/* * 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/slab.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");