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SubjectRe: [PATCH v2 04/15] drm/bridge: tc358767: Simplify tc_set_video_mode()
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On 22/03/2019 05:28, Andrey Smirnov wrote:
> Simplify tc_set_video_mode() by replacing repreated calls to
> tc_write()/regmap_write() with a single call to
> regmap_multi_reg_write(). While at it, simplify explicit shifting by
> using macros from <linux/bitfield.h>. No functional change intended.
>
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> Cc: Archit Taneja <architt@codeaurora.org>
> Cc: Andrzej Hajda <a.hajda@samsung.com>
> Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
> Cc: Andrey Gusakov <andrey.gusakov@cogentembedded.com>
> Cc: Philipp Zabel <p.zabel@pengutronix.de>
> Cc: Chris Healy <cphealy@gmail.com>
> Cc: Lucas Stach <l.stach@pengutronix.de>
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-kernel@vger.kernel.org
> ---
> drivers/gpu/drm/bridge/tc358767.c | 146 +++++++++++++++++-------------
> 1 file changed, 85 insertions(+), 61 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> index 38d542f553cd..d99c9f32a133 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -24,6 +24,7 @@
> * GNU General Public License for more details.
> */
>
> +#include <linux/bitfield.h>
> #include <linux/clk.h>
> #include <linux/device.h>
> #include <linux/gpio/consumer.h>
> @@ -56,6 +57,7 @@
>
> /* Video Path */
> #define VPCTRL0 0x0450
> +#define VSDELAY GENMASK(31, 20)
> #define OPXLFMT_RGB666 (0 << 8)
> #define OPXLFMT_RGB888 (1 << 8)
> #define FRMSYNC_DISABLED (0 << 4) /* Video Timing Gen Disabled */
> @@ -63,9 +65,17 @@
> #define MSF_DISABLED (0 << 0) /* Magic Square FRC disabled */
> #define MSF_ENABLED (1 << 0) /* Magic Square FRC enabled */
> #define HTIM01 0x0454
> +#define HPW GENMASK(8, 0)
> +#define HBPR GENMASK(24, 16)
> #define HTIM02 0x0458
> +#define HDISPR GENMASK(10, 0)
> +#define HFPR GENMASK(24, 16)
> #define VTIM01 0x045c
> +#define VSPR GENMASK(7, 0)
> +#define VBPR GENMASK(23, 16)
> #define VTIM02 0x0460
> +#define VFPR GENMASK(23, 16)
> +#define VDISPR GENMASK(10, 0)
> #define VFUEN0 0x0464
> #define VFUEN BIT(0) /* Video Frame Timing Upload */
>
> @@ -100,14 +110,28 @@
> /* Main Channel */
> #define DP0_SECSAMPLE 0x0640
> #define DP0_VIDSYNCDELAY 0x0644
> +#define VID_SYNC_DLY GENMASK(15, 0)
> +#define THRESH_DLY GENMASK(31, 16)
> +
> #define DP0_TOTALVAL 0x0648
> +#define H_TOTAL GENMASK(15, 0)
> +#define V_TOTAL GENMASK(31, 16)
> #define DP0_STARTVAL 0x064c
> +#define H_START GENMASK(15, 0)
> +#define V_START GENMASK(31, 16)
> #define DP0_ACTIVEVAL 0x0650
> +#define H_ACT GENMASK(15, 0)
> +#define V_ACT GENMASK(31, 16)
> +
> #define DP0_SYNCVAL 0x0654
> +#define VS_WIDTH GENMASK(30, 16)
> +#define HS_WIDTH GENMASK(14, 0)
> #define SYNCVAL_HS_POL_ACTIVE_LOW (1 << 15)
> #define SYNCVAL_VS_POL_ACTIVE_LOW (1 << 31)
> #define DP0_MISC 0x0658
> #define TU_SIZE_RECOMMENDED (63) /* LSCLK cycles per TU */
> +#define MAX_TU_SYMBOL GENMASK(28, 23)
> +#define TU_SIZE GENMASK(21, 16)
> #define BPC_6 (0 << 5)
> #define BPC_8 (1 << 5)
>
> @@ -184,6 +208,12 @@
>
> /* Test & Debug */
> #define TSTCTL 0x0a00
> +#define COLOR_R GENMASK(31, 24)
> +#define COLOR_G GENMASK(23, 16)
> +#define COLOR_B GENMASK(15, 8)
> +#define ENI2CFILTER BIT(4)
> +#define COLOR_BAR_MODE GENMASK(1, 0)
> +#define COLOR_BAR_MODE_BARS 2
> #define PLL_DBG 0x0a04
>
> static bool tc_test_pattern;
> @@ -647,10 +677,6 @@ 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;
> @@ -659,76 +685,74 @@ 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 */
> -
> - /* 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));
> + const u32 vs_pol = mode->flags & DRM_MODE_FLAG_NVSYNC ?
> + SYNCVAL_VS_POL_ACTIVE_LOW : 0;
> + const u32 hs_pol = mode->flags & DRM_MODE_FLAG_NHSYNC ?
> + SYNCVAL_HS_POL_ACTIVE_LOW : 0;
> + const struct reg_sequence video_mode_settings[] = {
> + { VPCTRL0, FIELD_PREP(VSDELAY, 0) |
> + OPXLFMT_RGB888 | FRMSYNC_DISABLED | MSF_DISABLED },
> + { HTIM01, FIELD_PREP(HBPR, ALIGN(left_margin, 2)) |
> + FIELD_PREP(HPW, ALIGN(hsync_len, 2)) },
> + { HTIM02, FIELD_PREP(HDISPR, ALIGN(mode->hdisplay, 2)) |
> + FIELD_PREP(HFPR, ALIGN(right_margin, 2)) },
> + { VTIM01, FIELD_PREP(VBPR, upper_margin) |
> + FIELD_PREP(VSPR, vsync_len) },
> + { VTIM02, FIELD_PREP(VFPR, lower_margin) |
> + FIELD_PREP(VDISPR, mode->vdisplay) },
> + { VFUEN0, VFUEN },
> + { TSTCTL, FIELD_PREP(COLOR_R, 120) |
> + FIELD_PREP(COLOR_G, 20) |
> + FIELD_PREP(COLOR_B, 99) |
> + ENI2CFILTER |
> + FIELD_PREP(COLOR_BAR_MODE, COLOR_BAR_MODE_BARS) },
> + { DP0_VIDSYNCDELAY, FIELD_PREP(THRESH_DLY, max_tu_symbol) |
> + FIELD_PREP(VID_SYNC_DLY, vid_sync_dly) },
> + { DP0_TOTALVAL, FIELD_PREP(H_TOTAL, mode->htotal) |
> + FIELD_PREP(V_TOTAL, mode->vtotal) },
> + { DP0_STARTVAL, FIELD_PREP(H_START, left_margin + hsync_len) |
> + FIELD_PREP(V_START,
> + upper_margin + vsync_len) },
> + { DP0_ACTIVEVAL, FIELD_PREP(V_ACT, mode->vdisplay) |
> + FIELD_PREP(H_ACT, mode->hdisplay) },
> + { DP0_SYNCVAL, FIELD_PREP(VS_WIDTH, vsync_len) |
> + FIELD_PREP(HS_WIDTH, hsync_len) |
> + hs_pol | vs_pol },
> + { DPIPXLFMT, VS_POL_ACTIVE_LOW | HS_POL_ACTIVE_LOW |
> + DE_POL_ACTIVE_HIGH | SUB_CFG_TYPE_CONFIG1 |
> + DPI_BPP_RGB888 },
> + { DP0_MISC, FIELD_PREP(MAX_TU_SYMBOL, max_tu_symbol) |
> + FIELD_PREP(TU_SIZE, TU_SIZE_RECOMMENDED) |
> + BPC_8 },
> + };
>
> - tc_write(DP0_TOTALVAL, (mode->vtotal << 16) | (mode->htotal));
> -
> - tc_write(DP0_STARTVAL,
> - ((upper_margin + vsync_len) << 16) |
> - ((left_margin + hsync_len) << 0));
> -
> - tc_write(DP0_ACTIVEVAL, (mode->vdisplay << 16) | (mode->hdisplay));
> -
> - tc_write(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));
> -
> - tc_write(DPIPXLFMT, VS_POL_ACTIVE_LOW | HS_POL_ACTIVE_LOW |
> - DE_POL_ACTIVE_HIGH | SUB_CFG_TYPE_CONFIG1 | DPI_BPP_RGB888);
> -
> - tc_write(DP0_MISC, (max_tu_symbol << 23) | (TU_SIZE_RECOMMENDED << 16) |
> - BPC_8);
> + 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);
>
> - return 0;
> -err:
> - return ret;
> + return regmap_multi_reg_write(tc->regmap,
> + video_mode_settings,
> + ARRAY_SIZE(video_mode_settings));
> }
>
> static int tc_wait_link_training(struct tc_data *tc, u32 *error)

I don't like this change. I think multi_reg_write is good for writing
things like, say, color conversion table. But the data for video mode is
more complex and needs more logic (e.g. here ?: operator is used). You
need to stuff all that logic into variable initializers. You can't use
e.g. if() anymore, and you can't even insert a debug print between the
writes if you need to.

So, in my opinion, this doesn't look (much) cleaner, and makes life more
difficult.

Tomi

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