mfd: Add GPIO pin configuration support for WM8350

The WM8350 provides a number of user-configurable pins providing access
to various signals generated by the functions on the chip. These are
referred to as GPIO pins in the device documentation but in Linux terms
they are more general than that, providing configuration of alternate
functions.

This patch implements support for selecting the alternate functions for
these pins. They can also be used as GPIOs in the normal Linux sense -
a subsequent patch will add support for doing so.

This code was all written by Liam Girdwood and has had minor updates
and rearrangements by Mark Brown.

Signed-off-by: Mark Brown <[e-mail]>
Acked-by: Samuel Ortiz <[e-mail]>
Signed-off-by: Liam Girdwood <[e-mail]>

drivers/mfd/Makefile

···
 obj-$(CONFIG_MFD_TC6393XB)	+= tc6393xb.o
 
 obj-$(CONFIG_MFD_WM8400)	+= wm8400-core.o
-wm8350-objs			:= wm8350-core.o wm8350-regmap.o
+wm8350-objs			:= wm8350-core.o wm8350-regmap.o wm8350-gpio.o
 obj-$(CONFIG_MFD_WM8350)	+= wm8350.o
 obj-$(CONFIG_MFD_WM8350_I2C)	+= wm8350-i2c.o
 

drivers/mfd/wm8350-gpio.c

···
+/*
+ * wm8350-core.c  --  Device access for Wolfson WM8350
+ *
+ * Copyright 2007, 2008 Wolfson Microelectronics PLC.
+ *
+ * Author: Liam Girdwood
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+
+#include <linux/mfd/wm8350/core.h>
+#include <linux/mfd/wm8350/gpio.h>
+#include <linux/mfd/wm8350/pmic.h>
+
+static int gpio_set_dir(struct wm8350 *wm8350, int gpio, int dir)
+{
+	int ret;
+
+	wm8350_reg_unlock(wm8350);
+	if (dir == WM8350_GPIO_DIR_OUT)
+		ret = wm8350_clear_bits(wm8350,
+					WM8350_GPIO_CONFIGURATION_I_O,
+					1 << gpio);
+	else
+		ret = wm8350_set_bits(wm8350,
+				      WM8350_GPIO_CONFIGURATION_I_O,
+				      1 << gpio);
+	wm8350_reg_lock(wm8350);
+	return ret;
+}
+
+static int gpio_set_debounce(struct wm8350 *wm8350, int gpio, int db)
+{
+	if (db == WM8350_GPIO_DEBOUNCE_ON)
+		return wm8350_set_bits(wm8350, WM8350_GPIO_DEBOUNCE,
+				       1 << gpio);
+	else
+		return wm8350_clear_bits(wm8350,
+					 WM8350_GPIO_DEBOUNCE, 1 << gpio);
+}
+
+static int gpio_set_func(struct wm8350 *wm8350, int gpio, int func)
+{
+	u16 reg;
+
+	wm8350_reg_unlock(wm8350);
+	switch (gpio) {
+	case 0:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_1)
+		    & ~WM8350_GP0_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_1,
+				 reg | ((func & 0xf) << 0));
+		break;
+	case 1:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_1)
+		    & ~WM8350_GP1_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_1,
+				 reg | ((func & 0xf) << 4));
+		break;
+	case 2:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_1)
+		    & ~WM8350_GP2_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_1,
+				 reg | ((func & 0xf) << 8));
+		break;
+	case 3:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_1)
+		    & ~WM8350_GP3_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_1,
+				 reg | ((func & 0xf) << 12));
+		break;
+	case 4:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_2)
+		    & ~WM8350_GP4_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_2,
+				 reg | ((func & 0xf) << 0));
+		break;
+	case 5:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_2)
+		    & ~WM8350_GP5_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_2,
+				 reg | ((func & 0xf) << 4));
+		break;
+	case 6:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_2)
+		    & ~WM8350_GP6_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_2,
+				 reg | ((func & 0xf) << 8));
+		break;
+	case 7:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_2)
+		    & ~WM8350_GP7_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_2,
+				 reg | ((func & 0xf) << 12));
+		break;
+	case 8:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_3)
+		    & ~WM8350_GP8_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_3,
+				 reg | ((func & 0xf) << 0));
+		break;
+	case 9:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_3)
+		    & ~WM8350_GP9_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_3,
+				 reg | ((func & 0xf) << 4));
+		break;
+	case 10:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_3)
+		    & ~WM8350_GP10_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_3,
+				 reg | ((func & 0xf) << 8));
+		break;
+	case 11:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_3)
+		    & ~WM8350_GP11_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_3,
+				 reg | ((func & 0xf) << 12));
+		break;
+	case 12:
+		reg = wm8350_reg_read(wm8350, WM8350_GPIO_FUNCTION_SELECT_4)
+		    & ~WM8350_GP12_FN_MASK;
+		wm8350_reg_write(wm8350, WM8350_GPIO_FUNCTION_SELECT_4,
+				 reg | ((func & 0xf) << 0));
+		break;
+	default:
+		wm8350_reg_lock(wm8350);
+		return -EINVAL;
+	}
+
+	wm8350_reg_lock(wm8350);
+	return 0;
+}
+
+static int gpio_set_pull_up(struct wm8350 *wm8350, int gpio, int up)
+{
+	if (up)
+		return wm8350_set_bits(wm8350,
+				       WM8350_GPIO_PIN_PULL_UP_CONTROL,
+				       1 << gpio);
+	else
+		return wm8350_clear_bits(wm8350,
+					 WM8350_GPIO_PIN_PULL_UP_CONTROL,
+					 1 << gpio);
+}
+
+static int gpio_set_pull_down(struct wm8350 *wm8350, int gpio, int down)
+{
+	if (down)
+		return wm8350_set_bits(wm8350,
+				       WM8350_GPIO_PULL_DOWN_CONTROL,
+				       1 << gpio);
+	else
+		return wm8350_clear_bits(wm8350,
+					 WM8350_GPIO_PULL_DOWN_CONTROL,
+					 1 << gpio);
+}
+
+static int gpio_set_polarity(struct wm8350 *wm8350, int gpio, int pol)
+{
+	if (pol == WM8350_GPIO_ACTIVE_HIGH)
+		return wm8350_set_bits(wm8350,
+				       WM8350_GPIO_PIN_POLARITY_TYPE,
+				       1 << gpio);
+	else
+		return wm8350_clear_bits(wm8350,
+					 WM8350_GPIO_PIN_POLARITY_TYPE,
+					 1 << gpio);
+}
+
+static int gpio_set_invert(struct wm8350 *wm8350, int gpio, int invert)
+{
+	if (invert == WM8350_GPIO_INVERT_ON)
+		return wm8350_set_bits(wm8350, WM8350_GPIO_INT_MODE, 1 << gpio);
+	else
+		return wm8350_clear_bits(wm8350,
+					 WM8350_GPIO_INT_MODE, 1 << gpio);
+}
+
+int wm8350_gpio_config(struct wm8350 *wm8350, int gpio, int dir, int func,
+		       int pol, int pull, int invert, int debounce)
+{
+	/* make sure we never pull up and down at the same time */
+	if (pull == WM8350_GPIO_PULL_NONE) {
+		if (gpio_set_pull_up(wm8350, gpio, 0))
+			goto err;
+		if (gpio_set_pull_down(wm8350, gpio, 0))
+			goto err;
+	} else if (pull == WM8350_GPIO_PULL_UP) {
+		if (gpio_set_pull_down(wm8350, gpio, 0))
+			goto err;
+		if (gpio_set_pull_up(wm8350, gpio, 1))
+			goto err;
+	} else if (pull == WM8350_GPIO_PULL_DOWN) {
+		if (gpio_set_pull_up(wm8350, gpio, 0))
+			goto err;
+		if (gpio_set_pull_down(wm8350, gpio, 1))
+			goto err;
+	}
+
+	if (gpio_set_invert(wm8350, gpio, invert))
+		goto err;
+	if (gpio_set_polarity(wm8350, gpio, pol))
+		goto err;
+	if (gpio_set_debounce(wm8350, gpio, debounce))
+		goto err;
+	if (gpio_set_dir(wm8350, gpio, dir))
+		goto err;
+	return gpio_set_func(wm8350, gpio, func);
+
+err:
+	return -EIO;
+}
+EXPORT_SYMBOL_GPL(wm8350_gpio_config);

include/linux/mfd/wm8350/gpio.h

···
 #define WM8350_GP1_LVL                          0x0002
 #define WM8350_GP0_LVL                          0x0001
 
+struct wm8350;
+
+int wm8350_gpio_config(struct wm8350 *wm8350, int gpio, int dir, int func,
+		       int pol, int pull, int invert, int debounce);
+
+/*
+ * GPIO Interrupts
+ */
+#define WM8350_IRQ_GPIO(x)                      (50 + x)
+
 #endif