1 files changed, 190 insertions, 0 deletions
diff --git a/include/linux/gpio/generic.h b/include/linux/gpio/generic.h
new file mode 100644
index 000000000000..ff566dc9c3cb
--- /dev/null
+++ b/include/linux/gpio/generic.h
@@ -0,0 +1,190 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __LINUX_GPIO_GENERIC_H
+#define __LINUX_GPIO_GENERIC_H
+
+#include <linux/cleanup.h>
+#include <linux/gpio/driver.h>
+#include <linux/spinlock.h>
+
+struct device;
+
+#define GPIO_GENERIC_BIG_ENDIAN			BIT(0)
+#define GPIO_GENERIC_UNREADABLE_REG_SET		BIT(1) /* reg_set is unreadable */
+#define GPIO_GENERIC_UNREADABLE_REG_DIR		BIT(2) /* reg_dir is unreadable */
+#define GPIO_GENERIC_BIG_ENDIAN_BYTE_ORDER	BIT(3)
+#define GPIO_GENERIC_READ_OUTPUT_REG_SET	BIT(4) /* reg_set stores output value */
+#define GPIO_GENERIC_NO_OUTPUT			BIT(5) /* only input */
+#define GPIO_GENERIC_NO_SET_ON_INPUT		BIT(6)
+#define GPIO_GENERIC_PINCTRL_BACKEND		BIT(7) /* Call pinctrl direction setters */
+#define GPIO_GENERIC_NO_INPUT			BIT(8) /* only output */
+
+/**
+ * struct gpio_generic_chip_config - Generic GPIO chip configuration data
+ * @dev: Parent device of the new GPIO chip (compulsory).
+ * @sz: Size (width) of the MMIO registers in bytes, typically 1, 2 or 4.
+ * @dat: MMIO address for the register to READ the value of the GPIO lines, it
+ *       is expected that a 1 in the corresponding bit in this register means
+ *       the line is asserted.
+ * @set: MMIO address for the register to SET the value of the GPIO lines, it
+ *       is expected that we write the line with 1 in this register to drive
+ *       the GPIO line high.
+ * @clr: MMIO address for the register to CLEAR the value of the GPIO lines,
+ *       it is expected that we write the line with 1 in this register to
+ *       drive the GPIO line low. It is allowed to leave this address as NULL,
+ *       in that case the SET register will be assumed to also clear the GPIO
+ *       lines, by actively writing the line with 0.
+ * @dirout: MMIO address for the register to set the line as OUTPUT. It is
+ *          assumed that setting a line to 1 in this register will turn that
+ *          line into an output line. Conversely, setting the line to 0 will
+ *          turn that line into an input.
+ * @dirin: MMIO address for the register to set this line as INPUT. It is
+ *         assumed that setting a line to 1 in this register will turn that
+ *         line into an input line. Conversely, setting the line to 0 will
+ *         turn that line into an output.
+ * @flags: Different flags that will affect the behaviour of the device, such
+ *         as endianness etc.
+ */
+struct gpio_generic_chip_config {
+	struct device *dev;
+	unsigned long sz;
+	void __iomem *dat;
+	void __iomem *set;
+	void __iomem *clr;
+	void __iomem *dirout;
+	void __iomem *dirin;
+	unsigned long flags;
+};
+
+/**
+ * struct gpio_generic_chip - Generic GPIO chip implementation.
+ * @gc: The underlying struct gpio_chip object, implementing low-level GPIO
+ *      chip routines.
+ * @read_reg: reader function for generic GPIO
+ * @write_reg: writer function for generic GPIO
+ * @be_bits: if the generic GPIO has big endian bit order (bit 31 is
+ *           representing line 0, bit 30 is line 1 ... bit 0 is line 31) this
+ *           is set to true by the generic GPIO core. It is for internal
+ *           housekeeping only.
+ * @reg_dat: data (in) register for generic GPIO
+ * @reg_set: output set register (out=high) for generic GPIO
+ * @reg_clr: output clear register (out=low) for generic GPIO
+ * @reg_dir_out: direction out setting register for generic GPIO
+ * @reg_dir_in: direction in setting register for generic GPIO
+ * @dir_unreadable: indicates that the direction register(s) cannot be read and
+ *                  we need to rely on out internal state tracking.
+ * @pinctrl: the generic GPIO uses a pin control backend.
+ * @bits: number of register bits used for a generic GPIO
+ *        i.e. <register width> * 8
+ * @lock: used to lock chip->sdata. Also, this is needed to keep
+ *        shadowed and real data registers writes together.
+ * @sdata: shadowed data register for generic GPIO to clear/set bits safely.
+ * @sdir: shadowed direction register for generic GPIO to clear/set direction
+ *        safely. A "1" in this word means the line is set as output.
+ */
+struct gpio_generic_chip {
+	struct gpio_chip gc;
+	unsigned long (*read_reg)(void __iomem *reg);
+	void (*write_reg)(void __iomem *reg, unsigned long data);
+	bool be_bits;
+	void __iomem *reg_dat;
+	void __iomem *reg_set;
+	void __iomem *reg_clr;
+	void __iomem *reg_dir_out;
+	void __iomem *reg_dir_in;
+	bool dir_unreadable;
+	bool pinctrl;
+	int bits;
+	raw_spinlock_t lock;
+	unsigned long sdata;
+	unsigned long sdir;
+};
+
+static inline struct gpio_generic_chip *
+to_gpio_generic_chip(struct gpio_chip *gc)
+{
+	return container_of(gc, struct gpio_generic_chip, gc);
+}
+
+int gpio_generic_chip_init(struct gpio_generic_chip *chip,
+			   const struct gpio_generic_chip_config *cfg);
+
+/**
+ * gpio_generic_chip_set() - Set the GPIO line value of the generic GPIO chip.
+ * @chip: Generic GPIO chip to use.
+ * @offset: Hardware offset of the line to set.
+ * @value: New GPIO line value.
+ *
+ * Some modules using the generic GPIO chip, need to set line values in their
+ * direction setters but they don't have access to the gpio-mmio symbols so
+ * they use the function pointer in struct gpio_chip directly. This is not
+ * optimal and can lead to crashes at run-time in some instances. This wrapper
+ * provides a safe interface for users.
+ *
+ * Returns: 0 on success, negative error number of failure.
+ */
+static inline int
+gpio_generic_chip_set(struct gpio_generic_chip *chip, unsigned int offset,
+		      int value)
+{
+	if (WARN_ON(!chip->gc.set))
+		return -EOPNOTSUPP;
+
+	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->read_reg))
+		return 0;
+
+	return chip->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->write_reg))
+		return;
+
+	chip->write_reg(reg, val);
+}
+
+#define gpio_generic_chip_lock(gen_gc) \
+	raw_spin_lock(&(gen_gc)->lock)
+
+#define gpio_generic_chip_unlock(gen_gc) \
+	raw_spin_unlock(&(gen_gc)->lock)
+
+#define gpio_generic_chip_lock_irqsave(gen_gc, flags) \
+	raw_spin_lock_irqsave(&(gen_gc)->lock, flags)
+
+#define gpio_generic_chip_unlock_irqrestore(gen_gc, flags) \
+	raw_spin_unlock_irqrestore(&(gen_gc)->lock, flags)
+
+DEFINE_LOCK_GUARD_1(gpio_generic_lock,
+		    struct gpio_generic_chip,
+		    gpio_generic_chip_lock(_T->lock),
+		    gpio_generic_chip_unlock(_T->lock))
+
+DEFINE_LOCK_GUARD_1(gpio_generic_lock_irqsave,
+		    struct gpio_generic_chip,
+		    gpio_generic_chip_lock_irqsave(_T->lock, _T->flags),
+		    gpio_generic_chip_unlock_irqrestore(_T->lock, _T->flags),
+		    unsigned long flags)
+
+#endif /* __LINUX_GPIO_GENERIC_H */