Re: [PATCH v7 2/4] media: ov5675: add device-tree support and support runtime PM

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Hi Jacopo,

On 7/6/22 09:30, Jacopo Mondi wrote:
Hi Quentin,

On Wed, Jun 08, 2022 at 03:44:18PM +0200, Quentin Schulz wrote:
From: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxxxxx>

Until now, this driver only supported ACPI. This adds support for
Device Tree too while enabling clock and regulators in runtime PM.

Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxxxxx>
---


seems like my r-b tag has been dropped from v7.

Any major change or it just slipped ?


No change at all, should have been there. Sorry for the oversight.

Cheers,
Quentin

Thanks
    j

v6:
  - inverted-xmas-tree ordering,
  - space alignment instead of tab after data type for clk and
  reset_gpio,
  - added pm_runtime_set_suspended to remove callback as suggested by
  Tommaso (please cc the mailing list next time too so everyone can
  benefit from your reviews :) ),
  c.f. https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.linuxfoundation.org_pipermail_linux-2Dpm_2012-2DJuly_034705.html&d=DwIBaQ&c=_sEr5x9kUWhuk4_nFwjJtA&r=LYjLexDn7rXIzVmkNPvw5ymA1XTSqHGq8yBP6m6qZZ4njZguQhZhkI_-172IIy1t&m=UUADoiN42MXp9pWA9wFQ7vAh8Y0-KlDmQVDA99hi5PBxa7lQPePNq2BuvpIeouvb&s=-NnrgHuWYBKbBeigK_pvYkeHUm1rGSe0l0Gb0HajSUc&e=
  - added Reviewed-by,

v5:
  - fixed -Wdeclaration-after-statement for delay_us,

v4:
  - added delays based on clock cycles as specified in datasheet for
  pre-power-off and post-power-on,
  - re-arranged clk handling, shutdown toggling and regulator handling to
  better match power up/down sequence defined in datasheet,
  - added comment on need for regulator being stable before releasing
  shutdown pin,

v3:
  - added linux/mod_devicetable.h include,
  - moved delay for reset pulse right after the regulators are enabled,
  - removed check on is_acpi_node in favor of checks on presence of OF
  properties (e.g. devm_clk_get_optional returns NULL),
  - moved power management out of system suspend/resume into runtime PM
  callbacks,
  - removed ACPI specific comment since it's not specific to this driver,
  - changed devm_clk_get to devm_clk_get_optional,
  - remove OF use of clock-frequency (handled by devm_clk_get_optional
  directly),
  - removed name of clock (only one, so no need for anything explicit)
  when requesting a clock from OF,
  - wrapped lines to 80 chars,

v2:
  - fixed unused-const-variable warning by removing of_match_ptr in
  of_match_table, reported by kernel test robot,
  drivers/media/i2c/ov5675.c | 150 +++++++++++++++++++++++++++++++------
  1 file changed, 129 insertions(+), 21 deletions(-)

diff --git a/drivers/media/i2c/ov5675.c b/drivers/media/i2c/ov5675.c
index 82ba9f56baec..e671fb24ebb4 100644
--- a/drivers/media/i2c/ov5675.c
+++ b/drivers/media/i2c/ov5675.c
@@ -3,10 +3,14 @@

  #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/mod_devicetable.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>
@@ -17,7 +21,7 @@

  #define OV5675_LINK_FREQ_450MHZ		450000000ULL
  #define OV5675_SCLK			90000000LL
-#define OV5675_MCLK			19200000
+#define OV5675_XVCLK_19_2		19200000
  #define OV5675_DATA_LANES		2
  #define OV5675_RGB_DEPTH		10

@@ -76,6 +80,14 @@

  #define to_ov5675(_sd)			container_of(_sd, struct ov5675, sd)

+static const char * const ov5675_supply_names[] = {
+	"avdd",		/* Analog power */
+	"dovdd",	/* Digital I/O power */
+	"dvdd",		/* Digital core power */
+};
+
+#define OV5675_NUM_SUPPLIES	ARRAY_SIZE(ov5675_supply_names)
+
  enum {
  	OV5675_LINK_FREQ_900MBPS,
  };
@@ -484,6 +496,9 @@ struct ov5675 {
  	struct v4l2_subdev sd;
  	struct media_pad pad;
  	struct v4l2_ctrl_handler ctrl_handler;
+	struct clk *xvclk;
+	struct gpio_desc *reset_gpio;
+	struct regulator_bulk_data supplies[OV5675_NUM_SUPPLIES];

  	/* V4L2 Controls */
  	struct v4l2_ctrl *link_freq;
@@ -944,6 +959,56 @@ static int ov5675_set_stream(struct v4l2_subdev *sd, int enable)
  	return ret;
  }

+static int ov5675_power_off(struct device *dev)
+{
+	/* 512 xvclk cycles after the last SCCB transation or MIPI frame end */
+	u32 delay_us = DIV_ROUND_UP(512, OV5675_XVCLK_19_2 / 1000 / 1000);
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct ov5675 *ov5675 = to_ov5675(sd);
+
+	usleep_range(delay_us, delay_us * 2);
+
+	clk_disable_unprepare(ov5675->xvclk);
+	gpiod_set_value_cansleep(ov5675->reset_gpio, 1);
+	regulator_bulk_disable(OV5675_NUM_SUPPLIES, ov5675->supplies);
+
+	return 0;
+}
+
+static int ov5675_power_on(struct device *dev)
+{
+	u32 delay_us = DIV_ROUND_UP(8192, OV5675_XVCLK_19_2 / 1000 / 1000);
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct ov5675 *ov5675 = to_ov5675(sd);
+	int ret;
+
+	ret = clk_prepare_enable(ov5675->xvclk);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable xvclk: %d\n", ret);
+		return ret;
+	}
+
+	gpiod_set_value_cansleep(ov5675->reset_gpio, 1);
+
+	ret = regulator_bulk_enable(OV5675_NUM_SUPPLIES, ov5675->supplies);
+	if (ret) {
+		clk_disable_unprepare(ov5675->xvclk);
+		return ret;
+	}
+
+	/* Reset pulse should be at least 2ms and reset gpio released only once
+	 * regulators are stable.
+	 */
+	usleep_range(2000, 2200);
+
+	gpiod_set_value_cansleep(ov5675->reset_gpio, 0);
+
+	/* 8192 xvclk cycles prior to the first SCCB transation */
+	usleep_range(delay_us, delay_us * 2);
+
+	return 0;
+}
+
  static int __maybe_unused ov5675_suspend(struct device *dev)
  {
  	struct v4l2_subdev *sd = dev_get_drvdata(dev);
@@ -1106,32 +1171,60 @@ static const struct v4l2_subdev_internal_ops ov5675_internal_ops = {
  	.open = ov5675_open,
  };

-static int ov5675_check_hwcfg(struct device *dev)
+static int ov5675_get_hwcfg(struct ov5675 *ov5675, struct device *dev)
  {
  	struct fwnode_handle *ep;
  	struct fwnode_handle *fwnode = dev_fwnode(dev);
  	struct v4l2_fwnode_endpoint bus_cfg = {
  		.bus_type = V4L2_MBUS_CSI2_DPHY
  	};
-	u32 mclk;
+	u32 xvclk_rate;
  	int ret;
  	unsigned int i, j;

  	if (!fwnode)
  		return -ENXIO;

-	ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
+	ov5675->xvclk = devm_clk_get_optional(dev, NULL);
+	if (IS_ERR(ov5675->xvclk))
+		return dev_err_probe(dev, PTR_ERR(ov5675->xvclk),
+				     "failed to get xvclk: %ld\n",
+				     PTR_ERR(ov5675->xvclk));

-	if (ret) {
-		dev_err(dev, "can't get clock frequency");
-		return ret;
+	if (ov5675->xvclk) {
+		xvclk_rate = clk_get_rate(ov5675->xvclk);
+	} else {
+		ret = fwnode_property_read_u32(fwnode, "clock-frequency",
+					       &xvclk_rate);
+
+		if (ret) {
+			dev_err(dev, "can't get clock frequency");
+			return ret;
+		}
  	}

-	if (mclk != OV5675_MCLK) {
-		dev_err(dev, "external clock %d is not supported", mclk);
+	if (xvclk_rate != OV5675_XVCLK_19_2) {
+		dev_err(dev, "external clock rate %u is unsupported",
+			xvclk_rate);
  		return -EINVAL;
  	}

+	ov5675->reset_gpio = devm_gpiod_get_optional(dev, "reset",
+						     GPIOD_OUT_HIGH);
+	if (IS_ERR(ov5675->reset_gpio)) {
+		ret = PTR_ERR(ov5675->reset_gpio);
+		dev_err(dev, "failed to get reset-gpios: %d\n", ret);
+		return ret;
+	}
+
+	for (i = 0; i < OV5675_NUM_SUPPLIES; i++)
+		ov5675->supplies[i].supply = ov5675_supply_names[i];
+
+	ret = devm_regulator_bulk_get(dev, OV5675_NUM_SUPPLIES,
+				      ov5675->supplies);
+	if (ret)
+		return ret;
+
  	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
  	if (!ep)
  		return -ENXIO;
@@ -1186,6 +1279,10 @@ static int ov5675_remove(struct i2c_client *client)
  	pm_runtime_disable(&client->dev);
  	mutex_destroy(&ov5675->mutex);

+	if (!pm_runtime_status_suspended(&client->dev))
+		ov5675_power_off(&client->dev);
+	pm_runtime_set_suspended(&client->dev);
+
  	return 0;
  }

@@ -1195,25 +1292,31 @@ static int ov5675_probe(struct i2c_client *client)
  	bool full_power;
  	int ret;

-	ret = ov5675_check_hwcfg(&client->dev);
+	ov5675 = devm_kzalloc(&client->dev, sizeof(*ov5675), GFP_KERNEL);
+	if (!ov5675)
+		return -ENOMEM;
+
+	ret = ov5675_get_hwcfg(ov5675, &client->dev);
  	if (ret) {
-		dev_err(&client->dev, "failed to check HW configuration: %d",
+		dev_err(&client->dev, "failed to get HW configuration: %d",
  			ret);
  		return ret;
  	}

-	ov5675 = devm_kzalloc(&client->dev, sizeof(*ov5675), GFP_KERNEL);
-	if (!ov5675)
-		return -ENOMEM;
-
  	v4l2_i2c_subdev_init(&ov5675->sd, client, &ov5675_subdev_ops);

+	ret = ov5675_power_on(&client->dev);
+	if (ret) {
+		dev_err(&client->dev, "failed to power on: %d\n", ret);
+		return ret;
+	}
+
  	full_power = acpi_dev_state_d0(&client->dev);
  	if (full_power) {
  		ret = ov5675_identify_module(ov5675);
  		if (ret) {
  			dev_err(&client->dev, "failed to find sensor: %d", ret);
-			return ret;
+			goto probe_power_off;
  		}
  	}

@@ -1243,11 +1346,6 @@ static int ov5675_probe(struct i2c_client *client)
  		goto probe_error_media_entity_cleanup;
  	}

-	/*
-	 * Device is already turned on by i2c-core with ACPI domain PM.
-	 * Enable runtime PM and turn off the device.
-	 */
-
  	/* Set the device's state to active if it's in D0 state. */
  	if (full_power)
  		pm_runtime_set_active(&client->dev);
@@ -1262,12 +1360,15 @@ static int ov5675_probe(struct i2c_client *client)
  probe_error_v4l2_ctrl_handler_free:
  	v4l2_ctrl_handler_free(ov5675->sd.ctrl_handler);
  	mutex_destroy(&ov5675->mutex);
+probe_power_off:
+	ov5675_power_off(&client->dev);

  	return ret;
  }

  static const struct dev_pm_ops ov5675_pm_ops = {
  	SET_SYSTEM_SLEEP_PM_OPS(ov5675_suspend, ov5675_resume)
+	SET_RUNTIME_PM_OPS(ov5675_power_off, ov5675_power_on, NULL)
  };

  #ifdef CONFIG_ACPI
@@ -1279,11 +1380,18 @@ static const struct acpi_device_id ov5675_acpi_ids[] = {
  MODULE_DEVICE_TABLE(acpi, ov5675_acpi_ids);
  #endif

+static const struct of_device_id ov5675_of_match[] = {
+	{ .compatible = "ovti,ov5675", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ov5675_of_match);
+
  static struct i2c_driver ov5675_i2c_driver = {
  	.driver = {
  		.name = "ov5675",
  		.pm = &ov5675_pm_ops,
  		.acpi_match_table = ACPI_PTR(ov5675_acpi_ids),
+		.of_match_table = ov5675_of_match,
  	},
  	.probe_new = ov5675_probe,
  	.remove = ov5675_remove,
--
2.36.1




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