Re: [PATCH v2 3/3] media: i2c: ak7375: Add regulator management

[Christophe JAILLET]

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@xxxxxxxxxxxxxx>
> >
> > Make the driver get needed regulators on probe and enable/disable
> > them on runtime PM callbacks.
> >
> > Signed-off-by: Yassine Oudjana <y.oudjana@xxxxxxxxxxxxxx>
> > ---
> > 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