pwm: berlin: Add suspend/resume support

This patch adds suspend-to-RAM support to the Berlin PWM driver.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

diff --git a/drivers/pwm/pwm-berlin.c b/drivers/pwm/pwm-berlin.c
index 65108129d50597eff28c7eb10de9e2d0ac477f20..01339c152ab00bb69b4ff1ee0c87c096151bd91c 100644 (file)
--- a/drivers/pwm/pwm-berlin.c
+++ b/drivers/pwm/pwm-berlin.c
@@ -16,6 +16,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
+#include <linux/slab.h>
 
 #define BERLIN_PWM_EN                  0x0
 #define  BERLIN_PWM_ENABLE             BIT(0)
@@ -27,6 +28,13 @@
 #define BERLIN_PWM_TCNT                        0xc
 #define  BERLIN_PWM_MAX_TCNT           65535
 
+struct berlin_pwm_channel {
+       u32 enable;
+       u32 ctrl;
+       u32 duty;
+       u32 tcnt;
+};
+
 struct berlin_pwm_chip {
        struct pwm_chip chip;
        struct clk *clk;
@@ -55,6 +63,25 @@ static inline void berlin_pwm_writel(struct berlin_pwm_chip *chip,
        writel_relaxed(value, chip->base + channel * 0x10 + offset);
 }
 
+static int berlin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+       struct berlin_pwm_channel *channel;
+
+       channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+       if (!channel)
+               return -ENOMEM;
+
+       return pwm_set_chip_data(pwm, channel);
+}
+
+static void berlin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+       struct berlin_pwm_channel *channel = pwm_get_chip_data(pwm);
+
+       pwm_set_chip_data(pwm, NULL);
+       kfree(channel);
+}
+
 static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm_dev,
                             int duty_ns, int period_ns)
 {
@@ -137,6 +164,8 @@ static void berlin_pwm_disable(struct pwm_chip *chip,
 }
 
 static const struct pwm_ops berlin_pwm_ops = {
+       .request = berlin_pwm_request,
+       .free = berlin_pwm_free,
        .config = berlin_pwm_config,
        .set_polarity = berlin_pwm_set_polarity,
        .enable = berlin_pwm_enable,
@@ -204,12 +233,67 @@ static int berlin_pwm_remove(struct platform_device *pdev)
        return ret;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int berlin_pwm_suspend(struct device *dev)
+{
+       struct berlin_pwm_chip *pwm = dev_get_drvdata(dev);
+       unsigned int i;
+
+       for (i = 0; i < pwm->chip.npwm; i++) {
+               struct berlin_pwm_channel *channel;
+
+               channel = pwm_get_chip_data(&pwm->chip.pwms[i]);
+               if (!channel)
+                       continue;
+
+               channel->enable = berlin_pwm_readl(pwm, i, BERLIN_PWM_ENABLE);
+               channel->ctrl = berlin_pwm_readl(pwm, i, BERLIN_PWM_CONTROL);
+               channel->duty = berlin_pwm_readl(pwm, i, BERLIN_PWM_DUTY);
+               channel->tcnt = berlin_pwm_readl(pwm, i, BERLIN_PWM_TCNT);
+       }
+
+       clk_disable_unprepare(pwm->clk);
+
+       return 0;
+}
+
+static int berlin_pwm_resume(struct device *dev)
+{
+       struct berlin_pwm_chip *pwm = dev_get_drvdata(dev);
+       unsigned int i;
+       int ret;
+
+       ret = clk_prepare_enable(pwm->clk);
+       if (ret)
+               return ret;
+
+       for (i = 0; i < pwm->chip.npwm; i++) {
+               struct berlin_pwm_channel *channel;
+
+               channel = pwm_get_chip_data(&pwm->chip.pwms[i]);
+               if (!channel)
+                       continue;
+
+               berlin_pwm_writel(pwm, i, channel->ctrl, BERLIN_PWM_CONTROL);
+               berlin_pwm_writel(pwm, i, channel->duty, BERLIN_PWM_DUTY);
+               berlin_pwm_writel(pwm, i, channel->tcnt, BERLIN_PWM_TCNT);
+               berlin_pwm_writel(pwm, i, channel->enable, BERLIN_PWM_ENABLE);
+       }
+
+       return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(berlin_pwm_pm_ops, berlin_pwm_suspend,
+                        berlin_pwm_resume);
+
 static struct platform_driver berlin_pwm_driver = {
        .probe = berlin_pwm_probe,
        .remove = berlin_pwm_remove,
        .driver = {
                .name = "berlin-pwm",
                .of_match_table = berlin_pwm_match,
+               .pm = &berlin_pwm_pm_ops,
        },
 };
 module_platform_driver(berlin_pwm_driver);