diff options
Diffstat (limited to 'drivers/pwm/pwm-jz4740.c')
| -rw-r--r-- | drivers/pwm/pwm-jz4740.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c new file mode 100644 index 0000000..10250fc --- /dev/null +++ b/drivers/pwm/pwm-jz4740.c @@ -0,0 +1,221 @@ +/* + * 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 __devinit jz4740_pwm_probe(struct platform_device *pdev) +{ + struct jz4740_pwm_chip *jz4740; + int ret; + + jz4740 = devm_kzalloc(&pdev->dev, sizeof(*jz4740), GFP_KERNEL); + if (!jz4740) + return -ENOMEM; + + jz4740->clk = clk_get(NULL, "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; + + ret = pwmchip_add(&jz4740->chip); + if (ret < 0) { + clk_put(jz4740->clk); + return ret; + } + + platform_set_drvdata(pdev, jz4740); + + return 0; +} + +static int __devexit jz4740_pwm_remove(struct platform_device *pdev) +{ + struct jz4740_pwm_chip *jz4740 = platform_get_drvdata(pdev); + int ret; + + ret = pwmchip_remove(&jz4740->chip); + if (ret < 0) + return ret; + + clk_put(jz4740->clk); + + return 0; +} + +static struct platform_driver jz4740_pwm_driver = { + .driver = { + .name = "jz4740-pwm", + .owner = THIS_MODULE, + }, + .probe = jz4740_pwm_probe, + .remove = __devexit_p(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"); |