diff options
Diffstat (limited to 'drivers/misc/ep93xx_pwm.c')
| -rw-r--r-- | drivers/misc/ep93xx_pwm.c | 384 |
1 files changed, 384 insertions, 0 deletions
diff --git a/drivers/misc/ep93xx_pwm.c b/drivers/misc/ep93xx_pwm.c new file mode 100644 index 000000000000..ba4694169d79 --- /dev/null +++ b/drivers/misc/ep93xx_pwm.c @@ -0,0 +1,384 @@ +/* + * Simple PWM driver for EP93XX + * + * (c) Copyright 2009 Matthieu Crapet <mcrapet@gmail.com> + * (c) Copyright 2009 H Hartley Sweeten <hsweeten@visionengravers.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * EP9307 has only one channel: + * - PWMOUT + * + * EP9301/02/12/15 have two channels: + * - PWMOUT + * - PWMOUT1 (alternate function for EGPIO14) + */ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> + +#include <mach/platform.h> + +#define EP93XX_PWMx_TERM_COUNT 0x00 +#define EP93XX_PWMx_DUTY_CYCLE 0x04 +#define EP93XX_PWMx_ENABLE 0x08 +#define EP93XX_PWMx_INVERT 0x0C + +#define EP93XX_PWM_MAX_COUNT 0xFFFF + +struct ep93xx_pwm { + void __iomem *mmio_base; + struct clk *clk; + u32 duty_percent; +}; + +static inline void ep93xx_pwm_writel(struct ep93xx_pwm *pwm, + unsigned int val, unsigned int off) +{ + __raw_writel(val, pwm->mmio_base + off); +} + +static inline unsigned int ep93xx_pwm_readl(struct ep93xx_pwm *pwm, + unsigned int off) +{ + return __raw_readl(pwm->mmio_base + off); +} + +static inline void ep93xx_pwm_write_tc(struct ep93xx_pwm *pwm, u16 value) +{ + ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_TERM_COUNT); +} + +static inline u16 ep93xx_pwm_read_tc(struct ep93xx_pwm *pwm) +{ + return ep93xx_pwm_readl(pwm, EP93XX_PWMx_TERM_COUNT); +} + +static inline void ep93xx_pwm_write_dc(struct ep93xx_pwm *pwm, u16 value) +{ + ep93xx_pwm_writel(pwm, value, EP93XX_PWMx_DUTY_CYCLE); +} + +static inline void ep93xx_pwm_enable(struct ep93xx_pwm *pwm) +{ + ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_ENABLE); +} + +static inline void ep93xx_pwm_disable(struct ep93xx_pwm *pwm) +{ + ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_ENABLE); +} + +static inline int ep93xx_pwm_is_enabled(struct ep93xx_pwm *pwm) +{ + return ep93xx_pwm_readl(pwm, EP93XX_PWMx_ENABLE) & 0x1; +} + +static inline void ep93xx_pwm_invert(struct ep93xx_pwm *pwm) +{ + ep93xx_pwm_writel(pwm, 0x1, EP93XX_PWMx_INVERT); +} + +static inline void ep93xx_pwm_normal(struct ep93xx_pwm *pwm) +{ + ep93xx_pwm_writel(pwm, 0x0, EP93XX_PWMx_INVERT); +} + +static inline int ep93xx_pwm_is_inverted(struct ep93xx_pwm *pwm) +{ + return ep93xx_pwm_readl(pwm, EP93XX_PWMx_INVERT) & 0x1; +} + +/* + * /sys/devices/platform/ep93xx-pwm.N + * /min_freq read-only minimum pwm output frequency + * /max_req read-only maximum pwm output frequency + * /freq read-write pwm output frequency (0 = disable output) + * /duty_percent read-write pwm duty cycle percent (1..99) + * /invert read-write invert pwm output + */ + +static ssize_t ep93xx_pwm_get_min_freq(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct platform_device *pdev = to_platform_device(dev); + struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); + unsigned long rate = clk_get_rate(pwm->clk); + + return sprintf(buf, "%ld\n", rate / (EP93XX_PWM_MAX_COUNT + 1)); +} + +static ssize_t ep93xx_pwm_get_max_freq(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct platform_device *pdev = to_platform_device(dev); + struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); + unsigned long rate = clk_get_rate(pwm->clk); + + return sprintf(buf, "%ld\n", rate / 2); +} + +static ssize_t ep93xx_pwm_get_freq(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct platform_device *pdev = to_platform_device(dev); + struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); + + if (ep93xx_pwm_is_enabled(pwm)) { + unsigned long rate = clk_get_rate(pwm->clk); + u16 term = ep93xx_pwm_read_tc(pwm); + + return sprintf(buf, "%ld\n", rate / (term + 1)); + } else { + return sprintf(buf, "disabled\n"); + } +} + +static ssize_t ep93xx_pwm_set_freq(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct platform_device *pdev = to_platform_device(dev); + struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); + long val; + int err; + + err = strict_strtol(buf, 10, &val); + if (err) + return -EINVAL; + + if (val == 0) { + ep93xx_pwm_disable(pwm); + } else if (val <= (clk_get_rate(pwm->clk) / 2)) { + u32 term, duty; + + val = (clk_get_rate(pwm->clk) / val) - 1; + if (val > EP93XX_PWM_MAX_COUNT) + val = EP93XX_PWM_MAX_COUNT; + if (val < 1) + val = 1; + + term = ep93xx_pwm_read_tc(pwm); + duty = ((val + 1) * pwm->duty_percent / 100) - 1; + + /* If pwm is running, order is important */ + if (val > term) { + ep93xx_pwm_write_tc(pwm, val); + ep93xx_pwm_write_dc(pwm, duty); + } else { + ep93xx_pwm_write_dc(pwm, duty); + ep93xx_pwm_write_tc(pwm, val); + } + + if (!ep93xx_pwm_is_enabled(pwm)) + ep93xx_pwm_enable(pwm); + } else { + return -EINVAL; + } + + return count; +} + +static ssize_t ep93xx_pwm_get_duty_percent(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct platform_device *pdev = to_platform_device(dev); + struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); + + return sprintf(buf, "%d\n", pwm->duty_percent); +} + +static ssize_t ep93xx_pwm_set_duty_percent(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct platform_device *pdev = to_platform_device(dev); + struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); + long val; + int err; + + err = strict_strtol(buf, 10, &val); + if (err) + return -EINVAL; + + if (val > 0 && val < 100) { + u32 term = ep93xx_pwm_read_tc(pwm); + ep93xx_pwm_write_dc(pwm, ((term + 1) * val / 100) - 1); + pwm->duty_percent = val; + return count; + } + + return -EINVAL; +} + +static ssize_t ep93xx_pwm_get_invert(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct platform_device *pdev = to_platform_device(dev); + struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); + + return sprintf(buf, "%d\n", ep93xx_pwm_is_inverted(pwm)); +} + +static ssize_t ep93xx_pwm_set_invert(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct platform_device *pdev = to_platform_device(dev); + struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); + long val; + int err; + + err = strict_strtol(buf, 10, &val); + if (err) + return -EINVAL; + + if (val == 0) + ep93xx_pwm_normal(pwm); + else if (val == 1) + ep93xx_pwm_invert(pwm); + else + return -EINVAL; + + return count; +} + +static DEVICE_ATTR(min_freq, S_IRUGO, ep93xx_pwm_get_min_freq, NULL); +static DEVICE_ATTR(max_freq, S_IRUGO, ep93xx_pwm_get_max_freq, NULL); +static DEVICE_ATTR(freq, S_IWUGO | S_IRUGO, + ep93xx_pwm_get_freq, ep93xx_pwm_set_freq); +static DEVICE_ATTR(duty_percent, S_IWUGO | S_IRUGO, + ep93xx_pwm_get_duty_percent, ep93xx_pwm_set_duty_percent); +static DEVICE_ATTR(invert, S_IWUGO | S_IRUGO, + ep93xx_pwm_get_invert, ep93xx_pwm_set_invert); + +static struct attribute *ep93xx_pwm_attrs[] = { + &dev_attr_min_freq.attr, + &dev_attr_max_freq.attr, + &dev_attr_freq.attr, + &dev_attr_duty_percent.attr, + &dev_attr_invert.attr, + NULL +}; + +static const struct attribute_group ep93xx_pwm_sysfs_files = { + .attrs = ep93xx_pwm_attrs, +}; + +static int __init ep93xx_pwm_probe(struct platform_device *pdev) +{ + struct ep93xx_pwm *pwm; + struct resource *res; + int err; + + err = ep93xx_pwm_acquire_gpio(pdev); + if (err) + return err; + + pwm = kzalloc(sizeof(struct ep93xx_pwm), GFP_KERNEL); + if (!pwm) { + err = -ENOMEM; + goto fail_no_mem; + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (res == NULL) { + err = -ENXIO; + goto fail_no_mem_resource; + } + + res = request_mem_region(res->start, resource_size(res), pdev->name); + if (res == NULL) { + err = -EBUSY; + goto fail_no_mem_resource; + } + + pwm->mmio_base = ioremap(res->start, resource_size(res)); + if (pwm->mmio_base == NULL) { + err = -ENXIO; + goto fail_no_ioremap; + } + + err = sysfs_create_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files); + if (err) + goto fail_no_sysfs; + + pwm->clk = clk_get(&pdev->dev, "pwm_clk"); + if (IS_ERR(pwm->clk)) { + err = PTR_ERR(pwm->clk); + goto fail_no_clk; + } + + pwm->duty_percent = 50; + + platform_set_drvdata(pdev, pwm); + + /* disable pwm at startup. Avoids zero value. */ + ep93xx_pwm_disable(pwm); + ep93xx_pwm_write_tc(pwm, EP93XX_PWM_MAX_COUNT); + ep93xx_pwm_write_dc(pwm, EP93XX_PWM_MAX_COUNT / 2); + + clk_enable(pwm->clk); + + return 0; + +fail_no_clk: + sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files); +fail_no_sysfs: + iounmap(pwm->mmio_base); +fail_no_ioremap: + release_mem_region(res->start, resource_size(res)); +fail_no_mem_resource: + kfree(pwm); +fail_no_mem: + ep93xx_pwm_release_gpio(pdev); + return err; +} + +static int __exit ep93xx_pwm_remove(struct platform_device *pdev) +{ + struct ep93xx_pwm *pwm = platform_get_drvdata(pdev); + struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + ep93xx_pwm_disable(pwm); + clk_disable(pwm->clk); + clk_put(pwm->clk); + platform_set_drvdata(pdev, NULL); + sysfs_remove_group(&pdev->dev.kobj, &ep93xx_pwm_sysfs_files); + iounmap(pwm->mmio_base); + release_mem_region(res->start, resource_size(res)); + kfree(pwm); + ep93xx_pwm_release_gpio(pdev); + + return 0; +} + +static struct platform_driver ep93xx_pwm_driver = { + .driver = { + .name = "ep93xx-pwm", + .owner = THIS_MODULE, + }, + .remove = __exit_p(ep93xx_pwm_remove), +}; + +static int __init ep93xx_pwm_init(void) +{ + return platform_driver_probe(&ep93xx_pwm_driver, ep93xx_pwm_probe); +} + +static void __exit ep93xx_pwm_exit(void) +{ + platform_driver_unregister(&ep93xx_pwm_driver); +} + +module_init(ep93xx_pwm_init); +module_exit(ep93xx_pwm_exit); + +MODULE_AUTHOR("Matthieu Crapet <mcrapet@gmail.com>, " + "H Hartley Sweeten <hsweeten@visionengravers.com>"); +MODULE_DESCRIPTION("EP93xx PWM driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:ep93xx-pwm"); |