Re: [PATCH v3 3/3] media: i2c: imx274: Add IMX274 power on and off sequence

[Sowjanya Komatineni]

On 8/27/20 3:55 PM, Sowjanya Komatineni wrote:
> On 8/13/20 3:01 PM, Sakari Ailus wrote:
> > Hi Sowjanya,
> >
> > On Fri, Jul 31, 2020 at 09:34:15AM -0700, Sowjanya Komatineni wrote:
> > > On 7/31/20 9:26 AM, Sakari Ailus wrote:
> > > > Hi Sowjanya,
> > > >
> > > > Thanks for the patch.
> > > >
> > > > On Mon, Jul 20, 2020 at 10:01:34AM -0700, Sowjanya Komatineni wrote:
> > > > > IMX274 has VANA analog 2.8V supply, VDIG digital core 1.8V supply,
> > > > > and VDDL digital io 1.2V supply which are optional based on camera
> > > > > module design.
> > > > >
> > > > > IMX274 also need external 24Mhz clock and is optional based on
> > > > > camera module design.
> > > > The sensor appears to be able to use other frequencies, too. Could you
> > > > check in the driver the frequency is correct? This should be found 
> > > > in DT
> > > > bindings, too.
> > > External input clock is not in DT. So added it as part of this series.
> > >
> > > We are mostly using 24Mhz I/P with IMX274 on designs we have and 
> > > also on
> > > leopard module which has onboard XTAL for 24Mhz
> > Yes. This information still should be found in DT as the xtal isn't 
> > part of
> > the sensor.
> >
> > > > > This patch adds support for IMX274 power on and off to enable and
> > > > > disable these supplies and external clock.
> > > > >
> > > > > Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
> > > > > ---
> > > > >    drivers/media/i2c/imx274.c | 132 
> > > > > +++++++++++++++++++++++++++++++++++++++++++--
> > > > >    1 file changed, 129 insertions(+), 3 deletions(-)
> > > > >
> > > > > diff --git a/drivers/media/i2c/imx274.c b/drivers/media/i2c/imx274.c
> > > > > index 55869ff..7157b1d 100644
> > > > > --- a/drivers/media/i2c/imx274.c
> > > > > +++ b/drivers/media/i2c/imx274.c
> > > > > @@ -19,6 +19,7 @@
> > > > >    #include <linux/module.h>
> > > > >    #include <linux/of_gpio.h>
> > > > >    #include <linux/regmap.h>
> > > > > +#include <linux/regulator/consumer.h>
> > > > >    #include <linux/slab.h>
> > > > >    #include <linux/v4l2-mediabus.h>
> > > > >    #include <linux/videodev2.h>
> > > > > @@ -131,6 +132,15 @@
> > > > >    #define IMX274_TABLE_WAIT_MS            0
> > > > >    #define IMX274_TABLE_END            1
> > > > > +/* regulator supplies */
> > > > > +static const char * const imx274_supply_names[] = {
> > > > > +    "VDDL",  /* IF (1.2V) supply */
> > > > > +    "VDIG",  /* Digital Core (1.8V) supply */
> > > > > +    "VANA",  /* Analog (2.8V) supply */
> > > > > +};
> > > > > +
> > > > > +#define IMX274_NUM_SUPPLIES ARRAY_SIZE(imx274_supply_names)
> > > > Please use ARRAY_SIZE() directly.
> > > >
> > > > > +
> > > > >    /*
> > > > >     * imx274 I2C operation related structure
> > > > >     */
> > > > > @@ -501,6 +511,8 @@ struct imx274_ctrls {
> > > > >     * @frame_rate: V4L2 frame rate structure
> > > > >     * @regmap: Pointer to regmap structure
> > > > >     * @reset_gpio: Pointer to reset gpio
> > > > > + * @supplies: imx274 analog and digital supplies
> > > > > + * @inck: input clock to imx274
> > > > >     * @lock: Mutex structure
> > > > >     * @mode: Parameters for the selected readout mode
> > > > >     */
> > > > > @@ -514,6 +526,8 @@ struct stimx274 {
> > > > >        struct v4l2_fract frame_interval;
> > > > >        struct regmap *regmap;
> > > > >        struct gpio_desc *reset_gpio;
> > > > > +    struct regulator *supplies[IMX274_NUM_SUPPLIES];
> > > > > +    struct clk *inck;
> > > > >        struct mutex lock; /* mutex lock for operations */
> > > > >        const struct imx274_mode *mode;
> > > > >    };
> > > > > @@ -767,6 +781,99 @@ static void imx274_reset(struct stimx274 
> > > > > *priv, int rst)
> > > > >        usleep_range(IMX274_RESET_DELAY1, IMX274_RESET_DELAY2);
> > > > >    }
> > > > > +/*
> > > > > + * imx274_power_on - Function called to power on the sensor
> > > > > + * @imx274: Pointer to device structure
> > > > > + */
> > > > > +static int imx274_power_on(struct device *dev)
> > > > > +{
> > > > > +    struct i2c_client *client = to_i2c_client(dev);
> > > > > +    struct v4l2_subdev *sd = i2c_get_clientdata(client);
> > > > > +    struct stimx274 *imx274 = to_imx274(sd);
> > > > > +    int i, ret;
> > > > > +
> > > > > +    ret = clk_prepare_enable(imx274->inck);
> > > > > +    if (ret) {
> > > > > +        dev_err(&imx274->client->dev,
> > > > > +            "Failed to enable input clock: %d\n", ret);
> > > > > +        return ret;
> > > > > +    }
> > > > > +
> > > > Could you use regulator_bulk_enable() instead? Same for disable.
> > > Using regulator_bulk_enable() makes these regulators mandatory.
> > How? regulator_bulk_enable() simply does call regulator_enable() on 
> > all the
> > regulators.
> regulator_bulk APIs uses regulator_bulk_data and so had to retrieve 
> regulators from DT with devm_regulator_bulk_get() which don't use 
> optional regulator get.
Sorry, please ignore my above comment. Yes, will fix in v4 to use 
bulk_enable()