On Tue, Sep 20, 2022 at 11:43:37AM +0200, Jacopo Mondi wrote: > On Fri, Sep 16, 2022 at 03:57:11PM +0200, Marco Felsch wrote: > > Add support to report the link frequency. > > > > Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx> > > --- > > The v1 of this small series can be found here: > > https://lore.kernel.org/all/20220818144712.997477-1-m.felsch@xxxxxxxxxxxxxx/ > > > > Thanks a lot to Jacopo for the review feedback on my v1. > > > > Changelog: > > > > v2: > > - use V4L2_CID_LINK_FREQ instead of V4L2_CID_PIXEL_RATE > > --- > > drivers/media/i2c/mt9m111.c | 21 ++++++++++++++++++++- > > 1 file changed, 20 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/i2c/mt9m111.c b/drivers/media/i2c/mt9m111.c > > index afc86efa9e3e..52be1c310455 100644 > > --- a/drivers/media/i2c/mt9m111.c > > +++ b/drivers/media/i2c/mt9m111.c > > @@ -1249,6 +1249,8 @@ static int mt9m111_probe(struct i2c_client *client) > > { > > struct mt9m111 *mt9m111; > > struct i2c_adapter *adapter = client->adapter; > > + static s64 extclk_rate; > > Why static ? I missed that one indeed. I assume it's static because the pointer is stored in the v4l2_ctrl structure by v4l2_ctrl_new_int_menu(), but that's wrong. The data should be in the mt9m111 structure instead, otherwise it won't work right when using multiple sensors. > Also clk_get_rate() returns an unsigned long v4l2_ctrl_new_int_menu() requires an s64 pointer. > > + struct v4l2_ctrl *ctrl; > > int ret; > > > > if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA)) { > > @@ -1271,6 +1273,13 @@ static int mt9m111_probe(struct i2c_client *client) > > if (IS_ERR(mt9m111->clk)) > > return PTR_ERR(mt9m111->clk); > > > > + ret = clk_prepare_enable(mt9m111->clk); > > + if (ret < 0) > > + return ret; > > + > > + extclk_rate = clk_get_rate(mt9m111->clk); > > + clk_disable_unprepare(mt9m111->clk); > > + > > mt9m111->regulator = devm_regulator_get(&client->dev, "vdd"); > > if (IS_ERR(mt9m111->regulator)) { > > dev_err(&client->dev, "regulator not found: %ld\n", > > @@ -1285,7 +1294,7 @@ static int mt9m111_probe(struct i2c_client *client) > > mt9m111->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE | > > V4L2_SUBDEV_FL_HAS_EVENTS; > > > > - v4l2_ctrl_handler_init(&mt9m111->hdl, 7); > > + v4l2_ctrl_handler_init(&mt9m111->hdl, 8); > > v4l2_ctrl_new_std(&mt9m111->hdl, &mt9m111_ctrl_ops, > > V4L2_CID_VFLIP, 0, 1, 1, 0); > > v4l2_ctrl_new_std(&mt9m111->hdl, &mt9m111_ctrl_ops, > > @@ -1309,6 +1318,16 @@ static int mt9m111_probe(struct i2c_client *client) > > BIT(V4L2_COLORFX_NEGATIVE) | > > BIT(V4L2_COLORFX_SOLARIZATION)), > > V4L2_COLORFX_NONE); > > Empty line maybe ? > > > + /* > > + * The extclk rate equals the link freq. if reg default values are used, > > + * which is the case. This must be adapted as soon as we don't use the > > + * default values anymore. > > + */ > > + ctrl = v4l2_ctrl_new_int_menu(&mt9m111->hdl, &mt9m111_ctrl_ops, > > + V4L2_CID_LINK_FREQ, 0, 0, &extclk_rate); > > + if (ctrl) > > + ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY; > > + > > I'm sorry I have not replied to your previous email about using > LINK_FREQ for parallel busses.. I see it mentioned in ext-ctrls-image-process.rst > as you said: > > ``V4L2_CID_LINK_FREQ (integer menu)`` > The frequency of the data bus (e.g. parallel or CSI-2). > > I still have a bit of troubles seeing it apply nicely on a parallel > bus. Isn't PIXEL_RATE more appropriate ? They are different. When transmitting YUYV_2X8 for instance, the link frequency is twice the pixel clock rate. > You said you need to know the > overall bus bandwidth in bytes , and pixel_rate * bpp / 8 is equally > valid and easy as link_freq / num_lanes, which requires the receiver > to fetch the remote subdev media bus configuration instead of relying > on the input format. Also LINK_FREQ is a menu control, something nasty > already for CSI-2 busses, which requires to pre-calculate the link > freqs based on the input mclk. It is also meant to be changed by > userspace, while PIXEL_RATE is RO by default. > > Sakari, Laurent, what's your take here ? Ideally both should be implemented by the driver. > > mt9m111->subdev.ctrl_handler = &mt9m111->hdl; > > if (mt9m111->hdl.error) { > > ret = mt9m111->hdl.error; -- Regards, Laurent Pinchart
