gpio: idio-16: Introduce the ACCES IDIO-16 GPIO library module

Exposes consumer library functions to facilitate communication with
devices within the ACCES IDIO-16 family such as the 104-IDIO-16 and
the PCI-IDIO-16.

A CONFIG_GPIO_IDIO_16 Kconfig option is introduced by this patch.
Modules wanting access to these idio-16 library functions should select
this Kconfig option and import the GPIO_IDIO_16 symbol namespace.

Cc: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

1 files changed, 71 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-idio-16.h b/drivers/gpio/gpio-idio-16.h
new file mode 100644
index 000000000000..928f8251a2bd
--- /dev/null
+++ b/drivers/gpio/gpio-idio-16.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright 2022 William Breathitt Gray */
+#ifndef _IDIO_16_H_
+#define _IDIO_16_H_
+
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+/**
+ * struct idio_16 - IDIO-16 registers structure
+ * @out0_7:	Read: FET Drive Outputs 0-7
+ *		Write: FET Drive Outputs 0-7
+ * @in0_7:	Read: Isolated Inputs 0-7
+ *		Write: Clear Interrupt
+ * @irq_ctl:	Read: Enable IRQ
+ *		Write: Disable IRQ
+ * @filter_ctl:	Read: Activate Input Filters 0-15
+ *		Write: Deactivate Input Filters 0-15
+ * @out8_15:	Read: FET Drive Outputs 8-15
+ *		Write: FET Drive Outputs 8-15
+ * @in8_15:	Read: Isolated Inputs 8-15
+ *		Write: Unused
+ * @irq_status:	Read: Interrupt status
+ *		Write: Unused
+ */
+struct idio_16 {
+	u8 out0_7;
+	u8 in0_7;
+	u8 irq_ctl;
+	u8 filter_ctl;
+	u8 out8_15;
+	u8 in8_15;
+	u8 irq_status;
+};
+
+#define IDIO_16_NOUT 16
+
+/**
+ * struct idio_16_state - IDIO-16 state structure
+ * @lock:	synchronization lock for accessing device state
+ * @out_state:	output signals state
+ */
+struct idio_16_state {
+	spinlock_t lock;
+	DECLARE_BITMAP(out_state, IDIO_16_NOUT);
+};
+
+/**
+ * idio_16_get_direction - get the I/O direction for a signal offset
+ * @offset:	offset of signal to get direction
+ *
+ * Returns the signal direction (0=output, 1=input) for the signal at @offset.
+ */
+static inline int idio_16_get_direction(const unsigned long offset)
+{
+	return (offset >= IDIO_16_NOUT) ? 1 : 0;
+}
+
+int idio_16_get(struct idio_16 __iomem *reg, struct idio_16_state *state,
+		unsigned long offset);
+void idio_16_get_multiple(struct idio_16 __iomem *reg,
+			  struct idio_16_state *state,
+			  const unsigned long *mask, unsigned long *bits);
+void idio_16_set(struct idio_16 __iomem *reg, struct idio_16_state *state,
+		 unsigned long offset, unsigned long value);
+void idio_16_set_multiple(struct idio_16 __iomem *reg,
+			  struct idio_16_state *state,
+			  const unsigned long *mask, const unsigned long *bits);
+void idio_16_state_init(struct idio_16_state *state);
+
+#endif /* _IDIO_16_H_ */