[PATCH v6 4/8] pwm: sun4i: Add an optional probe for bus clock

From: "Clément Péron" <peron.clem@gmail.com>
To: "Thierry Reding" <thierry.reding@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Chen-Yu Tsai" <wens@csie.org>,
	"Philipp Zabel" <pza@pengutronix.de>
Cc: linux-pwm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com,
	"Jernej Skrabec" <jernej.skrabec@siol.net>,
	"Clément Péron" <peron.clem@gmail.com>
Subject: [PATCH v6 4/8] pwm: sun4i: Add an optional probe for bus clock
Date: Mon, 18 Nov 2019 12:00:30 +0100	[thread overview]
Message-ID: <20191118110034.19444-5-peron.clem@gmail.com> (raw)
In-Reply-To: <20191118110034.19444-1-peron.clem@gmail.com>

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

H6 PWM core needs bus clock to be enabled 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 | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 6d97fef4ed43..ce83d479ba0e 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -78,6 +78,7 @@ struct sun4i_pwm_data {
 
 struct sun4i_pwm_chip {
 	struct pwm_chip chip;
+	struct clk *bus_clk;
 	struct clk *clk;
 	struct reset_control *rst;
 	void __iomem *base;
@@ -391,6 +392,14 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 		}
 	}
 
+	pwm->bus_clk = devm_clk_get_optional(&pdev->dev, "bus");
+	if (IS_ERR(pwm->bus_clk)) {
+		if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
+			dev_err(&pdev->dev, "get bus clock failed %pe\n",
+				pwm->bus_clk);
+		return PTR_ERR(pwm->bus_clk);
+	}
+
 	pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
 	if (IS_ERR(pwm->rst)) {
 		if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
@@ -406,6 +415,16 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/*
+	 * We're keeping the bus clock on for the sake of simplicity.
+	 * Actually it only needs to be on for hardware register accesses.
+	 */
+	ret = clk_prepare_enable(pwm->bus_clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Cannot prepare and enable bus_clk\n");
+		goto err_bus;
+	}
+
 	pwm->chip.dev = &pdev->dev;
 	pwm->chip.ops = &sun4i_pwm_ops;
 	pwm->chip.base = -1;
@@ -426,6 +445,8 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 	return 0;
 
 err_pwm_add:
+	clk_disable_unprepare(pwm->bus_clk);
+err_bus:
 	reset_control_assert(pwm->rst);
 
 	return ret;
@@ -440,6 +461,7 @@ static int sun4i_pwm_remove(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	clk_disable_unprepare(pwm->bus_clk);
 	reset_control_assert(pwm->rst);
 
 	return 0;
-- 
2.20.1

