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

Kao, Ben
2020-05-08T09:51:02Z

Hi Robert,

On Thu, May 7, 2020 16:39 Robert Foss wrote:
> On Thu, 7 May 2020 at 10:06, Kao, Ben <ben.kao@intel.com> wrote:
> >
> > 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@linaro.org>
> > > ---
> > >
> > > - 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;
> > > + 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);
> > > + 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;
> > > +
> >
> > In case of ACPI this cannot get ov8856->reset_gpio and ov8856->supplies,
> please add the check for ACPI case:
> > if (!is_acpi_node(fwnode)) { }
>
> Do you prefer the explicit check for clarity reasons or for functional reasons?
>
> As far as I understand it, reset_gpio will be NULL and supplies will be populated
> with dummy supplies in the ACPI case.
> Both can be treated as if they were initialized fully during later calls to their
> respective APIs.
Understood, the check is unnecessary.

Ben.
>
> >
> > Thanks.
> > Ben
> >
> > > 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
> >