linux-kernel - [PATCH v2 4/5] media: i2c: imx319: Support probe while the device is off

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Date:   Mon, 26 Aug 2019 11:31:11 +0300
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     linux-acpi@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH v2 4/5] media: i2c: imx319: Support probe while the device is off

From: Rajmohan Mani <rajmohan.mani@...el.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@...el.com>
Signed-off-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
---
 drivers/media/i2c/imx319.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/media/i2c/imx319.c b/drivers/media/i2c/imx319.c
index 17c2e4b41221e..1a01946f4d5bf 100644
--- a/drivers/media/i2c/imx319.c
+++ b/drivers/media/i2c/imx319.c
@@ -2424,6 +2424,7 @@ 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;
 
@@ -2436,11 +2437,14 @@ 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_low_power_state_probe(&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);
@@ -2493,10 +2497,10 @@ 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);
 
@@ -2536,7 +2540,7 @@ static const struct dev_pm_ops imx319_pm_ops = {
 };
 
 static const struct acpi_device_id imx319_acpi_ids[] = {
-	{ "SONY319A" },
+	{ "SONY319A", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(acpi, imx319_acpi_ids);
@@ -2544,6 +2548,7 @@ MODULE_DEVICE_TABLE(acpi, imx319_acpi_ids);
 static struct i2c_driver imx319_i2c_driver = {
 	.driver = {
 		.name = "imx319",
+		.probe_low_power = true,
 		.pm = &imx319_pm_ops,
 		.acpi_match_table = ACPI_PTR(imx319_acpi_ids),
 	},
-- 
2.20.1