linux-kernel - [PATCH AUTOSEL 5.4 09/16] regulator: slg51000: Wait after asserting CS pin

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Date:   Mon, 28 Nov 2022 12:41:52 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>,
        support.opensource@...semi.com, lgirdwood@...il.com
Subject: [PATCH AUTOSEL 5.4 09/16] regulator: slg51000: Wait after asserting CS pin

From: Konrad Dybcio <konrad.dybcio@...aro.org>

[ Upstream commit 0b24dfa587c6cc7484cfb170da5c7dd73451f670 ]

Sony's downstream driver [1], among some other changes, adds a
seemingly random 10ms usleep_range, which turned out to be necessary
for the hardware to function properly on at least Sony Xperia 1 IV.
Without this, I2C transactions with the SLG51000 straight up fail.

Relax (10-10ms -> 10-11ms) and add the aforementioned sleep to make
sure the hardware has some time to wake up.

(nagara-2.0.0-mlc/vendor/semc/hardware/camera-kernel-module/)
[1] https://developer.sony.com/file/download/open-source-archive-for-64-0-m-4-29/

Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
Link: https://lore.kernel.org/r/20221118131035.54874-1-konrad.dybcio@linaro.org
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/regulator/slg51000-regulator.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/regulator/slg51000-regulator.c b/drivers/regulator/slg51000-regulator.c
index a0565daecace..5a18d7e620a5 100644
--- a/drivers/regulator/slg51000-regulator.c
+++ b/drivers/regulator/slg51000-regulator.c
@@ -465,6 +465,8 @@ static int slg51000_i2c_probe(struct i2c_client *client,
 		chip->cs_gpiod = cs_gpiod;
 	}
 
+	usleep_range(10000, 11000);
+
 	i2c_set_clientdata(client, chip);
 	chip->chip_irq = client->irq;
 	chip->dev = dev;
-- 
2.35.1