[PATCH 2/3] Input: ads7846 - always set last command to PWRDOWN
From: Luca Ellero <hidden>
Date: 2023-01-26 11:11:45
Also in:
lkml
Subsystem:
input (keyboard, mouse, joystick, touchscreen) drivers, the rest · Maintainers:
Dmitry Torokhov, Linus Torvalds
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 <redacted>
---
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;
--
2.25.1