[PATCH v6 08/13] gpio: regmap: support write_data_after_dir and girq

[Long Zhao via B4 Relay <devnull+longzhao.ambarella.com@kernel.org>]

From: Long Zhao <longzhao@ambarella.com>

Add an optional write-after-direction-output quirk for controllers
that ignore data-register writes while a line is still configured as
input, and allow drivers to pass an existing gpio_irq_chip through
gpio_regmap_register() so IRQ setup can stay with the caller.

Signed-off-by: Long Zhao <longzhao@ambarella.com>
---
 drivers/gpio/gpio-regmap.c  | 24 +++++++++++++++++++++++-
 include/linux/gpio/regmap.h | 13 +++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-regmap.c b/drivers/gpio/gpio-regmap.c
index 51b4d69b8740..b4b492a1765c 100644
--- a/drivers/gpio/gpio-regmap.c
+++ b/drivers/gpio/gpio-regmap.c
@@ -33,6 +33,7 @@ struct gpio_regmap {
 	unsigned int reg_dir_out_base;
 	unsigned long *fixed_direction_mask;
 	unsigned long *fixed_direction_output;
+	bool write_data_after_dir;
 
 #ifdef CONFIG_REGMAP_IRQ
 	int regmap_irq_line;
@@ -273,7 +274,15 @@ static int gpio_regmap_direction_output(struct gpio_chip *chip,
 
 	gpio_regmap_set(chip, offset, value);
 
-	return gpio_regmap_set_direction(chip, offset, true);
+	ret = gpio_regmap_set_direction(chip, offset, true);
+	if (ret)
+		return ret;
+
+	/* Some controllers ignore data writes while the line is still an input. */
+	if (gpio->write_data_after_dir)
+		gpio_regmap_set(chip, offset, value);
+
+	return 0;
 }
 
 void *gpio_regmap_get_drvdata(struct gpio_regmap *gpio)
@@ -311,6 +320,14 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
 	if (config->reg_dir_out_base && config->reg_dir_in_base)
 		return ERR_PTR(-EINVAL);
 
+	if (config->girq && config->irq_domain)
+		return ERR_PTR(-EINVAL);
+
+#ifdef CONFIG_REGMAP_IRQ
+	if (config->girq && config->regmap_irq_chip)
+		return ERR_PTR(-EINVAL);
+#endif
+
 	gpio = kzalloc_obj(*gpio);
 	if (!gpio)
 		return ERR_PTR(-ENOMEM);
@@ -376,6 +393,8 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
 			    config->fixed_direction_output, chip->ngpio);
 	}
 
+	gpio->write_data_after_dir = config->write_data_after_dir;
+
 	/* if not set, assume there is only one register */
 	gpio->ngpio_per_reg = config->ngpio_per_reg;
 	if (!gpio->ngpio_per_reg)
@@ -390,6 +409,9 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
 	if (!gpio->reg_mask_xlate)
 		gpio->reg_mask_xlate = gpio_regmap_simple_xlate;
 
+	if (config->girq)
+		chip->irq = *config->girq;
+
 	ret = gpiochip_add_data(chip, gpio);
 	if (ret < 0)
 		goto err_free_bitmap_output;
diff --git a/include/linux/gpio/regmap.h b/include/linux/gpio/regmap.h
index 06255756710d..f94dd95d330f 100644
--- a/include/linux/gpio/regmap.h
+++ b/include/linux/gpio/regmap.h
@@ -7,6 +7,7 @@ struct device;
 struct fwnode_handle;
 struct gpio_regmap;
 struct gpio_chip;
+struct gpio_irq_chip;
 struct irq_domain;
 struct regmap;
 
@@ -34,6 +35,11 @@ struct regmap;
  * @ngpio_per_reg:	(Optional) Number of GPIOs per register
  * @irq_domain:		(Optional) IRQ domain if the controller is
  *			interrupt-capable
+ * @girq:		(Optional) Interrupt chip settings for the gpio_chip,
+ *			prepared by the driver as for a direct gpiochip
+ *			registration. The gpio_chip will then create and
+ *			manage its own IRQ domain. Mutually exclusive with
+ *			@irq_domain and @regmap_irq_chip.
  * @reg_mask_xlate:     (Optional) Translates base address and GPIO
  *			offset to a register/bitmask pair. If not
  *			given the default gpio_regmap_simple_xlate()
@@ -48,6 +54,11 @@ struct regmap;
  *			(Optional) Bitmap representing the fixed direction of
  *			the GPIO lines. Useful when there are GPIO lines with a
  *			fixed direction mixed together in the same register.
+ * @write_data_after_dir:
+ *			(Optional) Write the output value again after
+ *			switching a line to output in ->direction_output().
+ *			Needed for hardware which ignores data register
+ *			writes while the line is configured as an input.
  * @drvdata:		(Optional) Pointer to driver specific data which is
  *			not used by gpio-remap but is provided "as is" to the
  *			driver callback(s).
@@ -95,8 +106,10 @@ struct gpio_regmap_config {
 	int reg_stride;
 	int ngpio_per_reg;
 	struct irq_domain *irq_domain;
+	const struct gpio_irq_chip *girq;
 	unsigned long *fixed_direction_mask;
 	unsigned long *fixed_direction_output;
+	bool write_data_after_dir;
 
 #ifdef CONFIG_REGMAP_IRQ
 	struct regmap_irq_chip *regmap_irq_chip;

-- 
2.34.1