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SubjectRe: [PATCH 2/2] media: i2c: imx219: Support four-lane operation
On Wed, Jul 27, 2022 at 9:30 AM Dave Stevenson
<dave.stevenson@raspberrypi.com> wrote:
>
> Hi Adam
>
> Sorry for the delay in reviewing.
>
> On Sat, 9 Jul 2022 at 14:51, Adam Ford <aford173@gmail.com> wrote:
> >
> > The imx219 camera is capable of either two-lane or four-lane
> > operation. When operating in four-lane, both the pixel rate and
> > link frequency change. Regardless of the mode, however, both
> > frequencies remain fixed.
> >
> > Helper functions are needed to read and set pixel and link frequencies
> > which also reduces the number of fixed registers in the table of modes.
> >
> > Since the link frequency and number of lanes is extracted from the
> > endpoint, move the endpoint handling into the probe function and
> > out of the imx219_check_hwcfg. This simplifies the imx219_check_hwcfg
> > just a bit.
>
> This paragraph isn't relevant any more.

Oops. I forgot to review the commit message. I'll fix on V4.
>
> > Signed-off-by: Adam Ford <aford173@gmail.com>
> > ---
> > V3: Keep the helper function doing the link and lane parsing to
> > keep th probe function small.
> >
> > diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> > index faa5dab3c2ec..bb4125e7e113 100644
> > --- a/drivers/media/i2c/imx219.c
> > +++ b/drivers/media/i2c/imx219.c
> > @@ -42,10 +42,16 @@
> > /* External clock frequency is 24.0M */
> > #define IMX219_XCLK_FREQ 24000000
> >
> > -/* Pixel rate is fixed at 182.4M for all the modes */
> > +/* Pixel rate is fixed for all the modes */
> > #define IMX219_PIXEL_RATE 182400000
> > +#define IMX219_PIXEL_RATE_4LANE 280800000
> >
> > #define IMX219_DEFAULT_LINK_FREQ 456000000
> > +#define IMX219_DEFAULT_LINK_FREQ_4LANE 363000000
> > +
> > +#define IMX219_REG_CSI_LANE_MODE 0x0114
> > +#define IMX219_CSI_2_LANE_MODE 0x01
> > +#define IMX219_CSI_4_LANE_MODE 0x03
> >
> > /* V_TIMING internal */
> > #define IMX219_REG_VTS 0x0160
> > @@ -299,6 +305,10 @@ static const s64 imx219_link_freq_menu[] = {
> > IMX219_DEFAULT_LINK_FREQ,
> > };
> >
> > +static const s64 imx219_link_freq_4lane_menu[] = {
> > + IMX219_DEFAULT_LINK_FREQ_4LANE,
> > +};
> > +
> > static const char * const imx219_test_pattern_menu[] = {
> > "Disabled",
> > "Color Bars",
> > @@ -474,6 +484,9 @@ struct imx219 {
> >
> > /* Streaming on/off */
> > bool streaming;
> > +
> > + /* Two or Four lanes */
> > + u8 lanes;
> > };
> >
> > static inline struct imx219 *to_imx219(struct v4l2_subdev *_sd)
> > @@ -936,6 +949,13 @@ static int imx219_get_selection(struct v4l2_subdev *sd,
> > return -EINVAL;
> > }
> >
> > +static int imx219_configure_lanes(struct imx219 *imx219)
> > +{
> > + return imx219_write_reg(imx219, IMX219_REG_CSI_LANE_MODE,
> > + IMX219_REG_VALUE_08BIT, (imx219->lanes == 2) ?
> > + IMX219_CSI_2_LANE_MODE : IMX219_CSI_4_LANE_MODE);
> > +};
> > +
> > static int imx219_start_streaming(struct imx219 *imx219)
> > {
> > struct i2c_client *client = v4l2_get_subdevdata(&imx219->sd);
> > @@ -953,6 +973,13 @@ static int imx219_start_streaming(struct imx219 *imx219)
> > goto err_rpm_put;
> > }
> >
> > + /* Configure two or four Lane mode */
> > + ret = imx219_configure_lanes(imx219);
> > + if (ret) {
> > + dev_err(&client->dev, "%s failed to configure lanes\n", __func__);
> > + goto err_rpm_put;
> > + }
> > +
> > /* Apply default values of current mode */
> > reg_list = &imx219->mode->reg_list;
> > ret = imx219_write_regs(imx219, reg_list->regs, reg_list->num_of_regs);
> > @@ -1184,6 +1211,11 @@ static const struct v4l2_subdev_internal_ops imx219_internal_ops = {
> > .open = imx219_open,
> > };
> >
> > +static unsigned long imx219_get_pixel_rate(struct imx219 *imx219)
> > +{
> > + return (imx219->lanes == 2) ? IMX219_PIXEL_RATE : IMX219_PIXEL_RATE_4LANE;
> > +}
> > +
> > /* Initialize control handlers */
> > static int imx219_init_controls(struct imx219 *imx219)
> > {
> > @@ -1205,15 +1237,16 @@ static int imx219_init_controls(struct imx219 *imx219)
> > /* By default, PIXEL_RATE is read only */
> > imx219->pixel_rate = v4l2_ctrl_new_std(ctrl_hdlr, &imx219_ctrl_ops,
> > V4L2_CID_PIXEL_RATE,
> > - IMX219_PIXEL_RATE,
> > - IMX219_PIXEL_RATE, 1,
> > - IMX219_PIXEL_RATE);
> > + imx219_get_pixel_rate(imx219),
> > + imx219_get_pixel_rate(imx219), 1,
> > + imx219_get_pixel_rate(imx219));
> >
> > imx219->link_freq =
> > v4l2_ctrl_new_int_menu(ctrl_hdlr, &imx219_ctrl_ops,
> > V4L2_CID_LINK_FREQ,
> > ARRAY_SIZE(imx219_link_freq_menu) - 1, 0,
> > - imx219_link_freq_menu);
> > + (imx219->lanes == 2) ? imx219_link_freq_menu :
> > + imx219_link_freq_4lane_menu);
> > if (imx219->link_freq)
> > imx219->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> >
> > @@ -1308,7 +1341,7 @@ static void imx219_free_controls(struct imx219 *imx219)
> > mutex_destroy(&imx219->mutex);
> > }
> >
> > -static int imx219_check_hwcfg(struct device *dev)
> > +static int imx219_check_hwcfg(struct device *dev, struct imx219 *imx219)
> > {
> > struct fwnode_handle *endpoint;
> > struct v4l2_fwnode_endpoint ep_cfg = {
> > @@ -1328,10 +1361,12 @@ static int imx219_check_hwcfg(struct device *dev)
> > }
> >
> > /* Check the number of MIPI CSI2 data lanes */
> > - if (ep_cfg.bus.mipi_csi2.num_data_lanes != 2) {
> > - dev_err(dev, "only 2 data lanes are currently supported\n");
> > + if (ep_cfg.bus.mipi_csi2.num_data_lanes != 2 &&
> > + ep_cfg.bus.mipi_csi2.num_data_lanes != 4) {
> > + dev_err(dev, "only 2 or 4 data lanes are currently supported\n");
> > goto error_out;
> > }
> > + imx219->lanes = ep_cfg.bus.mipi_csi2.num_data_lanes;
> >
> > /* Check the link frequency set in device tree */
> > if (!ep_cfg.nr_of_link_frequencies) {
> > @@ -1339,8 +1374,8 @@ static int imx219_check_hwcfg(struct device *dev)
> > goto error_out;
> > }
> >
> > - if (ep_cfg.nr_of_link_frequencies != 1 ||
> > - ep_cfg.link_frequencies[0] != IMX219_DEFAULT_LINK_FREQ) {
> > + if (ep_cfg.link_frequencies[0] != ((imx219->lanes == 2) ?
> > + IMX219_DEFAULT_LINK_FREQ : IMX219_DEFAULT_LINK_FREQ_4LANE)) {
>
> You've lost the check of ep_cfg.nr_of_link_frequencies != 1 in this update.

oops. I'll fix in V4.
>
> Otherwise it looks good to me.
>
Thanks for the review and feedback.

adam

> Dave
>
> > dev_err(dev, "Link frequency not supported: %lld\n",
> > ep_cfg.link_frequencies[0]);
> > goto error_out;
> > @@ -1368,7 +1403,7 @@ static int imx219_probe(struct i2c_client *client)
> > v4l2_i2c_subdev_init(&imx219->sd, client, &imx219_subdev_ops);
> >
> > /* Check the hardware configuration in device tree */
> > - if (imx219_check_hwcfg(dev))
> > + if (imx219_check_hwcfg(dev, imx219))
> > return -EINVAL;
> >
> > /* Get system clock (xclk) */
> > --
> > 2.34.1
> >

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