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authorSascha Hauer <s.hauer@pengutronix.de>2012-03-15 10:04:36 +0100
committerThierry Reding <thierry.reding@avionic-design.de>2012-07-02 21:39:02 +0200
commit215c29d3d0e925189ade522d1ea6052a320d7692 (patch)
tree8540120b08bc764be976d9503acd93ebdd9d8fdb /drivers/pwm/pwm-samsung.c
parent29693248edf10830db2ef82b36806e378ff75c67 (diff)
ARM Samsung: Move s3c pwm driver to pwm framework
Move the driver to drivers/pwm/ and convert it to use the framework. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Cc: Ben Dooks <ben-linux@fluff.org> Cc: Kukjin Kim <kgene.kim@samsung.com> [eric@eukrea.com: fix pwmchip_add return code test] Signed-off-by: Eric BĂ©nard <eric@eukrea.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Diffstat (limited to 'drivers/pwm/pwm-samsung.c')
-rw-r--r--drivers/pwm/pwm-samsung.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-samsung.c b/drivers/pwm/pwm-samsung.c
new file mode 100644
index 000000000000..c40c37e968e6
--- /dev/null
+++ b/drivers/pwm/pwm-samsung.c
@@ -0,0 +1,366 @@
+/* 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/export.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+
+#include <mach/map.h>
+
+#include <plat/regs-timer.h>
+
+struct s3c_chip {
+ 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 pwm_id;
+ struct pwm_chip chip;
+};
+
+#define to_s3c_chip(chip) container_of(chip, struct s3c_chip, chip)
+
+#define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg)
+
+static struct clk *clk_scaler[2];
+
+static inline int pwm_is_tdiv(struct s3c_chip *chip)
+{
+ return clk_get_parent(chip->clk) == chip->clk_div;
+}
+
+#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))
+
+static int s3c_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct s3c_chip *s3c = to_s3c_chip(chip);
+ unsigned long flags;
+ unsigned long tcon;
+
+ local_irq_save(flags);
+
+ tcon = __raw_readl(S3C2410_TCON);
+ tcon |= pwm_tcon_start(s3c);
+ __raw_writel(tcon, S3C2410_TCON);
+
+ local_irq_restore(flags);
+
+ return 0;
+}
+
+static void s3c_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct s3c_chip *s3c = to_s3c_chip(chip);
+ unsigned long flags;
+ unsigned long tcon;
+
+ local_irq_save(flags);
+
+ tcon = __raw_readl(S3C2410_TCON);
+ tcon &= ~pwm_tcon_start(s3c);
+ __raw_writel(tcon, S3C2410_TCON);
+
+ local_irq_restore(flags);
+}
+
+static unsigned long pwm_calc_tin(struct s3c_chip *s3c, unsigned long freq)
+{
+ unsigned long tin_parent_rate;
+ unsigned int div;
+
+ tin_parent_rate = clk_get_rate(clk_get_parent(s3c->clk_div));
+ pwm_dbg(s3c, "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)
+
+static int s3c_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct s3c_chip *s3c = to_s3c_chip(chip);
+ 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 == s3c->period_ns &&
+ duty_ns == s3c->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(s3c->pwm_id));
+ tcnt = __raw_readl(S3C2410_TCNTB(s3c->pwm_id));
+
+ period = NS_IN_HZ / period_ns;
+
+ pwm_dbg(s3c, "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 (s3c->period_ns != period_ns) {
+ if (pwm_is_tdiv(s3c)) {
+ tin_rate = pwm_calc_tin(s3c, period);
+ clk_set_rate(s3c->clk_div, tin_rate);
+ } else
+ tin_rate = clk_get_rate(s3c->clk);
+
+ s3c->period_ns = period_ns;
+
+ pwm_dbg(s3c, "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(s3c->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(s3c, "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(s3c->pwm_id));
+ __raw_writel(tcnt, S3C2410_TCNTB(s3c->pwm_id));
+
+ tcon = __raw_readl(S3C2410_TCON);
+ tcon |= pwm_tcon_manulupdate(s3c);
+ tcon |= pwm_tcon_autoreload(s3c);
+ __raw_writel(tcon, S3C2410_TCON);
+
+ tcon &= ~pwm_tcon_manulupdate(s3c);
+ __raw_writel(tcon, S3C2410_TCON);
+
+ local_irq_restore(flags);
+
+ return 0;
+}
+
+static struct pwm_ops s3c_pwm_ops = {
+ .enable = s3c_pwm_enable,
+ .disable = s3c_pwm_disable,
+ .config = s3c_pwm_config,
+ .owner = THIS_MODULE,
+};
+
+static int s3c_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct s3c_chip *s3c;
+ 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;
+ }
+
+ s3c = kzalloc(sizeof(*s3c), GFP_KERNEL);
+ if (s3c == NULL) {
+ dev_err(dev, "failed to allocate pwm_device\n");
+ return -ENOMEM;
+ }
+
+ /* calculate base of control bits in TCON */
+ s3c->tcon_base = id == 0 ? 0 : (id * 4) + 4;
+ s3c->chip.ops = &s3c_pwm_ops;
+ s3c->chip.base = -1;
+ s3c->chip.npwm = 1;
+
+ s3c->clk = clk_get(dev, "pwm-tin");
+ if (IS_ERR(s3c->clk)) {
+ dev_err(dev, "failed to get pwm tin clk\n");
+ ret = PTR_ERR(s3c->clk);
+ goto err_alloc;
+ }
+
+ s3c->clk_div = clk_get(dev, "pwm-tdiv");
+ if (IS_ERR(s3c->clk_div)) {
+ dev_err(dev, "failed to get pwm tdiv clk\n");
+ ret = PTR_ERR(s3c->clk_div);
+ goto err_clk_tin;
+ }
+
+ clk_enable(s3c->clk);
+ clk_enable(s3c->clk_div);
+
+ local_irq_save(flags);
+
+ tcon = __raw_readl(S3C2410_TCON);
+ tcon |= pwm_tcon_invert(s3c);
+ __raw_writel(tcon, S3C2410_TCON);
+
+ local_irq_restore(flags);
+
+ ret = pwmchip_add(&s3c->chip);
+ if (ret < 0) {
+ dev_err(dev, "failed to register pwm\n");
+ goto err_clk_tdiv;
+ }
+
+ pwm_dbg(s3c, "config bits %02x\n",
+ (__raw_readl(S3C2410_TCON) >> s3c->tcon_base) & 0x0f);
+
+ dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n",
+ clk_get_rate(s3c->clk),
+ clk_get_rate(s3c->clk_div),
+ pwm_is_tdiv(s3c) ? "div" : "ext", s3c->tcon_base);
+
+ platform_set_drvdata(pdev, s3c);
+ return 0;
+
+ err_clk_tdiv:
+ clk_disable(s3c->clk_div);
+ clk_disable(s3c->clk);
+ clk_put(s3c->clk_div);
+
+ err_clk_tin:
+ clk_put(s3c->clk);
+
+ err_alloc:
+ kfree(s3c);
+ return ret;
+}
+
+static int __devexit s3c_pwm_remove(struct platform_device *pdev)
+{
+ struct s3c_chip *s3c = platform_get_drvdata(pdev);
+ int err;
+
+ err = pwmchip_remove(&s3c->chip);
+ if (err < 0)
+ return err;
+
+ clk_disable(s3c->clk_div);
+ clk_disable(s3c->clk);
+ clk_put(s3c->clk_div);
+ clk_put(s3c->clk);
+ kfree(s3c);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int s3c_pwm_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct s3c_chip *s3c = 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
+ */
+ s3c->period_ns = 0;
+ s3c->duty_ns = 0;
+
+ return 0;
+}
+
+static int s3c_pwm_resume(struct platform_device *pdev)
+{
+ struct s3c_chip *s3c = platform_get_drvdata(pdev);
+ unsigned long tcon;
+
+ /* Restore invertion */
+ tcon = __raw_readl(S3C2410_TCON);
+ tcon |= pwm_tcon_invert(s3c);
+ __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);

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