[PATCH v2 3/5] ov5670: Support probe whilst the device is in a low power state

From: Sakari Ailus
Date: Mon Aug 26 2019 - 04:32:29 EST


Tell ACPI device PM code that the driver supports the device being in a
low power state when the driver's probe function is entered.

Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
drivers/media/i2c/ov5670.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/media/i2c/ov5670.c b/drivers/media/i2c/ov5670.c
index 041fcbb4eebdf..760fce93337cd 100644
--- a/drivers/media/i2c/ov5670.c
+++ b/drivers/media/i2c/ov5670.c
@@ -2444,6 +2444,7 @@ static int ov5670_probe(struct i2c_client *client)
struct ov5670 *ov5670;
const char *err_msg;
u32 input_clk = 0;
+ bool low_power;
int ret;

device_property_read_u32(&client->dev, "clock-frequency", &input_clk);
@@ -2460,11 +2461,14 @@ static int ov5670_probe(struct i2c_client *client)
/* Initialize subdev */
v4l2_i2c_subdev_init(&ov5670->sd, client, &ov5670_subdev_ops);

- /* Check module identity */
- ret = ov5670_identify_module(ov5670);
- if (ret) {
- err_msg = "ov5670_identify_module() error";
- goto error_print;
+ low_power = acpi_dev_low_power_state_probe(&client->dev);
+ if (!low_power) {
+ /* Check module identity */
+ ret = ov5670_identify_module(ov5670);
+ if (ret) {
+ err_msg = "ov5670_identify_module() error";
+ goto error_print;
+ }
}

mutex_init(&ov5670->mutex);
@@ -2501,10 +2505,10 @@ static int ov5670_probe(struct i2c_client *client)
ov5670->streaming = false;

/*
- * 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);

@@ -2546,7 +2550,7 @@ static const struct dev_pm_ops ov5670_pm_ops = {

#ifdef CONFIG_ACPI
static const struct acpi_device_id ov5670_acpi_ids[] = {
- {"INT3479"},
+ { "INT3479" },
{ /* sentinel */ }
};

@@ -2556,6 +2560,7 @@ MODULE_DEVICE_TABLE(acpi, ov5670_acpi_ids);
static struct i2c_driver ov5670_i2c_driver = {
.driver = {
.name = "ov5670",
+ .probe_low_power = true,
.pm = &ov5670_pm_ops,
.acpi_match_table = ACPI_PTR(ov5670_acpi_ids),
},
--
2.20.1