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From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: linux-i2c@vger.kernel.org
Cc: Wolfram Sang <wsa@the-dreams.de>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	rajmohan.mani@intel.com, Tomasz Figa <tfiga@chromium.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Bingbu Cao <bingbu.cao@intel.com>,
	Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>,
	Hyungwoo Yang <hyungwoo.yang@intel.com>,
	linux-media@vger.kernel.org
Subject: [PATCH v11 7/7] at24: Support probing while in non-zero ACPI D state
Date: Thu, 11 Feb 2021 01:08:00 +0200	[thread overview]
Message-ID: <20210210230800.30291-8-sakari.ailus@linux.intel.com> (raw)
In-Reply-To: <20210210230800.30291-1-sakari.ailus@linux.intel.com>

In certain use cases (where the chip is part of a camera module, and the
camera module is wired together with a camera privacy LED), powering on
the device during probe is undesirable. Add support for the at24 to
execute probe while being in ACPI D state other than 0 (which means fully
powered on).

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
---
 drivers/misc/eeprom/at24.c | 43 +++++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 926408b41270c..427520af9961e 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -595,6 +595,7 @@ static int at24_probe(struct i2c_client *client)
 	bool i2c_fn_i2c, i2c_fn_block;
 	unsigned int i, num_addresses;
 	struct at24_data *at24;
+	bool full_power;
 	struct regmap *regmap;
 	bool writable;
 	u8 test_byte;
@@ -750,14 +751,16 @@ static int at24_probe(struct i2c_client *client)
 
 	i2c_set_clientdata(client, at24);
 
-	err = regulator_enable(at24->vcc_reg);
-	if (err) {
-		dev_err(dev, "Failed to enable vcc regulator\n");
-		return err;
-	}
+	full_power = acpi_dev_state_d0(&client->dev);
+	if (full_power) {
+		err = regulator_enable(at24->vcc_reg);
+		if (err) {
+			dev_err(dev, "Failed to enable vcc regulator\n");
+			return err;
+		}
 
-	/* enable runtime pm */
-	pm_runtime_set_active(dev);
+		pm_runtime_set_active(dev);
+	}
 	pm_runtime_enable(dev);
 
 	at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
@@ -768,14 +771,17 @@ static int at24_probe(struct i2c_client *client)
 	}
 
 	/*
-	 * Perform a one-byte test read to verify that the
-	 * chip is functional.
+	 * Perform a one-byte test read to verify that the chip is functional,
+	 * unless powering on the device is to be avoided during probe (i.e.
+	 * it's powered off right now).
 	 */
-	err = at24_read(at24, 0, &test_byte, 1);
-	if (err) {
-		pm_runtime_disable(dev);
-		regulator_disable(at24->vcc_reg);
-		return -ENODEV;
+	if (full_power) {
+		err = at24_read(at24, 0, &test_byte, 1);
+		if (err) {
+			pm_runtime_disable(dev);
+			regulator_disable(at24->vcc_reg);
+			return -ENODEV;
+		}
 	}
 
 	pm_runtime_idle(dev);
@@ -795,9 +801,11 @@ static int at24_remove(struct i2c_client *client)
 	struct at24_data *at24 = i2c_get_clientdata(client);
 
 	pm_runtime_disable(&client->dev);
-	if (!pm_runtime_status_suspended(&client->dev))
-		regulator_disable(at24->vcc_reg);
-	pm_runtime_set_suspended(&client->dev);
+	if (acpi_dev_state_d0(&client->dev)) {
+		if (!pm_runtime_status_suspended(&client->dev))
+			regulator_disable(at24->vcc_reg);
+		pm_runtime_set_suspended(&client->dev);
+	}
 
 	return 0;
 }
@@ -834,6 +842,7 @@ static struct i2c_driver at24_driver = {
 	.probe_new = at24_probe,
 	.remove = at24_remove,
 	.id_table = at24_ids,
+	.flags = I2C_DRV_ACPI_WAIVE_D0_PROBE,
 };
 
 static int __init at24_init(void)
-- 
2.20.1


  parent reply	other threads:[~2021-02-10 23:16 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-10 23:07 [PATCH v11 0/7] Support running driver's probe for a device powered off Sakari Ailus
2021-02-10 23:07 ` [PATCH v11 1/7] ACPI: scan: Obtain device's desired enumeration power state Sakari Ailus
2021-02-11 19:10   ` Rafael J. Wysocki
2021-10-07  2:25   ` Rajat Jain
2021-10-18 20:23     ` Sakari Ailus
2021-10-19 20:07       ` Rajat Jain
2022-01-10 18:55       ` Rajat Jain
2022-01-10 22:31         ` Sakari Ailus
2021-02-10 23:07 ` [PATCH v11 2/7] i2c: Allow an ACPI driver to manage the device's power state during probe Sakari Ailus
2021-02-10 23:07 ` [PATCH v11 3/7] Documentation: ACPI: Document _DSE object usage for enum power state Sakari Ailus
2021-02-10 23:07 ` [PATCH v11 4/7] ACPI: Add a convenience function to tell a device is in D0 state Sakari Ailus
2021-02-10 23:07 ` [PATCH v11 5/7] ov5670: Support probe whilst the device is in ACPI D state other than 0 Sakari Ailus
2021-02-10 23:07 ` [PATCH v11 6/7] media: i2c: imx319: Support device probe in non-zero ACPI D state Sakari Ailus
2021-02-10 23:08 ` Sakari Ailus [this message]
2021-02-11  9:50   ` [PATCH v11 7/7] at24: Support probing while " Bartosz Golaszewski

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