gpio: generic: provide helpers for reading and writing registers

Provide helpers wrapping the read_reg() and write_reg() callbacks of the
generic GPIO API that are called directly by many users. This is done to
hide their implementation ahead of moving them into the separate generic
GPIO struct.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250825-gpio-mmio-gpio-conv-v1-2-356b4b1d5110@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/include/linux/gpio/generic.h b/include/linux/gpio/generic.h
index 5a85ecbef8d2..4c0626b53ec9 100644
--- a/include/linux/gpio/generic.h
+++ b/include/linux/gpio/generic.h
@@ -100,6 +100,37 @@ gpio_generic_chip_set(struct gpio_generic_chip *chip, unsigned int offset,
 	return chip->gc.set(&chip->gc, offset, value);
 }
 
+/**
+ * gpio_generic_read_reg() - Read a register using the underlying callback.
+ * @chip: Generic GPIO chip to use.
+ * @reg: Register to read.
+ *
+ * Returns: value read from register.
+ */
+static inline unsigned long
+gpio_generic_read_reg(struct gpio_generic_chip *chip, void __iomem *reg)
+{
+	if (WARN_ON(!chip->gc.read_reg))
+		return 0;
+
+	return chip->gc.read_reg(reg);
+}
+
+/**
+ * gpio_generic_write_reg() - Write a register using the underlying callback.
+ * @chip: Generic GPIO chip to use.
+ * @reg: Register to write to.
+ * @val: New value to write.
+ */
+static inline void gpio_generic_write_reg(struct gpio_generic_chip *chip,
+					  void __iomem *reg, unsigned long val)
+{
+	if (WARN_ON(!chip->gc.write_reg))
+		return;
+
+	chip->gc.write_reg(reg, val);
+}
+
 #define gpio_generic_chip_lock(gen_gc) \
 	raw_spin_lock(&(gen_gc)->gc.bgpio_lock)