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Commit 1e77fc82 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Linus Walleij
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gpio: Add missing open drain/source handling to gpiod_set_value_cansleep() 



Since commit f11a0446 ("i2c: gpio: Enable working over slow
can_sleep GPIOs"), probing the i2c RTC connected to an i2c-gpio bus on
r8a7740/armadillo fails with:

    rtc-s35390a 0-0030: error resetting chip
    rtc-s35390a: probe of 0-0030 failed with error -5

More debug code reveals:

    i2c i2c-0: master_xfer[0] R, addr=0x30, len=1
    i2c i2c-0: NAK from device addr 0x30 msg #0
    s35390a_get_reg: ret = -6

Commit 02e47980 ("gpio: Alter semantics of *raw* operations to
actually be raw") moved open drain/source handling from
gpiod_set_raw_value_commit() to gpiod_set_value(), but forgot to take
into account that gpiod_set_value_cansleep() also needs this handling.
The i2c protocol mandates that i2c signals are open drain, hence i2c
communication fails.

Fix this by adding the missing handling to gpiod_set_value_cansleep(),
using a new common helper gpiod_set_value_nocheck().

Fixes: 02e47980 ("gpio: Alter semantics of *raw* operations to actually be raw")
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
[removed underscore syntax, added kerneldoc]
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent b2cd1df6

drivers/gpio/gpiolib.c

+23 −12
Original line number Diff line number Diff line
@@ -2892,6 +2892,27 @@ void gpiod_set_raw_value(struct gpio_desc *desc, int value) 
}

EXPORT_SYMBOL_GPL(gpiod_set_raw_value);



/**

 * gpiod_set_value_nocheck() - set a GPIO line value without checking

 * @desc: the descriptor to set the value on

 * @value: value to set

 *

 * This sets the value of a GPIO line backing a descriptor, applying

 * different semantic quirks like active low and open drain/source

 * handling.

 */

static void gpiod_set_value_nocheck(struct gpio_desc *desc, int value)

{

	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))

		value = !value;

	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))

		gpio_set_open_drain_value_commit(desc, value);

	else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))

		gpio_set_open_source_value_commit(desc, value);

	else

		gpiod_set_raw_value_commit(desc, value);

}



/**

 * gpiod_set_value() - assign a gpio's value

 * @desc: gpio whose value will be assigned
@@ -2906,16 +2927,8 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value); 
void gpiod_set_value(struct gpio_desc *desc, int value)

{

	VALIDATE_DESC_VOID(desc);

	/* Should be using gpiod_set_value_cansleep() */

	WARN_ON(desc->gdev->chip->can_sleep);

	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))

		value = !value;

	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))

		gpio_set_open_drain_value_commit(desc, value);

	else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))

		gpio_set_open_source_value_commit(desc, value);

	else

		gpiod_set_raw_value_commit(desc, value);

	gpiod_set_value_nocheck(desc, value);

}

EXPORT_SYMBOL_GPL(gpiod_set_value);
@@ -3243,9 +3256,7 @@ void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) 
{

	might_sleep_if(extra_checks);

	VALIDATE_DESC_VOID(desc);

	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))

		value = !value;

	gpiod_set_raw_value_commit(desc, value);

	gpiod_set_value_nocheck(desc, value);

}

EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);