74 lines
2.2 KiB
Diff
74 lines
2.2 KiB
Diff
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From c849eec33180044637f72a2e8b2c3787ae1eae22 Mon Sep 17 00:00:00 2001
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From: Ondrej Jirman <megous@megous.com>
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Date: Sun, 5 Jul 2020 16:00:16 +0200
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Subject: [PATCH 215/351] drm/panel: st7703: Improve the power up sequence of
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the panel
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The datasheet 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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This fixes panel initialization failures during resume from sleep
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on PinePhone.
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Signed-off-by: Ondrej Jirman <megous@megous.com>
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---
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drivers/gpu/drm/panel/panel-sitronix-st7703.c | 25 ++++++++++---------
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1 file changed, 13 insertions(+), 12 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 3af2a6c280dd..1fe0e72995cd 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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@@ -425,29 +425,30 @@ 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 int st7703_get_modes(struct drm_panel *panel,
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--
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2.34.0
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