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Subject[PATCH v10 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>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Reviewed-by: Bingbu Cao <bingbu.cao@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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