platform: arm64: thinkpad-t14s-ec: sleep after EC access

The ACPI ECRD and ECWR functions have a 10ms sleep at the end. It turns
out, that this is sometimes needed to avoid I2C transmission failures,
especially for functions doing regmap_update_bits (and thus read + write
shortly after each other). This fixes problems like the following
appearing in the kernel log:

leds platform::micmute: Setting an LED's brightness failed (-6)
leds platform::kbd_backlight: Setting an LED's brightness failed (-6)

The ACPI QEVT function used to read the interrupt status register also
has a 10ms sleep at the end. Without that there are problems with
reading multiple events following directly after each other resulting
in the following error message being logged:

thinkpad-t14s-ec 4-0028: Failed to read event

Fixes: 60b7ab6ce030 ("platform: arm64: thinkpad-t14s-ec: new driver")
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Link: https://patch.msgid.link/20251119-thinkpad-t14s-ec-improvements-v2-2-441219857c02@kernel.org
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

diff --git a/drivers/platform/arm64/lenovo-thinkpad-t14s.c b/drivers/platform/arm64/lenovo-thinkpad-t14s.c
index c1c01b977f2bd04160a180936d7cb59c977f122a..cf6a1d3b2617802949b2b427d407e9eaa7c66081 100644 (file)
--- a/drivers/platform/arm64/lenovo-thinkpad-t14s.c
+++ b/drivers/platform/arm64/lenovo-thinkpad-t14s.c
@@ -120,6 +120,7 @@ static int t14s_ec_write(void *context, unsigned int reg,
        if (ret < 0)
                return ret;
 
+       fsleep(10000);
        return 0;
 }
 
@@ -157,6 +158,7 @@ static int t14s_ec_read(void *context, unsigned int reg,
 
 out:
        i2c_unlock_bus(client->adapter, I2C_LOCK_SEGMENT);
+       fsleep(10000);
        return ret;
 }
 
@@ -191,6 +193,8 @@ static int t14s_ec_read_evt(struct t14s_ec *ec, u8 *val)
        if (ret < 0)
                goto out;
 
+       fsleep(10000);
+
        ret = 0;
 
 out: