Re: [PATCH 1/2] media: imx: imx7-media-csi: add support for imx8mq

[Rui Miguel Silva]

Hi Laurent,
On Wed Nov 17, 2021 at 5:16 PM WET, Laurent Pinchart wrote:

> On Wed, Nov 17, 2021 at 02:51:48PM +0000, Rui Miguel Silva wrote:
> > Hi Martin,
> > Thanks for the patch.
> > 
> > On Wed Nov 17, 2021 at 9:27 AM WET, Martin Kepplinger wrote:
> > 
> > > Modeled after the NXP driver mx6s_capture.c that this driver is based on,
> > > imx8mq needs different settings for the baseaddr_switch mechanism. Define
> > > the needed bits and set that for imx8mq.
> > >
> > > Without these settings, the system will "sometimes" hang completely when
> > > starting to stream (the interrupt will never be called).
>
> Do we know why ? Are all the bits that you set required ?
>
> > > Signed-off-by: Martin Kepplinger <martin.kepplinger@xxxxxxx>
> > > ---
> > >  drivers/staging/media/imx/imx7-media-csi.c | 34 ++++++++++++++++++++--
> > >  1 file changed, 32 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/staging/media/imx/imx7-media-csi.c b/drivers/staging/media/imx/imx7-media-csi.c
> > > index 2288dadb2683..8619cf2fc694 100644
> > > --- a/drivers/staging/media/imx/imx7-media-csi.c
> > > +++ b/drivers/staging/media/imx/imx7-media-csi.c
> > > @@ -12,6 +12,7 @@
> > >  #include <linux/interrupt.h>
> > >  #include <linux/mfd/syscon.h>
> > >  #include <linux/module.h>
> > > +#include <linux/of_device.h>
> > >  #include <linux/of_graph.h>
> > >  #include <linux/pinctrl/consumer.h>
> > >  #include <linux/platform_device.h>
> > > @@ -122,6 +123,10 @@
> > >  #define BIT_DATA_FROM_MIPI		BIT(22)
> > >  #define BIT_MIPI_YU_SWAP		BIT(21)
> > >  #define BIT_MIPI_DOUBLE_CMPNT		BIT(20)
> > > +#define BIT_MASK_OPTION_FIRST_FRAME	(0 << 18)
> > > +#define BIT_MASK_OPTION_CSI_EN		(1 << 18)
> > > +#define BIT_MASK_OPTION_SECOND_FRAME	(2 << 18)
> > > +#define BIT_MASK_OPTION_ON_DATA		(3 << 18)
> > >  #define BIT_BASEADDR_CHG_ERR_EN		BIT(9)
> > >  #define BIT_BASEADDR_SWITCH_SEL		BIT(5)
> > >  #define BIT_BASEADDR_SWITCH_EN		BIT(4)
> > > @@ -154,6 +159,12 @@
> > >  #define CSI_CSICR18			0x48
> > >  #define CSI_CSICR19			0x4c
> > >  
> > > +enum imx_soc {
> > > +	IMX6UL = 0,
> > > +	IMX7,
> > > +	IMX8MQ,
> > 
> > maybe instead of this enum we could use a bool in structure...
>
> An enum would be more extensible, but we shouldn't define different
> values for IMX6UL and IMX7 if they're compatible. Maybe an enum
> imx_csi_model with two values (IMX_CSI_IMX7 and IMX_CSI_IMX8MQ ?).

If there are only 2 possible values, for now, I think a enum would be
overkill. But do not have a strong feeling about it. So, an enum it is
more extensible and ok too, but with the IMX_CSI or even better 
IMX7_CSI prefix.

>
> Are there other SoCs in the i.MX8 family that require this ? The BSP
> driver sets the baseaddr switch mechanism for i.MX8MM too, but it seems
> to work fine without it.
>
> > >+};
> > > +
> > >  struct imx7_csi {
> > >  	struct device *dev;
> > >  	struct v4l2_subdev sd;
> > > @@ -189,6 +200,8 @@ struct imx7_csi {
> > >  	bool is_csi2;
> > >  
> > >  	struct completion last_eof_completion;
> > > +
> > > +	enum imx_soc type;
> > 
> > here, bool is_imx8mq?
> > 
> > >  };
> > >  
> > >  static struct imx7_csi *
> > > @@ -537,6 +550,16 @@ static void imx7_csi_deinit(struct imx7_csi *csi,
> > >  	clk_disable_unprepare(csi->mclk);
> > >  }
> > >  
> > > +static void imx8mq_baseaddr_switch(struct imx7_csi *csi)
> > 
> > I think this function needs a better name. First add the imx7_csi
> > prefix that all functions have, and also you are setting it specific
> > to second frame and the function should not be specific to imx8.
> > 
> > maybe something:
> > 
> > imx7_csi_write_on_second_frame_enable, maybe?
> > 
> > > +{
> > > +	u32 cr18 = imx7_csi_reg_read(csi, CSI_CSICR18);
> > > +
> > > +	cr18 |= BIT_BASEADDR_SWITCH_EN | BIT_BASEADDR_SWITCH_SEL |
> > > +		BIT_BASEADDR_CHG_ERR_EN;
> > > +	cr18 |= BIT_MASK_OPTION_SECOND_FRAME;
> > > +	imx7_csi_reg_write(csi, cr18, CSI_CSICR18);
> > > +}
> > > +
> > >  static void imx7_csi_enable(struct imx7_csi *csi)
> > >  {
> > >  	/* Clear the Rx FIFO and reflash the DMA controller. */
> > > @@ -551,7 +574,11 @@ static void imx7_csi_enable(struct imx7_csi *csi)
> > >  
> > >  	/* Enable the RxFIFO DMA and the CSI. */
> > >  	imx7_csi_dmareq_rff_enable(csi);
> > > +
> > 
> > unrelated new line.
> > 
> > >  	imx7_csi_hw_enable(csi);
> > > +
> > > +	if (csi->type == IMX8MQ)
> > > +		imx8mq_baseaddr_switch(csi);
> > 
> > change this to new types and names?
> > 
> > >  }
> > >  
> > >  static void imx7_csi_disable(struct imx7_csi *csi)
> > > @@ -1155,6 +1182,8 @@ static int imx7_csi_probe(struct platform_device *pdev)
> > >  	if (IS_ERR(csi->regbase))
> > >  		return PTR_ERR(csi->regbase);
> > >  
> > > +	csi->type = (enum imx_soc)of_device_get_match_data(&pdev->dev);
> > 
> > here something:
> >         csi->is_imx8mq = of_device_is_compatible(np, "fsl,imx8mq-csi");
> >
> > > +
> > >  	spin_lock_init(&csi->irqlock);
> > >  	mutex_init(&csi->lock);
> > >  
> > > @@ -1249,8 +1278,9 @@ static int imx7_csi_remove(struct platform_device *pdev)
> > >  }
> > >  
> > >  static const struct of_device_id imx7_csi_of_match[] = {
> > > -	{ .compatible = "fsl,imx7-csi" },
> > > -	{ .compatible = "fsl,imx6ul-csi" },
> > > +	{ .compatible = "fsl,imx8mq-csi", .data = (void *)IMX8MQ },
> > 
> > and with the above you should not need to add the data field here.
>
> I like match data personally (especially if we keep a device model
> enum). This is exactly what match data has been designed for, to avoid
> is_compatible() checks.

agree.

Many thanks Laurent,
------
Cheers,
     Rui
>
> > > +	{ .compatible = "fsl,imx7-csi", .data = (void *)IMX7 },
> > > +	{ .compatible = "fsl,imx6ul-csi", .data = (void *)IMX6UL },
> > >  	{ },
> > >  };
> > >  MODULE_DEVICE_TABLE(of, imx7_csi_of_match);
>
> -- 
> Regards,
>
> Laurent Pinchart