[PATCH 3/7] drm: adv7511: Add max_lane_freq variable to struct adv7511_chip_info

[Biju Das]

Hi Laurent,

> Subject: Re: [PATCH 3/7] drm: adv7511: Add max_lane_freq variable to struct
> adv7511_chip_info
> 
> Hi Biju,
> 
> Thank you for the patch.
> 
> On Sun, Aug 13, 2023 at 07:05:08PM +0100, Biju Das wrote:
> > The ADV7533 supports a maximum lane clock of 800MHz whereas it is
> > 891MHz for ADV7535.  Add max_lane_freq variable to struct
> > adv7511_chip_info to handle this difference.
> >
> > While at it, drop the unused local variable max_lane_freq.
> >
> > Signed-off-by: Biju Das <biju.das.jz at bp.renesas.com>
> > ---
> >  drivers/gpu/drm/bridge/adv7511/adv7511.h     | 1 +
> >  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 6 ++++--
> >  drivers/gpu/drm/bridge/adv7511/adv7533.c     | 5 +----
> >  3 files changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h
> > b/drivers/gpu/drm/bridge/adv7511/adv7511.h
> > index f8190442ffca..0e2c721a856f 100644
> > --- a/drivers/gpu/drm/bridge/adv7511/adv7511.h
> > +++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h
> > @@ -336,6 +336,7 @@ enum adv7511_type {  struct adv7511_chip_info {
> >  	enum adv7511_type type;
> >  	unsigned long max_mode_clock;
> > +	unsigned long max_lane_freq;
> 
> Same comment as for patch 2/7, you could name the field max_lane_freq_khz.
> An unsigned int may be enough too if the calculation below doesn't
> overflow.

Agreed.

2 power 32 = 4,294,967,295 is large value compared to below calculation to trigger an overflow.

Cheers,
Biju

 
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
> 
> >  };
> >
> >  struct adv7511 {
> > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > index 193b2d5bc7e6..29e087e6d721 100644
> > --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> > @@ -1372,12 +1372,14 @@ static const struct adv7511_chip_info
> > adv7511_chip_info = {
> >
> >  static const struct adv7511_chip_info adv7533_chip_info = {
> >  	.type = ADV7533,
> > -	.max_mode_clock = 80000
> > +	.max_mode_clock = 80000,
> > +	.max_lane_freq = 800000,
> >  };
> >
> >  static const struct adv7511_chip_info adv7535_chip_info = {
> >  	.type = ADV7535,
> > -	.max_mode_clock = 148500
> > +	.max_mode_clock = 148500,
> > +	.max_lane_freq = 891000,
> >  };
> >
> >  static const struct i2c_device_id adv7511_i2c_ids[] = { diff --git
> > a/drivers/gpu/drm/bridge/adv7511/adv7533.c
> > b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> > index e92b27e0afd1..c1e744d4f2b1 100644
> > --- a/drivers/gpu/drm/bridge/adv7511/adv7533.c
> > +++ b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> > @@ -103,7 +103,6 @@ void adv7533_dsi_power_off(struct adv7511 *adv)
> > enum drm_mode_status adv7533_mode_valid(struct adv7511 *adv,
> >  					const struct drm_display_mode *mode)  {
> > -	unsigned long max_lane_freq;
> >  	struct mipi_dsi_device *dsi = adv->dsi;
> >  	u8 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
> >
> > @@ -112,9 +111,7 @@ enum drm_mode_status adv7533_mode_valid(struct
> adv7511 *adv,
> >  		return MODE_CLOCK_HIGH;
> >
> >  	/* Check max clock for each lane */
> > -	max_lane_freq = (adv->info->type == ADV7533 ? 800000 : 891000);
> > -
> > -	if (mode->clock * bpp > max_lane_freq * adv->num_dsi_lanes)
> > +	if (mode->clock * bpp > adv->info->max_lane_freq *
> > +adv->num_dsi_lanes)
> >  		return MODE_CLOCK_HIGH;
> >
> >  	return MODE_OK;
> 
> --
> Regards,
> 
> Laurent Pinchart