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Date:   Tue, 26 May 2020 12:16:20 +0300
From:   Sakari Ailus <sakari.ailus@iki.fi>
To:     Andrey Konovalov <andrey.konovalov@linaro.org>
Cc:     mchehab@kernel.org, manivannan.sadhasivam@linaro.org,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        c.barrett@framos.com, a.brela@framos.com, peter.griffin@linaro.org
Subject: Re: [PATCH v3 04/10] media: i2c: imx290: Add support for 2 data lanes
Message-ID: <20200526091620.GI8214@valkosipuli.retiisi.org.uk>
References: <20200524192505.20682-1-andrey.konovalov@linaro.org>
 <20200524192505.20682-5-andrey.konovalov@linaro.org>
 <20200526090127.GG8214@valkosipuli.retiisi.org.uk>
 <d68dda83-2911-be57-c5b9-b482fe1fa0ca@linaro.org>
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Hi Andrey,

On Tue, May 26, 2020 at 12:14:33PM +0300, Andrey Konovalov wrote:
> Hi Sakari,
> 
> Thank you for the review
> 
> On 26.05.2020 12:01, Sakari Ailus wrote:
> > Hi Andrey,
> > 
> > On Sun, May 24, 2020 at 10:24:59PM +0300, Andrey Konovalov wrote:
> > > From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > 
> > > The IMX290 sensor can output frames with 2/4 CSI2 data lanes. This commit
> > > adds support for 2 lane mode in addition to the 4 lane and also
> > > configuring the data lane settings in the driver based on system
> > > configuration.
> > > 
> > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
> > > ---
> > >   drivers/media/i2c/imx290.c | 133 ++++++++++++++++++++++++++++++++++---
> > >   1 file changed, 124 insertions(+), 9 deletions(-)
> > > 
> > > diff --git a/drivers/media/i2c/imx290.c b/drivers/media/i2c/imx290.c
> > > index 7b1de1f0c8b7..a361c9ac8bd5 100644
> > > --- a/drivers/media/i2c/imx290.c
> > > +++ b/drivers/media/i2c/imx290.c
> > > @@ -25,7 +25,18 @@
> > >   #define IMX290_STANDBY 0x3000
> > >   #define IMX290_REGHOLD 0x3001
> > >   #define IMX290_XMSTA 0x3002
> > > +#define IMX290_FR_FDG_SEL 0x3009
> > >   #define IMX290_GAIN 0x3014
> > > +#define IMX290_HMAX_LOW 0x301c
> > > +#define IMX290_HMAX_HIGH 0x301d
> > > +#define IMX290_PHY_LANE_NUM 0x3407
> > > +#define IMX290_CSI_LANE_MODE 0x3443
> > > +
> > > +/* HMAX fields */
> > > +#define IMX290_HMAX_2_1920 0x1130
> > > +#define IMX290_HMAX_4_1920 0x0898
> > > +#define IMX290_HMAX_2_720 0x19C8
> > > +#define IMX290_HMAX_4_720 0x0CE4
> > >   #define IMX290_DEFAULT_LINK_FREQ 445500000
> > > @@ -56,6 +67,7 @@ struct imx290 {
> > >   	struct device *dev;
> > >   	struct clk *xclk;
> > >   	struct regmap *regmap;
> > > +	u8 nlanes;
> > >   	struct v4l2_subdev sd;
> > >   	struct v4l2_fwnode_endpoint ep;
> > > @@ -89,14 +101,11 @@ static const struct regmap_config imx290_regmap_config = {
> > >   static const struct imx290_regval imx290_global_init_settings[] = {
> > >   	{ 0x3007, 0x00 },
> > > -	{ 0x3009, 0x00 },
> > >   	{ 0x3018, 0x65 },
> > >   	{ 0x3019, 0x04 },
> > >   	{ 0x301a, 0x00 },
> > > -	{ 0x3443, 0x03 },
> > >   	{ 0x3444, 0x20 },
> > >   	{ 0x3445, 0x25 },
> > > -	{ 0x3407, 0x03 },
> > >   	{ 0x303a, 0x0c },
> > >   	{ 0x3040, 0x00 },
> > >   	{ 0x3041, 0x00 },
> > > @@ -169,7 +178,6 @@ static const struct imx290_regval imx290_1080p_settings[] = {
> > >   	{ 0x3164, 0x1a },
> > >   	{ 0x3480, 0x49 },
> > >   	/* data rate settings */
> > > -	{ 0x3009, 0x01 },
> > >   	{ 0x3405, 0x10 },
> > >   	{ 0x3446, 0x57 },
> > >   	{ 0x3447, 0x00 },
> > > @@ -187,8 +195,6 @@ static const struct imx290_regval imx290_1080p_settings[] = {
> > >   	{ 0x3453, 0x00 },
> > >   	{ 0x3454, 0x17 },
> > >   	{ 0x3455, 0x00 },
> > > -	{ 0x301c, 0x98 },
> > > -	{ 0x301d, 0x08 },
> > >   };
> > >   static const struct imx290_regval imx290_720p_settings[] = {
> > > @@ -210,7 +216,6 @@ static const struct imx290_regval imx290_720p_settings[] = {
> > >   	{ 0x3164, 0x1a },
> > >   	{ 0x3480, 0x49 },
> > >   	/* data rate settings */
> > > -	{ 0x3009, 0x01 },
> > >   	{ 0x3405, 0x10 },
> > >   	{ 0x3446, 0x4f },
> > >   	{ 0x3447, 0x00 },
> > > @@ -228,8 +233,6 @@ static const struct imx290_regval imx290_720p_settings[] = {
> > >   	{ 0x3453, 0x00 },
> > >   	{ 0x3454, 0x17 },
> > >   	{ 0x3455, 0x00 },
> > > -	{ 0x301c, 0xe4 },
> > > -	{ 0x301d, 0x0c },
> > >   };
> > >   static const struct imx290_regval imx290_10bit_settings[] = {
> > > @@ -522,6 +525,25 @@ static int imx290_write_current_format(struct imx290 *imx290,
> > >   	return 0;
> > >   }
> > > +static int imx290_set_hmax(struct imx290 *imx290, u32 val)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = imx290_write_reg(imx290, IMX290_HMAX_LOW, (val & 0xff));
> > > +	if (ret) {
> > > +		dev_err(imx290->dev, "Error setting HMAX register\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	ret = imx290_write_reg(imx290, IMX290_HMAX_HIGH, ((val >> 8) & 0xff));
> > > +	if (ret) {
> > > +		dev_err(imx290->dev, "Error setting HMAX register\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > >   /* Start streaming */
> > >   static int imx290_start_streaming(struct imx290 *imx290)
> > >   {
> > > @@ -551,6 +573,40 @@ static int imx290_start_streaming(struct imx290 *imx290)
> > >   		return ret;
> > >   	}
> > > +	switch (imx290->nlanes) {
> > > +	case 2:
> > > +		if (imx290->current_mode->width == 1920) {
> > > +			ret = imx290_set_hmax(imx290, IMX290_HMAX_2_1920);
> > > +			if (ret < 0)
> > > +				return ret;
> > > +		} else {
> > > +			ret = imx290_set_hmax(imx290, IMX290_HMAX_2_720);
> > > +			if (ret < 0)
> > > +				return ret;
> > > +		}
> > > +
> > > +		break;
> > > +	case 4:
> > > +		if (imx290->current_mode->width == 1920) {
> > > +			ret = imx290_set_hmax(imx290, IMX290_HMAX_4_1920);
> > > +			if (ret < 0)
> > > +				return ret;
> > > +		} else {
> > > +			ret = imx290_set_hmax(imx290, IMX290_HMAX_4_720);
> > > +			if (ret < 0)
> > > +				return ret;
> > 
> > I think it'd be nicer to put this where the mode definitions are, to avoid
> > scattering the configuration around the driver.
> 
> Would it be OK if I move this inside imx290_write_current_format()?

It'd still be separated from the mode there. My point was that it is
specific to the mode, and should be associated with it.

> 
> > > +		}
> > > +
> > > +		break;
> > > +	default:
> > > +		/*
> > > +		 * We should never hit this since the data lane count is
> > > +		 * validated in probe itself
> > > +		 */
> > > +		dev_err(imx290->dev, "Lane configuration not supported\n");
> > > +		return -EINVAL;
> > > +	}
> > > +
> > >   	/* Apply customized values from user */
> > >   	ret = v4l2_ctrl_handler_setup(imx290->sd.ctrl_handler);
> > >   	if (ret) {
> > > @@ -607,6 +663,49 @@ static int imx290_get_regulators(struct device *dev, struct imx290 *imx290)
> > >   				       imx290->supplies);
> > >   }
> > > +static int imx290_set_data_lanes(struct imx290 *imx290)
> > > +{
> > > +	int ret = 0, laneval, frsel;
> > > +
> > > +	switch (imx290->nlanes) {
> > > +	case 2:
> > > +		laneval = 0x01;
> > > +		frsel = 0x02;
> > > +		break;
> > > +	case 4:
> > > +		laneval = 0x03;
> > > +		frsel = 0x01;
> > > +		break;
> > > +	default:
> > > +		/*
> > > +		 * We should never hit this since the data lane count is
> > > +		 * validated in probe itself
> > > +		 */
> > > +		dev_err(imx290->dev, "Lane configuration not supported\n");
> > > +		ret = -EINVAL;
> > > +		goto exit;
> > > +	}
> > > +
> > > +	ret = imx290_write_reg(imx290, IMX290_PHY_LANE_NUM, laneval);
> > > +	if (ret) {
> > > +		dev_err(imx290->dev, "Error setting Physical Lane number register\n");
> > > +		goto exit;
> > > +	}
> > > +
> > > +	ret = imx290_write_reg(imx290, IMX290_CSI_LANE_MODE, laneval);
> > > +	if (ret) {
> > > +		dev_err(imx290->dev, "Error setting CSI Lane mode register\n");
> > > +		goto exit;
> > > +	}
> > > +
> > > +	ret = imx290_write_reg(imx290, IMX290_FR_FDG_SEL, frsel);
> > > +	if (ret)
> > > +		dev_err(imx290->dev, "Error setting FR/FDG SEL register\n");
> > > +
> > > +exit:
> > > +	return ret;
> > > +}
> > > +
> > >   static int imx290_power_on(struct device *dev)
> > >   {
> > >   	struct i2c_client *client = to_i2c_client(dev);
> > > @@ -631,6 +730,9 @@ static int imx290_power_on(struct device *dev)
> > >   	gpiod_set_value_cansleep(imx290->rst_gpio, 0);
> > >   	usleep_range(30000, 31000);
> > > +	/* Set data lane count */
> > > +	imx290_set_data_lanes(imx290);
> > > +
> > >   	return 0;
> > >   }
> > > @@ -703,6 +805,16 @@ static int imx290_probe(struct i2c_client *client)
> > >   		goto free_err;
> > >   	}
> > > +	/* Get number of data lanes */
> > 
> > While at it, could you set the PHY type in the V4L2 fwnode endpoint before
> > parsing the data using v4l2_fwnode_endpoint_alloc_parse()?
> 
> This is currently done in "[PATCH v3 10/10] media: i2c: imx290: set bus_type
> before calling v4l2_fwnode_endpoint_alloc_parse()" (along with some more
> clean-ups for the probe()). I can merge the PHY type in the V4L2 fwnode endpoint
> change into this patch.

Ack, I hadn't gotten that far yet. It's fine to keep it as-is.

-- 
Regards,

Sakari Ailus