[v2 2/3] media: ov8856: Add devicetree support

[Robert Foss <robert.foss@linaro.org>]

Add devicetree match table, and enable ov8856_probe()
to initialize power, clocks and reset pins.

Signed-off-by: Robert Foss <robert.foss@linaro.org>
---

- Changes since v1:
  * Fabio: Change n_shutdown_gpio name to reset_gpio
  * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH -> GPIO_ACTIVE_LOW change
  * Fabio: Remove empty line
  * Fabio: Remove real error from devm_gpiod_get() failures
  * Andy & Sakari: Make XVCLK optional since to not break ACPI
  * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
  * Sakari: Use XVCLK rate as provided by DT

 drivers/media/i2c/ov8856.c | 109 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 107 insertions(+), 2 deletions(-)

diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
index 8655842af275..db61eed223e8 100644
--- a/drivers/media/i2c/ov8856.c
+++ b/drivers/media/i2c/ov8856.c
@@ -3,10 +3,13 @@
 
 #include <asm/unaligned.h>
 #include <linux/acpi.h>
+#include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-fwnode.h>
@@ -19,6 +22,8 @@
 #define OV8856_LINK_FREQ_180MHZ		180000000ULL
 #define OV8856_SCLK			144000000ULL
 #define OV8856_MCLK			19200000
+#define OV8856_XVCLK_19_2		19200000
+#define OV8856_XVCLK_24			24000000
 #define OV8856_DATA_LANES		4
 #define OV8856_RGB_DEPTH		10
 
@@ -64,6 +69,12 @@
 
 #define to_ov8856(_sd)			container_of(_sd, struct ov8856, sd)
 
+static const char * const ov8856_supply_names[] = {
+	"dovdd",	/* Digital I/O power */
+	"avdd",		/* Analog power */
+	"dvdd",		/* Digital core power */
+};
+
 enum {
 	OV8856_LINK_FREQ_720MBPS,
 	OV8856_LINK_FREQ_360MBPS,
@@ -566,6 +577,10 @@ struct ov8856 {
 	struct media_pad pad;
 	struct v4l2_ctrl_handler ctrl_handler;
 
+	struct clk		*xvclk;
+	struct gpio_desc	*reset_gpio;
+	struct regulator_bulk_data supplies[ARRAY_SIZE(ov8856_supply_names)];
+
 	/* V4L2 Controls */
 	struct v4l2_ctrl *link_freq;
 	struct v4l2_ctrl *pixel_rate;
@@ -908,6 +923,46 @@ static int ov8856_set_stream(struct v4l2_subdev *sd, int enable)
 	return ret;
 }
 
+static int __ov8856_power_on(struct ov8856 *ov8856)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
+	int ret;
+
+	ret = clk_prepare_enable(ov8856->xvclk);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed to enable xvclk\n");
+		return ret;
+	}
+
+	gpiod_set_value_cansleep(ov8856->reset_gpio, GPIOD_OUT_HIGH);
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
+				    ov8856->supplies);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed to enable regulators\n");
+		goto disable_clk;
+	}
+
+	gpiod_set_value_cansleep(ov8856->reset_gpio, GPIOD_OUT_LOW);
+
+	usleep_range(1500, 1800);
+
+	return 0;
+
+disable_clk:
+	clk_disable_unprepare(ov8856->xvclk);
+
+	return ret;
+}
+
+static void __ov8856_power_off(struct ov8856 *ov8856)
+{
+	gpiod_set_value_cansleep(ov8856->reset_gpio, GPIOD_OUT_HIGH);
+	regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
+			       ov8856->supplies);
+	clk_disable_unprepare(ov8856->xvclk);
+}
+
 static int __maybe_unused ov8856_suspend(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
@@ -1175,7 +1230,7 @@ static int ov8856_remove(struct i2c_client *client)
 static int ov8856_probe(struct i2c_client *client)
 {
 	struct ov8856 *ov8856;
-	int ret;
+	int i, ret;
 
 	ret = ov8856_check_hwcfg(&client->dev);
 	if (ret) {
@@ -1189,10 +1244,50 @@ static int ov8856_probe(struct i2c_client *client)
 		return -ENOMEM;
 
 	v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
+	ov8856->xvclk = devm_clk_get(&client->dev, "xvclk");
+	if (PTR_ERR(ov8856->xvclk) == -ENOENT) {
+		dev_info(&client->dev, "xvclk clock not defined, continuing...\n");
+		ov8856->xvclk = NULL;
+	} else if (IS_ERR(ov8856->xvclk)) {
+		dev_err(&client->dev, "could not get xvclk clock (%ld)\n",
+			PTR_ERR(ov8856->xvclk));
+		return PTR_ERR(ov8856->xvclk);
+	}
+
+	ret = clk_set_rate(ov8856->xvclk, OV8856_XVCLK_24);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed to set xvclk rate (24MHz)\n");
+		return ret;
+	}
+
+	ov8856->reset_gpio = devm_gpiod_get(&client->dev, "reset",
+					       GPIOD_OUT_HIGH);
+	if (IS_ERR(ov8856->reset_gpio)) {
+		dev_err(&client->dev, "failed to get reset-gpios\n");
+		return PTR_ERR(ov8856->reset_gpio);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(ov8856_supply_names); i++)
+		ov8856->supplies[i].supply = ov8856_supply_names[i];
+
+	ret = devm_regulator_bulk_get(&client->dev,
+				      ARRAY_SIZE(ov8856_supply_names),
+				      ov8856->supplies);
+	if (ret) {
+		dev_warn(&client->dev, "failed to get regulators\n");
+		return ret;
+	}
+
+	ret = __ov8856_power_on(ov8856);
+	if (ret) {
+		dev_warn(&client->dev, "failed to power on\n");
+		return ret;
+	}
+
 	ret = ov8856_identify_module(ov8856);
 	if (ret) {
 		dev_err(&client->dev, "failed to find sensor: %d", ret);
-		return ret;
+		goto probe_power_off;
 	}
 
 	mutex_init(&ov8856->mutex);
@@ -1238,6 +1333,9 @@ static int ov8856_probe(struct i2c_client *client)
 	v4l2_ctrl_handler_free(ov8856->sd.ctrl_handler);
 	mutex_destroy(&ov8856->mutex);
 
+probe_power_off:
+	__ov8856_power_off(ov8856);
+
 	return ret;
 }
 
@@ -1254,11 +1352,18 @@ static const struct acpi_device_id ov8856_acpi_ids[] = {
 MODULE_DEVICE_TABLE(acpi, ov8856_acpi_ids);
 #endif
 
+static const struct of_device_id ov8856_of_match[] = {
+	{ .compatible = "ovti,ov8856" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ov8856_of_match);
+
 static struct i2c_driver ov8856_i2c_driver = {
 	.driver = {
 		.name = "ov8856",
 		.pm = &ov8856_pm_ops,
 		.acpi_match_table = ACPI_PTR(ov8856_acpi_ids),
+		.of_match_table = ov8856_of_match,
 	},
 	.probe_new = ov8856_probe,
 	.remove = ov8856_remove,
-- 
2.20.1