| /* arch/arm/plat-s3c/pwm.c |
| * |
| * Copyright (c) 2007 Ben Dooks |
| * Copyright (c) 2008 Simtec Electronics |
| * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org> |
| * |
| * S3C series PWM device core |
| * |
| * 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. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/kernel.h> |
| #include <linux/platform_device.h> |
| #include <linux/err.h> |
| #include <linux/clk.h> |
| #include <linux/io.h> |
| #include <linux/pwm.h> |
| |
| #include <mach/irqs.h> |
| #include <mach/map.h> |
| |
| #include <plat/devs.h> |
| #include <plat/regs-timer.h> |
| |
| struct pwm_device { |
| struct list_head list; |
| struct platform_device *pdev; |
| |
| struct clk *clk_div; |
| struct clk *clk; |
| const char *label; |
| |
| unsigned int period_ns; |
| unsigned int duty_ns; |
| |
| unsigned char tcon_base; |
| unsigned char running; |
| unsigned char use_count; |
| unsigned char pwm_id; |
| }; |
| |
| #define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg) |
| |
| static struct clk *clk_scaler[2]; |
| |
| /* Standard setup for a timer block. */ |
| |
| #define TIMER_RESOURCE_SIZE (1) |
| |
| #define TIMER_RESOURCE(_tmr, _irq) \ |
| (struct resource [TIMER_RESOURCE_SIZE]) { \ |
| [0] = { \ |
| .start = _irq, \ |
| .end = _irq, \ |
| .flags = IORESOURCE_IRQ \ |
| } \ |
| } |
| |
| #define DEFINE_S3C_TIMER(_tmr_no, _irq) \ |
| .name = "s3c24xx-pwm", \ |
| .id = _tmr_no, \ |
| .num_resources = TIMER_RESOURCE_SIZE, \ |
| .resource = TIMER_RESOURCE(_tmr_no, _irq), \ |
| |
| /* since we already have an static mapping for the timer, we do not |
| * bother setting any IO resource for the base. |
| */ |
| |
| struct platform_device s3c_device_timer[] = { |
| [0] = { DEFINE_S3C_TIMER(0, IRQ_TIMER0) }, |
| [1] = { DEFINE_S3C_TIMER(1, IRQ_TIMER1) }, |
| [2] = { DEFINE_S3C_TIMER(2, IRQ_TIMER2) }, |
| [3] = { DEFINE_S3C_TIMER(3, IRQ_TIMER3) }, |
| [4] = { DEFINE_S3C_TIMER(4, IRQ_TIMER4) }, |
| }; |
| |
| static inline int pwm_is_tdiv(struct pwm_device *pwm) |
| { |
| return clk_get_parent(pwm->clk) == pwm->clk_div; |
| } |
| |
| static DEFINE_MUTEX(pwm_lock); |
| static LIST_HEAD(pwm_list); |
| |
| struct pwm_device *pwm_request(int pwm_id, const char *label) |
| { |
| struct pwm_device *pwm; |
| int found = 0; |
| |
| mutex_lock(&pwm_lock); |
| |
| list_for_each_entry(pwm, &pwm_list, list) { |
| if (pwm->pwm_id == pwm_id) { |
| found = 1; |
| break; |
| } |
| } |
| |
| if (found) { |
| if (pwm->use_count == 0) { |
| pwm->use_count = 1; |
| pwm->label = label; |
| } else |
| pwm = ERR_PTR(-EBUSY); |
| } else |
| pwm = ERR_PTR(-ENOENT); |
| |
| mutex_unlock(&pwm_lock); |
| return pwm; |
| } |
| |
| EXPORT_SYMBOL(pwm_request); |
| |
| |
| void pwm_free(struct pwm_device *pwm) |
| { |
| mutex_lock(&pwm_lock); |
| |
| if (pwm->use_count) { |
| pwm->use_count--; |
| pwm->label = NULL; |
| } else |
| printk(KERN_ERR "PWM%d device already freed\n", pwm->pwm_id); |
| |
| mutex_unlock(&pwm_lock); |
| } |
| |
| EXPORT_SYMBOL(pwm_free); |
| |
| #define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0)) |
| #define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2)) |
| #define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3)) |
| #define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1)) |
| |
| int pwm_enable(struct pwm_device *pwm) |
| { |
| unsigned long flags; |
| unsigned long tcon; |
| |
| local_irq_save(flags); |
| |
| tcon = __raw_readl(S3C2410_TCON); |
| tcon |= pwm_tcon_start(pwm); |
| __raw_writel(tcon, S3C2410_TCON); |
| |
| local_irq_restore(flags); |
| |
| pwm->running = 1; |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(pwm_enable); |
| |
| void pwm_disable(struct pwm_device *pwm) |
| { |
| unsigned long flags; |
| unsigned long tcon; |
| |
| local_irq_save(flags); |
| |
| tcon = __raw_readl(S3C2410_TCON); |
| tcon &= ~pwm_tcon_start(pwm); |
| __raw_writel(tcon, S3C2410_TCON); |
| |
| local_irq_restore(flags); |
| |
| pwm->running = 0; |
| } |
| |
| EXPORT_SYMBOL(pwm_disable); |
| |
| static unsigned long pwm_calc_tin(struct pwm_device *pwm, unsigned long freq) |
| { |
| unsigned long tin_parent_rate; |
| unsigned int div; |
| |
| tin_parent_rate = clk_get_rate(clk_get_parent(pwm->clk_div)); |
| pwm_dbg(pwm, "tin parent at %lu\n", tin_parent_rate); |
| |
| for (div = 2; div <= 16; div *= 2) { |
| if ((tin_parent_rate / (div << 16)) < freq) |
| return tin_parent_rate / div; |
| } |
| |
| return tin_parent_rate / 16; |
| } |
| |
| #define NS_IN_HZ (1000000000UL) |
| |
| int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) |
| { |
| unsigned long tin_rate; |
| unsigned long tin_ns; |
| unsigned long period; |
| unsigned long flags; |
| unsigned long tcon; |
| unsigned long tcnt; |
| long tcmp; |
| |
| /* We currently avoid using 64bit arithmetic by using the |
| * fact that anything faster than 1Hz is easily representable |
| * by 32bits. */ |
| |
| if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ) |
| return -ERANGE; |
| |
| if (duty_ns > period_ns) |
| return -EINVAL; |
| |
| if (period_ns == pwm->period_ns && |
| duty_ns == pwm->duty_ns) |
| return 0; |
| |
| /* The TCMP and TCNT can be read without a lock, they're not |
| * shared between the timers. */ |
| |
| tcmp = __raw_readl(S3C2410_TCMPB(pwm->pwm_id)); |
| tcnt = __raw_readl(S3C2410_TCNTB(pwm->pwm_id)); |
| |
| period = NS_IN_HZ / period_ns; |
| |
| pwm_dbg(pwm, "duty_ns=%d, period_ns=%d (%lu)\n", |
| duty_ns, period_ns, period); |
| |
| /* Check to see if we are changing the clock rate of the PWM */ |
| |
| if (pwm->period_ns != period_ns) { |
| if (pwm_is_tdiv(pwm)) { |
| tin_rate = pwm_calc_tin(pwm, period); |
| clk_set_rate(pwm->clk_div, tin_rate); |
| } else |
| tin_rate = clk_get_rate(pwm->clk); |
| |
| pwm->period_ns = period_ns; |
| |
| pwm_dbg(pwm, "tin_rate=%lu\n", tin_rate); |
| |
| tin_ns = NS_IN_HZ / tin_rate; |
| tcnt = period_ns / tin_ns; |
| } else |
| tin_ns = NS_IN_HZ / clk_get_rate(pwm->clk); |
| |
| /* Note, counters count down */ |
| |
| tcmp = duty_ns / tin_ns; |
| tcmp = tcnt - tcmp; |
| /* the pwm hw only checks the compare register after a decrement, |
| so the pin never toggles if tcmp = tcnt */ |
| if (tcmp == tcnt) |
| tcmp--; |
| |
| pwm_dbg(pwm, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt); |
| |
| if (tcmp < 0) |
| tcmp = 0; |
| |
| /* Update the PWM register block. */ |
| |
| local_irq_save(flags); |
| |
| __raw_writel(tcmp, S3C2410_TCMPB(pwm->pwm_id)); |
| __raw_writel(tcnt, S3C2410_TCNTB(pwm->pwm_id)); |
| |
| tcon = __raw_readl(S3C2410_TCON); |
| tcon |= pwm_tcon_manulupdate(pwm); |
| tcon |= pwm_tcon_autoreload(pwm); |
| __raw_writel(tcon, S3C2410_TCON); |
| |
| tcon &= ~pwm_tcon_manulupdate(pwm); |
| __raw_writel(tcon, S3C2410_TCON); |
| |
| local_irq_restore(flags); |
| |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(pwm_config); |
| |
| static int pwm_register(struct pwm_device *pwm) |
| { |
| pwm->duty_ns = -1; |
| pwm->period_ns = -1; |
| |
| mutex_lock(&pwm_lock); |
| list_add_tail(&pwm->list, &pwm_list); |
| mutex_unlock(&pwm_lock); |
| |
| return 0; |
| } |
| |
| static int s3c_pwm_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct pwm_device *pwm; |
| unsigned long flags; |
| unsigned long tcon; |
| unsigned int id = pdev->id; |
| int ret; |
| |
| if (id == 4) { |
| dev_err(dev, "TIMER4 is currently not supported\n"); |
| return -ENXIO; |
| } |
| |
| pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); |
| if (pwm == NULL) { |
| dev_err(dev, "failed to allocate pwm_device\n"); |
| return -ENOMEM; |
| } |
| |
| pwm->pdev = pdev; |
| pwm->pwm_id = id; |
| |
| /* calculate base of control bits in TCON */ |
| pwm->tcon_base = id == 0 ? 0 : (id * 4) + 4; |
| |
| pwm->clk = clk_get(dev, "pwm-tin"); |
| if (IS_ERR(pwm->clk)) { |
| dev_err(dev, "failed to get pwm tin clk\n"); |
| ret = PTR_ERR(pwm->clk); |
| goto err_alloc; |
| } |
| |
| pwm->clk_div = clk_get(dev, "pwm-tdiv"); |
| if (IS_ERR(pwm->clk_div)) { |
| dev_err(dev, "failed to get pwm tdiv clk\n"); |
| ret = PTR_ERR(pwm->clk_div); |
| goto err_clk_tin; |
| } |
| |
| local_irq_save(flags); |
| |
| tcon = __raw_readl(S3C2410_TCON); |
| tcon |= pwm_tcon_invert(pwm); |
| __raw_writel(tcon, S3C2410_TCON); |
| |
| local_irq_restore(flags); |
| |
| |
| ret = pwm_register(pwm); |
| if (ret) { |
| dev_err(dev, "failed to register pwm\n"); |
| goto err_clk_tdiv; |
| } |
| |
| pwm_dbg(pwm, "config bits %02x\n", |
| (__raw_readl(S3C2410_TCON) >> pwm->tcon_base) & 0x0f); |
| |
| dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n", |
| clk_get_rate(pwm->clk), |
| clk_get_rate(pwm->clk_div), |
| pwm_is_tdiv(pwm) ? "div" : "ext", pwm->tcon_base); |
| |
| platform_set_drvdata(pdev, pwm); |
| return 0; |
| |
| err_clk_tdiv: |
| clk_put(pwm->clk_div); |
| |
| err_clk_tin: |
| clk_put(pwm->clk); |
| |
| err_alloc: |
| kfree(pwm); |
| return ret; |
| } |
| |
| static int __devexit s3c_pwm_remove(struct platform_device *pdev) |
| { |
| struct pwm_device *pwm = platform_get_drvdata(pdev); |
| |
| clk_put(pwm->clk_div); |
| clk_put(pwm->clk); |
| kfree(pwm); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_PM |
| static int s3c_pwm_suspend(struct platform_device *pdev, pm_message_t state) |
| { |
| struct pwm_device *pwm = platform_get_drvdata(pdev); |
| |
| /* No one preserve these values during suspend so reset them |
| * Otherwise driver leaves PWM unconfigured if same values |
| * passed to pwm_config |
| */ |
| pwm->period_ns = 0; |
| pwm->duty_ns = 0; |
| |
| return 0; |
| } |
| |
| static int s3c_pwm_resume(struct platform_device *pdev) |
| { |
| struct pwm_device *pwm = platform_get_drvdata(pdev); |
| unsigned long tcon; |
| |
| /* Restore invertion */ |
| tcon = __raw_readl(S3C2410_TCON); |
| tcon |= pwm_tcon_invert(pwm); |
| __raw_writel(tcon, S3C2410_TCON); |
| |
| return 0; |
| } |
| |
| #else |
| #define s3c_pwm_suspend NULL |
| #define s3c_pwm_resume NULL |
| #endif |
| |
| static struct platform_driver s3c_pwm_driver = { |
| .driver = { |
| .name = "s3c24xx-pwm", |
| .owner = THIS_MODULE, |
| }, |
| .probe = s3c_pwm_probe, |
| .remove = __devexit_p(s3c_pwm_remove), |
| .suspend = s3c_pwm_suspend, |
| .resume = s3c_pwm_resume, |
| }; |
| |
| static int __init pwm_init(void) |
| { |
| int ret; |
| |
| clk_scaler[0] = clk_get(NULL, "pwm-scaler0"); |
| clk_scaler[1] = clk_get(NULL, "pwm-scaler1"); |
| |
| if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) { |
| printk(KERN_ERR "%s: failed to get scaler clocks\n", __func__); |
| return -EINVAL; |
| } |
| |
| ret = platform_driver_register(&s3c_pwm_driver); |
| if (ret) |
| printk(KERN_ERR "%s: failed to add pwm driver\n", __func__); |
| |
| return ret; |
| } |
| |
| arch_initcall(pwm_init); |