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i2c: aspeed: added driver for Aspeed I2C
Added initial master support for Aspeed I2C controller. Supports fourteen busses present in AST24XX and AST25XX BMC SoCs by Aspeed. Signed-off-by: Brendan Higgins <brendanhiggins@google.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Brendan Higgins
Wolfram Sang
parent
10a6218e38
commit
f327c686d3
@ -328,6 +328,16 @@ config I2C_POWERMAC
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comment "I2C system bus drivers (mostly embedded / system-on-chip)"
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comment "I2C system bus drivers (mostly embedded / system-on-chip)"
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config I2C_ASPEED
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tristate "Aspeed I2C Controller"
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depends on ARCH_ASPEED || COMPILE_TEST
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help
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If you say yes to this option, support will be included for the
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Aspeed I2C controller.
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This driver can also be built as a module. If so, the module
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will be called i2c-aspeed.
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config I2C_AT91
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config I2C_AT91
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tristate "Atmel AT91 I2C Two-Wire interface (TWI)"
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tristate "Atmel AT91 I2C Two-Wire interface (TWI)"
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depends on ARCH_AT91
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depends on ARCH_AT91
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@ -29,6 +29,7 @@ obj-$(CONFIG_I2C_HYDRA) += i2c-hydra.o
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obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o
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obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o
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# Embedded system I2C/SMBus host controller drivers
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# Embedded system I2C/SMBus host controller drivers
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obj-$(CONFIG_I2C_ASPEED) += i2c-aspeed.o
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obj-$(CONFIG_I2C_AT91) += i2c-at91.o
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obj-$(CONFIG_I2C_AT91) += i2c-at91.o
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obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
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obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o
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obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
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obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
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690
drivers/i2c/busses/i2c-aspeed.c
Normal file
690
drivers/i2c/busses/i2c-aspeed.c
Normal file
@ -0,0 +1,690 @@
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/*
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* Aspeed 24XX/25XX I2C Controller.
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*
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* Copyright (C) 2012-2017 ASPEED Technology Inc.
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* Copyright 2017 IBM Corporation
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* Copyright 2017 Google, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/clk.h>
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#include <linux/completion.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/io.h>
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#include <linux/irq.h>
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#include <linux/irqchip/chained_irq.h>
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#include <linux/irqdomain.h>
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#include <linux/kernel.h>
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#include <linux/module.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/slab.h>
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/* I2C Register */
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#define ASPEED_I2C_FUN_CTRL_REG 0x00
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#define ASPEED_I2C_AC_TIMING_REG1 0x04
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#define ASPEED_I2C_AC_TIMING_REG2 0x08
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#define ASPEED_I2C_INTR_CTRL_REG 0x0c
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#define ASPEED_I2C_INTR_STS_REG 0x10
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#define ASPEED_I2C_CMD_REG 0x14
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#define ASPEED_I2C_DEV_ADDR_REG 0x18
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#define ASPEED_I2C_BYTE_BUF_REG 0x20
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/* Global Register Definition */
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/* 0x00 : I2C Interrupt Status Register */
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/* 0x08 : I2C Interrupt Target Assignment */
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/* Device Register Definition */
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/* 0x00 : I2CD Function Control Register */
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#define ASPEED_I2CD_MULTI_MASTER_DIS BIT(15)
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#define ASPEED_I2CD_SDA_DRIVE_1T_EN BIT(8)
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#define ASPEED_I2CD_M_SDA_DRIVE_1T_EN BIT(7)
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#define ASPEED_I2CD_M_HIGH_SPEED_EN BIT(6)
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#define ASPEED_I2CD_MASTER_EN BIT(0)
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/* 0x04 : I2CD Clock and AC Timing Control Register #1 */
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#define ASPEED_I2CD_TIME_SCL_HIGH_SHIFT 16
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#define ASPEED_I2CD_TIME_SCL_HIGH_MASK GENMASK(19, 16)
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#define ASPEED_I2CD_TIME_SCL_LOW_SHIFT 12
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#define ASPEED_I2CD_TIME_SCL_LOW_MASK GENMASK(15, 12)
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#define ASPEED_I2CD_TIME_BASE_DIVISOR_MASK GENMASK(3, 0)
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#define ASPEED_I2CD_TIME_SCL_REG_MAX GENMASK(3, 0)
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/* 0x08 : I2CD Clock and AC Timing Control Register #2 */
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#define ASPEED_NO_TIMEOUT_CTRL 0
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/* 0x0c : I2CD Interrupt Control Register &
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* 0x10 : I2CD Interrupt Status Register
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*
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* These share bit definitions, so use the same values for the enable &
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* status bits.
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*/
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#define ASPEED_I2CD_INTR_SDA_DL_TIMEOUT BIT(14)
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#define ASPEED_I2CD_INTR_BUS_RECOVER_DONE BIT(13)
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#define ASPEED_I2CD_INTR_SCL_TIMEOUT BIT(6)
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#define ASPEED_I2CD_INTR_ABNORMAL BIT(5)
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#define ASPEED_I2CD_INTR_NORMAL_STOP BIT(4)
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#define ASPEED_I2CD_INTR_ARBIT_LOSS BIT(3)
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#define ASPEED_I2CD_INTR_RX_DONE BIT(2)
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#define ASPEED_I2CD_INTR_TX_NAK BIT(1)
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#define ASPEED_I2CD_INTR_TX_ACK BIT(0)
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#define ASPEED_I2CD_INTR_ALL \
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(ASPEED_I2CD_INTR_SDA_DL_TIMEOUT | \
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ASPEED_I2CD_INTR_BUS_RECOVER_DONE | \
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ASPEED_I2CD_INTR_SCL_TIMEOUT | \
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ASPEED_I2CD_INTR_ABNORMAL | \
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ASPEED_I2CD_INTR_NORMAL_STOP | \
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ASPEED_I2CD_INTR_ARBIT_LOSS | \
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ASPEED_I2CD_INTR_RX_DONE | \
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ASPEED_I2CD_INTR_TX_NAK | \
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ASPEED_I2CD_INTR_TX_ACK)
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/* 0x14 : I2CD Command/Status Register */
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#define ASPEED_I2CD_SCL_LINE_STS BIT(18)
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#define ASPEED_I2CD_SDA_LINE_STS BIT(17)
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#define ASPEED_I2CD_BUS_BUSY_STS BIT(16)
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#define ASPEED_I2CD_BUS_RECOVER_CMD BIT(11)
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/* Command Bit */
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#define ASPEED_I2CD_M_STOP_CMD BIT(5)
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#define ASPEED_I2CD_M_S_RX_CMD_LAST BIT(4)
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#define ASPEED_I2CD_M_RX_CMD BIT(3)
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#define ASPEED_I2CD_S_TX_CMD BIT(2)
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#define ASPEED_I2CD_M_TX_CMD BIT(1)
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#define ASPEED_I2CD_M_START_CMD BIT(0)
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enum aspeed_i2c_master_state {
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ASPEED_I2C_MASTER_START,
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ASPEED_I2C_MASTER_TX_FIRST,
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ASPEED_I2C_MASTER_TX,
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ASPEED_I2C_MASTER_RX_FIRST,
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ASPEED_I2C_MASTER_RX,
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ASPEED_I2C_MASTER_STOP,
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ASPEED_I2C_MASTER_INACTIVE,
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};
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struct aspeed_i2c_bus {
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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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/* Synchronizes I/O mem access to base. */
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spinlock_t lock;
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struct completion cmd_complete;
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unsigned long parent_clk_frequency;
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u32 bus_frequency;
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/* Transaction state. */
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enum aspeed_i2c_master_state master_state;
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struct i2c_msg *msgs;
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size_t buf_index;
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size_t msgs_index;
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size_t msgs_count;
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bool send_stop;
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int cmd_err;
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/* Protected only by i2c_lock_bus */
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int master_xfer_result;
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};
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static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus);
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static int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus)
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{
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unsigned long time_left, flags;
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int ret = 0;
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u32 command;
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spin_lock_irqsave(&bus->lock, flags);
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command = readl(bus->base + ASPEED_I2C_CMD_REG);
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if (command & ASPEED_I2CD_SDA_LINE_STS) {
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/* Bus is idle: no recovery needed. */
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if (command & ASPEED_I2CD_SCL_LINE_STS)
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goto out;
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dev_dbg(bus->dev, "SCL hung (state %x), attempting recovery\n",
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command);
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reinit_completion(&bus->cmd_complete);
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writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
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spin_unlock_irqrestore(&bus->lock, flags);
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time_left = wait_for_completion_timeout(
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&bus->cmd_complete, bus->adap.timeout);
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spin_lock_irqsave(&bus->lock, flags);
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if (time_left == 0)
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goto reset_out;
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else if (bus->cmd_err)
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goto reset_out;
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/* Recovery failed. */
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else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
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ASPEED_I2CD_SCL_LINE_STS))
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goto reset_out;
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/* Bus error. */
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} else {
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dev_dbg(bus->dev, "SDA hung (state %x), attempting recovery\n",
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command);
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reinit_completion(&bus->cmd_complete);
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/* Writes 1 to 8 SCL clock cycles until SDA is released. */
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writel(ASPEED_I2CD_BUS_RECOVER_CMD,
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bus->base + ASPEED_I2C_CMD_REG);
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spin_unlock_irqrestore(&bus->lock, flags);
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time_left = wait_for_completion_timeout(
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&bus->cmd_complete, bus->adap.timeout);
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spin_lock_irqsave(&bus->lock, flags);
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if (time_left == 0)
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goto reset_out;
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else if (bus->cmd_err)
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goto reset_out;
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/* Recovery failed. */
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else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
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ASPEED_I2CD_SDA_LINE_STS))
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goto reset_out;
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}
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out:
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spin_unlock_irqrestore(&bus->lock, flags);
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return ret;
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reset_out:
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spin_unlock_irqrestore(&bus->lock, flags);
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return aspeed_i2c_reset(bus);
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}
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/* precondition: bus.lock has been acquired. */
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static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus)
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{
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u32 command = ASPEED_I2CD_M_START_CMD | ASPEED_I2CD_M_TX_CMD;
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struct i2c_msg *msg = &bus->msgs[bus->msgs_index];
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u8 slave_addr = msg->addr << 1;
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bus->master_state = ASPEED_I2C_MASTER_START;
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bus->buf_index = 0;
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if (msg->flags & I2C_M_RD) {
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slave_addr |= 1;
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command |= ASPEED_I2CD_M_RX_CMD;
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/* Need to let the hardware know to NACK after RX. */
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if (msg->len == 1 && !(msg->flags & I2C_M_RECV_LEN))
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command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
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}
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writel(slave_addr, bus->base + ASPEED_I2C_BYTE_BUF_REG);
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writel(command, bus->base + ASPEED_I2C_CMD_REG);
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}
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/* precondition: bus.lock has been acquired. */
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static void aspeed_i2c_do_stop(struct aspeed_i2c_bus *bus)
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{
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bus->master_state = ASPEED_I2C_MASTER_STOP;
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writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
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}
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/* precondition: bus.lock has been acquired. */
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static void aspeed_i2c_next_msg_or_stop(struct aspeed_i2c_bus *bus)
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{
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if (bus->msgs_index + 1 < bus->msgs_count) {
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bus->msgs_index++;
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aspeed_i2c_do_start(bus);
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} else {
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aspeed_i2c_do_stop(bus);
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}
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}
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static int aspeed_i2c_is_irq_error(u32 irq_status)
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{
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if (irq_status & ASPEED_I2CD_INTR_ARBIT_LOSS)
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return -EAGAIN;
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if (irq_status & (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |
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ASPEED_I2CD_INTR_SCL_TIMEOUT))
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return -EBUSY;
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if (irq_status & (ASPEED_I2CD_INTR_ABNORMAL))
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return -EPROTO;
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return 0;
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}
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static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus)
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{
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u32 irq_status, status_ack = 0, command = 0;
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struct i2c_msg *msg;
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u8 recv_byte;
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int ret;
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spin_lock(&bus->lock);
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irq_status = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
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/* Ack all interrupt bits. */
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writel(irq_status, bus->base + ASPEED_I2C_INTR_STS_REG);
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if (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE) {
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bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
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status_ack |= ASPEED_I2CD_INTR_BUS_RECOVER_DONE;
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goto out_complete;
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}
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/*
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* We encountered an interrupt that reports an error: the hardware
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* should clear the command queue effectively taking us back to the
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* INACTIVE state.
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*/
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ret = aspeed_i2c_is_irq_error(irq_status);
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if (ret < 0) {
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dev_dbg(bus->dev, "received error interrupt: 0x%08x",
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irq_status);
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bus->cmd_err = ret;
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bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
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goto out_complete;
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}
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/* We are in an invalid state; reset bus to a known state. */
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if (!bus->msgs && bus->master_state != ASPEED_I2C_MASTER_STOP) {
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dev_err(bus->dev, "bus in unknown state");
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bus->cmd_err = -EIO;
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aspeed_i2c_do_stop(bus);
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goto out_no_complete;
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}
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msg = &bus->msgs[bus->msgs_index];
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/*
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||||||
|
* START is a special case because we still have to handle a subsequent
|
||||||
|
* TX or RX immediately after we handle it, so we handle it here and
|
||||||
|
* then update the state and handle the new state below.
|
||||||
|
*/
|
||||||
|
if (bus->master_state == ASPEED_I2C_MASTER_START) {
|
||||||
|
if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
|
||||||
|
pr_devel("no slave present at %02x", msg->addr);
|
||||||
|
status_ack |= ASPEED_I2CD_INTR_TX_NAK;
|
||||||
|
bus->cmd_err = -ENXIO;
|
||||||
|
aspeed_i2c_do_stop(bus);
|
||||||
|
goto out_no_complete;
|
||||||
|
}
|
||||||
|
status_ack |= ASPEED_I2CD_INTR_TX_ACK;
|
||||||
|
if (msg->len == 0) { /* SMBUS_QUICK */
|
||||||
|
aspeed_i2c_do_stop(bus);
|
||||||
|
goto out_no_complete;
|
||||||
|
}
|
||||||
|
if (msg->flags & I2C_M_RD)
|
||||||
|
bus->master_state = ASPEED_I2C_MASTER_RX_FIRST;
|
||||||
|
else
|
||||||
|
bus->master_state = ASPEED_I2C_MASTER_TX_FIRST;
|
||||||
|
}
|
||||||
|
|
||||||
|
switch (bus->master_state) {
|
||||||
|
case ASPEED_I2C_MASTER_TX:
|
||||||
|
if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_NAK)) {
|
||||||
|
dev_dbg(bus->dev, "slave NACKed TX");
|
||||||
|
status_ack |= ASPEED_I2CD_INTR_TX_NAK;
|
||||||
|
goto error_and_stop;
|
||||||
|
} else if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
|
||||||
|
dev_err(bus->dev, "slave failed to ACK TX");
|
||||||
|
goto error_and_stop;
|
||||||
|
}
|
||||||
|
status_ack |= ASPEED_I2CD_INTR_TX_ACK;
|
||||||
|
/* fallthrough intended */
|
||||||
|
case ASPEED_I2C_MASTER_TX_FIRST:
|
||||||
|
if (bus->buf_index < msg->len) {
|
||||||
|
bus->master_state = ASPEED_I2C_MASTER_TX;
|
||||||
|
writel(msg->buf[bus->buf_index++],
|
||||||
|
bus->base + ASPEED_I2C_BYTE_BUF_REG);
|
||||||
|
writel(ASPEED_I2CD_M_TX_CMD,
|
||||||
|
bus->base + ASPEED_I2C_CMD_REG);
|
||||||
|
} else {
|
||||||
|
aspeed_i2c_next_msg_or_stop(bus);
|
||||||
|
}
|
||||||
|
goto out_no_complete;
|
||||||
|
case ASPEED_I2C_MASTER_RX_FIRST:
|
||||||
|
/* RX may not have completed yet (only address cycle) */
|
||||||
|
if (!(irq_status & ASPEED_I2CD_INTR_RX_DONE))
|
||||||
|
goto out_no_complete;
|
||||||
|
/* fallthrough intended */
|
||||||
|
case ASPEED_I2C_MASTER_RX:
|
||||||
|
if (unlikely(!(irq_status & ASPEED_I2CD_INTR_RX_DONE))) {
|
||||||
|
dev_err(bus->dev, "master failed to RX");
|
||||||
|
goto error_and_stop;
|
||||||
|
}
|
||||||
|
status_ack |= ASPEED_I2CD_INTR_RX_DONE;
|
||||||
|
|
||||||
|
recv_byte = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
|
||||||
|
msg->buf[bus->buf_index++] = recv_byte;
|
||||||
|
|
||||||
|
if (msg->flags & I2C_M_RECV_LEN) {
|
||||||
|
if (unlikely(recv_byte > I2C_SMBUS_BLOCK_MAX)) {
|
||||||
|
bus->cmd_err = -EPROTO;
|
||||||
|
aspeed_i2c_do_stop(bus);
|
||||||
|
goto out_no_complete;
|
||||||
|
}
|
||||||
|
msg->len = recv_byte +
|
||||||
|
((msg->flags & I2C_CLIENT_PEC) ? 2 : 1);
|
||||||
|
msg->flags &= ~I2C_M_RECV_LEN;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (bus->buf_index < msg->len) {
|
||||||
|
bus->master_state = ASPEED_I2C_MASTER_RX;
|
||||||
|
command = ASPEED_I2CD_M_RX_CMD;
|
||||||
|
if (bus->buf_index + 1 == msg->len)
|
||||||
|
command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
|
||||||
|
writel(command, bus->base + ASPEED_I2C_CMD_REG);
|
||||||
|
} else {
|
||||||
|
aspeed_i2c_next_msg_or_stop(bus);
|
||||||
|
}
|
||||||
|
goto out_no_complete;
|
||||||
|
case ASPEED_I2C_MASTER_STOP:
|
||||||
|
if (unlikely(!(irq_status & ASPEED_I2CD_INTR_NORMAL_STOP))) {
|
||||||
|
dev_err(bus->dev, "master failed to STOP");
|
||||||
|
bus->cmd_err = -EIO;
|
||||||
|
/* Do not STOP as we have already tried. */
|
||||||
|
} else {
|
||||||
|
status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
|
||||||
|
}
|
||||||
|
|
||||||
|
bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
|
||||||
|
goto out_complete;
|
||||||
|
case ASPEED_I2C_MASTER_INACTIVE:
|
||||||
|
dev_err(bus->dev,
|
||||||
|
"master received interrupt 0x%08x, but is inactive",
|
||||||
|
irq_status);
|
||||||
|
bus->cmd_err = -EIO;
|
||||||
|
/* Do not STOP as we should be inactive. */
|
||||||
|
goto out_complete;
|
||||||
|
default:
|
||||||
|
WARN(1, "unknown master state\n");
|
||||||
|
bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
|
||||||
|
bus->cmd_err = -EINVAL;
|
||||||
|
goto out_complete;
|
||||||
|
}
|
||||||
|
error_and_stop:
|
||||||
|
bus->cmd_err = -EIO;
|
||||||
|
aspeed_i2c_do_stop(bus);
|
||||||
|
goto out_no_complete;
|
||||||
|
out_complete:
|
||||||
|
bus->msgs = NULL;
|
||||||
|
if (bus->cmd_err)
|
||||||
|
bus->master_xfer_result = bus->cmd_err;
|
||||||
|
else
|
||||||
|
bus->master_xfer_result = bus->msgs_index + 1;
|
||||||
|
complete(&bus->cmd_complete);
|
||||||
|
out_no_complete:
|
||||||
|
if (irq_status != status_ack)
|
||||||
|
dev_err(bus->dev,
|
||||||
|
"irq handled != irq. expected 0x%08x, but was 0x%08x\n",
|
||||||
|
irq_status, status_ack);
|
||||||
|
spin_unlock(&bus->lock);
|
||||||
|
return !!irq_status;
|
||||||
|
}
|
||||||
|
|
||||||
|
static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
|
||||||
|
{
|
||||||
|
struct aspeed_i2c_bus *bus = dev_id;
|
||||||
|
|
||||||
|
return aspeed_i2c_master_irq(bus) ? IRQ_HANDLED : IRQ_NONE;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
|
||||||
|
struct i2c_msg *msgs, int num)
|
||||||
|
{
|
||||||
|
struct aspeed_i2c_bus *bus = i2c_get_adapdata(adap);
|
||||||
|
unsigned long time_left, flags;
|
||||||
|
int ret = 0;
|
||||||
|
|
||||||
|
spin_lock_irqsave(&bus->lock, flags);
|
||||||
|
bus->cmd_err = 0;
|
||||||
|
|
||||||
|
/* If bus is busy, attempt recovery. We assume a single master
|
||||||
|
* environment.
|
||||||
|
*/
|
||||||
|
if (readl(bus->base + ASPEED_I2C_CMD_REG) & ASPEED_I2CD_BUS_BUSY_STS) {
|
||||||
|
spin_unlock_irqrestore(&bus->lock, flags);
|
||||||
|
ret = aspeed_i2c_recover_bus(bus);
|
||||||
|
if (ret)
|
||||||
|
return ret;
|
||||||
|
spin_lock_irqsave(&bus->lock, flags);
|
||||||
|
}
|
||||||
|
|
||||||
|
bus->cmd_err = 0;
|
||||||
|
bus->msgs = msgs;
|
||||||
|
bus->msgs_index = 0;
|
||||||
|
bus->msgs_count = num;
|
||||||
|
|
||||||
|
reinit_completion(&bus->cmd_complete);
|
||||||
|
aspeed_i2c_do_start(bus);
|
||||||
|
spin_unlock_irqrestore(&bus->lock, flags);
|
||||||
|
|
||||||
|
time_left = wait_for_completion_timeout(&bus->cmd_complete,
|
||||||
|
bus->adap.timeout);
|
||||||
|
|
||||||
|
if (time_left == 0)
|
||||||
|
return -ETIMEDOUT;
|
||||||
|
else
|
||||||
|
return bus->master_xfer_result;
|
||||||
|
}
|
||||||
|
|
||||||
|
static u32 aspeed_i2c_functionality(struct i2c_adapter *adap)
|
||||||
|
{
|
||||||
|
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
|
||||||
|
}
|
||||||
|
|
||||||
|
static const struct i2c_algorithm aspeed_i2c_algo = {
|
||||||
|
.master_xfer = aspeed_i2c_master_xfer,
|
||||||
|
.functionality = aspeed_i2c_functionality,
|
||||||
|
};
|
||||||
|
|
||||||
|
static u32 aspeed_i2c_get_clk_reg_val(u32 divisor)
|
||||||
|
{
|
||||||
|
u32 base_clk, clk_high, clk_low, tmp;
|
||||||
|
|
||||||
|
/*
|
||||||
|
* The actual clock frequency of SCL is:
|
||||||
|
* SCL_freq = APB_freq / (base_freq * (SCL_high + SCL_low))
|
||||||
|
* = APB_freq / divisor
|
||||||
|
* where base_freq is a programmable clock divider; its value is
|
||||||
|
* base_freq = 1 << base_clk
|
||||||
|
* SCL_high is the number of base_freq clock cycles that SCL stays high
|
||||||
|
* and SCL_low is the number of base_freq clock cycles that SCL stays
|
||||||
|
* low for a period of SCL.
|
||||||
|
* The actual register has a minimum SCL_high and SCL_low minimum of 1;
|
||||||
|
* thus, they start counting at zero. So
|
||||||
|
* SCL_high = clk_high + 1
|
||||||
|
* SCL_low = clk_low + 1
|
||||||
|
* Thus,
|
||||||
|
* SCL_freq = APB_freq /
|
||||||
|
* ((1 << base_clk) * (clk_high + 1 + clk_low + 1))
|
||||||
|
* The documentation recommends clk_high >= 8 and clk_low >= 7 when
|
||||||
|
* possible; this last constraint gives us the following solution:
|
||||||
|
*/
|
||||||
|
base_clk = divisor > 33 ? ilog2((divisor - 1) / 32) + 1 : 0;
|
||||||
|
tmp = divisor / (1 << base_clk);
|
||||||
|
clk_high = tmp / 2 + tmp % 2;
|
||||||
|
clk_low = tmp - clk_high;
|
||||||
|
|
||||||
|
clk_high -= 1;
|
||||||
|
clk_low -= 1;
|
||||||
|
|
||||||
|
return ((clk_high << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT)
|
||||||
|
& ASPEED_I2CD_TIME_SCL_HIGH_MASK)
|
||||||
|
| ((clk_low << ASPEED_I2CD_TIME_SCL_LOW_SHIFT)
|
||||||
|
& ASPEED_I2CD_TIME_SCL_LOW_MASK)
|
||||||
|
| (base_clk & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK);
|
||||||
|
}
|
||||||
|
|
||||||
|
/* precondition: bus.lock has been acquired. */
|
||||||
|
static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus)
|
||||||
|
{
|
||||||
|
u32 divisor, clk_reg_val;
|
||||||
|
|
||||||
|
divisor = bus->parent_clk_frequency / bus->bus_frequency;
|
||||||
|
clk_reg_val = aspeed_i2c_get_clk_reg_val(divisor);
|
||||||
|
writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1);
|
||||||
|
writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* precondition: bus.lock has been acquired. */
|
||||||
|
static int aspeed_i2c_init(struct aspeed_i2c_bus *bus,
|
||||||
|
struct platform_device *pdev)
|
||||||
|
{
|
||||||
|
u32 fun_ctrl_reg = ASPEED_I2CD_MASTER_EN;
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
/* Disable everything. */
|
||||||
|
writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG);
|
||||||
|
|
||||||
|
ret = aspeed_i2c_init_clk(bus);
|
||||||
|
if (ret < 0)
|
||||||
|
return ret;
|
||||||
|
|
||||||
|
if (!of_property_read_bool(pdev->dev.of_node, "multi-master"))
|
||||||
|
fun_ctrl_reg |= ASPEED_I2CD_MULTI_MASTER_DIS;
|
||||||
|
|
||||||
|
/* Enable Master Mode */
|
||||||
|
writel(readl(bus->base + ASPEED_I2C_FUN_CTRL_REG) | fun_ctrl_reg,
|
||||||
|
bus->base + ASPEED_I2C_FUN_CTRL_REG);
|
||||||
|
|
||||||
|
/* Set interrupt generation of I2C controller */
|
||||||
|
writel(ASPEED_I2CD_INTR_ALL, bus->base + ASPEED_I2C_INTR_CTRL_REG);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus)
|
||||||
|
{
|
||||||
|
struct platform_device *pdev = to_platform_device(bus->dev);
|
||||||
|
unsigned long flags;
|
||||||
|
int ret;
|
||||||
|
|
||||||
|
spin_lock_irqsave(&bus->lock, flags);
|
||||||
|
|
||||||
|
/* Disable and ack all interrupts. */
|
||||||
|
writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
|
||||||
|
writel(0xffffffff, bus->base + ASPEED_I2C_INTR_STS_REG);
|
||||||
|
|
||||||
|
ret = aspeed_i2c_init(bus, pdev);
|
||||||
|
|
||||||
|
spin_unlock_irqrestore(&bus->lock, flags);
|
||||||
|
|
||||||
|
return ret;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int aspeed_i2c_probe_bus(struct platform_device *pdev)
|
||||||
|
{
|
||||||
|
struct aspeed_i2c_bus *bus;
|
||||||
|
struct clk *parent_clk;
|
||||||
|
struct resource *res;
|
||||||
|
int irq, ret;
|
||||||
|
|
||||||
|
bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
|
||||||
|
if (!bus)
|
||||||
|
return -ENOMEM;
|
||||||
|
|
||||||
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
||||||
|
bus->base = devm_ioremap_resource(&pdev->dev, res);
|
||||||
|
if (IS_ERR(bus->base))
|
||||||
|
return PTR_ERR(bus->base);
|
||||||
|
|
||||||
|
parent_clk = devm_clk_get(&pdev->dev, NULL);
|
||||||
|
if (IS_ERR(parent_clk))
|
||||||
|
return PTR_ERR(parent_clk);
|
||||||
|
bus->parent_clk_frequency = clk_get_rate(parent_clk);
|
||||||
|
/* We just need the clock rate, we don't actually use the clk object. */
|
||||||
|
devm_clk_put(&pdev->dev, parent_clk);
|
||||||
|
|
||||||
|
ret = of_property_read_u32(pdev->dev.of_node,
|
||||||
|
"bus-frequency", &bus->bus_frequency);
|
||||||
|
if (ret < 0) {
|
||||||
|
dev_err(&pdev->dev,
|
||||||
|
"Could not read bus-frequency property\n");
|
||||||
|
bus->bus_frequency = 100000;
|
||||||
|
}
|
||||||
|
|
||||||
|
/* Initialize the I2C adapter */
|
||||||
|
spin_lock_init(&bus->lock);
|
||||||
|
init_completion(&bus->cmd_complete);
|
||||||
|
bus->adap.owner = THIS_MODULE;
|
||||||
|
bus->adap.retries = 0;
|
||||||
|
bus->adap.timeout = 5 * HZ;
|
||||||
|
bus->adap.algo = &aspeed_i2c_algo;
|
||||||
|
bus->adap.dev.parent = &pdev->dev;
|
||||||
|
bus->adap.dev.of_node = pdev->dev.of_node;
|
||||||
|
strlcpy(bus->adap.name, pdev->name, sizeof(bus->adap.name));
|
||||||
|
i2c_set_adapdata(&bus->adap, bus);
|
||||||
|
|
||||||
|
bus->dev = &pdev->dev;
|
||||||
|
|
||||||
|
/* Clean up any left over interrupt state. */
|
||||||
|
writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
|
||||||
|
writel(0xffffffff, bus->base + ASPEED_I2C_INTR_STS_REG);
|
||||||
|
/*
|
||||||
|
* bus.lock does not need to be held because the interrupt handler has
|
||||||
|
* not been enabled yet.
|
||||||
|
*/
|
||||||
|
ret = aspeed_i2c_init(bus, pdev);
|
||||||
|
if (ret < 0)
|
||||||
|
return ret;
|
||||||
|
|
||||||
|
irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
|
||||||
|
ret = devm_request_irq(&pdev->dev, irq, aspeed_i2c_bus_irq,
|
||||||
|
0, dev_name(&pdev->dev), bus);
|
||||||
|
if (ret < 0)
|
||||||
|
return ret;
|
||||||
|
|
||||||
|
ret = i2c_add_adapter(&bus->adap);
|
||||||
|
if (ret < 0)
|
||||||
|
return ret;
|
||||||
|
|
||||||
|
platform_set_drvdata(pdev, bus);
|
||||||
|
|
||||||
|
dev_info(bus->dev, "i2c bus %d registered, irq %d\n",
|
||||||
|
bus->adap.nr, irq);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static int aspeed_i2c_remove_bus(struct platform_device *pdev)
|
||||||
|
{
|
||||||
|
struct aspeed_i2c_bus *bus = platform_get_drvdata(pdev);
|
||||||
|
unsigned long flags;
|
||||||
|
|
||||||
|
spin_lock_irqsave(&bus->lock, flags);
|
||||||
|
|
||||||
|
/* Disable everything. */
|
||||||
|
writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG);
|
||||||
|
writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
|
||||||
|
|
||||||
|
spin_unlock_irqrestore(&bus->lock, flags);
|
||||||
|
|
||||||
|
i2c_del_adapter(&bus->adap);
|
||||||
|
|
||||||
|
return 0;
|
||||||
|
}
|
||||||
|
|
||||||
|
static const struct of_device_id aspeed_i2c_bus_of_table[] = {
|
||||||
|
{ .compatible = "aspeed,ast2400-i2c-bus", },
|
||||||
|
{ .compatible = "aspeed,ast2500-i2c-bus", },
|
||||||
|
{ },
|
||||||
|
};
|
||||||
|
MODULE_DEVICE_TABLE(of, aspeed_i2c_bus_of_table);
|
||||||
|
|
||||||
|
static struct platform_driver aspeed_i2c_bus_driver = {
|
||||||
|
.probe = aspeed_i2c_probe_bus,
|
||||||
|
.remove = aspeed_i2c_remove_bus,
|
||||||
|
.driver = {
|
||||||
|
.name = "aspeed-i2c-bus",
|
||||||
|
.of_match_table = aspeed_i2c_bus_of_table,
|
||||||
|
},
|
||||||
|
};
|
||||||
|
module_platform_driver(aspeed_i2c_bus_driver);
|
||||||
|
|
||||||
|
MODULE_AUTHOR("Brendan Higgins <brendanhiggins@google.com>");
|
||||||
|
MODULE_DESCRIPTION("Aspeed I2C Bus Driver");
|
||||||
|
MODULE_LICENSE("GPL v2");
|
||||||
Loading…
Reference in New Issue
Block a user