[PATCH v2 2/7] pwm: sun4i: Add an optional probe for reset line

Clément Péron
2019-11-03T20:33:53Z

From: Jernej Skrabec <jernej.skrabec@siol.net>

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>
Signed-off-by: Clément Péron <peron.clem@gmail.com>
---
drivers/pwm/pwm-sun4i.c | 32 ++++++++++++++++++++++++++++++--
1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 6f5840a1a82d..d194b8ebdb00 100644
--- 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;
@@ -365,6 +367,20 @@ 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(&pdev->dev, NULL);
+ if (IS_ERR(pwm->rst)) {
+ if (PTR_ERR(pwm->rst) == -EPROBE_DEFER)
+ return PTR_ERR(pwm->rst);
+ dev_info(&pdev->dev, "no reset control found\n");
+ }
+
+ /* Deassert reset */
+ ret = reset_control_deassert(pwm->rst);
+ if (ret) {
+ dev_err(&pdev->dev, "Cannot deassert reset control\n");
+ return ret;
+ }
+
pwm->chip.dev = &pdev->dev;
pwm->chip.ops = &sun4i_pwm_ops;
pwm->chip.base = -1;
@@ -377,19 +393,31 @@ 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 = {
--
2.20.1