--- /dev/null
+/* 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 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;
+}
+
+static struct platform_driver s3c_pwm_driver = {
+ .driver = {
+ .name = "s3c24xx-pwm",
+ .owner = THIS_MODULE,
+ },
+ .probe = s3c_pwm_probe,
+ .remove = __devexit_p(s3c_pwm_remove),
+};
+
+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);
projects / linux-drm-fsl-dcu.git / commitdiff