Re: [PATCH v3 05/10] media: i2c: imx290: Add configurable link frequency and pixel rate

From: Andrey Konovalov
Date: Tue May 26 2020 - 05:27:25 EST


Hi Sakari,

Thank you for the review!

On 26.05.2020 12:12, Sakari Ailus wrote:
Hi Andrey,

On Sun, May 24, 2020 at 10:25:00PM +0300, Andrey Konovalov wrote:
From: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>

IMX290 operates with multiple link frequency and pixel rate combinations.
The initial driver used a single setting for both but since we now have
the lane count support in place, let's add configurable link frequency
and pixel rate.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Signed-off-by: Andrey Konovalov <andrey.konovalov@xxxxxxxxxx>
---
drivers/media/i2c/imx290.c | 100 ++++++++++++++++++++++++-------------
1 file changed, 66 insertions(+), 34 deletions(-)

diff --git a/drivers/media/i2c/imx290.c b/drivers/media/i2c/imx290.c
index a361c9ac8bd5..e800557cf423 100644
--- a/drivers/media/i2c/imx290.c
+++ b/drivers/media/i2c/imx290.c
@@ -38,8 +38,6 @@
#define IMX290_HMAX_2_720 0x19C8
#define IMX290_HMAX_4_720 0x0CE4
-#define IMX290_DEFAULT_LINK_FREQ 445500000
-
static const char * const imx290_supply_name[] = {
"vdda",
"vddd",
@@ -56,8 +54,6 @@ struct imx290_regval {
struct imx290_mode {
u32 width;
u32 height;
- u32 pixel_rate;
- u32 link_freq_index;
const struct imx290_regval *data;
u32 data_size;
@@ -248,8 +244,13 @@ static const struct imx290_regval imx290_10bit_settings[] = {
};
/* supported link frequencies */
-static const s64 imx290_link_freq[] = {
- IMX290_DEFAULT_LINK_FREQ,
+static const s64 imx290_link_freq_2lanes[] = {
+ 891000000, /* 1920x1080 - 2 lane */
+ 594000000, /* 1280x720 - 2 lane */
+};
+static const s64 imx290_link_freq_4lanes[] = {
+ 445500000, /* 1920x1080 - 4 lane */
+ 297000000, /* 1280x720 - 4 lane */
};
/* Mode configs */
@@ -259,16 +260,12 @@ static const struct imx290_mode imx290_modes[] = {
.height = 1080,
.data = imx290_1080p_settings,
.data_size = ARRAY_SIZE(imx290_1080p_settings),
- .pixel_rate = 178200000,
- .link_freq_index = 0,
},
{
.width = 1280,
.height = 720,
.data = imx290_720p_settings,
.data_size = ARRAY_SIZE(imx290_720p_settings),
- .pixel_rate = 178200000,
- .link_freq_index = 0,
},
};
@@ -442,6 +439,32 @@ static int imx290_get_fmt(struct v4l2_subdev *sd,
return 0;
}
+static u8 imx290_get_link_freq_index(struct imx290 *imx290)
+{
+ const struct imx290_mode *cur_mode = imx290->current_mode;
+
+ return (cur_mode->width == 1920) ? 0 : 1;

Could you use (imx290->current_mode - imx290_modes) / sizeof(*imx290_modes)
or something like that? It'd have fewer chances of breaking if new modes
are added.

+}
+
+static s64 imx290_get_link_freq(struct imx290 *imx290)
+{
+ u8 index = imx290_get_link_freq_index(imx290);
+
+ if (imx290->nlanes == 4)
+ return imx290_link_freq_4lanes[index];
+ else
+ return imx290_link_freq_2lanes[index];

Or even better: store the link frequencies to the modes themselves. They
are a property of the modes after all.

Then we will get two sets (for 2 lanes and for 4 lanes) of two modes (1080p and 720p), right?

+}
+
+static u64 imx290_calc_pixel_rate(struct imx290 *imx290)
+{
+ s64 link_freq = imx290_get_link_freq(imx290);
+ u8 nlanes = imx290->nlanes;
+
+ /* pixel rate = link_freq * 2 * nr_of_lanes / bits_per_sample */
+ return (link_freq * 2 * nlanes / 10);
+}
+
static int imx290_set_fmt(struct v4l2_subdev *sd,
struct v4l2_subdev_pad_config *cfg,
struct v4l2_subdev_format *fmt)
@@ -475,10 +498,14 @@ static int imx290_set_fmt(struct v4l2_subdev *sd,
format = v4l2_subdev_get_try_format(sd, cfg, fmt->pad);
} else {
format = &imx290->current_format;
- __v4l2_ctrl_s_ctrl(imx290->link_freq, mode->link_freq_index);
- __v4l2_ctrl_s_ctrl_int64(imx290->pixel_rate, mode->pixel_rate);
-
imx290->current_mode = mode;
+
+ if (imx290->link_freq)
+ __v4l2_ctrl_s_ctrl(imx290->link_freq,
+ imx290_get_link_freq_index(imx290));
+ if (imx290->pixel_rate)
+ __v4l2_ctrl_s_ctrl_int64(imx290->pixel_rate,
+ imx290_calc_pixel_rate(imx290));
}
*format = fmt->format;
@@ -502,12 +529,11 @@ static int imx290_entity_init_cfg(struct v4l2_subdev *subdev,
return 0;
}
-static int imx290_write_current_format(struct imx290 *imx290,
- struct v4l2_mbus_framefmt *format)
+static int imx290_write_current_format(struct imx290 *imx290)
{
int ret;
- switch (format->code) {
+ switch (imx290->current_format.code) {
case MEDIA_BUS_FMT_SRGGB10_1X10:
ret = imx290_set_register_array(imx290, imx290_10bit_settings,
ARRAY_SIZE(
@@ -558,8 +584,8 @@ static int imx290_start_streaming(struct imx290 *imx290)
return ret;
}
- /* Set current frame format */
- ret = imx290_write_current_format(imx290, &imx290->current_format);
+ /* Apply the register values related to current frame format */
+ ret = imx290_write_current_format(imx290);
if (ret < 0) {
dev_err(imx290->dev, "Could not set frame format\n");
return ret;
@@ -821,12 +847,6 @@ static int imx290_probe(struct i2c_client *client)
goto free_err;
}
- if (imx290->ep.link_frequencies[0] != IMX290_DEFAULT_LINK_FREQ) {

This check needs to be modified to correspond to the driver's new
capabilities, not removed.

Agreed.
Do I understand correct that as the driver uses two link frequencies
for a given number of lanes now, it must check that *the both* frequencies
(for the given number of lanes) are listed in the device tree node?

Thanks,
Andrey

- dev_err(dev, "Unsupported link frequency\n");
- ret = -EINVAL;
- goto free_err;
- }
-
/* Only CSI2 is supported for now */
if (imx290->ep.bus_type != V4L2_MBUS_CSI2_DPHY) {
dev_err(dev, "Unsupported bus type, should be CSI2\n");
@@ -879,23 +899,38 @@ static int imx290_probe(struct i2c_client *client)
mutex_init(&imx290->lock);
+ /*
+ * Initialize the frame format. In particular, imx290->current_mode
+ * and imx290->bpp are set to defaults: imx290_calc_pixel_rate() call
+ * below relies on these fields.
+ */
+ imx290_entity_init_cfg(&imx290->sd, NULL);
+
v4l2_ctrl_handler_init(&imx290->ctrls, 3);
v4l2_ctrl_new_std(&imx290->ctrls, &imx290_ctrl_ops,
V4L2_CID_GAIN, 0, 72, 1, 0);
- imx290->link_freq =
- v4l2_ctrl_new_int_menu(&imx290->ctrls,
- &imx290_ctrl_ops,
- V4L2_CID_LINK_FREQ,
- ARRAY_SIZE(imx290_link_freq) - 1,
- 0, imx290_link_freq);
+ if (imx290->nlanes == 4)
+ imx290->link_freq =
+ v4l2_ctrl_new_int_menu(&imx290->ctrls,
+ &imx290_ctrl_ops,
+ V4L2_CID_LINK_FREQ,
+ ARRAY_SIZE(imx290_link_freq_4lanes) - 1,
+ 0, imx290_link_freq_4lanes);
+ else
+ imx290->link_freq =
+ v4l2_ctrl_new_int_menu(&imx290->ctrls,
+ &imx290_ctrl_ops,
+ V4L2_CID_LINK_FREQ,
+ ARRAY_SIZE(imx290_link_freq_2lanes) - 1,
+ 0, imx290_link_freq_2lanes);
if (imx290->link_freq)
imx290->link_freq->flags |= V4L2_CTRL_FLAG_READ_ONLY;
imx290->pixel_rate = v4l2_ctrl_new_std(&imx290->ctrls, &imx290_ctrl_ops,
V4L2_CID_PIXEL_RATE, 1,
INT_MAX, 1,
- imx290_modes[0].pixel_rate);
+ imx290_calc_pixel_rate(imx290));
imx290->sd.ctrl_handler = &imx290->ctrls;
@@ -919,9 +954,6 @@ static int imx290_probe(struct i2c_client *client)
goto free_ctrl;
}
- /* Initialize the frame format (this also sets imx290->current_mode) */
- imx290_entity_init_cfg(&imx290->sd, NULL);
-
ret = v4l2_async_register_subdev(&imx290->sd);
if (ret < 0) {
dev_err(dev, "Could not register v4l2 device\n");