
||||
u32 cr1, cr2;
|
||||
|
||||
f7_msg->addr = msg->addr;
|
||||
f7_msg->buf = msg->buf;
|
||||
f7_msg->count = msg->len;
|
||||
f7_msg->result = 0;
|
||||
f7_msg->stop = (i2c_dev->msg_id >= i2c_dev->msg_num - 1);
|
||||
|
||||
reinit_completion(&i2c_dev->complete);
|
||||
|
||||
cr1 = readl_relaxed(base + STM32F7_I2C_CR1);
|
||||
cr2 = readl_relaxed(base + STM32F7_I2C_CR2);
|
||||
|
||||
/* Set transfer direction */
|
||||
cr2 &= ~STM32F7_I2C_CR2_RD_WRN;
|
||||
if (msg->flags & I2C_M_RD)
|
||||
cr2 |= STM32F7_I2C_CR2_RD_WRN;
|
||||
|
||||
/* Set slave address */
|
||||
cr2 &= ~STM32F7_I2C_CR2_SADD7_MASK;
|
||||
cr2 |= STM32F7_I2C_CR2_SADD7(f7_msg->addr);
|
||||
|
||||
/* Set nb bytes to transfer and reload if needed */
|
||||
cr2 &= ~(STM32F7_I2C_CR2_NBYTES_MASK | STM32F7_I2C_CR2_RELOAD);
|
||||
if (f7_msg->count > STM32F7_I2C_MAX_LEN) {
|
||||
cr2 |= STM32F7_I2C_CR2_NBYTES(STM32F7_I2C_MAX_LEN);
|
||||
cr2 |= STM32F7_I2C_CR2_RELOAD;
|
||||
} else {
|
||||
cr2 |= STM32F7_I2C_CR2_NBYTES(f7_msg->count);
|
||||
}
|
||||
|
||||
/* Enable NACK, STOP, error and transfer complete interrupts */
|
||||
cr1 |= STM32F7_I2C_CR1_ERRIE | STM32F7_I2C_CR1_TCIE |
|
||||
STM32F7_I2C_CR1_STOPIE | STM32F7_I2C_CR1_NACKIE;
|
||||
|
||||
/* Clear TX/RX interrupt */
|
||||
cr1 &= ~(STM32F7_I2C_CR1_RXIE | STM32F7_I2C_CR1_TXIE);
|
||||
|
||||
/* Enable RX/TX interrupt according to msg direction */
|
||||
if (msg->flags & I2C_M_RD)
|
||||
cr1 |= STM32F7_I2C_CR1_RXIE;
|
||||
else
|
||||
cr1 |= STM32F7_I2C_CR1_TXIE;
|
||||
|
||||
/* Configure Start/Repeated Start */
|
||||
cr2 |= STM32F7_I2C_CR2_START;
|
||||
|
||||
/* Write configurations registers */
|
||||
writel_relaxed(cr1, base + STM32F7_I2C_CR1);
|
||||
writel_relaxed(cr2, base + STM32F7_I2C_CR2);
|
||||
}
|
||||
|
||||
static void stm32f7_i2c_disable_irq(struct stm32f7_i2c_dev *i2c_dev, u32 mask)
|
||||
{
|
||||
stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, mask);
|
||||
}
|
||||
|
||||
static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
|
||||
{
|
||||
struct stm32f7_i2c_dev *i2c_dev = data;
|
||||
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
|
||||
void __iomem *base = i2c_dev->base;
|
||||
u32 status, mask;
|
||||
|
||||
status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
|
||||
|
||||
/* Tx empty */
|
||||
if (status & STM32F7_I2C_ISR_TXIS)
|
||||
stm32f7_i2c_write_tx_data(i2c_dev);
|
||||
|
||||
/* RX not empty */
|
||||
if (status & STM32F7_I2C_ISR_RXNE)
|
||||
stm32f7_i2c_read_rx_data(i2c_dev);
|
||||
|
||||
/* NACK received */
|
||||
if (status & STM32F7_I2C_ISR_NACKF) {
|
||||
dev_dbg(i2c_dev->dev, "<%s>: Receive NACK\n", __func__);
|
||||
writel_relaxed(STM32F7_I2C_ICR_NACKCF, base + STM32F7_I2C_ICR);
|
||||
f7_msg->result = -ENXIO;
|
||||
}
|
||||
|
||||
/* STOP detection flag */
|
||||
if (status & STM32F7_I2C_ISR_STOPF) {
|
||||
/* Disable interrupts */
|
||||
stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
|
||||
|
||||
/* Clear STOP flag */
|
||||
writel_relaxed(STM32F7_I2C_ICR_STOPCF, base + STM32F7_I2C_ICR);
|
||||
|
||||
complete(&i2c_dev->complete);
|
||||
}
|
||||
|
||||
/* Transfer complete */
|
||||
if (status & STM32F7_I2C_ISR_TC) {
|
||||
if (f7_msg->stop) {
|
||||
mask = STM32F7_I2C_CR2_STOP;
|
||||
stm32f7_i2c_set_bits(base + STM32F7_I2C_CR2, mask);
|
||||
} else {
|
||||
i2c_dev->msg_id++;
|
||||
i2c_dev->msg++;
|
||||
stm32f7_i2c_xfer_msg(i2c_dev, i2c_dev->msg);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Transfer Complete Reload: 255 data bytes have been transferred
|
||||
* We have to prepare the I2C controller to transfer the remaining
|
||||
* data.
|
||||
*/
|
||||
if (status & STM32F7_I2C_ISR_TCR)
|
||||
stm32f7_i2c_reload(i2c_dev);
|
||||
|
||||
return IRQ_HANDLED;
|
||||
}
|
||||
|
||||
static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data)
|
||||
{
|
||||
struct stm32f7_i2c_dev *i2c_dev = data;
|
||||
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
|
||||
void __iomem *base = i2c_dev->base;
|
||||
struct device *dev = i2c_dev->dev;
|
||||
u32 status;
|
||||
|
||||
status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
|
||||
|
||||
/* Bus error */
|
||||
if (status & STM32F7_I2C_ISR_BERR) {
|
||||
dev_err(dev, "<%s>: Bus error\n", __func__);
|
||||
writel_relaxed(STM32F7_I2C_ICR_BERRCF, base + STM32F7_I2C_ICR);
|
||||
f7_msg->result = -EIO;
|
||||
}
|
||||
|
||||
/* Arbitration loss */
|
||||
if (status & STM32F7_I2C_ISR_ARLO) {
|
||||
dev_dbg(dev, "<%s>: Arbitration loss\n", __func__);
|
||||
writel_relaxed(STM32F7_I2C_ICR_ARLOCF, base + STM32F7_I2C_ICR);
|
||||
f7_msg->result = -EAGAIN;
|
||||
}
|
||||
|
||||
stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
|
||||
|
||||
complete(&i2c_dev->complete);
|
||||
|
||||
return IRQ_HANDLED;
|
||||
}
|
||||
|
||||
static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
|
||||
struct i2c_msg msgs[], int num)
|
||||
{
|
||||
struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
|
||||
struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
|
||||
unsigned long time_left;
|
||||
int ret;
|
||||
|
||||
i2c_dev->msg = msgs;
|
||||
i2c_dev->msg_num = num;
|
||||
i2c_dev->msg_id = 0;
|
||||
|
||||
ret = clk_enable(i2c_dev->clk);
|
||||
if (ret) {
|
||||
dev_err(i2c_dev->dev, "Failed to enable clock\n");
|
||||
return ret;
|
||||
}
|
||||
|
||||
ret = stm32f7_i2c_wait_free_bus(i2c_dev);
|
||||
if (ret)
|
||||
goto clk_free;
|
||||
|
||||
stm32f7_i2c_xfer_msg(i2c_dev, msgs);
|
||||
|
||||
time_left = wait_for_completion_timeout(&i2c_dev->complete,
|
||||
i2c_dev->adap.timeout);
|
||||
ret = f7_msg->result;
|
||||
|
||||
if (!time_left) {
|
||||
dev_dbg(i2c_dev->dev, "Access to slave 0x%x timed out\n",
|
||||
i2c_dev->msg->addr);
|
||||
ret = -ETIMEDOUT;
|
||||
}
|
||||
|
||||
clk_free:
|
||||
clk_disable(i2c_dev->clk);
|
||||
|
||||
return (ret < 0) ? ret : num;
|
||||
}
|
||||
|
||||
static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
|
||||
{
|
||||
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
|
||||
}
|
||||
|
||||
static struct i2c_algorithm stm32f7_i2c_algo = {
|
||||
.master_xfer = stm32f7_i2c_xfer,
|
||||
.functionality = stm32f7_i2c_func,
|
||||
};
|
||||
|
||||
static int stm32f7_i2c_probe(struct platform_device *pdev)
|
||||
{
|
||||
struct device_node *np = pdev->dev.of_node;
|
||||
struct stm32f7_i2c_dev *i2c_dev;
|
||||
const struct stm32f7_i2c_setup *setup;
|
||||
struct resource *res;
|
||||
u32 irq_error, irq_event, clk_rate, rise_time, fall_time;
|
||||
struct i2c_adapter *adap;
|
||||
struct reset_control *rst;
|
||||
int ret;
|
||||
|
||||
i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
|
||||
if (!i2c_dev)
|
||||
return -ENOMEM;
|
||||
|
||||
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||
i2c_dev->base = devm_ioremap_resource(&pdev->dev, res);
|
||||
if (IS_ERR(i2c_dev->base))
|
||||
return PTR_ERR(i2c_dev->base);
|
||||
|
||||
irq_event = irq_of_parse_and_map(np, 0);
|
||||
if (!irq_event) {
|
||||
dev_err(&pdev->dev, "IRQ event missing or invalid\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
irq_error = irq_of_parse_and_map(np, 1);
|
||||
if (!irq_error) {
|
||||
dev_err(&pdev->dev, "IRQ error missing or invalid\n");
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
i2c_dev->clk = devm_clk_get(&pdev->dev, NULL);
|
||||
if (IS_ERR(i2c_dev->clk)) {
|
||||
dev_err(&pdev->dev, "Error: Missing controller clock\n");
|
||||
return PTR_ERR(i2c_dev->clk);
|
||||
}
|
||||
ret = clk_prepare_enable(i2c_dev->clk);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "Failed to prepare_enable clock\n");
|
||||
return ret;
|
||||
}
|
||||
|
||||
i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
|
||||
ret = device_property_read_u32(&pdev->dev, "clock-frequency",
|
||||
&clk_rate);
|
||||
if (!ret && clk_rate >= 1000000)
|
||||
i2c_dev->speed = STM32_I2C_SPEED_FAST_PLUS;
|
||||
else if (!ret && clk_rate >= 400000)
|
||||
i2c_dev->speed = STM32_I2C_SPEED_FAST;
|
||||
else if (!ret && clk_rate >= 100000)
|
||||
i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
|
||||
|
||||
rst = devm_reset_control_get(&pdev->dev, NULL);
|
||||
if (IS_ERR(rst)) {
|
||||
dev_err(&pdev->dev, "Error: Missing controller reset\n");
|
||||
ret = PTR_ERR(rst);
|
||||
goto clk_free;
|
||||
}
|
||||
reset_control_assert(rst);
|
||||
udelay(2);
|
||||
reset_control_deassert(rst);
|
||||
|
||||
i2c_dev->dev = &pdev->dev;
|
||||
|
||||
ret = devm_request_irq(&pdev->dev, irq_event, stm32f7_i2c_isr_event, 0,
|
||||
pdev->name, i2c_dev);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "Failed to request irq event %i\n",
|
||||
irq_event);
|
||||
goto clk_free;
|
||||
}
|
||||
|
||||
ret = devm_request_irq(&pdev->dev, irq_error, stm32f7_i2c_isr_error, 0,
|
||||
pdev->name, i2c_dev);
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "Failed to request irq error %i\n",
|
||||
irq_error);
|
||||
goto clk_free;
|
||||
}
|
||||
|
||||
setup = of_device_get_match_data(&pdev->dev);
|
||||
i2c_dev->setup->rise_time = setup->rise_time;
|
||||
i2c_dev->setup->fall_time = setup->fall_time;
|
||||
i2c_dev->setup->dnf = setup->dnf;
|
||||
i2c_dev->setup->analog_filter = setup->analog_filter;
|
||||
|
||||
ret = device_property_read_u32(i2c_dev->dev, "i2c-scl-rising-time-ns",
|
||||
&rise_time);
|
||||
if (!ret)
|
||||
i2c_dev->setup->rise_time = rise_time;
|
||||
|
||||
ret = device_property_read_u32(i2c_dev->dev, "i2c-scl-falling-time-ns",
|
||||
&fall_time);
|
||||
if (!ret)
|
||||
i2c_dev->setup->fall_time = fall_time;
|
||||
|
||||
ret = stm32f7_i2c_setup_timing(i2c_dev, i2c_dev->setup);
|
||||
if (ret)
|
||||
goto clk_free;
|
||||
|
||||
stm32f7_i2c_hw_config(i2c_dev);
|
||||
|
||||
adap = &i2c_dev->adap;
|
||||
i2c_set_adapdata(adap, i2c_dev);
|
||||
snprintf(adap->name, sizeof(adap->name), "STM32F7 I2C(%pa)",
|
||||
&res->start);
|
||||
adap->owner = THIS_MODULE;
|
||||
adap->timeout = 2 * HZ;
|
||||
adap->retries = 3;
|
||||
adap->algo = &stm32f7_i2c_algo;
|
||||
adap->dev.parent = &pdev->dev;
|
||||
adap->dev.of_node = pdev->dev.of_node;
|
||||
|
||||
init_completion(&i2c_dev->complete);
|
||||
|
||||
ret = i2c_add_adapter(adap);
|
||||
if (ret)
|
||||
goto clk_free;
|
||||
|
||||
platform_set_drvdata(pdev, i2c_dev);
|
||||
|
||||
clk_disable(i2c_dev->clk);
|
||||
|
||||
dev_info(i2c_dev->dev, "STM32F7 I2C-%d bus adapter\n", adap->nr);
|
||||
|
||||
return 0;
|
||||
|
||||
clk_free:
|
||||
clk_disable_unprepare(i2c_dev->clk);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
static int stm32f7_i2c_remove(struct platform_device *pdev)
|
||||
{
|
||||
struct stm32f7_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
|
||||
|
||||
i2c_del_adapter(&i2c_dev->adap);
|
||||
|
||||
clk_unprepare(i2c_dev->clk);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static const struct of_device_id stm32f7_i2c_match[] = {
|
||||
{ .compatible = "st,stm32f7-i2c", .data = &stm32f7_setup},
|
||||
{},
|
||||
};
|
||||
MODULE_DEVICE_TABLE(of, stm32f7_i2c_match);
|
||||
|
||||
static struct platform_driver stm32f7_i2c_driver = {
|
||||
.driver = {
|
||||
.name = "stm32f7-i2c",
|
||||
.of_match_table = stm32f7_i2c_match,
|
||||
},
|
||||
.probe = stm32f7_i2c_probe,
|
||||
.remove = stm32f7_i2c_remove,
|
||||
};
|
||||
|
||||
module_platform_driver(stm32f7_i2c_driver);
|
||||
|
||||
MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
|
||||
MODULE_DESCRIPTION("STMicroelectronics STM32F7 I2C driver");
|
||||
MODULE_LICENSE("GPL v2");
|
||||
Loading…
Reference in New Issue
Block a user