From 13f82ca3878db8284a70ef9711d7f710a31eb562 Mon Sep 17 00:00:00 2001
From: Luca Ellero <l.ellero@asem.it>
Date: Thu, 26 Jan 2023 11:52:26 +0100
Subject: [PATCH] Input: ads7846 - always set last command to PWRDOWN
Git-commit: 13f82ca3878db8284a70ef9711d7f710a31eb562
Patch-mainline: v6.3-rc1
References: git-fixes
Controllers that report pressure (e.g. ADS7846) use 5 commands and the
correct sequence is READ_X, READ_Y, READ_Z1, READ_Z2, PWRDOWN.
Controllers that don't report pressure (e.g. ADS7845/ADS7843) use only 3
commands and the correct sequence should be READ_X, READ_Y, PWRDOWN. But
the sequence sent was incorrect: READ_X, READ_Y, READ_Z1.
Fix this by setting the third (and last) command to PWRDOWN.
Fixes: ffa458c1bd9b ("spi: ads7846 driver")
Signed-off-by: Luca Ellero <l.ellero@asem.it>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230126105227.47648-3-l.ellero@asem.it
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/input/touchscreen/ads7846.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index f11b444f2138..15da1047a577 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -1066,6 +1066,9 @@ static int ads7846_setup_spi_msg(struct ads7846 *ts,
struct ads7846_buf_layout *l = &packet->l[cmd_idx];
unsigned int max_count;
+ if (cmd_idx == packet->cmds - 1)
+ cmd_idx = ADS7846_PWDOWN;
+
if (ads7846_cmd_need_settle(cmd_idx))
max_count = packet->count + packet->count_skip;
else
@@ -1102,7 +1105,12 @@ static int ads7846_setup_spi_msg(struct ads7846 *ts,
for (cmd_idx = 0; cmd_idx < packet->cmds; cmd_idx++) {
struct ads7846_buf_layout *l = &packet->l[cmd_idx];
- u8 cmd = ads7846_get_cmd(cmd_idx, vref);
+ u8 cmd;
+
+ if (cmd_idx == packet->cmds - 1)
+ cmd_idx = ADS7846_PWDOWN;
+
+ cmd = ads7846_get_cmd(cmd_idx, vref);
for (b = 0; b < l->count; b++)
packet->tx[l->offset + b].cmd = cmd;
--
2.35.3