linux-kernel - [PATCH v3] regulator: gpio: Honor regulator-boot-on property

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Message-Id: <20200720132809.26908-1-wens@kernel.org>
Date:   Mon, 20 Jul 2020 21:28:09 +0800
From:   Chen-Yu Tsai <wens@...nel.org>
To:     Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>
Cc:     Chen-Yu Tsai <wens@...e.org>, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Maxime Ripard <mripard@...nel.org>
Subject: [PATCH v3] regulator: gpio: Honor regulator-boot-on property

From: Chen-Yu Tsai <wens@...e.org>

When requesting the enable GPIO, the driver should do so with the
correct output level matching some expected state. This is especially
important if the regulator is a critical one, such as a supply for
the boot CPU. This is currently done by checking for the enable-at-boot
property, but this is not documented in the device tree binding, nor
does it match the common regulator properties.

Honor the common regulator-boot-on property by checking the boot_on
constraint setting within the DT probe path. This is the same as what
is done in the fixed regulator driver.

Also add a comment stating that the enable-at-boot property should not
be used.

Fixes: 006694d099e8 ("regulator: gpio-regulator: Allow use of GPIO controlled regulators though DT")
Signed-off-by: Chen-Yu Tsai <wens@...e.org>
---
Changes since v2:
  - Keep enable-at-boot property support
  - Add comment stating enable-at-boot should not be used

Changes since v1:
  - Reworded commit log
  - Fixed typo in subject
---
 drivers/regulator/gpio-regulator.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/regulator/gpio-regulator.c b/drivers/regulator/gpio-regulator.c
index 110ee6fe76c4..044e45ee9629 100644
--- a/drivers/regulator/gpio-regulator.c
+++ b/drivers/regulator/gpio-regulator.c
@@ -148,6 +148,13 @@ of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
 
 	config->supply_name = config->init_data->constraints.name;
 
+	if (config->init_data->constraints.boot_on)
+		config->enabled_at_boot = true;
+
+	/*
+	 * Do not use: undocumented device tree property.
+	 * This is kept around solely for device tree ABI stability.
+	 */
 	if (of_property_read_bool(np, "enable-at-boot"))
 		config->enabled_at_boot = true;
 
-- 
2.27.0