Re: [PATCH 3/9] drm/bridge: tc358767: Simplify tc_set_video_mode()
From: Andrey Smirnov
Date: Mon Mar 11 2019 - 13:57:13 EST
On Mon, Mar 4, 2019 at 4:26 AM Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
>
> Hi Andrey,
>
> Thank you for the patch.
>
> On Tue, Feb 26, 2019 at 11:36:03AM -0800, Andrey Smirnov wrote:
> > Simplify tc_set_video_mode() by replacing repreated calls to
> > tc_write()/regmap_write() with a single call regmap_multi_reg_write().
> > No functional change intended.
> >
> > Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
> > Cc: Archit Taneja <architt@xxxxxxxxxxxxxx>
> > Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> > Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
> > Cc: Chris Healy <cphealy@xxxxxxxxx>
> > Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > ---
> > drivers/gpu/drm/bridge/tc358767.c | 125 ++++++++++++++++--------------
> > 1 file changed, 65 insertions(+), 60 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> > index 86ebd49194b7..c85468fcc157 100644
> > --- a/drivers/gpu/drm/bridge/tc358767.c
> > +++ b/drivers/gpu/drm/bridge/tc358767.c
> > @@ -641,10 +641,6 @@ static int tc_get_display_props(struct tc_data *tc)
> >
> > static int tc_set_video_mode(struct tc_data *tc, struct drm_display_mode *mode)
> > {
> > - int ret;
> > - int vid_sync_dly;
> > - int max_tu_symbol;
> > -
> > int left_margin = mode->htotal - mode->hsync_end;
> > int right_margin = mode->hsync_start - mode->hdisplay;
> > int hsync_len = mode->hsync_end - mode->hsync_start;
> > @@ -653,76 +649,85 @@ static int tc_set_video_mode(struct tc_data *tc, struct drm_display_mode *mode)
> > int vsync_len = mode->vsync_end - mode->vsync_start;
> >
> > /*
> > - * Recommended maximum number of symbols transferred in a transfer unit:
> > + * Recommended maximum number of symbols transferred in a
> > + * transfer unit:
> > * DIV_ROUND_UP((input active video bandwidth in bytes) * tu_size,
> > * (output active video bandwidth in bytes))
> > * Must be less than tu_size.
> > */
> > - max_tu_symbol = TU_SIZE_RECOMMENDED - 1;
> > -
> > - dev_dbg(tc->dev, "set mode %dx%d\n",
> > - mode->hdisplay, mode->vdisplay);
> > - dev_dbg(tc->dev, "H margin %d,%d sync %d\n",
> > - left_margin, right_margin, hsync_len);
> > - dev_dbg(tc->dev, "V margin %d,%d sync %d\n",
> > - upper_margin, lower_margin, vsync_len);
> > - dev_dbg(tc->dev, "total: %dx%d\n", mode->htotal, mode->vtotal);
> > -
> > + int max_tu_symbol = TU_SIZE_RECOMMENDED - 1;
> >
> > + /* DP Main Stream Attributes */
> > + int vid_sync_dly = hsync_len + left_margin + mode->hdisplay;
> > /*
> > * LCD Ctl Frame Size
> > * datasheet is not clear of vsdelay in case of DPI
> > * assume we do not need any delay when DPI is a source of
> > * sync signals
> > */
> > - tc_write(VPCTRL0, (0 << 20) /* VSDELAY */ |
> > - OPXLFMT_RGB888 | FRMSYNC_DISABLED | MSF_DISABLED);
> > - tc_write(HTIM01, (ALIGN(left_margin, 2) << 16) | /* H back porch */
> > - (ALIGN(hsync_len, 2) << 0)); /* Hsync */
> > - tc_write(HTIM02, (ALIGN(right_margin, 2) << 16) | /* H front porch */
> > - (ALIGN(mode->hdisplay, 2) << 0)); /* width */
> > - tc_write(VTIM01, (upper_margin << 16) | /* V back porch */
> > - (vsync_len << 0)); /* Vsync */
> > - tc_write(VTIM02, (lower_margin << 16) | /* V front porch */
> > - (mode->vdisplay << 0)); /* height */
> > - tc_write(VFUEN0, VFUEN); /* update settings */
> > -
> > + u32 vpctrl0 = (0 << 20) /* VSDELAY */ |
> > + OPXLFMT_RGB888 | FRMSYNC_DISABLED |
> > + MSF_DISABLED;
> > + u32 htim01 = (ALIGN(left_margin, 2) << 16) | /* H back porch */
> > + (ALIGN(hsync_len, 2) << 0); /* Hsync */
> > + u32 htim02 = (ALIGN(right_margin, 2) << 16) | /* H front porch */
> > + (ALIGN(mode->hdisplay, 2) << 0); /* width */
> > + u32 vtim01 = (upper_margin << 16) | /* V back porch */
> > + (vsync_len << 0); /* Vsync */
> > + u32 vtim02 = (lower_margin << 16) | /* V front porch */
> > + (mode->vdisplay << 0); /* height */
> > /* Test pattern settings */
> > - tc_write(TSTCTL,
> > - (120 << 24) | /* Red Color component value */
> > - (20 << 16) | /* Green Color component value */
> > - (99 << 8) | /* Blue Color component value */
> > - (1 << 4) | /* Enable I2C Filter */
> > - (2 << 0) | /* Color bar Mode */
> > - 0);
> > -
> > - /* DP Main Stream Attributes */
> > - vid_sync_dly = hsync_len + left_margin + mode->hdisplay;
> > - tc_write(DP0_VIDSYNCDELAY,
> > - (max_tu_symbol << 16) | /* thresh_dly */
> > - (vid_sync_dly << 0));
> > + u32 tstctl = (120 << 24) | /* Red Color component value */
> > + (20 << 16) | /* Green Color component value */
> > + (99 << 8) | /* Blue Color component value */
> > + (1 << 4) | /* Enable I2C Filter */
> > + (2 << 0); /* Color bar Mode */
> > + u32 dp0_vidsyncdelay = (max_tu_symbol << 16) | /* thresh_dly */
> > + (vid_sync_dly << 0);
> > + u32 dp0_totalval = (mode->vtotal << 16) | (mode->htotal);
> > + u32 dp0_startval = ((upper_margin + vsync_len) << 16) |
> > + ((left_margin + hsync_len) << 0);
> > + u32 dp0_activeval = (mode->vdisplay << 16) | (mode->hdisplay);
> > + u32 dp0_syncval = (vsync_len << 16) | (hsync_len << 0) |
> > + (mode->flags & DRM_MODE_FLAG_NHSYNC) ?
> > + SYNCVAL_HS_POL_ACTIVE_LOW : 0 |
> > + (mode->flags & DRM_MODE_FLAG_NVSYNC) ?
> > + SYNCVAL_VS_POL_ACTIVE_LOW : 0;
> > + u32 dpipxlfmt = VS_POL_ACTIVE_LOW | HS_POL_ACTIVE_LOW |
> > + DE_POL_ACTIVE_HIGH | SUB_CFG_TYPE_CONFIG1 |
> > + DPI_BPP_RGB888;
> > + u32 dp0_misc = (max_tu_symbol << 23) |
> > + (TU_SIZE_RECOMMENDED << 16) |
> > + BPC_8;
> > +
> > + const struct reg_sequence video_mode_settings[] = {
> > + { VPCTRL0, vpctrl0 },
> > + { HTIM01, htim01 },
> > + { HTIM02, htim02 },
> > + { VTIM01, vtim01 },
> > + { VTIM02, vtim02 },
> > + { VFUEN0, VFUEN }, /* update settings */
> > + { TSTCTL, tstctl },
> > + { DP0_VIDSYNCDELAY, dp0_vidsyncdelay },
> > + { DP0_TOTALVAL, dp0_totalval },
> > + { DP0_STARTVAL, dp0_startval },
> > + { DP0_ACTIVEVAL, dp0_activeval },
> > + { DP0_SYNCVAL, dp0_syncval },
> > + { DPIPXLFMT, dpipxlfmt },
> > + { DP0_MISC, dp0_misc },
> > + };
>
> I like the removal of the tc_write() macro, but slightly dislike the
> need for this array. Another possible option to handle errors in a nicer
> way would be
>
> static int tc_write(struct tc_data *tc, unsigned int reg, unsigned int val,
> int *status)
> {
> if (!*status)
> *status = regmap_write(tc->regmap, reg, val);
> return *status;
> }
>
> ...
> int err = 0;
>
> tc_write(tc, ..., ..., &err);
> tc_write(tc, ..., ..., &err);
> tc_write(tc, ..., ..., &err);
> tc_write(tc, ..., ..., &err);
> tc_write(tc, ..., ..., &err);
>
> return err;
>
I'd rather not define any new helper functions just for the sake of
avoiding using regmap_multi_reg_write(). I updated this patch in v2 to
combine register value initialization and array declaration, so maybe
you'll find it less displeasing.
Thanks,
Andrey Smirnov