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Message-ID: <772469b0-c279-6762-091d-821c58717941@wanadoo.fr>
Date: Wed, 20 Jul 2022 09:36:21 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Jacopo Mondi <jacopo@...ndi.org>,
Yassine Oudjana <yassine.oudjana@...il.com>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Tianshu Qiu <tian.shu.qiu@...el.com>,
Bingbu Cao <bingbu.cao@...el.com>,
Yassine Oudjana <y.oudjana@...tonmail.com>,
linux-media@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/3] media: i2c: ak7375: Add regulator management
Le 11/07/2022 à 19:31, Jacopo Mondi a écrit :
> Hi Yassine,
>
> On Mon, Jul 11, 2022 at 06:40:39PM +0400, Yassine Oudjana wrote:
>> From: Yassine Oudjana <y.oudjana@...tonmail.com>
>>
>> Make the driver get needed regulators on probe and enable/disable
>> them on runtime PM callbacks.
>>
>> Signed-off-by: Yassine Oudjana <y.oudjana@...tonmail.com>
>> ---
>> Changes since v1:
>> - Reorganize variable declaration
>> - Change the power-on delay range to 3000-3500 microseconds.
>>
>> drivers/media/i2c/ak7375.c | 39 ++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 39 insertions(+)
>>
>> diff --git a/drivers/media/i2c/ak7375.c b/drivers/media/i2c/ak7375.c
>> index 40b1a4aa846c..c2b2542a0056 100644
>> --- a/drivers/media/i2c/ak7375.c
>> +++ b/drivers/media/i2c/ak7375.c
>> @@ -6,6 +6,7 @@
>> #include <linux/i2c.h>
>> #include <linux/module.h>
>> #include <linux/pm_runtime.h>
>> +#include <linux/regulator/consumer.h>
>> #include <media/v4l2-ctrls.h>
>> #include <media/v4l2-device.h>
>>
>> @@ -23,17 +24,32 @@
>> */
>> #define AK7375_CTRL_STEPS 64
>> #define AK7375_CTRL_DELAY_US 1000
>> +/*
>> + * The vcm takes around 3 ms to power on and start taking
>> + * I2C messages. This value was found experimentally due to
>> + * lack of documentation.
>> + */
>> +#define AK7375_POWER_DELAY_US 3000
>>
>> #define AK7375_REG_POSITION 0x0
>> #define AK7375_REG_CONT 0x2
>> #define AK7375_MODE_ACTIVE 0x0
>> #define AK7375_MODE_STANDBY 0x40
>>
>> +static const char * const ak7375_supply_names[] = {
>> + "vdd",
>> + "vio",
>> +};
>> +
>> +#define AK7375_NUM_SUPPLIES ARRAY_SIZE(ak7375_supply_names)
>> +
>> /* ak7375 device structure */
>> struct ak7375_device {
>> struct v4l2_ctrl_handler ctrls_vcm;
>> struct v4l2_subdev sd;
>> struct v4l2_ctrl *focus;
>> + struct regulator_bulk_data supplies[AK7375_NUM_SUPPLIES];
>> +
>> /* active or standby mode */
>> bool active;
>> };
>> @@ -133,12 +149,24 @@ static int ak7375_probe(struct i2c_client *client)
>> {
>> struct ak7375_device *ak7375_dev;
>> int ret;
>> + int i;
>>
>> ak7375_dev = devm_kzalloc(&client->dev, sizeof(*ak7375_dev),
>> GFP_KERNEL);
>> if (!ak7375_dev)
>> return -ENOMEM;
>>
>> + for (i = 0; i < AK7375_NUM_SUPPLIES; i++)
>> + ak7375_dev->supplies[i].supply = ak7375_supply_names[i];
>> +
>> + ret = devm_regulator_bulk_get(&client->dev, AK7375_NUM_SUPPLIES,
>> + ak7375_dev->supplies);
>> + if (ret) {
>> + dev_err(&client->dev, "Failed to get regulators: %pe",
>> + ERR_PTR(ret));
>
> Why are you using %pe here ? Your return value is not a pointer
> (Also, missing \n at the end of the string)
>
> From Documentation/core-api/printk-formats.rst:
> %pe -ENOSPC
>
> For printing error pointers (i.e. a pointer for which IS_ERR() is true)
> as a symbolic error name. Error values for which no symbolic name is
> known are printed in decimal, while a non-ERR_PTR passed as the
> argument to %pe gets treated as ordinary %p.
>
Nit: using:
+ return dev_err_probe(&client->dev, ret, "Failed to get regulators);
would be even simpler.
CJ
>> + return ret;
>> + }
>> +
>> v4l2_i2c_subdev_init(&ak7375_dev->sd, client, &ak7375_ops);
>> ak7375_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>> ak7375_dev->sd.internal_ops = &ak7375_int_ops;
>> @@ -210,6 +238,10 @@ static int __maybe_unused ak7375_vcm_suspend(struct device *dev)
>> if (ret)
>> dev_err(dev, "%s I2C failure: %d\n", __func__, ret);
>>
>> + ret = regulator_bulk_disable(AK7375_NUM_SUPPLIES, ak7375_dev->supplies);
>> + if (ret)
>> + return ret;
>> +
>> ak7375_dev->active = false;
>>
>> return 0;
>> @@ -230,6 +262,13 @@ static int __maybe_unused ak7375_vcm_resume(struct device *dev)
>> if (ak7375_dev->active)
>> return 0;
>>
>> + ret = regulator_bulk_enable(AK7375_NUM_SUPPLIES, ak7375_dev->supplies);
>> + if (ret)
>> + return ret;
>> +
>> + /* Wait for vcm to become ready */
>> + usleep_range(AK7375_POWER_DELAY_US, AK7375_POWER_DELAY_US + 500);
>> +
>> ret = ak7375_i2c_write(ak7375_dev, AK7375_REG_CONT,
>> AK7375_MODE_ACTIVE, 1);
>> if (ret) {
>> --
>> 2.37.0
>>
>
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