120 lines
3.6 KiB
Diff
120 lines
3.6 KiB
Diff
From 5230873bb686dd52cd0c52fa5e90bfb3be9da42d Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Ond=C5=99ej=20Jirman?= <megi@xff.cz>
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Date: Sun, 5 Jul 2020 15:55:46 +0200
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Subject: [PATCH 195/389] drm/panel: st7703: Improve the power up/down sequence
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of the panel
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The datasheet specifies that there needs to be 120ms delay after
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the sleep out command, not after reset as the driver assumes.
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The delay between init commands and the sleep out is not necessary.
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The datasheet also specifies that it's better to keep reset asserted
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while powering up the supplies, and that IOVCC should be enabled
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first.
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There also needs to be a delay after enabling the supplies and
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before deasserting the reset. The datasheet specifies 1ms after
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the supplies reach the required voltage. Use 10-20ms to give the
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power supplies some time to reach the required voltage, too.
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After issuing SLEEP IN, it's necessary to let the controller complete
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the blanking sequence and drain the charge from the panel. (According
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to the datasheet.)
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This fixes panel initialization failures during resume from sleep
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on PinePhone.
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Signed-off-by: Ondrej Jirman <megi@xff.cz>
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---
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drivers/gpu/drm/panel/panel-sitronix-st7703.c | 35 ++++++++++---------
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1 file changed, 18 insertions(+), 17 deletions(-)
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diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7703.c b/drivers/gpu/drm/panel/panel-sitronix-st7703.c
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index 86a472b01360..97fdff0cc496 100644
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--- a/drivers/gpu/drm/panel/panel-sitronix-st7703.c
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+++ b/drivers/gpu/drm/panel/panel-sitronix-st7703.c
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@@ -290,7 +290,6 @@ static int xbd599_init_sequence(struct st7703 *ctx)
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dsi_dcs_write_seq(dsi, ST7703_CMD_SETBGP,
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0x07, /* VREF_SEL = 4.2V */
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0x07 /* NVREF_SEL = 4.2V */);
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- msleep(20);
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dsi_dcs_write_seq(dsi, ST7703_CMD_SETVCOM,
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0x2C, /* VCOMDC_F = -0.67V */
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@@ -367,16 +366,14 @@ static int st7703_enable(struct drm_panel *panel)
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return ret;
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}
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- msleep(20);
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-
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ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
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if (ret < 0) {
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dev_err(ctx->dev, "Failed to exit sleep mode: %d\n", ret);
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return ret;
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}
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- /* Panel is operational 120 msec after reset */
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- msleep(60);
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+ /* Display on can be issued 120 msec after sleep out */
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+ msleep(120);
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ret = mipi_dsi_dcs_set_display_on(dsi);
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if (ret)
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@@ -401,6 +398,9 @@ static int st7703_disable(struct drm_panel *panel)
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if (ret < 0)
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dev_err(ctx->dev, "Failed to enter sleep mode: %d\n", ret);
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+ /* Display needs to be drained of charge, in order to work correctly on next power on. */
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+ msleep(120);
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+
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return 0;
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}
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@@ -428,29 +428,30 @@ static int st7703_prepare(struct drm_panel *panel)
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return 0;
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dev_dbg(ctx->dev, "Resetting the panel\n");
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- ret = regulator_enable(ctx->vcc);
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+ gpiod_set_value_cansleep(ctx->reset_gpio, 1);
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+
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+ ret = regulator_enable(ctx->iovcc);
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if (ret < 0) {
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- dev_err(ctx->dev, "Failed to enable vcc supply: %d\n", ret);
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+ dev_err(ctx->dev, "Failed to enable iovcc supply: %d\n", ret);
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return ret;
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}
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- ret = regulator_enable(ctx->iovcc);
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+
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+ ret = regulator_enable(ctx->vcc);
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if (ret < 0) {
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- dev_err(ctx->dev, "Failed to enable iovcc supply: %d\n", ret);
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- goto disable_vcc;
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+ dev_err(ctx->dev, "Failed to enable vcc supply: %d\n", ret);
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+ regulator_disable(ctx->iovcc);
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+ return ret;
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}
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- gpiod_set_value_cansleep(ctx->reset_gpio, 1);
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- usleep_range(20, 40);
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+ /* Give power supplies time to stabilize before deasserting reset. */
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+ usleep_range(10000, 20000);
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+
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gpiod_set_value_cansleep(ctx->reset_gpio, 0);
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- msleep(20);
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+ usleep_range(15000, 20000);
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ctx->prepared = true;
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return 0;
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-
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-disable_vcc:
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- regulator_disable(ctx->vcc);
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- return ret;
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}
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static const u32 mantix_bus_formats[] = {
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--
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2.35.3
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