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 v8 6/6] at24: Support probing while off
Date: Thu, 3 Sep 2020 11:15:50 +0300 [thread overview]
Message-ID: <20200903081550.6012-7-sakari.ailus@linux.intel.com> (raw)
In-Reply-To: <20200903081550.6012-1-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>
---
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 8f5de5f10bbea..2d24e33788d7d 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 low_power;
struct regmap *regmap;
bool writable;
u8 test_byte;
@@ -733,25 +734,30 @@ 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;
- }
+ low_power = acpi_dev_state_low_power(&client->dev);
+ if (!low_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);
/*
- * 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 (!low_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);
@@ -771,9 +777,11 @@ 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;
}
@@ -810,6 +818,7 @@ 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:[~2020-09-03 8:16 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 8:15 [PATCH v8 0/6] Support running driver's probe for a device powered off Sakari Ailus
2020-09-03 8:15 ` [PATCH v8 1/6] i2c: Allow an ACPI driver to manage the device's power state during probe Sakari Ailus
2020-09-03 8:15 ` [PATCH v8 2/6] Documentation: ACPI: Document i2c-allow-low-power-probe _DSD property Sakari Ailus
2020-09-03 8:15 ` [PATCH v8 3/6] ACPI: Add a convenience function to tell a device is in low power state Sakari Ailus
[not found] ` <0c2d4728-6e32-ef93-8961-381fe36cfdaa@linux.intel.com>
2020-09-11 13:01 ` Sakari Ailus
2020-09-03 8:15 ` [PATCH v8 4/6] ov5670: Support probe whilst the device is in a " Sakari Ailus
2020-09-03 8:15 ` [PATCH v8 5/6] media: i2c: imx319: Support probe while the device is off Sakari Ailus
2020-09-03 8:15 ` Sakari Ailus [this message]
2020-09-09 9:35 ` [PATCH v8 6/6] at24: Support probing while off Bartosz Golaszewski
2020-09-09 11:11 ` Wolfram Sang
2020-09-09 11:56 ` Bartosz Golaszewski
2020-09-09 12:16 ` Sakari Ailus
2020-09-11 12:11 ` Sakari Ailus
2020-10-06 11:20 ` Tomasz Figa
2020-10-06 11:23 ` Tomasz Figa
2020-09-11 12:49 ` [PATCH v8 0/6] Support running driver's probe for a device powered off Luca Ceresoli
2020-09-11 13:01 ` Sakari Ailus
2020-09-14 7:58 ` Luca Ceresoli
[not found] ` <20200914094727.GM26842@paasikivi.fi.intel.com>
2020-09-14 16:49 ` Luca Ceresoli
2020-09-23 11:08 ` Sakari Ailus
2020-09-23 15:37 ` Luca Ceresoli
2020-09-26 12:38 ` Tomasz Figa
2020-09-27 19:39 ` Wolfram Sang
2020-09-27 19:44 ` Tomasz Figa
2020-09-28 14:17 ` Rafael J. Wysocki
2020-09-28 16:49 ` Tomasz Figa
2020-09-28 20:49 ` Sakari Ailus
2020-09-26 12:46 ` Tomasz Figa
2021-01-28 23:27 ` [PATCH v9 1/7] ACPI: scan: Obtain device's desired enumeration power state Sakari Ailus
[not found] ` <CAJZ5v0hdG1W0D5E6GbrTDiAjMyC0mSgb3Z2WEBy3hhb4iJhDNw@mail.gmail.com>
2021-01-29 16:45 ` Sakari Ailus
2021-01-29 16:57 ` Rafael J. Wysocki
2021-01-29 21:22 ` Sakari Ailus
2021-02-01 11:44 ` Rafael J. Wysocki
2021-01-28 23:27 ` [PATCH v9 2/7] i2c: Allow an ACPI driver to manage the device's power state during probe Sakari Ailus
2021-01-28 23:27 ` [PATCH v9 3/7] Documentation: ACPI: Document _PRE object usage for enum power state Sakari Ailus
2021-01-28 23:27 ` [PATCH v9 4/7] ACPI: Add a convenience function to tell a device is in low " Sakari Ailus
2021-01-28 23:27 ` [PATCH v9 5/7] ov5670: Support probe whilst the device is in a " Sakari Ailus
2021-01-28 23:27 ` [PATCH v9 6/7] media: i2c: imx319: Support probe while the device is off Sakari Ailus
2021-01-29 2:58 ` Bingbu Cao
2021-01-28 23:27 ` [PATCH v9 7/7] at24: Support probing while off Sakari Ailus
[not found] ` <CAMpxmJVTPgvxOVdTkmt4VjUnGabNBKauKF_DKtnnkV6O0QYTWA@mail.gmail.com>
[not found] ` <20210129121955.GH32460@paasikivi.fi.intel.com>
2021-02-01 8:57 ` Bartosz Golaszewski
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