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    Subject[PATCH v9 6/7] media: i2c: imx319: Support probe while the device is off
    Date
    From: Rajmohan Mani <rajmohan.mani@intel.com>

    Tell ACPI device PM code that the driver supports the device being powered
    off when the driver's probe function is entered.

    Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
    Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
    ---
    drivers/media/i2c/imx319.c | 72 +++++++++++++++++++++++---------------
    1 file changed, 44 insertions(+), 28 deletions(-)

    diff --git a/drivers/media/i2c/imx319.c b/drivers/media/i2c/imx319.c
    index 8473c0bbb35d6..e0b22e9318fed 100644
    --- a/drivers/media/i2c/imx319.c
    +++ b/drivers/media/i2c/imx319.c
    @@ -140,6 +140,8 @@ struct imx319 {

    /* Streaming on/off */
    bool streaming;
    + /* True if the device has been identified */
    + bool identified;
    };

    static const struct imx319_reg imx319_global_regs[] = {
    @@ -2084,6 +2086,31 @@ imx319_set_pad_format(struct v4l2_subdev *sd,
    return 0;
    }

    +/* Verify chip ID */
    +static int imx319_identify_module(struct imx319 *imx319)
    +{
    + struct i2c_client *client = v4l2_get_subdevdata(&imx319->sd);
    + int ret;
    + u32 val;
    +
    + if (imx319->identified)
    + return 0;
    +
    + ret = imx319_read_reg(imx319, IMX319_REG_CHIP_ID, 2, &val);
    + if (ret)
    + return ret;
    +
    + if (val != IMX319_CHIP_ID) {
    + dev_err(&client->dev, "chip id mismatch: %x!=%x",
    + IMX319_CHIP_ID, val);
    + return -EIO;
    + }
    +
    + imx319->identified = true;
    +
    + return 0;
    +}
    +
    /* Start streaming */
    static int imx319_start_streaming(struct imx319 *imx319)
    {
    @@ -2091,6 +2118,10 @@ static int imx319_start_streaming(struct imx319 *imx319)
    const struct imx319_reg_list *reg_list;
    int ret;

    + ret = imx319_identify_module(imx319);
    + if (ret)
    + return ret;
    +
    /* Global Setting */
    reg_list = &imx319_global_setting;
    ret = imx319_write_regs(imx319, reg_list->regs, reg_list->num_of_regs);
    @@ -2208,26 +2239,6 @@ static int __maybe_unused imx319_resume(struct device *dev)
    return ret;
    }

    -/* Verify chip ID */
    -static int imx319_identify_module(struct imx319 *imx319)
    -{
    - struct i2c_client *client = v4l2_get_subdevdata(&imx319->sd);
    - int ret;
    - u32 val;
    -
    - ret = imx319_read_reg(imx319, IMX319_REG_CHIP_ID, 2, &val);
    - if (ret)
    - return ret;
    -
    - if (val != IMX319_CHIP_ID) {
    - dev_err(&client->dev, "chip id mismatch: %x!=%x",
    - IMX319_CHIP_ID, val);
    - return -EIO;
    - }
    -
    - return 0;
    -}
    -
    static const struct v4l2_subdev_core_ops imx319_subdev_core_ops = {
    .subscribe_event = v4l2_ctrl_subdev_subscribe_event,
    .unsubscribe_event = v4l2_event_subdev_unsubscribe,
    @@ -2422,6 +2433,7 @@ static struct imx319_hwcfg *imx319_get_hwcfg(struct device *dev)
    static int imx319_probe(struct i2c_client *client)
    {
    struct imx319 *imx319;
    + bool low_power;
    int ret;
    u32 i;

    @@ -2434,11 +2446,14 @@ static int imx319_probe(struct i2c_client *client)
    /* Initialize subdev */
    v4l2_i2c_subdev_init(&imx319->sd, client, &imx319_subdev_ops);

    - /* Check module identity */
    - ret = imx319_identify_module(imx319);
    - if (ret) {
    - dev_err(&client->dev, "failed to find sensor: %d", ret);
    - goto error_probe;
    + low_power = acpi_dev_state_low_power(&client->dev);
    + if (!low_power) {
    + /* Check module identity */
    + ret = imx319_identify_module(imx319);
    + if (ret) {
    + dev_err(&client->dev, "failed to find sensor: %d", ret);
    + goto error_probe;
    + }
    }

    imx319->hwcfg = imx319_get_hwcfg(&client->dev);
    @@ -2491,10 +2506,10 @@ static int imx319_probe(struct i2c_client *client)
    goto error_media_entity;

    /*
    - * Device is already turned on by i2c-core with ACPI domain PM.
    - * Enable runtime PM and turn off the device.
    + * Don't set the device's state to active if it's in a low power state.
    */
    - pm_runtime_set_active(&client->dev);
    + if (!low_power)
    + pm_runtime_set_active(&client->dev);
    pm_runtime_enable(&client->dev);
    pm_runtime_idle(&client->dev);

    @@ -2547,6 +2562,7 @@ static struct i2c_driver imx319_i2c_driver = {
    },
    .probe_new = imx319_probe,
    .remove = imx319_remove,
    + .flags = I2C_DRV_FL_ALLOW_LOW_POWER_PROBE,
    };
    module_i2c_driver(imx319_i2c_driver);

    --
    2.20.1
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