diff mbox series

[v6,2/3] media: ov8856: Add devicetree support

Message ID 20200429162437.2025699-3-robert.foss@linaro.org (mailing list archive)
State Superseded
Headers show
Series media: ov8856: Add devicetree support | expand

Commit Message

Robert Foss April 29, 2020, 4:24 p.m. UTC
Add match table, enable ov8856_probe() to support
both ACPI and DT modes.

ACPI and DT modes are primarily distinguished from
each other by relying on devm_XXX_get_optional()
will return NULL instead of a reference for the
desired managed resource.

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

- Changes since v5:
  * Maxime & Sakari: Replaced clock tolerance check with warning

- Changes since v4:
  * Maxime & Sakari: Switch to clock-frequency

- Changes since v3:
  * Remove redundant {}-brackets
  * Compare xvclk_rate to 5% tolerance
  * Andy: Use dev_fwnode()
  * Andy: Use %pe instead of %ld + PTR_ERR()
  * Andy: Invert reset_gpio logic
  * Andy: Remove dev_dbg() from failing reset_gpio setup
  * Andy: Use dev_err for logging for failures
  * Andy: Remove dev_warn from EDEFER/regulator error path
  * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
  * Maxime & Sakari: Verify clock frequency from DT
  * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
  * Sakari: Remove duplicate ov8856->dev assignment

- Changes since v2:
  * Added "struct device *dev" member to struct ov8856
  * Andy: Switch to optional version of devm_gpiod_get
  * Andy: Switch to optional version of devm_clk_get
  * Fabio: Add reset sleep period
  * Sakari: Unify defines for 19.2Mhz
  * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
  * Sakari: Replace dev_info() with dev_dbg()
  * Sakari: Switch induction variable type to unsigned
  * Sakari: Don't wait for reset_gpio when in ACPI mode
  * Sakari: Pull reset GPIO high on power on failure
  * Sakari: Add power on/off to resume/suspend
  * Sakari: Fix indentation
  * Sakari: Power off during ov8856_remove()
  * Sakari: Don't sleep during power-on in ACPI mode
  * Sakari: Switch to getting xvclk from clk_get_rate

- Changes since v1:
  * Andy & Sakari: Make XVCLK optional since to not break ACPI
  * 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
  * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
  * Sakari: Use XVCLK rate as provided by DT

 drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
 1 file changed, 123 insertions(+), 14 deletions(-)

Comments

Marco Felsch April 30, 2020, 9:35 a.m. UTC | #1
Hi Robert,

thnakf for the patch but pls keep in mind to do one thing per patch.
IMHO this patch do a lot more. Anyway below are my comment :)

On 20-04-29 18:24, Robert Foss wrote:
> Add match table, enable ov8856_probe() to support
> both ACPI and DT modes.

You are also adding the support for reset-gpios and regualtors. IMHO the
commit message don't belong to the changes you made anymore.

> ACPI and DT modes are primarily distinguished from
> each other by relying on devm_XXX_get_optional()
> will return NULL instead of a reference for the
> desired managed resource.
> 
> Signed-off-by: Robert Foss <robert.foss@linaro.org>
> ---
> 
> - Changes since v5:
>   * Maxime & Sakari: Replaced clock tolerance check with warning
> 
> - Changes since v4:
>   * Maxime & Sakari: Switch to clock-frequency
> 
> - Changes since v3:
>   * Remove redundant {}-brackets
>   * Compare xvclk_rate to 5% tolerance
>   * Andy: Use dev_fwnode()
>   * Andy: Use %pe instead of %ld + PTR_ERR()
>   * Andy: Invert reset_gpio logic
>   * Andy: Remove dev_dbg() from failing reset_gpio setup
>   * Andy: Use dev_err for logging for failures
>   * Andy: Remove dev_warn from EDEFER/regulator error path
>   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
>   * Maxime & Sakari: Verify clock frequency from DT
>   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
>   * Sakari: Remove duplicate ov8856->dev assignment
> 
> - Changes since v2:
>   * Added "struct device *dev" member to struct ov8856
>   * Andy: Switch to optional version of devm_gpiod_get
>   * Andy: Switch to optional version of devm_clk_get
>   * Fabio: Add reset sleep period
>   * Sakari: Unify defines for 19.2Mhz
>   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
>   * Sakari: Replace dev_info() with dev_dbg()
>   * Sakari: Switch induction variable type to unsigned
>   * Sakari: Don't wait for reset_gpio when in ACPI mode
>   * Sakari: Pull reset GPIO high on power on failure
>   * Sakari: Add power on/off to resume/suspend
>   * Sakari: Fix indentation
>   * Sakari: Power off during ov8856_remove()
>   * Sakari: Don't sleep during power-on in ACPI mode
>   * Sakari: Switch to getting xvclk from clk_get_rate
> 
> - Changes since v1:
>   * Andy & Sakari: Make XVCLK optional since to not break ACPI
>   * 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
>   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
>   * Sakari: Use XVCLK rate as provided by DT
> 
>  drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
>  1 file changed, 123 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> index 8655842af275..4749dc74d5ad 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>
> @@ -18,7 +21,7 @@
>  #define OV8856_LINK_FREQ_360MHZ		360000000ULL
>  #define OV8856_LINK_FREQ_180MHZ		180000000ULL
>  #define OV8856_SCLK			144000000ULL
> -#define OV8856_MCLK			19200000
> +#define OV8856_XVCLK_19_2		19200000
>  #define OV8856_DATA_LANES		4
>  #define OV8856_RGB_DEPTH		10
>  
> @@ -64,6 +67,12 @@
>  
>  #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 +575,11 @@ struct ov8856 {
>  	struct media_pad pad;
>  	struct v4l2_ctrl_handler ctrl_handler;
>  
> +	struct device		*dev;
> +	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 +922,52 @@ 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);

You're request the clk only in DT case or do I miss something? If so you
have to check if the clk is available.

> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to enable xvclk\n");
> +		return ret;
> +	}
> +
> +	if (is_acpi_node(dev_fwnode(ov8856->dev)))
> +		return 0;
> +
> +	if (ov8856->reset_gpio) {
> +		gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> +		usleep_range(1000, 2000);
> +	}
> +
> +	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, 0);

You need to check the existance of the gpio here too.

> +	usleep_range(1500, 1800);
> +
> +	return 0;
> +
> +disable_clk:
> +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);

And here.. pls check the whole patch.

> +	clk_disable_unprepare(ov8856->xvclk);
> +
> +	return ret;
> +}
> +
> +static void __ov8856_power_off(struct ov8856 *ov8856)
> +{
> +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> +	regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> +			       ov8856->supplies);
> +	clk_disable_unprepare(ov8856->xvclk);

Clk is only availabel in DT use-case.

> +}
> +
>  static int __maybe_unused ov8856_suspend(struct device *dev)
>  {
>  	struct i2c_client *client = to_i2c_client(dev);
> @@ -918,6 +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev)
>  	if (ov8856->streaming)
>  		ov8856_stop_streaming(ov8856);
>  
> +	__ov8856_power_off(ov8856);
>  	mutex_unlock(&ov8856->mutex);
>  
>  	return 0;
> @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct device *dev)
>  	int ret;
>  
>  	mutex_lock(&ov8856->mutex);
> +
> +	__ov8856_power_on(ov8856);
>  	if (ov8856->streaming) {
>  		ret = ov8856_start_streaming(ov8856);
>  		if (ret) {
> @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
>  	return 0;
>  }
>  
> -static int ov8856_check_hwcfg(struct device *dev)
> +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
>  {
> +	struct device *dev = ov8856->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);
> +	ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> +		&xvclk_rate);
>  	if (ret)
>  		return ret;
>  
> -	if (mclk != OV8856_MCLK) {
> -		dev_err(dev, "external clock %d is not supported", mclk);
> -		return -EINVAL;
> +	if (!is_acpi_node(fwnode)) {
> +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> +		if (IS_ERR(ov8856->xvclk)) {
> +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> +					ov8856->xvclk);
> +			return PTR_ERR(ov8856->xvclk);
> +		}
> +
> +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> +		xvclk_rate = clk_get_rate(ov8856->xvclk);
>  	}

Why do we handle the clock only in DT case? Is there a problem with the
clock handling and ACPI?

> +	if (xvclk_rate != OV8856_XVCLK_19_2)
> +		dev_warn(dev, "external clock rate %d is unsupported", xvclk_rate);
> +
> +	ov8856->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> +		GPIOD_OUT_LOW);

Pls align this.

Regards,
  Marco

> +	if (IS_ERR(ov8856->reset_gpio))
> +		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(dev, ARRAY_SIZE(ov8856_supply_names),
> +				      ov8856->supplies);
> +	if (ret)
> +		return ret;
> +
>  	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
>  	if (!ep)
>  		return -ENXIO;
> @@ -1169,6 +1257,8 @@ static int ov8856_remove(struct i2c_client *client)
>  	pm_runtime_disable(&client->dev);
>  	mutex_destroy(&ov8856->mutex);
>  
> +	__ov8856_power_off(ov8856);
> +
>  	return 0;
>  }
>  
> @@ -1177,22 +1267,31 @@ static int ov8856_probe(struct i2c_client *client)
>  	struct ov8856 *ov8856;
>  	int ret;
>  
> -	ret = ov8856_check_hwcfg(&client->dev);
> +	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> +	if (!ov8856)
> +		return -ENOMEM;
> +
> +	ov8856->dev = &client->dev;
> +
> +	ret = ov8856_get_hwcfg(ov8856);
>  	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;
>  	}
>  
> -	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> -	if (!ov8856)
> -		return -ENOMEM;
> -
>  	v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
> +
> +	ret = __ov8856_power_on(ov8856);
> +	if (ret) {
> +		dev_err(&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 +1337,9 @@ 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 +1356,18 @@ 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,
> -- 
> 2.25.1
>
Sakari Ailus April 30, 2020, 9:45 a.m. UTC | #2
Hi Marco,

On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:
> Hi Robert,
> 
> thnakf for the patch but pls keep in mind to do one thing per patch.
> IMHO this patch do a lot more. Anyway below are my comment :)
> 
> On 20-04-29 18:24, Robert Foss wrote:
> > Add match table, enable ov8856_probe() to support
> > both ACPI and DT modes.
> 
> You are also adding the support for reset-gpios and regualtors. IMHO the
> commit message don't belong to the changes you made anymore.
> 
> > ACPI and DT modes are primarily distinguished from
> > each other by relying on devm_XXX_get_optional()
> > will return NULL instead of a reference for the
> > desired managed resource.
> > 
> > Signed-off-by: Robert Foss <robert.foss@linaro.org>
> > ---
> > 
> > - Changes since v5:
> >   * Maxime & Sakari: Replaced clock tolerance check with warning
> > 
> > - Changes since v4:
> >   * Maxime & Sakari: Switch to clock-frequency
> > 
> > - Changes since v3:
> >   * Remove redundant {}-brackets
> >   * Compare xvclk_rate to 5% tolerance
> >   * Andy: Use dev_fwnode()
> >   * Andy: Use %pe instead of %ld + PTR_ERR()
> >   * Andy: Invert reset_gpio logic
> >   * Andy: Remove dev_dbg() from failing reset_gpio setup
> >   * Andy: Use dev_err for logging for failures
> >   * Andy: Remove dev_warn from EDEFER/regulator error path
> >   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
> >   * Maxime & Sakari: Verify clock frequency from DT
> >   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
> >   * Sakari: Remove duplicate ov8856->dev assignment
> > 
> > - Changes since v2:
> >   * Added "struct device *dev" member to struct ov8856
> >   * Andy: Switch to optional version of devm_gpiod_get
> >   * Andy: Switch to optional version of devm_clk_get
> >   * Fabio: Add reset sleep period
> >   * Sakari: Unify defines for 19.2Mhz
> >   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
> >   * Sakari: Replace dev_info() with dev_dbg()
> >   * Sakari: Switch induction variable type to unsigned
> >   * Sakari: Don't wait for reset_gpio when in ACPI mode
> >   * Sakari: Pull reset GPIO high on power on failure
> >   * Sakari: Add power on/off to resume/suspend
> >   * Sakari: Fix indentation
> >   * Sakari: Power off during ov8856_remove()
> >   * Sakari: Don't sleep during power-on in ACPI mode
> >   * Sakari: Switch to getting xvclk from clk_get_rate
> > 
> > - Changes since v1:
> >   * Andy & Sakari: Make XVCLK optional since to not break ACPI
> >   * 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
> >   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
> >   * Sakari: Use XVCLK rate as provided by DT
> > 
> >  drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
> >  1 file changed, 123 insertions(+), 14 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> > index 8655842af275..4749dc74d5ad 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>
> > @@ -18,7 +21,7 @@
> >  #define OV8856_LINK_FREQ_360MHZ		360000000ULL
> >  #define OV8856_LINK_FREQ_180MHZ		180000000ULL
> >  #define OV8856_SCLK			144000000ULL
> > -#define OV8856_MCLK			19200000
> > +#define OV8856_XVCLK_19_2		19200000
> >  #define OV8856_DATA_LANES		4
> >  #define OV8856_RGB_DEPTH		10
> >  
> > @@ -64,6 +67,12 @@
> >  
> >  #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 +575,11 @@ struct ov8856 {
> >  	struct media_pad pad;
> >  	struct v4l2_ctrl_handler ctrl_handler;
> >  
> > +	struct device		*dev;
> > +	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 +922,52 @@ 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);
> 
> You're request the clk only in DT case or do I miss something? If so you
> have to check if the clk is available.
> 
> > +	if (ret < 0) {
> > +		dev_err(&client->dev, "failed to enable xvclk\n");
> > +		return ret;
> > +	}
> > +
> > +	if (is_acpi_node(dev_fwnode(ov8856->dev)))
> > +		return 0;
> > +
> > +	if (ov8856->reset_gpio) {
> > +		gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +		usleep_range(1000, 2000);
> > +	}
> > +
> > +	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, 0);
> 
> You need to check the existance of the gpio here too.

No need to; the GPIO framework can handle this internally.

> 
> > +	usleep_range(1500, 1800);
> > +
> > +	return 0;
> > +
> > +disable_clk:
> > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> 
> And here.. pls check the whole patch.
> 
> > +	clk_disable_unprepare(ov8856->xvclk);
> > +
> > +	return ret;
> > +}
> > +
> > +static void __ov8856_power_off(struct ov8856 *ov8856)
> > +{
> > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +	regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> > +			       ov8856->supplies);
> > +	clk_disable_unprepare(ov8856->xvclk);
> 
> Clk is only availabel in DT use-case.
> 
> > +}
> > +
> >  static int __maybe_unused ov8856_suspend(struct device *dev)
> >  {
> >  	struct i2c_client *client = to_i2c_client(dev);
> > @@ -918,6 +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev)
> >  	if (ov8856->streaming)
> >  		ov8856_stop_streaming(ov8856);
> >  
> > +	__ov8856_power_off(ov8856);
> >  	mutex_unlock(&ov8856->mutex);
> >  
> >  	return 0;
> > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct device *dev)
> >  	int ret;
> >  
> >  	mutex_lock(&ov8856->mutex);
> > +
> > +	__ov8856_power_on(ov8856);
> >  	if (ov8856->streaming) {
> >  		ret = ov8856_start_streaming(ov8856);
> >  		if (ret) {
> > @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
> >  	return 0;
> >  }
> >  
> > -static int ov8856_check_hwcfg(struct device *dev)
> > +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
> >  {
> > +	struct device *dev = ov8856->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);
> > +	ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> > +		&xvclk_rate);
> >  	if (ret)
> >  		return ret;
> >  
> > -	if (mclk != OV8856_MCLK) {
> > -		dev_err(dev, "external clock %d is not supported", mclk);
> > -		return -EINVAL;
> > +	if (!is_acpi_node(fwnode)) {
> > +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > +		if (IS_ERR(ov8856->xvclk)) {
> > +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> > +					ov8856->xvclk);
> > +			return PTR_ERR(ov8856->xvclk);
> > +		}
> > +
> > +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> > +		xvclk_rate = clk_get_rate(ov8856->xvclk);
> >  	}
> 
> Why do we handle the clock only in DT case? Is there a problem with the
> clock handling and ACPI?

Not really, it's just that ACPI does not provide an interface to the clocks
as such.
Marco Felsch April 30, 2020, 9:53 a.m. UTC | #3
Hi Sakari,

On 20-04-30 12:45, Sakari Ailus wrote:
> Hi Marco,
> 
> On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:
> > Hi Robert,
> > 
> > thnakf for the patch but pls keep in mind to do one thing per patch.
> > IMHO this patch do a lot more. Anyway below are my comment :)
> > 
> > On 20-04-29 18:24, Robert Foss wrote:
> > > Add match table, enable ov8856_probe() to support
> > > both ACPI and DT modes.
> > 
> > You are also adding the support for reset-gpios and regualtors. IMHO the
> > commit message don't belong to the changes you made anymore.
> > 
> > > ACPI and DT modes are primarily distinguished from
> > > each other by relying on devm_XXX_get_optional()
> > > will return NULL instead of a reference for the
> > > desired managed resource.
> > > 
> > > Signed-off-by: Robert Foss <robert.foss@linaro.org>
> > > ---
> > > 
> > > - Changes since v5:
> > >   * Maxime & Sakari: Replaced clock tolerance check with warning
> > > 
> > > - Changes since v4:
> > >   * Maxime & Sakari: Switch to clock-frequency
> > > 
> > > - Changes since v3:
> > >   * Remove redundant {}-brackets
> > >   * Compare xvclk_rate to 5% tolerance
> > >   * Andy: Use dev_fwnode()
> > >   * Andy: Use %pe instead of %ld + PTR_ERR()
> > >   * Andy: Invert reset_gpio logic
> > >   * Andy: Remove dev_dbg() from failing reset_gpio setup
> > >   * Andy: Use dev_err for logging for failures
> > >   * Andy: Remove dev_warn from EDEFER/regulator error path
> > >   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
> > >   * Maxime & Sakari: Verify clock frequency from DT
> > >   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
> > >   * Sakari: Remove duplicate ov8856->dev assignment
> > > 
> > > - Changes since v2:
> > >   * Added "struct device *dev" member to struct ov8856
> > >   * Andy: Switch to optional version of devm_gpiod_get
> > >   * Andy: Switch to optional version of devm_clk_get
> > >   * Fabio: Add reset sleep period
> > >   * Sakari: Unify defines for 19.2Mhz
> > >   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
> > >   * Sakari: Replace dev_info() with dev_dbg()
> > >   * Sakari: Switch induction variable type to unsigned
> > >   * Sakari: Don't wait for reset_gpio when in ACPI mode
> > >   * Sakari: Pull reset GPIO high on power on failure
> > >   * Sakari: Add power on/off to resume/suspend
> > >   * Sakari: Fix indentation
> > >   * Sakari: Power off during ov8856_remove()
> > >   * Sakari: Don't sleep during power-on in ACPI mode
> > >   * Sakari: Switch to getting xvclk from clk_get_rate
> > > 
> > > - Changes since v1:
> > >   * Andy & Sakari: Make XVCLK optional since to not break ACPI
> > >   * 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
> > >   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
> > >   * Sakari: Use XVCLK rate as provided by DT
> > > 
> > >  drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
> > >  1 file changed, 123 insertions(+), 14 deletions(-)
> > > 
> > > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> > > index 8655842af275..4749dc74d5ad 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>
> > > @@ -18,7 +21,7 @@
> > >  #define OV8856_LINK_FREQ_360MHZ		360000000ULL
> > >  #define OV8856_LINK_FREQ_180MHZ		180000000ULL
> > >  #define OV8856_SCLK			144000000ULL
> > > -#define OV8856_MCLK			19200000
> > > +#define OV8856_XVCLK_19_2		19200000
> > >  #define OV8856_DATA_LANES		4
> > >  #define OV8856_RGB_DEPTH		10
> > >  
> > > @@ -64,6 +67,12 @@
> > >  
> > >  #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 +575,11 @@ struct ov8856 {
> > >  	struct media_pad pad;
> > >  	struct v4l2_ctrl_handler ctrl_handler;
> > >  
> > > +	struct device		*dev;
> > > +	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 +922,52 @@ 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);
> > 
> > You're request the clk only in DT case or do I miss something? If so you
> > have to check if the clk is available.
> > 
> > > +	if (ret < 0) {
> > > +		dev_err(&client->dev, "failed to enable xvclk\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	if (is_acpi_node(dev_fwnode(ov8856->dev)))
> > > +		return 0;
> > > +
> > > +	if (ov8856->reset_gpio) {
> > > +		gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > +		usleep_range(1000, 2000);
> > > +	}
> > > +
> > > +	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, 0);
> > 
> > You need to check the existance of the gpio here too.
> 
> No need to; the GPIO framework can handle this internally.

Ahh, I said nothing :) so all my comments about that can be dropped. 

> > > +	usleep_range(1500, 1800);
> > > +
> > > +	return 0;
> > > +
> > > +disable_clk:
> > > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > 
> > And here.. pls check the whole patch.
> > 
> > > +	clk_disable_unprepare(ov8856->xvclk);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static void __ov8856_power_off(struct ov8856 *ov8856)
> > > +{
> > > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > +	regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> > > +			       ov8856->supplies);
> > > +	clk_disable_unprepare(ov8856->xvclk);
> > 
> > Clk is only availabel in DT use-case.
> > 
> > > +}
> > > +
> > >  static int __maybe_unused ov8856_suspend(struct device *dev)
> > >  {
> > >  	struct i2c_client *client = to_i2c_client(dev);
> > > @@ -918,6 +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev)
> > >  	if (ov8856->streaming)
> > >  		ov8856_stop_streaming(ov8856);
> > >  
> > > +	__ov8856_power_off(ov8856);
> > >  	mutex_unlock(&ov8856->mutex);
> > >  
> > >  	return 0;
> > > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct device *dev)
> > >  	int ret;
> > >  
> > >  	mutex_lock(&ov8856->mutex);
> > > +
> > > +	__ov8856_power_on(ov8856);
> > >  	if (ov8856->streaming) {
> > >  		ret = ov8856_start_streaming(ov8856);
> > >  		if (ret) {
> > > @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
> > >  	return 0;
> > >  }
> > >  
> > > -static int ov8856_check_hwcfg(struct device *dev)
> > > +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
> > >  {
> > > +	struct device *dev = ov8856->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);
> > > +	ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> > > +		&xvclk_rate);
> > >  	if (ret)
> > >  		return ret;
> > >  
> > > -	if (mclk != OV8856_MCLK) {
> > > -		dev_err(dev, "external clock %d is not supported", mclk);
> > > -		return -EINVAL;
> > > +	if (!is_acpi_node(fwnode)) {
> > > +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > +		if (IS_ERR(ov8856->xvclk)) {
> > > +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > +					ov8856->xvclk);
> > > +			return PTR_ERR(ov8856->xvclk);
> > > +		}
> > > +
> > > +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > +		xvclk_rate = clk_get_rate(ov8856->xvclk);
> > >  	}
> > 
> > Why do we handle the clock only in DT case? Is there a problem with the
> > clock handling and ACPI?
> 
> Not really, it's just that ACPI does not provide an interface to the clocks
> as such.

But you will get a clk by devm_clk_get()?

> 
> -- 
> Regards,
> 
> Sakari Ailus
>
Sakari Ailus April 30, 2020, 9:59 a.m. UTC | #4
Hi Marco,

On Thu, Apr 30, 2020 at 11:53:32AM +0200, Marco Felsch wrote:
> Hi Sakari,
> 
> On 20-04-30 12:45, Sakari Ailus wrote:
> > Hi Marco,
> > 
> > On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:
> > > Hi Robert,
> > > 
> > > thnakf for the patch but pls keep in mind to do one thing per patch.
> > > IMHO this patch do a lot more. Anyway below are my comment :)
> > > 
> > > On 20-04-29 18:24, Robert Foss wrote:
> > > > Add match table, enable ov8856_probe() to support
> > > > both ACPI and DT modes.
> > > 
> > > You are also adding the support for reset-gpios and regualtors. IMHO the
> > > commit message don't belong to the changes you made anymore.
> > > 
> > > > ACPI and DT modes are primarily distinguished from
> > > > each other by relying on devm_XXX_get_optional()
> > > > will return NULL instead of a reference for the
> > > > desired managed resource.
> > > > 
> > > > Signed-off-by: Robert Foss <robert.foss@linaro.org>
> > > > ---
> > > > 
> > > > - Changes since v5:
> > > >   * Maxime & Sakari: Replaced clock tolerance check with warning
> > > > 
> > > > - Changes since v4:
> > > >   * Maxime & Sakari: Switch to clock-frequency
> > > > 
> > > > - Changes since v3:
> > > >   * Remove redundant {}-brackets
> > > >   * Compare xvclk_rate to 5% tolerance
> > > >   * Andy: Use dev_fwnode()
> > > >   * Andy: Use %pe instead of %ld + PTR_ERR()
> > > >   * Andy: Invert reset_gpio logic
> > > >   * Andy: Remove dev_dbg() from failing reset_gpio setup
> > > >   * Andy: Use dev_err for logging for failures
> > > >   * Andy: Remove dev_warn from EDEFER/regulator error path
> > > >   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
> > > >   * Maxime & Sakari: Verify clock frequency from DT
> > > >   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
> > > >   * Sakari: Remove duplicate ov8856->dev assignment
> > > > 
> > > > - Changes since v2:
> > > >   * Added "struct device *dev" member to struct ov8856
> > > >   * Andy: Switch to optional version of devm_gpiod_get
> > > >   * Andy: Switch to optional version of devm_clk_get
> > > >   * Fabio: Add reset sleep period
> > > >   * Sakari: Unify defines for 19.2Mhz
> > > >   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
> > > >   * Sakari: Replace dev_info() with dev_dbg()
> > > >   * Sakari: Switch induction variable type to unsigned
> > > >   * Sakari: Don't wait for reset_gpio when in ACPI mode
> > > >   * Sakari: Pull reset GPIO high on power on failure
> > > >   * Sakari: Add power on/off to resume/suspend
> > > >   * Sakari: Fix indentation
> > > >   * Sakari: Power off during ov8856_remove()
> > > >   * Sakari: Don't sleep during power-on in ACPI mode
> > > >   * Sakari: Switch to getting xvclk from clk_get_rate
> > > > 
> > > > - Changes since v1:
> > > >   * Andy & Sakari: Make XVCLK optional since to not break ACPI
> > > >   * 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
> > > >   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
> > > >   * Sakari: Use XVCLK rate as provided by DT
> > > > 
> > > >  drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
> > > >  1 file changed, 123 insertions(+), 14 deletions(-)
> > > > 
> > > > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> > > > index 8655842af275..4749dc74d5ad 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>
> > > > @@ -18,7 +21,7 @@
> > > >  #define OV8856_LINK_FREQ_360MHZ		360000000ULL
> > > >  #define OV8856_LINK_FREQ_180MHZ		180000000ULL
> > > >  #define OV8856_SCLK			144000000ULL
> > > > -#define OV8856_MCLK			19200000
> > > > +#define OV8856_XVCLK_19_2		19200000
> > > >  #define OV8856_DATA_LANES		4
> > > >  #define OV8856_RGB_DEPTH		10
> > > >  
> > > > @@ -64,6 +67,12 @@
> > > >  
> > > >  #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 +575,11 @@ struct ov8856 {
> > > >  	struct media_pad pad;
> > > >  	struct v4l2_ctrl_handler ctrl_handler;
> > > >  
> > > > +	struct device		*dev;
> > > > +	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 +922,52 @@ 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);
> > > 
> > > You're request the clk only in DT case or do I miss something? If so you
> > > have to check if the clk is available.
> > > 
> > > > +	if (ret < 0) {
> > > > +		dev_err(&client->dev, "failed to enable xvclk\n");
> > > > +		return ret;
> > > > +	}
> > > > +
> > > > +	if (is_acpi_node(dev_fwnode(ov8856->dev)))
> > > > +		return 0;
> > > > +
> > > > +	if (ov8856->reset_gpio) {
> > > > +		gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > > +		usleep_range(1000, 2000);
> > > > +	}
> > > > +
> > > > +	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, 0);
> > > 
> > > You need to check the existance of the gpio here too.
> > 
> > No need to; the GPIO framework can handle this internally.
> 
> Ahh, I said nothing :) so all my comments about that can be dropped. 
> 
> > > > +	usleep_range(1500, 1800);
> > > > +
> > > > +	return 0;
> > > > +
> > > > +disable_clk:
> > > > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > 
> > > And here.. pls check the whole patch.
> > > 
> > > > +	clk_disable_unprepare(ov8856->xvclk);
> > > > +
> > > > +	return ret;
> > > > +}
> > > > +
> > > > +static void __ov8856_power_off(struct ov8856 *ov8856)
> > > > +{
> > > > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > > +	regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> > > > +			       ov8856->supplies);
> > > > +	clk_disable_unprepare(ov8856->xvclk);
> > > 
> > > Clk is only availabel in DT use-case.
> > > 
> > > > +}
> > > > +
> > > >  static int __maybe_unused ov8856_suspend(struct device *dev)
> > > >  {
> > > >  	struct i2c_client *client = to_i2c_client(dev);
> > > > @@ -918,6 +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev)
> > > >  	if (ov8856->streaming)
> > > >  		ov8856_stop_streaming(ov8856);
> > > >  
> > > > +	__ov8856_power_off(ov8856);
> > > >  	mutex_unlock(&ov8856->mutex);
> > > >  
> > > >  	return 0;
> > > > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct device *dev)
> > > >  	int ret;
> > > >  
> > > >  	mutex_lock(&ov8856->mutex);
> > > > +
> > > > +	__ov8856_power_on(ov8856);
> > > >  	if (ov8856->streaming) {
> > > >  		ret = ov8856_start_streaming(ov8856);
> > > >  		if (ret) {
> > > > @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
> > > >  	return 0;
> > > >  }
> > > >  
> > > > -static int ov8856_check_hwcfg(struct device *dev)
> > > > +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
> > > >  {
> > > > +	struct device *dev = ov8856->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);
> > > > +	ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> > > > +		&xvclk_rate);
> > > >  	if (ret)
> > > >  		return ret;
> > > >  
> > > > -	if (mclk != OV8856_MCLK) {
> > > > -		dev_err(dev, "external clock %d is not supported", mclk);
> > > > -		return -EINVAL;
> > > > +	if (!is_acpi_node(fwnode)) {
> > > > +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > > +		if (IS_ERR(ov8856->xvclk)) {
> > > > +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > > +					ov8856->xvclk);
> > > > +			return PTR_ERR(ov8856->xvclk);
> > > > +		}
> > > > +
> > > > +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > > +		xvclk_rate = clk_get_rate(ov8856->xvclk);
> > > >  	}
> > > 
> > > Why do we handle the clock only in DT case? Is there a problem with the
> > > clock handling and ACPI?
> > 
> > Not really, it's just that ACPI does not provide an interface to the clocks
> > as such.
> 
> But you will get a clk by devm_clk_get()?

No, because ACPI does not expose one to drivers. Effectively the entire
power sequences are implemented in ACPI, not in the driver.
Marco Felsch April 30, 2020, 10:11 a.m. UTC | #5
On 20-04-30 12:59, Sakari Ailus wrote:
> Hi Marco,
> 
> On Thu, Apr 30, 2020 at 11:53:32AM +0200, Marco Felsch wrote:
> > Hi Sakari,
> > 
> > On 20-04-30 12:45, Sakari Ailus wrote:
> > > Hi Marco,
> > > 
> > > On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:

...

> > > > > -	if (mclk != OV8856_MCLK) {
> > > > > -		dev_err(dev, "external clock %d is not supported", mclk);
> > > > > -		return -EINVAL;
> > > > > +	if (!is_acpi_node(fwnode)) {
> > > > > +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > > > +		if (IS_ERR(ov8856->xvclk)) {
> > > > > +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > > > +					ov8856->xvclk);
> > > > > +			return PTR_ERR(ov8856->xvclk);
> > > > > +		}
> > > > > +
> > > > > +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > > > +		xvclk_rate = clk_get_rate(ov8856->xvclk);
> > > > >  	}
> > > > 
> > > > Why do we handle the clock only in DT case? Is there a problem with the
> > > > clock handling and ACPI?
> > > 
> > > Not really, it's just that ACPI does not provide an interface to the clocks
> > > as such.
> > 
> > But you will get a clk by devm_clk_get()?
> 
> No, because ACPI does not expose one to drivers. Effectively the entire
> power sequences are implemented in ACPI, not in the driver.
> 

Ah okay, thanks for the explanation. I'm really not into the ACPI
stuff.. So this means the __power_off / power_on should only be done if
we are using DT's?

Regards,
  Marco
Sakari Ailus April 30, 2020, 10:20 a.m. UTC | #6
On Thu, Apr 30, 2020 at 12:11:57PM +0200, Marco Felsch wrote:
> On 20-04-30 12:59, Sakari Ailus wrote:
> > Hi Marco,
> > 
> > On Thu, Apr 30, 2020 at 11:53:32AM +0200, Marco Felsch wrote:
> > > Hi Sakari,
> > > 
> > > On 20-04-30 12:45, Sakari Ailus wrote:
> > > > Hi Marco,
> > > > 
> > > > On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:
> 
> ...
> 
> > > > > > -	if (mclk != OV8856_MCLK) {
> > > > > > -		dev_err(dev, "external clock %d is not supported", mclk);
> > > > > > -		return -EINVAL;
> > > > > > +	if (!is_acpi_node(fwnode)) {
> > > > > > +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > > > > +		if (IS_ERR(ov8856->xvclk)) {
> > > > > > +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > > > > +					ov8856->xvclk);
> > > > > > +			return PTR_ERR(ov8856->xvclk);
> > > > > > +		}
> > > > > > +
> > > > > > +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > > > > +		xvclk_rate = clk_get_rate(ov8856->xvclk);
> > > > > >  	}
> > > > > 
> > > > > Why do we handle the clock only in DT case? Is there a problem with the
> > > > > clock handling and ACPI?
> > > > 
> > > > Not really, it's just that ACPI does not provide an interface to the clocks
> > > > as such.
> > > 
> > > But you will get a clk by devm_clk_get()?
> > 
> > No, because ACPI does not expose one to drivers. Effectively the entire
> > power sequences are implemented in ACPI, not in the driver.
> > 
> 
> Ah okay, thanks for the explanation. I'm really not into the ACPI
> stuff.. So this means the __power_off / power_on should only be done if
> we are using DT's?

Correct. That's why it bails out early. It could be yet earlier though,
without doing anything.
Marco Felsch April 30, 2020, 12:07 p.m. UTC | #7
On 20-04-30 13:20, Sakari Ailus wrote:
> On Thu, Apr 30, 2020 at 12:11:57PM +0200, Marco Felsch wrote:
> > On 20-04-30 12:59, Sakari Ailus wrote:
> > > Hi Marco,
> > > 
> > > On Thu, Apr 30, 2020 at 11:53:32AM +0200, Marco Felsch wrote:
> > > > Hi Sakari,
> > > > 
> > > > On 20-04-30 12:45, Sakari Ailus wrote:
> > > > > Hi Marco,
> > > > > 
> > > > > On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:
> > 
> > ...
> > 
> > > > > > > -	if (mclk != OV8856_MCLK) {
> > > > > > > -		dev_err(dev, "external clock %d is not supported", mclk);
> > > > > > > -		return -EINVAL;
> > > > > > > +	if (!is_acpi_node(fwnode)) {
> > > > > > > +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > > > > > +		if (IS_ERR(ov8856->xvclk)) {
> > > > > > > +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > > > > > +					ov8856->xvclk);
> > > > > > > +			return PTR_ERR(ov8856->xvclk);
> > > > > > > +		}
> > > > > > > +
> > > > > > > +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > > > > > +		xvclk_rate = clk_get_rate(ov8856->xvclk);
> > > > > > >  	}
> > > > > > 
> > > > > > Why do we handle the clock only in DT case? Is there a problem with the
> > > > > > clock handling and ACPI?
> > > > > 
> > > > > Not really, it's just that ACPI does not provide an interface to the clocks
> > > > > as such.
> > > > 
> > > > But you will get a clk by devm_clk_get()?
> > > 
> > > No, because ACPI does not expose one to drivers. Effectively the entire
> > > power sequences are implemented in ACPI, not in the driver.
> > > 
> > 
> > Ah okay, thanks for the explanation. I'm really not into the ACPI
> > stuff.. So this means the __power_off / power_on should only be done if
> > we are using DT's?
> 
> Correct. That's why it bails out early. It could be yet earlier though,
> without doing anything.

Yes I see. For easier and error less prone handling I would prefer:

if (is_acpi_node())
	return 0;

as first instruction for __power_off/on().

Also I would refator the ov8856_check_hwcfg() so the common part can be
used by this function and by a ov8856_parse_of() function. But thats
only my opinion.

Regards,
  Marco
Sakari Ailus April 30, 2020, 1:32 p.m. UTC | #8
On Thu, Apr 30, 2020 at 02:07:41PM +0200, Marco Felsch wrote:
> On 20-04-30 13:20, Sakari Ailus wrote:
> > On Thu, Apr 30, 2020 at 12:11:57PM +0200, Marco Felsch wrote:
> > > On 20-04-30 12:59, Sakari Ailus wrote:
> > > > Hi Marco,
> > > > 
> > > > On Thu, Apr 30, 2020 at 11:53:32AM +0200, Marco Felsch wrote:
> > > > > Hi Sakari,
> > > > > 
> > > > > On 20-04-30 12:45, Sakari Ailus wrote:
> > > > > > Hi Marco,
> > > > > > 
> > > > > > On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:
> > > 
> > > ...
> > > 
> > > > > > > > -	if (mclk != OV8856_MCLK) {
> > > > > > > > -		dev_err(dev, "external clock %d is not supported", mclk);
> > > > > > > > -		return -EINVAL;
> > > > > > > > +	if (!is_acpi_node(fwnode)) {
> > > > > > > > +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > > > > > > +		if (IS_ERR(ov8856->xvclk)) {
> > > > > > > > +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > > > > > > +					ov8856->xvclk);
> > > > > > > > +			return PTR_ERR(ov8856->xvclk);
> > > > > > > > +		}
> > > > > > > > +
> > > > > > > > +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > > > > > > +		xvclk_rate = clk_get_rate(ov8856->xvclk);
> > > > > > > >  	}
> > > > > > > 
> > > > > > > Why do we handle the clock only in DT case? Is there a problem with the
> > > > > > > clock handling and ACPI?
> > > > > > 
> > > > > > Not really, it's just that ACPI does not provide an interface to the clocks
> > > > > > as such.
> > > > > 
> > > > > But you will get a clk by devm_clk_get()?
> > > > 
> > > > No, because ACPI does not expose one to drivers. Effectively the entire
> > > > power sequences are implemented in ACPI, not in the driver.
> > > > 
> > > 
> > > Ah okay, thanks for the explanation. I'm really not into the ACPI
> > > stuff.. So this means the __power_off / power_on should only be done if
> > > we are using DT's?
> > 
> > Correct. That's why it bails out early. It could be yet earlier though,
> > without doing anything.
> 
> Yes I see. For easier and error less prone handling I would prefer:
> 
> if (is_acpi_node())
> 	return 0;
> 
> as first instruction for __power_off/on().
> 
> Also I would refator the ov8856_check_hwcfg() so the common part can be
> used by this function and by a ov8856_parse_of() function. But thats
> only my opinion.

I guess it could be the same function, up to you.
Robert Foss April 30, 2020, 4:11 p.m. UTC | #9
Hey Marco,

On Thu, 30 Apr 2020 at 14:07, Marco Felsch <m.felsch@pengutronix.de> wrote:
>
> On 20-04-30 13:20, Sakari Ailus wrote:
> > On Thu, Apr 30, 2020 at 12:11:57PM +0200, Marco Felsch wrote:
> > > On 20-04-30 12:59, Sakari Ailus wrote:
> > > > Hi Marco,
> > > >
> > > > On Thu, Apr 30, 2020 at 11:53:32AM +0200, Marco Felsch wrote:
> > > > > Hi Sakari,
> > > > >
> > > > > On 20-04-30 12:45, Sakari Ailus wrote:
> > > > > > Hi Marco,
> > > > > >
> > > > > > On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:
> > >
> > > ...
> > >
> > > > > > > > - if (mclk != OV8856_MCLK) {
> > > > > > > > -         dev_err(dev, "external clock %d is not supported", mclk);
> > > > > > > > -         return -EINVAL;
> > > > > > > > + if (!is_acpi_node(fwnode)) {
> > > > > > > > +         ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > > > > > > +         if (IS_ERR(ov8856->xvclk)) {
> > > > > > > > +                 dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > > > > > > +                                 ov8856->xvclk);
> > > > > > > > +                 return PTR_ERR(ov8856->xvclk);
> > > > > > > > +         }
> > > > > > > > +
> > > > > > > > +         clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > > > > > > +         xvclk_rate = clk_get_rate(ov8856->xvclk);
> > > > > > > >   }
> > > > > > >
> > > > > > > Why do we handle the clock only in DT case? Is there a problem with the
> > > > > > > clock handling and ACPI?
> > > > > >
> > > > > > Not really, it's just that ACPI does not provide an interface to the clocks
> > > > > > as such.
> > > > >
> > > > > But you will get a clk by devm_clk_get()?
> > > >
> > > > No, because ACPI does not expose one to drivers. Effectively the entire
> > > > power sequences are implemented in ACPI, not in the driver.
> > > >
> > >
> > > Ah okay, thanks for the explanation. I'm really not into the ACPI
> > > stuff.. So this means the __power_off / power_on should only be done if
> > > we are using DT's?
> >
> > Correct. That's why it bails out early. It could be yet earlier though,
> > without doing anything.
>
> Yes I see. For easier and error less prone handling I would prefer:
>
> if (is_acpi_node())
>         return 0;
>
> as first instruction for __power_off/on().

__ov8856_power_on() does make a check like that, albeit only after
having run clk_prepare_enable() which won't do anything due to
ov8856->xvclk==NULL. So this should be fixed and be moved to after the
ACPI check.

__ov8856_power_off() has no ACPI check, but all of the calls it makes
are going to do nothing due to v8856->reset_gpio / v8856->reset_gpio /
ov8856->xvclk all being NULL or dummies. For the sake of clarity an
early ACPI check+return could be added, but if clarity is the goal a
comment would work too.

>
> Also I would refactor the ov8856_check_hwcfg() so the common part can be
> used by this function and by a ov8856_parse_of() function. But thats
> only my opinion.

I'm trying to grok the above paragraph. You'd like to see something in
the style of tc358743_probe_of()?

>
> Regards,
>   Marco
Marco Felsch May 4, 2020, 6:24 a.m. UTC | #10
Hi Robert,

On 20-04-30 18:11, Robert Foss wrote:
> Hey Marco,
> 
> On Thu, 30 Apr 2020 at 14:07, Marco Felsch <m.felsch@pengutronix.de> wrote:
> >
> > On 20-04-30 13:20, Sakari Ailus wrote:
> > > On Thu, Apr 30, 2020 at 12:11:57PM +0200, Marco Felsch wrote:
> > > > On 20-04-30 12:59, Sakari Ailus wrote:
> > > > > Hi Marco,
> > > > >
> > > > > On Thu, Apr 30, 2020 at 11:53:32AM +0200, Marco Felsch wrote:
> > > > > > Hi Sakari,
> > > > > >
> > > > > > On 20-04-30 12:45, Sakari Ailus wrote:
> > > > > > > Hi Marco,
> > > > > > >
> > > > > > > On Thu, Apr 30, 2020 at 11:35:24AM +0200, Marco Felsch wrote:
> > > >
> > > > ...
> > > >
> > > > > > > > > - if (mclk != OV8856_MCLK) {
> > > > > > > > > -         dev_err(dev, "external clock %d is not supported", mclk);
> > > > > > > > > -         return -EINVAL;
> > > > > > > > > + if (!is_acpi_node(fwnode)) {
> > > > > > > > > +         ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > > > > > > > +         if (IS_ERR(ov8856->xvclk)) {
> > > > > > > > > +                 dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > > > > > > > +                                 ov8856->xvclk);
> > > > > > > > > +                 return PTR_ERR(ov8856->xvclk);
> > > > > > > > > +         }
> > > > > > > > > +
> > > > > > > > > +         clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > > > > > > > +         xvclk_rate = clk_get_rate(ov8856->xvclk);
> > > > > > > > >   }
> > > > > > > >
> > > > > > > > Why do we handle the clock only in DT case? Is there a problem with the
> > > > > > > > clock handling and ACPI?
> > > > > > >
> > > > > > > Not really, it's just that ACPI does not provide an interface to the clocks
> > > > > > > as such.
> > > > > >
> > > > > > But you will get a clk by devm_clk_get()?
> > > > >
> > > > > No, because ACPI does not expose one to drivers. Effectively the entire
> > > > > power sequences are implemented in ACPI, not in the driver.
> > > > >
> > > >
> > > > Ah okay, thanks for the explanation. I'm really not into the ACPI
> > > > stuff.. So this means the __power_off / power_on should only be done if
> > > > we are using DT's?
> > >
> > > Correct. That's why it bails out early. It could be yet earlier though,
> > > without doing anything.
> >
> > Yes I see. For easier and error less prone handling I would prefer:
> >
> > if (is_acpi_node())
> >         return 0;
> >
> > as first instruction for __power_off/on().
> 
> __ov8856_power_on() does make a check like that, albeit only after
> having run clk_prepare_enable() which won't do anything due to
> ov8856->xvclk==NULL. So this should be fixed and be moved to after the
> ACPI check.

Yep, I saw that. I didn't checked the clk_prepare_enable() function and
just saw that we don't request the clk for the acpi case and enable it
in both cases. This doesn't sound right to me.

> __ov8856_power_off() has no ACPI check, but all of the calls it makes
> are going to do nothing due to v8856->reset_gpio / v8856->reset_gpio /
> ov8856->xvclk all being NULL or dummies. For the sake of clarity an
> early ACPI check+return could be added, but if clarity is the goal a
> comment would work too.

Thanks god that most of the library functions taking NULL into account
=) But I think we have to take the regulator count into account. Again I
don't know how the ACPI part is working. What happens if we request
regulators which aren't listed within the ACPI table? In case of DT
there will be added dummy-regulator. If this is the case for ACPI too we
are ending in an unbalanced regulator enable/disable count since you
enable it for the DT case and disable it in both cases.

> >
> > Also I would refactor the ov8856_check_hwcfg() so the common part can be
> > used by this function and by a ov8856_parse_of() function. But thats
> > only my opinion.
> 
> I'm trying to grok the above paragraph. You'd like to see something in
> the style of tc358743_probe_of()?

You don't have to if Saki is fine with the current patch. Just saying
that it would be a bit easier for the patch review.

Regards,
  Marco

> >
> > Regards,
> >   Marco
>
diff mbox series

Patch

diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
index 8655842af275..4749dc74d5ad 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>
@@ -18,7 +21,7 @@ 
 #define OV8856_LINK_FREQ_360MHZ		360000000ULL
 #define OV8856_LINK_FREQ_180MHZ		180000000ULL
 #define OV8856_SCLK			144000000ULL
-#define OV8856_MCLK			19200000
+#define OV8856_XVCLK_19_2		19200000
 #define OV8856_DATA_LANES		4
 #define OV8856_RGB_DEPTH		10
 
@@ -64,6 +67,12 @@ 
 
 #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 +575,11 @@  struct ov8856 {
 	struct media_pad pad;
 	struct v4l2_ctrl_handler ctrl_handler;
 
+	struct device		*dev;
+	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 +922,52 @@  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;
+	}
+
+	if (is_acpi_node(dev_fwnode(ov8856->dev)))
+		return 0;
+
+	if (ov8856->reset_gpio) {
+		gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
+		usleep_range(1000, 2000);
+	}
+
+	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, 0);
+	usleep_range(1500, 1800);
+
+	return 0;
+
+disable_clk:
+	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
+	clk_disable_unprepare(ov8856->xvclk);
+
+	return ret;
+}
+
+static void __ov8856_power_off(struct ov8856 *ov8856)
+{
+	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
+	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);
@@ -918,6 +978,7 @@  static int __maybe_unused ov8856_suspend(struct device *dev)
 	if (ov8856->streaming)
 		ov8856_stop_streaming(ov8856);
 
+	__ov8856_power_off(ov8856);
 	mutex_unlock(&ov8856->mutex);
 
 	return 0;
@@ -931,6 +992,8 @@  static int __maybe_unused ov8856_resume(struct device *dev)
 	int ret;
 
 	mutex_lock(&ov8856->mutex);
+
+	__ov8856_power_on(ov8856);
 	if (ov8856->streaming) {
 		ret = ov8856_start_streaming(ov8856);
 		if (ret) {
@@ -1092,29 +1155,54 @@  static int ov8856_identify_module(struct ov8856 *ov8856)
 	return 0;
 }
 
-static int ov8856_check_hwcfg(struct device *dev)
+static int ov8856_get_hwcfg(struct ov8856 *ov8856)
 {
+	struct device *dev = ov8856->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);
+	ret = fwnode_property_read_u32(fwnode, "clock-frequency",
+		&xvclk_rate);
 	if (ret)
 		return ret;
 
-	if (mclk != OV8856_MCLK) {
-		dev_err(dev, "external clock %d is not supported", mclk);
-		return -EINVAL;
+	if (!is_acpi_node(fwnode)) {
+		ov8856->xvclk = devm_clk_get(dev, "xvclk");
+		if (IS_ERR(ov8856->xvclk)) {
+			dev_err(dev, "could not get xvclk clock (%pe)\n",
+					ov8856->xvclk);
+			return PTR_ERR(ov8856->xvclk);
+		}
+
+		clk_set_rate(ov8856->xvclk, xvclk_rate);
+		xvclk_rate = clk_get_rate(ov8856->xvclk);
 	}
 
+	if (xvclk_rate != OV8856_XVCLK_19_2)
+		dev_warn(dev, "external clock rate %d is unsupported", xvclk_rate);
+
+	ov8856->reset_gpio = devm_gpiod_get_optional(dev, "reset",
+		GPIOD_OUT_LOW);
+	if (IS_ERR(ov8856->reset_gpio))
+		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(dev, ARRAY_SIZE(ov8856_supply_names),
+				      ov8856->supplies);
+	if (ret)
+		return ret;
+
 	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
 	if (!ep)
 		return -ENXIO;
@@ -1169,6 +1257,8 @@  static int ov8856_remove(struct i2c_client *client)
 	pm_runtime_disable(&client->dev);
 	mutex_destroy(&ov8856->mutex);
 
+	__ov8856_power_off(ov8856);
+
 	return 0;
 }
 
@@ -1177,22 +1267,31 @@  static int ov8856_probe(struct i2c_client *client)
 	struct ov8856 *ov8856;
 	int ret;
 
-	ret = ov8856_check_hwcfg(&client->dev);
+	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
+	if (!ov8856)
+		return -ENOMEM;
+
+	ov8856->dev = &client->dev;
+
+	ret = ov8856_get_hwcfg(ov8856);
 	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;
 	}
 
-	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
-	if (!ov8856)
-		return -ENOMEM;
-
 	v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
+
+	ret = __ov8856_power_on(ov8856);
+	if (ret) {
+		dev_err(&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 +1337,9 @@  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 +1356,18 @@  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,