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From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: linux-i2c <linux-i2c@vger.kernel.org>,
	Wolfram Sang <wsa@the-dreams.de>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Rajmohan Mani <rajmohan.mani@intel.com>,
	Tomasz Figa <tfiga@chromium.org>,
	Bingbu Cao <bingbu.cao@intel.com>,
	Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>,
	Hyungwoo Yang <hyungwoo.yang@intel.com>,
	linux-media <linux-media@vger.kernel.org>
Subject: Re: [PATCH v8 6/6] at24: Support probing while off
Date: Wed, 9 Sep 2020 11:35:45 +0200
Message-ID: <CAMpxmJX40=iYYxL9Uvs1Pjj9c3NvZBGJ9Mh9-87T0c==FKEXRw@mail.gmail.com> (raw)
In-Reply-To: <20200903081550.6012-7-sakari.ailus@linux.intel.com>

On Thu, Sep 3, 2020 at 10:15 AM Sakari Ailus
<sakari.ailus@linux.intel.com> wrote:
>
> 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
>

This currently conflicts with the fix I queued for at24 for v5.9.
Which tree is going to take this series?

Bartosz

  reply index

Thread overview: 28+ 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 ` [PATCH v8 6/6] at24: Support probing while off Sakari Ailus
2020-09-09  9:35   ` Bartosz Golaszewski [this message]
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

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