linux-kernel - [PATCH 2/6] pwm: sun4i: Add a quirk for reset line

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Message-Id: <20190726184045.14669-3-jernej.skrabec@siol.net>
Date:   Fri, 26 Jul 2019 20:40:41 +0200
From:   Jernej Skrabec <jernej.skrabec@...l.net>
To:     thierry.reding@...il.com, mripard@...nel.org, wens@...e.org
Cc:     robh+dt@...nel.org, mark.rutland@....com,
        linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-sunxi@...glegroups.com
Subject: [PATCH 2/6] pwm: sun4i: Add a quirk for reset line

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

Add a quirk for it.

Signed-off-by: Jernej Skrabec <jernej.skrabec@...l.net>
---
 drivers/pwm/pwm-sun4i.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index de78c824bbfd..1b7be8fbde86 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>
@@ -72,12 +73,14 @@ static const u32 prescaler_table[] = {
 
 struct sun4i_pwm_data {
 	bool has_prescaler_bypass;
+	bool has_reset;
 	unsigned int npwm;
 };
 
 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;
@@ -371,6 +374,14 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 	if (IS_ERR(pwm->clk))
 		return PTR_ERR(pwm->clk);
 
+	if (pwm->data->has_reset) {
+		pwm->rst = devm_reset_control_get(&pdev->dev, NULL);
+		if (IS_ERR(pwm->rst))
+			return PTR_ERR(pwm->rst);
+
+		reset_control_deassert(pwm->rst);
+	}
+
 	pwm->chip.dev = &pdev->dev;
 	pwm->chip.ops = &sun4i_pwm_ops;
 	pwm->chip.base = -1;
@@ -383,19 +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;
 
-	return pwmchip_remove(&pwm->chip);
+	reset_control_assert(pwm->rst);
+
+	return 0;
 }
 
 static struct platform_driver sun4i_pwm_driver = {
-- 
2.22.0