linux-kernel - [PATCH] gpio: regmap: move drvdata to config data

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Message-Id: <20210604110406.11006-1-michael@walle.cc>
Date:   Fri,  4 Jun 2021 13:04:06 +0200
From:   Michael Walle <michael@...le.cc>
To:     linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Michael Walle <michael@...le.cc>,
        Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Subject: [PATCH] gpio: regmap: move drvdata to config data

Drop gpio_regmap_set_drvdata() and instead add it to the configuration
data passed to gpio_regmap_register().

gpio_regmap_set_drvdata() can't really be used in a race free way. This
is because the gpio_regmap object which is needed by _set_drvdata() is
returned by gpio_regmap_register(). On the other hand, the callbacks
which use the drvdata might already be called right after the
gpiochip_add() call in gpio_regmap_register(). Therefore, we have to
provide the drvdata early before we call gpiochip_add().

Reported-by: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Signed-off-by: Michael Walle <michael@...le.cc>
---
Btw, I'm not sure how to handle this "was part of another patch by another
author" thing. Should I leave the Sob and just add mine? I certainly don't
want to take credit for work Matti had done. This patch isn't huge, but
still ;)

 drivers/gpio/gpio-regmap.c  | 7 +------
 include/linux/gpio/regmap.h | 6 +++++-
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/gpio/gpio-regmap.c b/drivers/gpio/gpio-regmap.c
index 134cedf151a7..583cd1cdead8 100644
--- a/drivers/gpio/gpio-regmap.c
+++ b/drivers/gpio/gpio-regmap.c
@@ -178,12 +178,6 @@ static int gpio_regmap_direction_output(struct gpio_chip *chip,
 	return gpio_regmap_set_direction(chip, offset, true);
 }
 
-void gpio_regmap_set_drvdata(struct gpio_regmap *gpio, void *data)
-{
-	gpio->driver_data = data;
-}
-EXPORT_SYMBOL_GPL(gpio_regmap_set_drvdata);
-
 void *gpio_regmap_get_drvdata(struct gpio_regmap *gpio)
 {
 	return gpio->driver_data;
@@ -226,6 +220,7 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
 		return ERR_PTR(-ENOMEM);
 
 	gpio->parent = config->parent;
+	gpio->driver_data = config->drvdata;
 	gpio->regmap = config->regmap;
 	gpio->ngpio_per_reg = config->ngpio_per_reg;
 	gpio->reg_stride = config->reg_stride;
diff --git a/include/linux/gpio/regmap.h b/include/linux/gpio/regmap.h
index 334dd928042b..a9f7b7faf57b 100644
--- a/include/linux/gpio/regmap.h
+++ b/include/linux/gpio/regmap.h
@@ -37,6 +37,9 @@ struct regmap;
  *			offset to a register/bitmask pair. If not
  *			given the default gpio_regmap_simple_xlate()
  *			is used.
+ * @drvdata:		(Optional) Pointer to driver specific data which is
+ *			not used by gpio-remap but is provided "as is" to the
+ *			driver callback(s).
  *
  * The ->reg_mask_xlate translates a given base address and GPIO offset to
  * register and mask pair. The base address is one of the given register
@@ -78,13 +81,14 @@ struct gpio_regmap_config {
 	int (*reg_mask_xlate)(struct gpio_regmap *gpio, unsigned int base,
 			      unsigned int offset, unsigned int *reg,
 			      unsigned int *mask);
+
+	void *drvdata;
 };
 
 struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config);
 void gpio_regmap_unregister(struct gpio_regmap *gpio);
 struct gpio_regmap *devm_gpio_regmap_register(struct device *dev,
 					      const struct gpio_regmap_config *config);
-void gpio_regmap_set_drvdata(struct gpio_regmap *gpio, void *data);
 void *gpio_regmap_get_drvdata(struct gpio_regmap *gpio);
 
 #endif /* _LINUX_GPIO_REGMAP_H */
-- 
2.20.1