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Subject[PATCH for 4.15] leds: pca955x: Fix configuration on GPIO request for input
Date
The prior patch which fixed the problem with output inversion failed to
account for a necessary change to requesting a pin for input, which is
affected by the open-drain nature of the hardware.

Previously pca955x_gpio_direction_input() called through
pca955x_set_value() to configure the direction, however continuing down
this route lead to a brain-hemorrhaging level of necessary inversions.
Instead, remove one layer by calling directly into pca955x_led_set(),
and define PCA955X_GPIO_INPUT to paper over the rest of the confusion.

Cc: Cédric Le Goater <clg@kaod.org>
Cc: Joel Stanley <joel@jms.id.au>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Tested-by: Matt Spinler <mspinler@linux.vnet.ibm.com>
---
Jacek:

The prior patch called out above is "eae1693fb026 leds: pca955x: Don't
invert requested value in pca955x_gpio_set_value()" (at the time of sending). I
think I've seen the leds tree be rebased in the past, so feel free to squash
this change in if desired.

drivers/leds/leds-pca955x.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/leds/leds-pca955x.c b/drivers/leds/leds-pca955x.c
index 6dcd2d7cc6a4..78183f90820e 100644
--- a/drivers/leds/leds-pca955x.c
+++ b/drivers/leds/leds-pca955x.c
@@ -61,6 +61,7 @@
#define PCA955X_LS_BLINK0 0x2 /* Blink at PWM0 rate */
#define PCA955X_LS_BLINK1 0x3 /* Blink at PWM1 rate */

+#define PCA955X_GPIO_INPUT LED_OFF
#define PCA955X_GPIO_HIGH LED_OFF
#define PCA955X_GPIO_LOW LED_FULL

@@ -358,8 +359,11 @@ static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
static int pca955x_gpio_direction_input(struct gpio_chip *gc,
unsigned int offset)
{
- /* To use as input ensure pin is not driven */
- return pca955x_set_value(gc, offset, 0);
+ struct pca955x *pca955x = gpiochip_get_data(gc);
+ struct pca955x_led *led = &pca955x->leds[offset];
+
+ /* To use as input ensure pin is not driven. */
+ return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_INPUT);
}

static int pca955x_gpio_direction_output(struct gpio_chip *gc,
--
2.11.0
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