linux-kernel - [PATCH v2] regulator: bd718x7: Fix the BUCK7 voltage setting on BD71837

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Date:   Wed, 2 Jun 2021 08:45:58 +0300
From:   Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
To:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
        Matti Vaittinen <mazziesaccount@...il.com>
Cc:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, linux-power@...rohmeurope.com,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] regulator: bd718x7: Fix the BUCK7 voltage setting on
 BD71837

Changing the BD71837 voltages for other regulators except the first 4 BUCKs
should be forbidden when the regulator is enabled. There may be out-of-spec
voltage spikes if the voltage of these "non DVS" bucks is changed when
enabled. This restriction was accidentally removed when the LDO voltage
change was allowed for BD71847. (It was not noticed that the BD71837
BUCK7 used same voltage setting function as LDOs).

Additionally this bug causes incorrect voltage monitoring register access.
The voltage change function accidentally used for bd71837 BUCK7 is
intended to only handle LDO voltage changes. A BD71847 LDO specific
voltage monitoring disabling code gets executed on BD71837 and register
offsets are wrongly calculated as regulator is assumed to be an LDO.

Prevent the BD71837 BUCK7 voltage change when BUCK7 is enabled by using
the correct voltage setting operation.

Fixes: 9bcbabafa19b ("regulator: bd718x7: remove voltage change restriction from BD71847 LDOs")
Signed-off-by: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>

---
v2: Improve commit message
---
 drivers/regulator/bd718x7-regulator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/regulator/bd718x7-regulator.c b/drivers/regulator/bd718x7-regulator.c
index e61295b30503..b1eb46961993 100644
--- a/drivers/regulator/bd718x7-regulator.c
+++ b/drivers/regulator/bd718x7-regulator.c
@@ -334,7 +334,7 @@ BD718XX_OPS(bd71837_buck_regulator_ops, regulator_list_voltage_linear_range,
 	    NULL);

 BD718XX_OPS(bd71837_buck_regulator_nolinear_ops, regulator_list_voltage_table,
-	    regulator_map_voltage_ascend, bd718xx_set_voltage_sel_restricted,
+	    regulator_map_voltage_ascend, bd71837_set_voltage_sel_restricted,
 	    regulator_get_voltage_sel_regmap, regulator_set_voltage_time_sel,
 	    NULL);
 /*

base-commit: 8124c8a6b35386f73523d27eacb71b5364a68c4c
-- 
2.25.4

-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =] 

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