[PATCH v4 4/6] media: i2c: og01a1b: Add support of xvclk supply clock in power management

[Vladimir Zapolskiy <vladimir.zapolskiy@xxxxxxxxxx>]

The OmniVision OG01A1B camera sensor has an xvclk supply clock, which
could be described and then explicitly controlled on OF platforms.

Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@xxxxxxxxxx>
---
 drivers/media/i2c/og01a1b.c | 46 ++++++++++++++++++++++++++++++++-----
 1 file changed, 40 insertions(+), 6 deletions(-)

diff --git a/drivers/media/i2c/og01a1b.c b/drivers/media/i2c/og01a1b.c
index d993ef4bad46..406847d18062 100644
--- a/drivers/media/i2c/og01a1b.c
+++ b/drivers/media/i2c/og01a1b.c
@@ -3,6 +3,7 @@
 
 #include <asm/unaligned.h>
 #include <linux/acpi.h>
+#include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
@@ -418,6 +419,8 @@ static const struct og01a1b_mode supported_modes[] = {
 };
 
 struct og01a1b {
+	struct clk *xvclk;
+
 	struct v4l2_subdev sd;
 	struct media_pad pad;
 	struct v4l2_ctrl_handler ctrl_handler;
@@ -898,8 +901,10 @@ static int og01a1b_identify_module(struct og01a1b *og01a1b)
 	return 0;
 }
 
-static int og01a1b_check_hwcfg(struct device *dev)
+static int og01a1b_check_hwcfg(struct og01a1b *og01a1b)
 {
+	struct i2c_client *client = v4l2_get_subdevdata(&og01a1b->sd);
+	struct device *dev = &client->dev;
 	struct fwnode_handle *ep;
 	struct fwnode_handle *fwnode = dev_fwnode(dev);
 	struct v4l2_fwnode_endpoint bus_cfg = {
@@ -913,10 +918,13 @@ static int og01a1b_check_hwcfg(struct device *dev)
 		return -ENXIO;
 
 	ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
-
 	if (ret) {
-		dev_err(dev, "can't get clock frequency");
-		return ret;
+		if (!og01a1b->xvclk) {
+			dev_err(dev, "can't get clock frequency");
+			return ret;
+		}
+
+		mclk = clk_get_rate(og01a1b->xvclk);
 	}
 
 	if (mclk != OG01A1B_MCLK) {
@@ -970,13 +978,32 @@ static int og01a1b_check_hwcfg(struct device *dev)
 /* Power/clock management functions */
 static int og01a1b_power_on(struct device *dev)
 {
-	/* Device is already turned on by i2c-core with ACPI domain PM. */
+	unsigned long delay = DIV_ROUND_UP(8192 * USEC_PER_SEC, OG01A1B_MCLK);
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct og01a1b *og01a1b = to_og01a1b(sd);
+	int ret;
+
+	ret = clk_prepare_enable(og01a1b->xvclk);
+	if (ret)
+		return ret;
+
+	if (og01a1b->xvclk)
+		usleep_range(delay, 2 * delay);
 
 	return 0;
 }
 
 static int og01a1b_power_off(struct device *dev)
 {
+	unsigned long delay = DIV_ROUND_UP(512 * USEC_PER_SEC, OG01A1B_MCLK);
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct og01a1b *og01a1b = to_og01a1b(sd);
+
+	if (og01a1b->xvclk)
+		usleep_range(delay, 2 * delay);
+
+	clk_disable_unprepare(og01a1b->xvclk);
+
 	return 0;
 }
 
@@ -1003,7 +1030,14 @@ static int og01a1b_probe(struct i2c_client *client)
 
 	v4l2_i2c_subdev_init(&og01a1b->sd, client, &og01a1b_subdev_ops);
 
-	ret = og01a1b_check_hwcfg(&client->dev);
+	og01a1b->xvclk = devm_clk_get_optional(&client->dev, NULL);
+	if (IS_ERR(og01a1b->xvclk)) {
+		ret = PTR_ERR(og01a1b->xvclk);
+		dev_err(&client->dev, "failed to get xvclk clock: %d\n", ret);
+		return ret;
+	}
+
+	ret = og01a1b_check_hwcfg(og01a1b);
 	if (ret) {
 		dev_err(&client->dev, "failed to check HW configuration: %d",
 			ret);
-- 
2.45.2