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authorLukas Wunner <lukas@wunner.de>2017-10-12 13:40:10 +0300
committerLinus Walleij <linus.walleij@linaro.org>2017-10-19 23:32:39 +0300
commiteec1d566cdf94b57e8f5ba9fe60eea214929bcfc (patch)
treef10fab2d393d231f711123fcf66c1b01fc893370 /drivers/gpio/gpiolib.h
parent5307e2ad69ab3b0e0622fdf8b254c1d4565eb924 (diff)
downloadlinux-eec1d566cdf94b57e8f5ba9fe60eea214929bcfc.tar.xz
gpio: Introduce ->get_multiple callback
SPI-attached GPIO controllers typically read out all inputs in one go. If callers desire the values of multipe inputs, ideally a single readout should take place to return the desired values. However the current driver API only offers a ->get callback but no ->get_multiple (unlike ->set_multiple, which is present). Thus, to read multiple inputs, a full readout needs to be performed for every single value (barring driver-internal caching), which is inefficient. In fact, the lack of a ->get_multiple callback has been bemoaned repeatedly by the gpio subsystem maintainer: http://www.spinics.net/lists/linux-gpio/msg10571.html http://www.spinics.net/lists/devicetree/msg121734.html Introduce the missing callback. Add corresponding consumer functions such as gpiod_get_array_value(). Amend linehandle_ioctl() to take advantage of the newly added infrastructure. Update the documentation. Cc: Rojhalat Ibrahim <imr@rtschenk.de> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/gpio/gpiolib.h')
-rw-r--r--drivers/gpio/gpiolib.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index d003ccb12781..10a48caf8477 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -180,6 +180,10 @@ static inline bool acpi_can_fallback_to_crs(struct acpi_device *adev,
#endif
struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip, u16 hwnum);
+int gpiod_get_array_value_complex(bool raw, bool can_sleep,
+ unsigned int array_size,
+ struct gpio_desc **desc_array,
+ int *value_array);
void gpiod_set_array_value_complex(bool raw, bool can_sleep,
unsigned int array_size,
struct gpio_desc **desc_array,