/* * Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de> * JZ4740 platform PWM support * * 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. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 675 Mass Ave, Cambridge, MA 02139, USA. * */ #include <linux/clk.h> #include <linux/err.h> #include <linux/gpio.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/pwm.h> #include <asm/mach-jz4740/gpio.h> #include <asm/mach-jz4740/timer.h> #define NUM_PWM 8 static const unsigned int jz4740_pwm_gpio_list[NUM_PWM] = { JZ_GPIO_PWM0, JZ_GPIO_PWM1, JZ_GPIO_PWM2, JZ_GPIO_PWM3, JZ_GPIO_PWM4, JZ_GPIO_PWM5, JZ_GPIO_PWM6, JZ_GPIO_PWM7, }; struct jz4740_pwm_chip { struct pwm_chip chip; struct clk *clk; }; static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip) { return container_of(chip, struct jz4740_pwm_chip, chip); } static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) { unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm]; int ret; /* * Timers 0 and 1 are used for system tasks, so they are unavailable * for use as PWMs. */ if (pwm->hwpwm < 2) return -EBUSY; ret = gpio_request(gpio, pwm->label); if (ret) { dev_err(chip->dev, "Failed to request GPIO#%u for PWM: %d\n", gpio, ret); return ret; } jz_gpio_set_function(gpio, JZ_GPIO_FUNC_PWM); jz4740_timer_start(pwm->hwpwm); return 0; } static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) { unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm]; jz4740_timer_set_ctrl(pwm->hwpwm, 0); jz_gpio_set_function(gpio, JZ_GPIO_FUNC_NONE); gpio_free(gpio); jz4740_timer_stop(pwm->hwpwm); } static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) { uint32_t ctrl = jz4740_timer_get_ctrl(pwm->pwm); ctrl |= JZ_TIMER_CTRL_PWM_ENABLE; jz4740_timer_set_ctrl(pwm->hwpwm, ctrl); jz4740_timer_enable(pwm->hwpwm); return 0; } static void jz4740_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { uint32_t ctrl = jz4740_timer_get_ctrl(pwm->hwpwm); ctrl &= ~JZ_TIMER_CTRL_PWM_ENABLE; jz4740_timer_disable(pwm->hwpwm); jz4740_timer_set_ctrl(pwm->hwpwm, ctrl); } static int jz4740_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip); unsigned long long tmp; unsigned long period, duty; unsigned int prescaler = 0; uint16_t ctrl; bool is_enabled; tmp = (unsigned long long)clk_get_rate(jz4740->clk) * period_ns; do_div(tmp, 1000000000); period = tmp; while (period > 0xffff && prescaler < 6) { period >>= 2; ++prescaler; } if (prescaler == 6) return -EINVAL; tmp = (unsigned long long)period * duty_ns; do_div(tmp, period_ns); duty = period - tmp; if (duty >= period) duty = period - 1; is_enabled = jz4740_timer_is_enabled(pwm->hwpwm); if (is_enabled) jz4740_pwm_disable(chip, pwm); jz4740_timer_set_count(pwm->hwpwm, 0); jz4740_timer_set_duty(pwm->hwpwm, duty); jz4740_timer_set_period(pwm->hwpwm, period); ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT | JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN; jz4740_timer_set_ctrl(pwm->hwpwm, ctrl); if (is_enabled) jz4740_pwm_enable(chip, pwm); return 0; } static const struct pwm_ops jz4740_pwm_ops = { .request = jz4740_pwm_request, .free = jz4740_pwm_free, .config = jz4740_pwm_config, .enable = jz4740_pwm_enable, .disable = jz4740_pwm_disable, .owner = THIS_MODULE, }; static int jz4740_pwm_probe(struct platform_device *pdev) { struct jz4740_pwm_chip *jz4740; jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL); if (!jz4740) return -ENOMEM; jz4740->clk = devm_clk_get(&pdev->dev, "ext"); if (IS_ERR(jz4740->clk)) return PTR_ERR(jz4740->clk); jz4740->chip.dev = &pdev->dev; jz4740->chip.ops = &jz4740_pwm_ops; jz4740->chip.npwm = NUM_PWM; jz4740->chip.base = -1; platform_set_drvdata(pdev, jz4740); return pwmchip_add(&jz4740->chip); } static int jz4740_pwm_remove(struct platform_device *pdev) { struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev); return pwmchip_remove(&jz4740->chip); } static struct platform_driver jz4740_pwm_driver = { .driver = { .name = "jz4740-pwm", .owner = THIS_MODULE, }, .probe = jz4740_pwm_probe, .remove = jz4740_pwm_remove, }; module_platform_driver(jz4740_pwm_driver); MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); MODULE_DESCRIPTION("Ingenic JZ4740 PWM driver"); MODULE_ALIAS("platform:jz4740-pwm"); MODULE_LICENSE("GPL");