linux-kernel - [PATCH 5/6] media: ov5675: Support device probe in non-zero ACPI D state

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Message-Id: <1636447715-15526-6-git-send-email-bingbu.cao@intel.com>
Date:   Tue,  9 Nov 2021 16:48:34 +0800
From:   Bingbu Cao <bingbu.cao@...el.com>
To:     linux-media@...r.kernel.org, sakari.ailus@...ux.intel.com,
        rafael@...nel.org
Cc:     shawnx.tu@...el.com, tian.shu.qiu@...el.com,
        chiranjeevi.rapolu@...el.com, hyungwoo.yang@...el.com,
        tfiga@...omium.org, senozhatsky@...omium.org,
        linux-kernel@...r.kernel.org, bingbu.cao@...el.com,
        bingbu.cao@...ux.intel.com
Subject: [PATCH 5/6] media: ov5675: Support device probe in non-zero ACPI D state

Tell ACPI device PM code that the driver supports the device being in
non-zero ACPI D state when the driver's probe function is entered.

Also do identification on the first access of the device, whether in probe
or when starting streaming.

Signed-off-by: Bingbu Cao <bingbu.cao@...el.com>
---
 drivers/media/i2c/ov5675.c | 71 ++++++++++++++++++++++++++++++----------------
 1 file changed, 46 insertions(+), 25 deletions(-)

diff --git a/drivers/media/i2c/ov5675.c b/drivers/media/i2c/ov5675.c
index da5850b7ad07..00925850fa7c 100644
--- a/drivers/media/i2c/ov5675.c
+++ b/drivers/media/i2c/ov5675.c
@@ -493,6 +493,9 @@ struct ov5675 {
 
 	/* Streaming on/off */
 	bool streaming;
+
+	/* True if the device has been identified */
+	bool identified;
 };
 
 static u64 to_pixel_rate(u32 f_index)
@@ -808,12 +811,41 @@ static void ov5675_update_pad_format(const struct ov5675_mode *mode,
 	fmt->field = V4L2_FIELD_NONE;
 }
 
+static int ov5675_identify_module(struct ov5675 *ov5675)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(&ov5675->sd);
+	int ret;
+	u32 val;
+
+	if (ov5675->identified)
+		return 0;
+
+	ret = ov5675_read_reg(ov5675, OV5675_REG_CHIP_ID,
+			      OV5675_REG_VALUE_24BIT, &val);
+	if (ret)
+		return ret;
+
+	if (val != OV5675_CHIP_ID) {
+		dev_err(&client->dev, "chip id mismatch: %x!=%x",
+			OV5675_CHIP_ID, val);
+		return -ENXIO;
+	}
+
+	ov5675->identified = true;
+
+	return 0;
+}
+
 static int ov5675_start_streaming(struct ov5675 *ov5675)
 {
 	struct i2c_client *client = v4l2_get_subdevdata(&ov5675->sd);
 	const struct ov5675_reg_list *reg_list;
 	int link_freq_index, ret;
 
+	ret = ov5675_identify_module(ov5675);
+	if (ret)
+		return ret;
+
 	link_freq_index = ov5675->cur_mode->link_freq_index;
 	reg_list = &link_freq_configs[link_freq_index].reg_list;
 	ret = ov5675_write_reg_list(ov5675, reg_list);
@@ -1048,26 +1080,6 @@ static const struct v4l2_subdev_internal_ops ov5675_internal_ops = {
 	.open = ov5675_open,
 };
 
-static int ov5675_identify_module(struct ov5675 *ov5675)
-{
-	struct i2c_client *client = v4l2_get_subdevdata(&ov5675->sd);
-	int ret;
-	u32 val;
-
-	ret = ov5675_read_reg(ov5675, OV5675_REG_CHIP_ID,
-			      OV5675_REG_VALUE_24BIT, &val);
-	if (ret)
-		return ret;
-
-	if (val != OV5675_CHIP_ID) {
-		dev_err(&client->dev, "chip id mismatch: %x!=%x",
-			OV5675_CHIP_ID, val);
-		return -ENXIO;
-	}
-
-	return 0;
-}
-
 static int ov5675_check_hwcfg(struct device *dev)
 {
 	struct fwnode_handle *ep;
@@ -1154,6 +1166,7 @@ static int ov5675_remove(struct i2c_client *client)
 static int ov5675_probe(struct i2c_client *client)
 {
 	struct ov5675 *ov5675;
+	bool full_power;
 	int ret;
 
 	ret = ov5675_check_hwcfg(&client->dev);
@@ -1168,10 +1181,14 @@ static int ov5675_probe(struct i2c_client *client)
 		return -ENOMEM;
 
 	v4l2_i2c_subdev_init(&ov5675->sd, client, &ov5675_subdev_ops);
-	ret = ov5675_identify_module(ov5675);
-	if (ret) {
-		dev_err(&client->dev, "failed to find sensor: %d", ret);
-		return ret;
+
+	full_power = acpi_dev_state_d0(&client->dev);
+	if (full_power) {
+		ret = ov5675_identify_module(ov5675);
+		if (ret) {
+			dev_err(&client->dev, "failed to find sensor: %d", ret);
+			return ret;
+		}
 	}
 
 	mutex_init(&ov5675->mutex);
@@ -1204,7 +1221,10 @@ static int ov5675_probe(struct i2c_client *client)
 	 * Device is already turned on by i2c-core with ACPI domain PM.
 	 * Enable runtime PM and turn off the device.
 	 */
-	pm_runtime_set_active(&client->dev);
+
+	/* Set the device's state to active if it's in D0 state. */
+	if (full_power)
+		pm_runtime_set_active(&client->dev);
 	pm_runtime_enable(&client->dev);
 	pm_runtime_idle(&client->dev);
 
@@ -1241,6 +1261,7 @@ static struct i2c_driver ov5675_i2c_driver = {
 	},
 	.probe_new = ov5675_probe,
 	.remove = ov5675_remove,
+	.flags = I2C_DRV_ACPI_WAIVE_D0_PROBE,
 };
 
 module_i2c_driver(ov5675_i2c_driver);
-- 
2.7.4