From: Bingbu Cao <bingbu.cao@linux.intel.com>
To: Sakari Ailus <sakari.ailus@linux.intel.com>, linux-i2c@vger.kernel.org
Cc: Wolfram Sang <wsa@the-dreams.de>,
"Rafael J. Wysocki" <rafael@kernel.org>,
linux-acpi@vger.kernel.org, Bingbu Cao <bingbu.cao@intel.com>,
linux-media@vger.kernel.org,
Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>,
Hyungwoo Yang <hyungwoo.yang@intel.com>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
rajmohan.mani@intel.com, Tomasz Figa <tfiga@chromium.org>,
"Qiu, Tian Shu" <tian.shu.qiu@intel.com>
Subject: Re: [PATCH v5 3/6] ov5670: Support probe whilst the device is in a low power state
Date: Fri, 14 Aug 2020 12:49:44 +0800 [thread overview]
Message-ID: <71c513bb-f367-2cc7-24cd-ce7f17c1e07d@linux.intel.com> (raw)
In-Reply-To: <7a1fa217-7fd1-1d36-0b1c-ad5d09ea11a0@linux.intel.com>
On 8/12/20 5:12 PM, Bingbu Cao wrote:
>
>
> On 8/10/20 10:27 PM, Sakari Ailus wrote:
>> Tell ACPI device PM code that the driver supports the device being in a
>> low power state when the driver's probe function is entered.
>>
>> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
>> ---
>> drivers/media/i2c/ov5670.c | 23 ++++++++++++++---------
>> 1 file changed, 14 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/media/i2c/ov5670.c b/drivers/media/i2c/ov5670.c
>> index f26252e35e08d..1f75b888d2a18 100644
>> --- a/drivers/media/i2c/ov5670.c
>> +++ b/drivers/media/i2c/ov5670.c
>> @@ -2456,6 +2456,7 @@ static int ov5670_probe(struct i2c_client *client)
>> struct ov5670 *ov5670;
>> const char *err_msg;
>> u32 input_clk = 0;
>> + bool low_power;
>> int ret;
>>
>> device_property_read_u32(&client->dev, "clock-frequency", &input_clk);
>> @@ -2472,11 +2473,14 @@ static int ov5670_probe(struct i2c_client *client)
>> /* Initialize subdev */
>> v4l2_i2c_subdev_init(&ov5670->sd, client, &ov5670_subdev_ops);
>>
>> - /* Check module identity */
>> - ret = ov5670_identify_module(ov5670);
>> - if (ret) {
>> - err_msg = "ov5670_identify_module() error";
>> - goto error_print;
>> + low_power = acpi_dev_state_low_power(&client->dev);
>> + if (!low_power) {
>> + /* Check module identity */
>> + ret = ov5670_identify_module(ov5670);
>> + if (ret) {
>> + err_msg = "ov5670_identify_module() error";
>> + goto error_print;
>> +
>
> Sakari, thanks for your patch.
> one question - With this change, there will be no chance for driver to guarantee
> that the camera sensor plugged in is the camera that the matched driver actually
> can drive until try to streaming the camera, so is it necessary to return
> appropriate error in .s_stream ops to notify user it is not the hardware that
> current driver can drive? if no other better way.
Sakari, please ignore my previous comment, it is not related to this change. I
see the sub device open is caused by v4l_id program from udev.
>
--
Best regards,
Bingbu Cao
next prev parent reply other threads:[~2020-08-14 4:51 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-10 14:27 [PATCH v5 0/6] Support running driver's probe for a device powered off Sakari Ailus
2020-08-10 14:27 ` [PATCH v5 1/6] i2c: Allow driver to manage the device's power state during probe Sakari Ailus
2020-08-10 14:41 ` Sudeep Holla
2020-08-11 8:57 ` Sakari Ailus
2020-08-10 14:27 ` [PATCH v5 2/6] ACPI: Add a convenience function to tell a device is in low power state Sakari Ailus
2020-08-10 14:27 ` [PATCH v5 3/6] ov5670: Support probe whilst the device is in a " Sakari Ailus
2020-08-12 9:12 ` Bingbu Cao
2020-08-12 9:22 ` Sakari Ailus
2020-08-14 4:49 ` Bingbu Cao [this message]
2020-08-10 14:27 ` [PATCH v5 4/6] media: i2c: imx319: Support probe while the device is off Sakari Ailus
2020-08-10 14:27 ` [PATCH v5 5/6] at24: Support probing while off Sakari Ailus
2020-08-10 14:27 ` [PATCH v5 6/6] Documentation: ACPI: Document allow-low-power-probe _DSD property Sakari Ailus
2020-08-14 4:11 ` [PATCH v5 0/6] Support running driver's probe for a device powered off Bingbu Cao
2020-08-14 6:18 ` Bingbu Cao
2020-08-14 13:17 ` Tomasz Figa
2020-08-18 11:04 ` Sakari Ailus
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