[PATCH v2] gpio: davinci: implement .get_direction()

[Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>]

It's strongly recommended for GPIO drivers to always implement the
.get_direction() callback - even for fixed-direction controllers.

GPIO core will even emit a warning if the callback is missing, when
users try to read the direction of a pin.

Implement .get_direction() for gpio-davinci.

Reported-by: Michael Walle <mwalle@kernel.org>
Closes: https://lore.kernel.org/all/DFJAFK3DTBOZ.3G2P3A5IH34GF@kernel.org/
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
---
I sent v1 too fast and forgot to Cc Keerthy. Sorry for the noise.

Changes in v2:
- use unsigned int instead of unsigned
- Cc davinci-gpio maintainer

 drivers/gpio/gpio-davinci.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/gpio/gpio-davinci.c b/drivers/gpio/gpio-davinci.c
index 538f27209ce7..97780f27ce5b 100644
--- a/drivers/gpio/gpio-davinci.c
+++ b/drivers/gpio/gpio-davinci.c
@@ -6,6 +6,7 @@
  * Copyright (c) 2007, MontaVista Software, Inc. <source@mvista.com>
  */
 
+#include <linux/cleanup.h>
 #include <linux/gpio/driver.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
@@ -109,6 +110,22 @@ davinci_direction_out(struct gpio_chip *chip, unsigned offset, int value)
 	return __davinci_direction(chip, offset, true, value);
 }
 
+static int davinci_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+	struct davinci_gpio_controller *d = gpiochip_get_data(chip);
+	struct davinci_gpio_regs __iomem *g;
+	u32 mask = __gpio_mask(offset), val;
+	int bank = offset / 32;
+
+	g = d->regs[bank];
+
+	guard(spinlock_irqsave)(&d->lock);
+
+	val = readl_relaxed(&g->dir);
+
+	return (val & mask) ? GPIO_LINE_DIRECTION_IN : GPIO_LINE_DIRECTION_OUT;
+}
+
 /*
  * Read the pin's value (works even if it's set up as output);
  * returns zero/nonzero.
@@ -203,6 +220,7 @@ static int davinci_gpio_probe(struct platform_device *pdev)
 	chips->chip.get = davinci_gpio_get;
 	chips->chip.direction_output = davinci_direction_out;
 	chips->chip.set = davinci_gpio_set;
+	chips->chip.get_direction = davinci_get_direction;
 
 	chips->chip.ngpio = ngpio;
 	chips->chip.base = -1;
-- 
2.47.3