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 v10 7/7] at24: Support probing while off
Date: Fri, 5 Feb 2021 15:25:05 +0200 [thread overview]
Message-ID: <20210205132505.20173-8-sakari.ailus@linux.intel.com> (raw)
In-Reply-To: <20210205132505.20173-1-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 powered off. For this to happen, a hint in form
of a device property is required from the firmware.
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..69a5e4023d9e1 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 off_during_probe;
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;
- }
+ off_during_probe = acpi_dev_state_low_power(&client->dev);
+ if (!off_during_probe) {
+ 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 (!off_during_probe) {
+ 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_low_power(&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_FL_ALLOW_LOW_POWER_PROBE,
};
static int __init at24_init(void)
--
2.20.1
next prev parent reply other threads:[~2021-02-05 13:37 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-05 13:24 [PATCH v10 0/7] Support running driver's probe for a device powered off Sakari Ailus
2021-02-05 13:24 ` [PATCH v10 1/7] ACPI: scan: Obtain device's desired enumeration power state Sakari Ailus
2021-02-05 13:25 ` [PATCH v10 2/7] i2c: Allow an ACPI driver to manage the device's power state during probe Sakari Ailus
2021-02-09 21:04 ` Wolfram Sang
2021-02-10 20:46 ` Sakari Ailus
2021-02-10 22:27 ` Sakari Ailus
2021-02-12 7:18 ` Wolfram Sang
2021-02-05 13:25 ` [PATCH v10 3/7] Documentation: ACPI: Document _DSE object usage for enum power state Sakari Ailus
2021-02-06 0:56 ` Randy Dunlap
2021-02-08 8:01 ` Sakari Ailus
2021-02-08 15:52 ` Randy Dunlap
2021-02-05 13:25 ` [PATCH v10 4/7] ACPI: Add a convenience function to tell a device is in low " Sakari Ailus
2021-02-05 13:25 ` [PATCH v10 5/7] ov5670: Support probe whilst the device is in a " Sakari Ailus
2021-02-05 13:25 ` [PATCH v10 6/7] media: i2c: imx319: Support probe while the device is off Sakari Ailus
2021-02-05 13:25 ` Sakari Ailus [this message]
2021-02-08 16:44 ` [PATCH v10 7/7] at24: Support probing while off Bartosz Golaszewski
2021-02-08 16:54 ` Rafael J. Wysocki
2021-02-09 15:49 ` Bartosz Golaszewski
2021-02-09 16:23 ` Sakari Ailus
2021-02-09 16:42 ` Rafael J. Wysocki
2021-02-09 16:54 ` Sakari Ailus
2021-02-09 16:58 ` Rafael J. Wysocki
2021-02-10 8:41 ` Sakari Ailus
2021-02-10 12:26 ` Bartosz Golaszewski
2021-02-10 20:46 ` Sakari Ailus
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