[ARM] S3C24XX: PWM API support.
authorBen Dooks <ben-linux@fluff.org>
Tue, 1 Jul 2008 12:17:24 +0000 (13:17 +0100)
committerBen Dooks <ben-linux@fluff.org>
Thu, 3 Jul 2008 15:51:30 +0000 (16:51 +0100)
Add support for PWM in the S3C24XX series of SoC via the
PWM API.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
arch/arm/plat-s3c24xx/Kconfig
arch/arm/plat-s3c24xx/Makefile
arch/arm/plat-s3c24xx/devs.c
arch/arm/plat-s3c24xx/pwm.c [new file with mode: 0644]
include/asm-arm/plat-s3c24xx/devs.h

index 1521f1c..5e28c21 100644 (file)
@@ -21,6 +21,13 @@ config CPU_S3C244X
        help
          Support for S3C2440 and S3C2442 Samsung Mobile CPU based systems.
 
+config S3C24XX_PWM
+       bool "PWM device support"
+       select HAVE_PWM
+       help
+         Support for exporting the PWM timer blocks via the pwm device
+         system.
+
 config PM_SIMTEC
        bool
        help
index c925d57..d82767b 100644 (file)
@@ -29,5 +29,6 @@ obj-$(CONFIG_CPU_S3C244X)     += s3c244x-clock.o
 obj-$(CONFIG_PM_SIMTEC)                += pm-simtec.o
 obj-$(CONFIG_PM)               += pm.o
 obj-$(CONFIG_PM)               += sleep.o
+obj-$(CONFIG_HAVE_PWM)         += pwm.o
 obj-$(CONFIG_S3C2410_DMA)      += dma.o
 obj-$(CONFIG_MACH_SMDK)                += common-smdk.o
index e546e93..eea3b32 100644 (file)
@@ -495,106 +495,6 @@ struct platform_device s3c_device_spi1 = {
 
 EXPORT_SYMBOL(s3c_device_spi1);
 
-/* pwm timer blocks */
-
-static struct resource s3c_timer0_resource[] = {
-       [0] = {
-               .start = S3C24XX_PA_TIMER + 0x0C,
-               .end   = S3C24XX_PA_TIMER + 0x0C + 0xB,
-               .flags = IORESOURCE_MEM,
-       },
-       [1] = {
-               .start = IRQ_TIMER0,
-               .end   = IRQ_TIMER0,
-               .flags = IORESOURCE_IRQ,
-       }
-
-};
-
-struct platform_device s3c_device_timer0 = {
-       .name             = "s3c2410-timer",
-       .id               = 0,
-       .num_resources    = ARRAY_SIZE(s3c_timer0_resource),
-       .resource         = s3c_timer0_resource,
-};
-
-EXPORT_SYMBOL(s3c_device_timer0);
-
-/* timer 1 */
-
-static struct resource s3c_timer1_resource[] = {
-       [0] = {
-               .start = S3C24XX_PA_TIMER + 0x18,
-               .end   = S3C24XX_PA_TIMER + 0x23,
-               .flags = IORESOURCE_MEM,
-       },
-       [1] = {
-               .start = IRQ_TIMER1,
-               .end   = IRQ_TIMER1,
-               .flags = IORESOURCE_IRQ,
-       }
-
-};
-
-struct platform_device s3c_device_timer1 = {
-       .name             = "s3c2410-timer",
-       .id               = 1,
-       .num_resources    = ARRAY_SIZE(s3c_timer1_resource),
-       .resource         = s3c_timer1_resource,
-};
-
-EXPORT_SYMBOL(s3c_device_timer1);
-
-/* timer 2 */
-
-static struct resource s3c_timer2_resource[] = {
-       [0] = {
-               .start = S3C24XX_PA_TIMER + 0x24,
-               .end   = S3C24XX_PA_TIMER + 0x2F,
-               .flags = IORESOURCE_MEM,
-       },
-       [1] = {
-               .start = IRQ_TIMER2,
-               .end   = IRQ_TIMER2,
-               .flags = IORESOURCE_IRQ,
-       }
-
-};
-
-struct platform_device s3c_device_timer2 = {
-       .name             = "s3c2410-timer",
-       .id               = 2,
-       .num_resources    = ARRAY_SIZE(s3c_timer2_resource),
-       .resource         = s3c_timer2_resource,
-};
-
-EXPORT_SYMBOL(s3c_device_timer2);
-
-/* timer 3 */
-
-static struct resource s3c_timer3_resource[] = {
-       [0] = {
-               .start = S3C24XX_PA_TIMER + 0x30,
-               .end   = S3C24XX_PA_TIMER + 0x3B,
-               .flags = IORESOURCE_MEM,
-       },
-       [1] = {
-               .start = IRQ_TIMER3,
-               .end   = IRQ_TIMER3,
-               .flags = IORESOURCE_IRQ,
-       }
-
-};
-
-struct platform_device s3c_device_timer3 = {
-       .name             = "s3c2410-timer",
-       .id               = 3,
-       .num_resources    = ARRAY_SIZE(s3c_timer3_resource),
-       .resource         = s3c_timer3_resource,
-};
-
-EXPORT_SYMBOL(s3c_device_timer3);
-
 #ifdef CONFIG_CPU_S3C2440
 
 /* Camif Controller */
diff --git a/arch/arm/plat-s3c24xx/pwm.c b/arch/arm/plat-s3c24xx/pwm.c
new file mode 100644 (file)
index 0000000..18c4bdc
--- /dev/null
@@ -0,0 +1,402 @@
+/* arch/arm/plat-s3c24xx/pwm.c
+ *
+ * Copyright (c) 2007 Ben Dooks
+ * Copyright (c) 2008 Simtec Electronics
+ *     Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
+ *
+ * S3C24XX 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 <asm/plat-s3c/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_info(&(_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_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_TIMER(0, IRQ_TIMER0) },
+       [1] = { DEFINE_TIMER(1, IRQ_TIMER1) },
+       [2] = { DEFINE_TIMER(2, IRQ_TIMER2) },
+       [3] = { DEFINE_TIMER(3, IRQ_TIMER3) },
+       [4] = { DEFINE_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);
+
+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;
+
+       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);
index f9d6f03..badaac9 100644 (file)
@@ -21,6 +21,8 @@ extern struct s3c24xx_uart_resources s3c2410_uart_resources[];
 extern struct platform_device *s3c24xx_uart_devs[];
 extern struct platform_device *s3c24xx_uart_src[];
 
+extern struct platform_device s3c_device_timer[];
+
 extern struct platform_device s3c_device_usb;
 extern struct platform_device s3c_device_lcd;
 extern struct platform_device s3c_device_wdt;
@@ -36,11 +38,6 @@ extern struct platform_device s3c_device_spi1;
 
 extern struct platform_device s3c_device_nand;
 
-extern struct platform_device s3c_device_timer0;
-extern struct platform_device s3c_device_timer1;
-extern struct platform_device s3c_device_timer2;
-extern struct platform_device s3c_device_timer3;
-
 extern struct platform_device s3c_device_usbgadget;
 
 /* s3c2440 specific devices */