35 lines
1.2 KiB
Diff
35 lines
1.2 KiB
Diff
From a8bb5f5ddbef4ac5b0e256c7c3bde4ac5636f429 Mon Sep 17 00:00:00 2001
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From: Dave Stevenson <dave.stevenson@raspberrypi.com>
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Date: Wed, 8 Sep 2021 14:21:38 +0100
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Subject: [PATCH] drm/panel/raspberrypi-touchscreen: Handle I2C errors.
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rpi_touchscreen_i2c_read returns any errors from i2c_transfer,
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or the 8 bit received value.
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Check for error values before trying to process the data as
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valid.
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Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
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---
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drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c | 5 +++--
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1 file changed, 3 insertions(+), 2 deletions(-)
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--- a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
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+++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
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@@ -296,13 +296,14 @@ static int rpi_touchscreen_noop(struct d
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static int rpi_touchscreen_prepare(struct drm_panel *panel)
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{
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struct rpi_touchscreen *ts = panel_to_ts(panel);
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- int i;
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+ int i, data;
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rpi_touchscreen_i2c_write(ts, REG_POWERON, 1);
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usleep_range(20000, 25000);
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/* Wait for nPWRDWN to go low to indicate poweron is done. */
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for (i = 0; i < 100; i++) {
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- if (rpi_touchscreen_i2c_read(ts, REG_PORTB) & 1)
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+ data = rpi_touchscreen_i2c_read(ts, REG_PORTB);
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+ if (data >= 0 && (data & 1))
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break;
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}
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