[PATCH 3/3] media: imx258: Get clock from device properties and enable it

[Krzysztof Kozlowski]

The IMX258 sensor driver checked in device properties for a
clock-frequency property which actually does not mean that the clock is
really running such frequency or is it even enabled.

Get the provided clock and check it frequency.  If none is provided,
fall back to old property.

Enable the clock when accessing the IMX258 registers and when streaming
starts.

Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
---
 drivers/media/i2c/imx258.c | 107 ++++++++++++++++++++++++++++++-------
 1 file changed, 87 insertions(+), 20 deletions(-)

diff --git a/drivers/media/i2c/imx258.c b/drivers/media/i2c/imx258.c
index c20bac9b00ec..4d763dcabb1d 100644
--- a/drivers/media/i2c/imx258.c
+++ b/drivers/media/i2c/imx258.c
@@ -2,6 +2,7 @@
 // Copyright (C) 2018 Intel Corporation
 
 #include <linux/acpi.h>
+#include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
@@ -68,6 +69,9 @@
 #define REG_CONFIG_MIRROR_FLIP		0x03
 #define REG_CONFIG_FLIP_TEST_PATTERN	0x02
 
+/* Input clock frequency in Hz */
+#define IMX258_INPUT_CLOCK_FREQ		19200000
+
 struct imx258_reg {
 	u16 address;
 	u8 val;
@@ -610,6 +614,8 @@ struct imx258 {
 
 	/* Streaming on/off */
 	bool streaming;
+
+	struct clk *clk;
 };
 
 static inline struct imx258 *to_imx258(struct v4l2_subdev *_sd)
@@ -747,6 +753,12 @@ static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
 	if (pm_runtime_get_if_in_use(&client->dev) == 0)
 		return 0;
 
+	ret = clk_prepare_enable(imx258->clk);
+	if (ret) {
+		dev_err(&client->dev, "failed to enable clock\n");
+		goto out;
+	}
+
 	switch (ctrl->id) {
 	case V4L2_CID_ANALOGUE_GAIN:
 		ret = imx258_write_reg(imx258, IMX258_REG_ANALOG_GAIN,
@@ -779,6 +791,8 @@ static int imx258_set_ctrl(struct v4l2_ctrl *ctrl)
 		break;
 	}
 
+out:
+	clk_disable_unprepare(imx258->clk);
 	pm_runtime_put(&client->dev);
 
 	return ret;
@@ -972,10 +986,40 @@ static int imx258_stop_streaming(struct imx258 *imx258)
 	return 0;
 }
 
+static int imx258_power_on(struct imx258 *imx258)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&imx258->sd);
+	int ret;
+
+	ret = pm_runtime_get_sync(&client->dev);
+	if (ret < 0)
+		goto err;
+
+	ret = clk_prepare_enable(imx258->clk);
+	if (ret) {
+		dev_err(&client->dev, "failed to enable clock\n");
+		goto err;
+	}
+
+	return 0;
+
+err:
+	pm_runtime_put_noidle(&client->dev);
+
+	return ret;
+}
+
+static void imx258_power_off(struct imx258 *imx258)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&imx258->sd);
+
+	clk_disable_unprepare(imx258->clk);
+	pm_runtime_put(&client->dev);
+}
+
 static int imx258_set_stream(struct v4l2_subdev *sd, int enable)
 {
 	struct imx258 *imx258 = to_imx258(sd);
-	struct i2c_client *client = v4l2_get_subdevdata(sd);
 	int ret = 0;
 
 	mutex_lock(&imx258->mutex);
@@ -985,11 +1029,9 @@ static int imx258_set_stream(struct v4l2_subdev *sd, int enable)
 	}
 
 	if (enable) {
-		ret = pm_runtime_get_sync(&client->dev);
-		if (ret < 0) {
-			pm_runtime_put_noidle(&client->dev);
+		ret = imx258_power_on(imx258);
+		if (ret < 0)
 			goto err_unlock;
-		}
 
 		/*
 		 * Apply default & customized values
@@ -997,10 +1039,10 @@ static int imx258_set_stream(struct v4l2_subdev *sd, int enable)
 		 */
 		ret = imx258_start_streaming(imx258);
 		if (ret)
-			goto err_rpm_put;
+			goto err_power_off;
 	} else {
 		imx258_stop_streaming(imx258);
-		pm_runtime_put(&client->dev);
+		imx258_power_off(imx258);
 	}
 
 	imx258->streaming = enable;
@@ -1008,8 +1050,8 @@ static int imx258_set_stream(struct v4l2_subdev *sd, int enable)
 
 	return ret;
 
-err_rpm_put:
-	pm_runtime_put(&client->dev);
+err_power_off:
+	imx258_power_off(imx258);
 err_unlock:
 	mutex_unlock(&imx258->mutex);
 
@@ -1201,21 +1243,41 @@ static int imx258_probe(struct i2c_client *client)
 	int ret;
 	u32 val = 0;
 
-	device_property_read_u32(&client->dev, "clock-frequency", &val);
-	if (val != 19200000)
-		return -EINVAL;
+	imx258 = devm_kzalloc(&client->dev, sizeof(*imx258), GFP_KERNEL);
+	if (!imx258)
+		return -ENOMEM;
+
+	imx258->clk = devm_clk_get_optional(&client->dev, NULL);
+	if (!imx258->clk) {
+		dev_info(&client->dev, "no clock provided, using clock-frequency property\n");
+
+		device_property_read_u32(&client->dev, "clock-frequency", &val);
+		if (val != IMX258_INPUT_CLOCK_FREQ)
+			return -EINVAL;
+	} else if (IS_ERR(imx258->clk)) {
+		return dev_err_probe(&client->dev, PTR_ERR(imx258->clk), "error getting clock\n");
+	} else {
+		if (clk_get_rate(imx258->clk) != IMX258_INPUT_CLOCK_FREQ) {
+			dev_err(&client->dev, "input clock frequency not supported\n");
+			return -EINVAL;
+		}
+
+		ret = clk_prepare_enable(imx258->clk);
+		if (ret) {
+			dev_err(&client->dev, "failed to enable clock\n");
+			return ret;
+		}
+	}
 
 	/*
 	 * Check that the device is mounted upside down. The driver only
 	 * supports a single pixel order right now.
 	 */
 	ret = device_property_read_u32(&client->dev, "rotation", &val);
-	if (ret || val != 180)
-		return -EINVAL;
-
-	imx258 = devm_kzalloc(&client->dev, sizeof(*imx258), GFP_KERNEL);
-	if (!imx258)
-		return -ENOMEM;
+	if (ret || val != 180) {
+		ret = -EINVAL;
+		goto error_prop_read;
+	}
 
 	/* Initialize subdev */
 	v4l2_i2c_subdev_init(&imx258->sd, client, &imx258_subdev_ops);
@@ -1223,14 +1285,14 @@ static int imx258_probe(struct i2c_client *client)
 	/* Check module identity */
 	ret = imx258_identify_module(imx258);
 	if (ret)
-		return ret;
+		goto error_prop_read;
 
 	/* Set default mode to max resolution */
 	imx258->cur_mode = &supported_modes[0];
 
 	ret = imx258_init_controls(imx258);
 	if (ret)
-		return ret;
+		goto error_prop_read;
 
 	/* Initialize subdev */
 	imx258->sd.internal_ops = &imx258_internal_ops;
@@ -1252,8 +1314,13 @@ static int imx258_probe(struct i2c_client *client)
 	pm_runtime_enable(&client->dev);
 	pm_runtime_idle(&client->dev);
 
+	clk_disable_unprepare(imx258->clk);
+
 	return 0;
 
+error_prop_read:
+	clk_disable_unprepare(imx258->clk);
+
 error_media_entity:
 	media_entity_cleanup(&imx258->sd.entity);
 
-- 
2.17.1