[PATCH v2 5/5] gpio: tqmx86: add support for changing GPIO directions

[Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>]

Only GPIOs 4..7 have IRQ support on the TQMx86 variants currently handled
by the driver, but apart from that, changing directions works fine. The
default directions are left unchanged (0..3 output, 4..7 input) to match
the COM Express specification.

A tqmx86_gpio_set() variant without locking is introduced as a new
helper.

Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
---

v2: use lock guards

 drivers/gpio/gpio-tqmx86.c | 44 ++++++++++++++++++++++++++------------
 1 file changed, 30 insertions(+), 14 deletions(-)

diff --git a/drivers/gpio/gpio-tqmx86.c b/drivers/gpio/gpio-tqmx86.c
index 4bef13cad1807..18f523a15b3c0 100644
--- a/drivers/gpio/gpio-tqmx86.c
+++ b/drivers/gpio/gpio-tqmx86.c
@@ -85,6 +85,14 @@ static int tqmx86_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	return !!(tqmx86_gpio_read(gpio, TQMX86_GPIOD) & BIT(offset));
 }
 
+static void _tqmx86_gpio_set(struct tqmx86_gpio_data *gpio, unsigned int offset,
+			     int value)
+	__must_hold(&gpio->spinlock)
+{
+	__assign_bit(offset, gpio->output, value);
+	tqmx86_gpio_write(gpio, bitmap_get_value8(gpio->output, 0), TQMX86_GPIOD);
+}
+
 static void tqmx86_gpio_set(struct gpio_chip *chip, unsigned int offset,
 			    int value)
 {
@@ -92,39 +100,47 @@ static void tqmx86_gpio_set(struct gpio_chip *chip, unsigned int offset,
 
 	guard(raw_spinlock_irqsave)(&gpio->spinlock);
 
-	__assign_bit(offset, gpio->output, value);
-	tqmx86_gpio_write(gpio, bitmap_get_value8(gpio->output, 0), TQMX86_GPIOD);
+	_tqmx86_gpio_set(gpio, offset, value);
 }
 
 static int tqmx86_gpio_direction_input(struct gpio_chip *chip,
 				       unsigned int offset)
 {
-	/* Direction cannot be changed. Validate is an input. */
-	if (BIT(offset) & TQMX86_DIR_INPUT_MASK)
-		return 0;
-	else
-		return -EINVAL;
+	struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
+
+	guard(raw_spinlock_irqsave)(&gpio->spinlock);
+
+	tqmx86_gpio_clrsetbits(gpio, BIT(offset), 0, TQMX86_GPIODD);
+
+	return 0;
 }
 
 static int tqmx86_gpio_direction_output(struct gpio_chip *chip,
 					unsigned int offset,
 					int value)
 {
-	/* Direction cannot be changed, validate is an output */
-	if (BIT(offset) & TQMX86_DIR_INPUT_MASK)
-		return -EINVAL;
+	struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
+
+	guard(raw_spinlock_irqsave)(&gpio->spinlock);
+
+	_tqmx86_gpio_set(gpio, offset, value);
+	tqmx86_gpio_clrsetbits(gpio, 0, BIT(offset), TQMX86_GPIODD);
 
-	tqmx86_gpio_set(chip, offset, value);
 	return 0;
 }
 
 static int tqmx86_gpio_get_direction(struct gpio_chip *chip,
 				     unsigned int offset)
 {
-	if (TQMX86_DIR_INPUT_MASK & BIT(offset))
-		return GPIO_LINE_DIRECTION_IN;
+	struct tqmx86_gpio_data *gpio = gpiochip_get_data(chip);
+	u8 val;
+
+	val = tqmx86_gpio_read(gpio, TQMX86_GPIODD);
+
+	if (val & BIT(offset))
+		return GPIO_LINE_DIRECTION_OUT;
 
-	return GPIO_LINE_DIRECTION_OUT;
+	return GPIO_LINE_DIRECTION_IN;
 }
 
 static void tqmx86_gpio_irq_config(struct tqmx86_gpio_data *gpio, int hwirq)
-- 
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Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
https://www.tq-group.com/