pwm: sun4i: Add an optional probe for reset line

H6 PWM core needs deasserted reset line in order to work.

Add an optional probe for it.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Clément Péron <peron.clem@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 581d232..487899d 100644 (file)
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -16,6 +16,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/time.h>
@@ -78,6 +79,7 @@ struct sun4i_pwm_data {
 struct sun4i_pwm_chip {
        struct pwm_chip chip;
        struct clk *clk;
+       struct reset_control *rst;
        void __iomem *base;
        spinlock_t ctrl_lock;
        const struct sun4i_pwm_data *data;
@@ -364,6 +366,22 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
        if (IS_ERR(pwm->clk))
                return PTR_ERR(pwm->clk);
 
+       pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
+       if (IS_ERR(pwm->rst)) {
+               if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
+                       dev_err(&pdev->dev, "get reset failed %pe\n",
+                               pwm->rst);
+               return PTR_ERR(pwm->rst);
+       }
+
+       /* Deassert reset */
+       ret = reset_control_deassert(pwm->rst);
+       if (ret) {
+               dev_err(&pdev->dev, "cannot deassert reset control: %pe\n",
+                       ERR_PTR(ret));
+               return ret;
+       }
+
        pwm->chip.dev = &pdev->dev;
        pwm->chip.ops = &sun4i_pwm_ops;
        pwm->chip.base = -1;
@@ -376,19 +394,31 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
        ret = pwmchip_add(&pwm->chip);
        if (ret < 0) {
                dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
-               return ret;
+               goto err_pwm_add;
        }
 
        platform_set_drvdata(pdev, pwm);
 
        return 0;
+
+err_pwm_add:
+       reset_control_assert(pwm->rst);
+
+       return ret;
 }
 
 static int sun4i_pwm_remove(struct platform_device *pdev)
 {
        struct sun4i_pwm_chip *pwm = platform_get_drvdata(pdev);
+       int ret;
+
+       ret = pwmchip_remove(&pwm->chip);
+       if (ret)
+               return ret;
+
+       reset_control_assert(pwm->rst);
 
-       return pwmchip_remove(&pwm->chip);
+       return 0;
 }
 
 static struct platform_driver sun4i_pwm_driver = {