From 9de00286e20a5f5edc419698373010f1cb6ff0ce Mon Sep 17 00:00:00 2001 From: John Crispin Date: Sun, 27 Jul 2014 09:25:02 +0100 Subject: [PATCH 19/57] MIPS: ralink: add pseudo pwm led trigger based on timer0 Signed-off-by: John Crispin --- arch/mips/ralink/timer.c | 213 ++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 197 insertions(+), 16 deletions(-) --- a/arch/mips/ralink/timer.c +++ b/arch/mips/ralink/timer.c @@ -12,6 +12,8 @@ #include #include #include +#include +#include #include @@ -23,16 +25,34 @@ #define TMR0CTL_ENABLE BIT(7) #define TMR0CTL_MODE_PERIODIC BIT(4) -#define TMR0CTL_PRESCALER 1 +#define TMR0CTL_PRESCALER 2 #define TMR0CTL_PRESCALE_VAL (0xf - TMR0CTL_PRESCALER) #define TMR0CTL_PRESCALE_DIV (65536 / BIT(TMR0CTL_PRESCALER)) +struct rt_timer_gpio { + struct list_head list; + struct led_classdev *led; +}; + struct rt_timer { - struct device *dev; - void __iomem *membase; - int irq; - unsigned long timer_freq; - unsigned long timer_div; + struct device *dev; + void __iomem *membase; + int irq; + + unsigned long timer_freq; + unsigned long timer_div; + + struct list_head gpios; + struct led_trigger led_trigger; + unsigned int duty_cycle; + unsigned int duty; + + unsigned int fade; + unsigned int fade_min; + unsigned int fade_max; + unsigned int fade_speed; + unsigned int fade_dir; + unsigned int fade_count; }; static inline void rt_timer_w32(struct rt_timer *rt, u8 reg, u32 val) @@ -48,8 +68,37 @@ static inline u32 rt_timer_r32(struct rt static irqreturn_t rt_timer_irq(int irq, void *_rt) { struct rt_timer *rt = (struct rt_timer *) _rt; + struct rt_timer_gpio *gpio; + unsigned int val; - rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div); + if (rt->fade && (rt->fade_count++ > rt->fade_speed)) { + rt->fade_count = 0; + if (rt->duty_cycle <= rt->fade_min) + rt->fade_dir = 1; + else if (rt->duty_cycle >= rt->fade_max) + rt->fade_dir = 0; + + if (rt->fade_dir) + rt->duty_cycle += 1; + else + rt->duty_cycle -= 1; + + } + + val = rt->timer_freq / rt->timer_div; + if (rt->duty) + val *= rt->duty_cycle; + else + val *= (100 - rt->duty_cycle); + val /= 100; + + if (!list_empty(&rt->gpios)) + list_for_each_entry(gpio, &rt->gpios, list) + led_set_brightness(gpio->led, !!rt->duty); + + rt->duty = !rt->duty; + + rt_timer_w32(rt, TIMER_REG_TMR0LOAD, val + 1); rt_timer_w32(rt, TIMER_REG_TMRSTAT, TMRSTAT_TMR0INT); return IRQ_HANDLED; @@ -58,8 +107,8 @@ static irqreturn_t rt_timer_irq(int irq, static int rt_timer_request(struct rt_timer *rt) { - int err = request_irq(rt->irq, rt_timer_irq, 0, - dev_name(rt->dev), rt); + int err = devm_request_irq(rt->dev, rt->irq, rt_timer_irq, + 0, dev_name(rt->dev), rt); if (err) { dev_err(rt->dev, "failed to request irq\n"); } else { @@ -81,8 +130,6 @@ static int rt_timer_config(struct rt_tim else rt->timer_div = divisor; - rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div); - return 0; } @@ -108,11 +155,128 @@ static void rt_timer_disable(struct rt_t rt_timer_w32(rt, TIMER_REG_TMR0CTL, t); } +static ssize_t led_fade_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct rt_timer *rt = container_of(led_cdev->trigger, struct rt_timer, led_trigger); + + return sprintf(buf, "speed: %d, min: %d, max: %d\n", rt->fade_speed, rt->fade_min, rt->fade_max); +} + +static ssize_t led_fade_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t size) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct rt_timer *rt = container_of(led_cdev->trigger, struct rt_timer, led_trigger); + unsigned int speed = 0, min = 0, max = 0; + ssize_t ret = -EINVAL; + + ret = sscanf(buf, "%u %u %u", &speed, &min, &max); + + if (ret == 3) { + rt->fade_speed = speed; + rt->fade_min = min; + rt->fade_max = max; + rt->fade = 1; + } else { + rt->fade = 0; + } + + return size; +} + +static DEVICE_ATTR(fade, 0644, led_fade_show, led_fade_store); + +static ssize_t led_duty_cycle_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct rt_timer *rt = container_of(led_cdev->trigger, struct rt_timer, led_trigger); + + return sprintf(buf, "%u\n", rt->duty_cycle); +} + +static ssize_t led_duty_cycle_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t size) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct rt_timer *rt = container_of(led_cdev->trigger, struct rt_timer, led_trigger); + unsigned long state; + ssize_t ret = -EINVAL; + + ret = kstrtoul(buf, 10, &state); + if (ret) + return ret; + + if (state <= 100) + rt->duty_cycle = state; + else + rt->duty_cycle = 100; + + rt->fade = 0; + + return size; +} + +static DEVICE_ATTR(duty_cycle, 0644, led_duty_cycle_show, led_duty_cycle_store); + +static void rt_timer_trig_activate(struct led_classdev *led_cdev) +{ + struct rt_timer *rt = container_of(led_cdev->trigger, struct rt_timer, led_trigger); + struct rt_timer_gpio *gpio_data; + int rc; + + led_cdev->trigger_data = NULL; + gpio_data = kzalloc(sizeof(*gpio_data), GFP_KERNEL); + if (!gpio_data) + return; + + rc = device_create_file(led_cdev->dev, &dev_attr_duty_cycle); + if (rc) + goto err_gpio; + rc = device_create_file(led_cdev->dev, &dev_attr_fade); + if (rc) + goto err_out_duty_cycle; + + led_cdev->activated = true; + led_cdev->trigger_data = gpio_data; + gpio_data->led = led_cdev; + list_add(&gpio_data->list, &rt->gpios); + led_cdev->trigger_data = gpio_data; + rt_timer_enable(rt); + return; + +err_out_duty_cycle: + device_remove_file(led_cdev->dev, &dev_attr_duty_cycle); + +err_gpio: + kfree(gpio_data); +} + +static void rt_timer_trig_deactivate(struct led_classdev *led_cdev) +{ + struct rt_timer *rt = container_of(led_cdev->trigger, struct rt_timer, led_trigger); + struct rt_timer_gpio *gpio_data = (struct rt_timer_gpio*) led_cdev->trigger_data; + + if (led_cdev->activated) { + device_remove_file(led_cdev->dev, &dev_attr_duty_cycle); + device_remove_file(led_cdev->dev, &dev_attr_fade); + led_cdev->activated = false; + } + + list_del(&gpio_data->list); + rt_timer_disable(rt); + led_set_brightness(led_cdev, LED_OFF); +} + static int rt_timer_probe(struct platform_device *pdev) { struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + const __be32 *divisor; struct rt_timer *rt; struct clk *clk; + int ret; rt = devm_kzalloc(&pdev->dev, sizeof(*rt), GFP_KERNEL); if (!rt) { @@ -140,12 +304,29 @@ static int rt_timer_probe(struct platfor if (!rt->timer_freq) return -EINVAL; + rt->duty_cycle = 100; rt->dev = &pdev->dev; platform_set_drvdata(pdev, rt); - rt_timer_request(rt); - rt_timer_config(rt, 2); - rt_timer_enable(rt); + ret = rt_timer_request(rt); + if (ret) + return ret; + + divisor = of_get_property(pdev->dev.of_node, "ralink,divisor", NULL); + if (divisor) + rt_timer_config(rt, be32_to_cpu(*divisor)); + else + rt_timer_config(rt, 200); + + rt->led_trigger.name = "pwmtimer", + rt->led_trigger.activate = rt_timer_trig_activate, + rt->led_trigger.deactivate = rt_timer_trig_deactivate, + + ret = led_trigger_register(&rt->led_trigger); + if (ret) + return ret; + + INIT_LIST_HEAD(&rt->gpios); dev_info(&pdev->dev, "maximum frequency is %luHz\n", rt->timer_freq); @@ -156,6 +337,7 @@ static int rt_timer_remove(struct platfo { struct rt_timer *rt = platform_get_drvdata(pdev); + led_trigger_unregister(&rt->led_trigger); rt_timer_disable(rt); rt_timer_free(rt); @@ -180,6 +362,6 @@ static struct platform_driver rt_timer_d module_platform_driver(rt_timer_driver); -MODULE_DESCRIPTION("Ralink RT2880 timer"); +MODULE_DESCRIPTION("Ralink RT2880 timer / pseudo pwm"); MODULE_AUTHOR("John Crispin