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ef12379f20
The EP93xx features two PWMs (one on the EP9307) with the following
features:
* Configurable dual output
* Separate input clocks for each PWM output
* 16-bit resolution
* Programmable pulse width (duty cycle), interval (frequency), and
polarity
This adds the necessary core support as well as the driver. A sysfs
interface is provided to control the PWM outputs.
Signed-off-by: Matthieu Crapet <mcrapet@gmail.com>
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
385 lines
9.5 KiB
C
385 lines
9.5 KiB
C
/*
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* Simple PWM driver for EP93XX
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*
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* (c) Copyright 2009 Matthieu Crapet <mcrapet@gmail.com>
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* (c) Copyright 2009 H Hartley Sweeten <hsweeten@visionengravers.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* EP9307 has only one channel:
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* - PWMOUT
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*
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* EP9301/02/12/15 have two channels:
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* - PWMOUT
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* - PWMOUT1 (alternate function for EGPIO14)
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*/
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <mach/platform.h>
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#define EP93XX_PWMx_TERM_COUNT 0x00
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#define EP93XX_PWMx_DUTY_CYCLE 0x04
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#define EP93XX_PWMx_ENABLE 0x08
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#define EP93XX_PWMx_INVERT 0x0C
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#define EP93XX_PWM_MAX_COUNT 0xFFFF
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struct ep93xx_pwm {
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void __iomem *mmio_base;
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struct clk *clk;
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u32 duty_percent;
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};
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static inline void ep93xx_pwm_writel(struct ep93xx_pwm *pwm,
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unsigned int val, unsigned int off)
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{
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__raw_writel(val, pwm->mmio_base + off);
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}
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static inline unsigned int ep93xx_pwm_readl(struct ep93xx_pwm *pwm,
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unsigned int off)
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{
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return __raw_readl(pwm->mmio_base + off);
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}
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static inline void ep93xx_pwm_write_tc(struct ep93xx_pwm *pwm, u16 value)
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{
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ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_TERM_COUNT);
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}
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static inline u16 ep93xx_pwm_read_tc(struct ep93xx_pwm *pwm)
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{
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return ep93xx_pwm_readl(pwm, EP93XX_PWMx_TERM_COUNT);
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}
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static inline void ep93xx_pwm_write_dc(struct ep93xx_pwm *pwm, u16 value)
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{
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ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_DUTY_CYCLE);
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}
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static inline void ep93xx_pwm_enable(struct ep93xx_pwm *pwm)
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{
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ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_ENABLE);
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}
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static inline void ep93xx_pwm_disable(struct ep93xx_pwm *pwm)
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{
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ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_ENABLE);
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}
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static inline int ep93xx_pwm_is_enabled(struct ep93xx_pwm *pwm)
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{
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return ep93xx_pwm_readl(pwm, EP93XX_PWMx_ENABLE) & 0x1;
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}
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static inline void ep93xx_pwm_invert(struct ep93xx_pwm *pwm)
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{
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ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_INVERT);
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}
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static inline void ep93xx_pwm_normal(struct ep93xx_pwm *pwm)
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{
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ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_INVERT);
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}
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static inline int ep93xx_pwm_is_inverted(struct ep93xx_pwm *pwm)
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{
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return ep93xx_pwm_readl(pwm, EP93XX_PWMx_INVERT) & 0x1;
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}
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/*
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* /sys/devices/platform/ep93xx-pwm.N
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* /min_freq read-only minimum pwm output frequency
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* /max_req read-only maximum pwm output frequency
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* /freq read-write pwm output frequency (0 = disable output)
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* /duty_percent read-write pwm duty cycle percent (1..99)
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* /invert read-write invert pwm output
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*/
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static ssize_t ep93xx_pwm_get_min_freq(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
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unsigned long rate = clk_get_rate(pwm->clk);
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return sprintf(buf, "%ld\n", rate / (EP93XX_PWM_MAX_COUNT + 1));
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}
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static ssize_t ep93xx_pwm_get_max_freq(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
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unsigned long rate = clk_get_rate(pwm->clk);
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return sprintf(buf, "%ld\n", rate / 2);
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}
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static ssize_t ep93xx_pwm_get_freq(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
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if (ep93xx_pwm_is_enabled(pwm)) {
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unsigned long rate = clk_get_rate(pwm->clk);
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u16 term = ep93xx_pwm_read_tc(pwm);
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return sprintf(buf, "%ld\n", rate / (term + 1));
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} else {
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return sprintf(buf, "disabled\n");
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}
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}
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static ssize_t ep93xx_pwm_set_freq(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
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long val;
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int err;
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err = strict_strtol(buf, 10, &val);
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if (err)
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return -EINVAL;
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if (val == 0) {
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ep93xx_pwm_disable(pwm);
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} else if (val <= (clk_get_rate(pwm->clk) / 2)) {
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u32 term, duty;
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val = (clk_get_rate(pwm->clk) / val) - 1;
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if (val > EP93XX_PWM_MAX_COUNT)
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val = EP93XX_PWM_MAX_COUNT;
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if (val < 1)
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val = 1;
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term = ep93xx_pwm_read_tc(pwm);
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duty = ((val + 1) * pwm->duty_percent / 100) - 1;
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/* If pwm is running, order is important */
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if (val > term) {
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ep93xx_pwm_write_tc(pwm, val);
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ep93xx_pwm_write_dc(pwm, duty);
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} else {
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ep93xx_pwm_write_dc(pwm, duty);
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ep93xx_pwm_write_tc(pwm, val);
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}
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if (!ep93xx_pwm_is_enabled(pwm))
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ep93xx_pwm_enable(pwm);
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} else {
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return -EINVAL;
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}
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return count;
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}
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static ssize_t ep93xx_pwm_get_duty_percent(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
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return sprintf(buf, "%d\n", pwm->duty_percent);
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}
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static ssize_t ep93xx_pwm_set_duty_percent(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
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long val;
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int err;
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err = strict_strtol(buf, 10, &val);
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if (err)
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return -EINVAL;
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if (val > 0 && val < 100) {
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u32 term = ep93xx_pwm_read_tc(pwm);
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ep93xx_pwm_write_dc(pwm, ((term + 1) * val / 100) - 1);
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pwm->duty_percent = val;
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return count;
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}
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return -EINVAL;
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}
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static ssize_t ep93xx_pwm_get_invert(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
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return sprintf(buf, "%d\n", ep93xx_pwm_is_inverted(pwm));
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}
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static ssize_t ep93xx_pwm_set_invert(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t count)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
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long val;
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int err;
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err = strict_strtol(buf, 10, &val);
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if (err)
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return -EINVAL;
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if (val == 0)
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ep93xx_pwm_normal(pwm);
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else if (val == 1)
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ep93xx_pwm_invert(pwm);
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else
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return -EINVAL;
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return count;
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}
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static DEVICE_ATTR(min_freq, S_IRUGO, ep93xx_pwm_get_min_freq, NULL);
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static DEVICE_ATTR(max_freq, S_IRUGO, ep93xx_pwm_get_max_freq, NULL);
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static DEVICE_ATTR(freq, S_IWUGO | S_IRUGO,
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ep93xx_pwm_get_freq, ep93xx_pwm_set_freq);
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static DEVICE_ATTR(duty_percent, S_IWUGO | S_IRUGO,
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ep93xx_pwm_get_duty_percent, ep93xx_pwm_set_duty_percent);
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static DEVICE_ATTR(invert, S_IWUGO | S_IRUGO,
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ep93xx_pwm_get_invert, ep93xx_pwm_set_invert);
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static struct attribute *ep93xx_pwm_attrs[] = {
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&dev_attr_min_freq.attr,
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&dev_attr_max_freq.attr,
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&dev_attr_freq.attr,
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&dev_attr_duty_percent.attr,
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&dev_attr_invert.attr,
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NULL
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};
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static const struct attribute_group ep93xx_pwm_sysfs_files = {
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.attrs = ep93xx_pwm_attrs,
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};
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static int __init ep93xx_pwm_probe(struct platform_device *pdev)
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{
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struct ep93xx_pwm *pwm;
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struct resource *res;
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int err;
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err = ep93xx_pwm_acquire_gpio(pdev);
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if (err)
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return err;
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pwm = kzalloc(sizeof(struct ep93xx_pwm), GFP_KERNEL);
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if (!pwm) {
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err = -ENOMEM;
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goto fail_no_mem;
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}
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (res == NULL) {
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err = -ENXIO;
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goto fail_no_mem_resource;
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}
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res = request_mem_region(res->start, resource_size(res), pdev->name);
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if (res == NULL) {
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err = -EBUSY;
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goto fail_no_mem_resource;
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}
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pwm->mmio_base = ioremap(res->start, resource_size(res));
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if (pwm->mmio_base == NULL) {
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err = -ENXIO;
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goto fail_no_ioremap;
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}
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err = sysfs_create_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
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if (err)
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goto fail_no_sysfs;
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pwm->clk = clk_get(&pdev->dev, "pwm_clk");
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if (IS_ERR(pwm->clk)) {
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err = PTR_ERR(pwm->clk);
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goto fail_no_clk;
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}
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pwm->duty_percent = 50;
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platform_set_drvdata(pdev, pwm);
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/* disable pwm at startup. Avoids zero value. */
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ep93xx_pwm_disable(pwm);
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ep93xx_pwm_write_tc(pwm, EP93XX_PWM_MAX_COUNT);
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ep93xx_pwm_write_dc(pwm, EP93XX_PWM_MAX_COUNT / 2);
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clk_enable(pwm->clk);
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return 0;
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fail_no_clk:
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sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
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fail_no_sysfs:
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iounmap(pwm->mmio_base);
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fail_no_ioremap:
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release_mem_region(res->start, resource_size(res));
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fail_no_mem_resource:
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kfree(pwm);
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fail_no_mem:
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ep93xx_pwm_release_gpio(pdev);
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return err;
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}
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static int __exit ep93xx_pwm_remove(struct platform_device *pdev)
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{
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struct ep93xx_pwm *pwm = platform_get_drvdata(pdev);
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struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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ep93xx_pwm_disable(pwm);
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clk_disable(pwm->clk);
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clk_put(pwm->clk);
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platform_set_drvdata(pdev, NULL);
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sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files);
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iounmap(pwm->mmio_base);
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release_mem_region(res->start, resource_size(res));
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kfree(pwm);
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ep93xx_pwm_release_gpio(pdev);
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return 0;
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}
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static struct platform_driver ep93xx_pwm_driver = {
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.driver = {
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.name = "ep93xx-pwm",
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.owner = THIS_MODULE,
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},
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.remove = __exit_p(ep93xx_pwm_remove),
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};
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static int __init ep93xx_pwm_init(void)
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{
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return platform_driver_probe(&ep93xx_pwm_driver, ep93xx_pwm_probe);
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}
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static void __exit ep93xx_pwm_exit(void)
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{
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platform_driver_unregister(&ep93xx_pwm_driver);
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}
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module_init(ep93xx_pwm_init);
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module_exit(ep93xx_pwm_exit);
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MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>, "
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"H Hartley Sweeten <hsweeten@visionengravers.com>");
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MODULE_DESCRIPTION("EP93xx PWM driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:ep93xx-pwm");
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