Re: [PATCH v7 2/3] media: ov8856: Add devicetree support

From: Marco Felsch
Date: Tue May 05 2020 - 06:16:17 EST

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In reply to: Robert Foss: "[PATCH v7 2/3] media: ov8856: Add devicetree support"
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Hi Robert,

On 20-05-05 12:01, Robert Foss wrote:
> Add match table, enable ov8856_probe() to support
> both ACPI and DT modes.
>
> ACPI and DT modes are primarily distinguished from
> by checking for ACPI mode and by having resource like
> be NULL.
>
> Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxx>
> ---
>
> - Changes since v6:
> * Marco: Bail out of __ov8856_power_on earlier if ACPI mode
>
> - 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..e6418a79801e 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;

Why do we need this reference here? We already have all information we
need to retrieve the device.

> + 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;
> +
> + if (is_acpi_node(dev_fwnode(ov8856->dev)))
> + return 0;
> +
> + ret = clk_prepare_enable(ov8856->xvclk);
> + if (ret < 0) {
> + dev_err(&client->dev, "failed to enable xvclk\n");
> + return ret;
> + }
> +
> + 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);

In case of ACPI this will still be a unbalanced regulator. Albeit it is a
dummy_regulator it will produce warnings in the ACPI case. Therefore I
said to add the check:

if (is_acpi_node(dev_fwnode(ov8856->dev)))
return 0;

here to at the begin of this function.

> + 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);

I tought I commented this to. Pls align it :)

Regards,
Marco

> + 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,
> --
> 2.25.1
>
>

Next message: Marco Felsch: "Re: [PATCH v7 3/3] media: ov8856: Implement sensor module revision identification"
Previous message: Po-Hsu Lin: "[PATCH] selftests/ftrace: mark irqsoff_tracer.tc test as unresolved if the test module does not exist"
In reply to: Robert Foss: "[PATCH v7 2/3] media: ov8856: Add devicetree support"
Next in thread: Robert Foss: "Re: [PATCH v7 2/3] media: ov8856: Add devicetree support"
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