Merge branch 'mcp23s08' into devel

10 files changed, 425 insertions, 308 deletions

diff --git a/arch/arm/configs/lpc32xx_defconfig b/arch/arm/configs/lpc32xx_defconfig
index 6ba430d..e15fa5f 100644
--- a/arch/arm/configs/lpc32xx_defconfig
+++ b/arch/arm/configs/lpc32xx_defconfig
@@ -112,7 +112,7 @@ CONFIG_GPIO_SX150X=y
 CONFIG_GPIO_74X164=y
 CONFIG_GPIO_MAX7301=y
 CONFIG_GPIO_MC33880=y
-CONFIG_GPIO_MCP23S08=y
+CONFIG_PINCTRL_MCP23S08=y
 CONFIG_SENSORS_DS620=y
 CONFIG_SENSORS_MAX6639=y
 CONFIG_WATCHDOG=y
diff --git a/arch/blackfin/configs/BF609-EZKIT_defconfig b/arch/blackfin/configs/BF609-EZKIT_defconfig
index ba4267f..3ce77f0 100644
--- a/arch/blackfin/configs/BF609-EZKIT_defconfig
+++ b/arch/blackfin/configs/BF609-EZKIT_defconfig
@@ -105,7 +105,7 @@ CONFIG_SPI=y
 CONFIG_SPI_ADI_V3=y
 CONFIG_GPIOLIB=y
 CONFIG_GPIO_SYSFS=y
-CONFIG_GPIO_MCP23S08=y
+CONFIG_PINCTRL_MCP23S08=y
 # CONFIG_HWMON is not set
 CONFIG_WATCHDOG=y
 CONFIG_BFIN_WDT=y
diff --git a/arch/blackfin/mach-bf527/boards/tll6527m.c b/arch/blackfin/mach-bf527/boards/tll6527m.c
index c1acce4..ce5488e 100644
--- a/arch/blackfin/mach-bf527/boards/tll6527m.c
+++ b/arch/blackfin/mach-bf527/boards/tll6527m.c
@@ -348,14 +348,14 @@ static struct platform_device bfin_i2s = {
 };
 #endif
 
-#if IS_ENABLED(CONFIG_GPIO_MCP23S08)
+#if IS_ENABLED(CONFIG_PINCTRL_MCP23S08)
 #include <linux/spi/mcp23s08.h>
 static const struct mcp23s08_platform_data bfin_mcp23s08_sys_gpio_info = {
-	.chip[0].is_present = true,
+	.spi_present_mask = BIT(0),
 	.base = 0x30,
 };
 static const struct mcp23s08_platform_data bfin_mcp23s08_usr_gpio_info = {
-	.chip[2].is_present = true,
+	.spi_present_mask = BIT(2),
 	.base = 0x38,
 };
 #endif
@@ -423,7 +423,7 @@ static struct spi_board_info bfin_spi_board_info[] __initdata = {
 		.mode = SPI_CPHA | SPI_CPOL,
 	},
 #endif
-#if IS_ENABLED(CONFIG_GPIO_MCP23S08)
+#if IS_ENABLED(CONFIG_PINCTRL_MCP23S08)
 	{
 		.modalias = "mcp23s08",
 		.platform_data = &bfin_mcp23s08_sys_gpio_info,
diff --git a/arch/blackfin/mach-bf609/boards/ezkit.c b/arch/blackfin/mach-bf609/boards/ezkit.c
index 9231e5a..51157a2 100644
--- a/arch/blackfin/mach-bf609/boards/ezkit.c
+++ b/arch/blackfin/mach-bf609/boards/ezkit.c
@@ -1887,7 +1887,7 @@ static struct platform_device i2c_bfin_twi1_device = {
 };
 #endif
 
-#if IS_ENABLED(CONFIG_GPIO_MCP23S08)
+#if IS_ENABLED(CONFIG_PINCTRL_MCP23S08)
 #include <linux/spi/mcp23s08.h>
 static const struct mcp23s08_platform_data bfin_mcp23s08_soft_switch0 = {
 	.base = 120,
@@ -1929,7 +1929,7 @@ static struct i2c_board_info __initdata bfin_i2c_board_info0[] = {
 		I2C_BOARD_INFO("ssm2602", 0x1b),
 	},
 #endif
-#if IS_ENABLED(CONFIG_GPIO_MCP23S08)
+#if IS_ENABLED(CONFIG_PINCTRL_MCP23S08)
 	{
 		I2C_BOARD_INFO("mcp23017", 0x21),
 		.platform_data = (void *)&bfin_mcp23s08_soft_switch0
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 45ed9ac..64bc995 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1237,23 +1237,6 @@ config GPIO_PISOSR
 
 endmenu
 
-menu "SPI or I2C GPIO expanders"
-	depends on (SPI_MASTER && !I2C) || I2C
-
-config GPIO_MCP23S08
-	tristate "Microchip MCP23xxx I/O expander"
-	depends on OF_GPIO
-	select GPIOLIB_IRQCHIP
-	select REGMAP_I2C if I2C
-	select REGMAP if SPI_MASTER
-	help
-	  SPI/I2C driver for Microchip MCP23S08/MCP23S17/MCP23008/MCP23017
-	  I/O expanders.
-	  This provides a GPIO interface supporting inputs and outputs.
-	  The I2C versions of the chips can be used as interrupt-controller.
-
-endmenu
-
 menu "USB GPIO expanders"
 	depends on USB
 
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index d293967..845f990 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -78,7 +78,6 @@ obj-$(CONFIG_GPIO_MENZ127)	+= gpio-menz127.o
 obj-$(CONFIG_GPIO_MERRIFIELD)	+= gpio-merrifield.o
 obj-$(CONFIG_GPIO_MC33880)	+= gpio-mc33880.o
 obj-$(CONFIG_GPIO_MC9S08DZ60)	+= gpio-mc9s08dz60.o
-obj-$(CONFIG_GPIO_MCP23S08)	+= gpio-mcp23s08.o
 obj-$(CONFIG_GPIO_ML_IOH)	+= gpio-ml-ioh.o
 obj-$(CONFIG_GPIO_MM_LANTIQ)	+= gpio-mm-lantiq.o
 obj-$(CONFIG_GPIO_MOCKUP)      += gpio-mockup.o
diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index 7cacf89..abc1cef 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -146,6 +146,19 @@ config PINCTRL_FALCON
 	depends on SOC_FALCON
 	depends on PINCTRL_LANTIQ
 
+config PINCTRL_MCP23S08
+	tristate "Microchip MCP23xxx I/O expander"
+	depends on SPI_MASTER || I2C
+	select GPIOLIB_IRQCHIP
+	select REGMAP_I2C if I2C
+	select REGMAP_SPI if SPI_MASTER
+	select GENERIC_PINCONF
+	help
+	  SPI/I2C driver for Microchip MCP23S08/MCP23S17/MCP23008/MCP23017
+	  I/O expanders.
+	  This provides a GPIO interface supporting inputs and outputs.
+	  The I2C versions of the chips can be used as interrupt-controller.
+
 config PINCTRL_MESON
 	bool
 	depends on OF
diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
index a054364..f6ec4bd 100644
--- a/drivers/pinctrl/Makefile
+++ b/drivers/pinctrl/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_PINCTRL_DA850_PUPD) += pinctrl-da850-pupd.o
 obj-$(CONFIG_PINCTRL_DIGICOLOR)	+= pinctrl-digicolor.o
 obj-$(CONFIG_PINCTRL_FALCON)	+= pinctrl-falcon.o
 obj-$(CONFIG_PINCTRL_MAX77620)	+= pinctrl-max77620.o
+obj-$(CONFIG_PINCTRL_MCP23S08)	+= pinctrl-mcp23s08.o
 obj-$(CONFIG_PINCTRL_MESON)	+= meson/
 obj-$(CONFIG_PINCTRL_OXNAS)	+= pinctrl-oxnas.o
 obj-$(CONFIG_PINCTRL_PALMAS)	+= pinctrl-palmas.o
diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/pinctrl/pinctrl-mcp23s08.c
index 2a57d024..3e40d42 100644
--- a/drivers/gpio/gpio-mcp23s08.c
+++ b/drivers/pinctrl/pinctrl-mcp23s08.c
@@ -1,14 +1,4 @@
-/*
- * MCP23S08 SPI/I2C GPIO gpio expander driver
- *
- * The inputs and outputs of the mcp23s08, mcp23s17, mcp23008 and mcp23017 are
- * supported.
- * For the I2C versions of the chips (mcp23008 and mcp23017) generation of
- * interrupts is also supported.
- * The hardware of the SPI versions of the chips (mcp23s08 and mcp23s17) is
- * also capable of generating interrupts, but the linux driver does not
- * support that yet.
- */
+/* MCP23S08 SPI/I2C GPIO driver */
 
 #include <linux/kernel.h>
 #include <linux/device.h>
@@ -21,11 +11,13 @@
 #include <linux/slab.h>
 #include <asm/byteorder.h>
 #include <linux/interrupt.h>
-#include <linux/of_irq.h>
 #include <linux/of_device.h>
 #include <linux/regmap.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinconf-generic.h>
 
-/**
+/*
  * MCP types supported by driver
  */
 #define MCP_TYPE_S08	0
@@ -34,6 +26,8 @@
 #define MCP_TYPE_017	3
 #define MCP_TYPE_S18    4
 
+#define MCP_MAX_DEV_PER_CS	8
+
 /* Registers are all 8 bits wide.
  *
  * The mcp23s17 has twice as many bits, and can be configured to work
@@ -64,19 +58,52 @@ struct mcp23s08 {
 	bool			irq_active_high;
 	bool			reg_shift;
 
-	u16			cache[11];
 	u16			irq_rise;
 	u16			irq_fall;
 	int			irq;
 	bool			irq_controller;
-	/* lock protects the cached values */
+	int			cached_gpio;
+	/* lock protects regmap access with bypass/cache flags */
 	struct mutex		lock;
-	struct mutex		irq_lock;
 
 	struct gpio_chip	chip;
 
 	struct regmap		*regmap;
 	struct device		*dev;
+
+	struct pinctrl_dev	*pctldev;
+	struct pinctrl_desc	pinctrl_desc;
+};
+
+static const struct reg_default mcp23x08_defaults[] = {
+	{.reg = MCP_IODIR,		.def = 0xff},
+	{.reg = MCP_IPOL,		.def = 0x00},
+	{.reg = MCP_GPINTEN,		.def = 0x00},
+	{.reg = MCP_DEFVAL,		.def = 0x00},
+	{.reg = MCP_INTCON,		.def = 0x00},
+	{.reg = MCP_IOCON,		.def = 0x00},
+	{.reg = MCP_GPPU,		.def = 0x00},
+	{.reg = MCP_OLAT,		.def = 0x00},
+};
+
+static const struct regmap_range mcp23x08_volatile_range = {
+	.range_min = MCP_INTF,
+	.range_max = MCP_GPIO,
+};
+
+static const struct regmap_access_table mcp23x08_volatile_table = {
+	.yes_ranges = &mcp23x08_volatile_range,
+	.n_yes_ranges = 1,
+};
+
+static const struct regmap_range mcp23x08_precious_range = {
+	.range_min = MCP_GPIO,
+	.range_max = MCP_GPIO,
+};
+
+static const struct regmap_access_table mcp23x08_precious_table = {
+	.yes_ranges = &mcp23x08_precious_range,
+	.n_yes_ranges = 1,
 };
 
 static const struct regmap_config mcp23x08_regmap = {
@@ -84,18 +111,203 @@ static const struct regmap_config mcp23x08_regmap = {
 	.val_bits = 8,
 
 	.reg_stride = 1,
+	.volatile_table = &mcp23x08_volatile_table,
+	.precious_table = &mcp23x08_precious_table,
+	.reg_defaults = mcp23x08_defaults,
+	.num_reg_defaults = ARRAY_SIZE(mcp23x08_defaults),
+	.cache_type = REGCACHE_FLAT,
 	.max_register = MCP_OLAT,
 };
 
+static const struct reg_default mcp23x16_defaults[] = {
+	{.reg = MCP_IODIR << 1,		.def = 0xffff},
+	{.reg = MCP_IPOL << 1,		.def = 0x0000},
+	{.reg = MCP_GPINTEN << 1,	.def = 0x0000},
+	{.reg = MCP_DEFVAL << 1,	.def = 0x0000},
+	{.reg = MCP_INTCON << 1,	.def = 0x0000},
+	{.reg = MCP_IOCON << 1,		.def = 0x0000},
+	{.reg = MCP_GPPU << 1,		.def = 0x0000},
+	{.reg = MCP_OLAT << 1,		.def = 0x0000},
+};
+
+static const struct regmap_range mcp23x16_volatile_range = {
+	.range_min = MCP_INTF << 1,
+	.range_max = MCP_GPIO << 1,
+};
+
+static const struct regmap_access_table mcp23x16_volatile_table = {
+	.yes_ranges = &mcp23x16_volatile_range,
+	.n_yes_ranges = 1,
+};
+
+static const struct regmap_range mcp23x16_precious_range = {
+	.range_min = MCP_GPIO << 1,
+	.range_max = MCP_GPIO << 1,
+};
+
+static const struct regmap_access_table mcp23x16_precious_table = {
+	.yes_ranges = &mcp23x16_precious_range,
+	.n_yes_ranges = 1,
+};
+
 static const struct regmap_config mcp23x17_regmap = {
 	.reg_bits = 8,
 	.val_bits = 16,
 
 	.reg_stride = 2,
 	.max_register = MCP_OLAT << 1,
+	.volatile_table = &mcp23x16_volatile_table,
+	.precious_table = &mcp23x16_precious_table,
+	.reg_defaults = mcp23x16_defaults,
+	.num_reg_defaults = ARRAY_SIZE(mcp23x16_defaults),
+	.cache_type = REGCACHE_FLAT,
 	.val_format_endian = REGMAP_ENDIAN_LITTLE,
 };
 
+static int mcp_read(struct mcp23s08 *mcp, unsigned int reg, unsigned int *val)
+{
+	return regmap_read(mcp->regmap, reg << mcp->reg_shift, val);
+}
+
+static int mcp_write(struct mcp23s08 *mcp, unsigned int reg, unsigned int val)
+{
+	return regmap_write(mcp->regmap, reg << mcp->reg_shift, val);
+}
+
+static int mcp_set_mask(struct mcp23s08 *mcp, unsigned int reg,
+		       unsigned int mask, bool enabled)
+{
+	u16 val  = enabled ? 0xffff : 0x0000;
+	return regmap_update_bits(mcp->regmap, reg << mcp->reg_shift,
+				  mask, val);
+}
+
+static int mcp_set_bit(struct mcp23s08 *mcp, unsigned int reg,
+		       unsigned int pin, bool enabled)
+{
+	u16 mask = BIT(pin);
+	return mcp_set_mask(mcp, reg, mask, enabled);
+}
+
+static const struct pinctrl_pin_desc mcp23x08_pins[] = {
+	PINCTRL_PIN(0, "gpio0"),
+	PINCTRL_PIN(1, "gpio1"),
+	PINCTRL_PIN(2, "gpio2"),
+	PINCTRL_PIN(3, "gpio3"),
+	PINCTRL_PIN(4, "gpio4"),
+	PINCTRL_PIN(5, "gpio5"),
+	PINCTRL_PIN(6, "gpio6"),
+	PINCTRL_PIN(7, "gpio7"),
+};
+
+static const struct pinctrl_pin_desc mcp23x17_pins[] = {
+	PINCTRL_PIN(0, "gpio0"),
+	PINCTRL_PIN(1, "gpio1"),
+	PINCTRL_PIN(2, "gpio2"),
+	PINCTRL_PIN(3, "gpio3"),
+	PINCTRL_PIN(4, "gpio4"),
+	PINCTRL_PIN(5, "gpio5"),
+	PINCTRL_PIN(6, "gpio6"),
+	PINCTRL_PIN(7, "gpio7"),
+	PINCTRL_PIN(8, "gpio8"),
+	PINCTRL_PIN(9, "gpio9"),
+	PINCTRL_PIN(10, "gpio10"),
+	PINCTRL_PIN(11, "gpio11"),
+	PINCTRL_PIN(12, "gpio12"),
+	PINCTRL_PIN(13, "gpio13"),
+	PINCTRL_PIN(14, "gpio14"),
+	PINCTRL_PIN(15, "gpio15"),
+};
+
+static int mcp_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	return 0;
+}
+
+static const char *mcp_pinctrl_get_group_name(struct pinctrl_dev *pctldev,
+						unsigned int group)
+{
+	return NULL;
+}
+
+static int mcp_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
+					unsigned int group,
+					const unsigned int **pins,
+					unsigned int *num_pins)
+{
+	return -ENOTSUPP;
+}
+
+static const struct pinctrl_ops mcp_pinctrl_ops = {
+	.get_groups_count = mcp_pinctrl_get_groups_count,
+	.get_group_name = mcp_pinctrl_get_group_name,
+	.get_group_pins = mcp_pinctrl_get_group_pins,
+#ifdef CONFIG_OF
+	.dt_node_to_map = pinconf_generic_dt_node_to_map_pin,
+	.dt_free_map = pinconf_generic_dt_free_map,
+#endif
+};
+
+static int mcp_pinconf_get(struct pinctrl_dev *pctldev, unsigned int pin,
+			      unsigned long *config)
+{
+	struct mcp23s08 *mcp = pinctrl_dev_get_drvdata(pctldev);
+	enum pin_config_param param = pinconf_to_config_param(*config);
+	unsigned int data, status;
+	int ret;
+
+	switch (param) {
+	case PIN_CONFIG_BIAS_PULL_UP:
+		ret = mcp_read(mcp, MCP_GPPU, &data);
+		if (ret < 0)
+			return ret;
+		status = (data & BIT(pin)) ? 1 : 0;
+		break;
+	default:
+		dev_err(mcp->dev, "Invalid config param %04x\n", param);
+		return -ENOTSUPP;
+	}
+
+	*config = 0;
+
+	return status ? 0 : -EINVAL;
+}
+
+static int mcp_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
+			      unsigned long *configs, unsigned int num_configs)
+{
+	struct mcp23s08 *mcp = pinctrl_dev_get_drvdata(pctldev);
+	enum pin_config_param param;
+	u32 arg, mask;
+	u16 val;
+	int ret = 0;
+	int i;
+
+	for (i = 0; i < num_configs; i++) {
+		param = pinconf_to_config_param(configs[i]);
+		arg = pinconf_to_config_argument(configs[i]);
+
+		switch (param) {
+		case PIN_CONFIG_BIAS_PULL_UP:
+			val = arg ? 0xFFFF : 0x0000;
+			mask = BIT(pin);
+			ret = mcp_set_bit(mcp, MCP_GPPU, pin, arg);
+			break;
+		default:
+			dev_err(mcp->dev, "Invalid config param %04x\n", param);
+			return -ENOTSUPP;
+		}
+	}
+
+	return ret;
+}
+
+static const struct pinconf_ops mcp_pinconf_ops = {
+	.pin_config_get = mcp_pinconf_get,
+	.pin_config_set = mcp_pinconf_set,
+	.is_generic = true,
+};
+
 /*----------------------------------------------------------------------*/
 
 #ifdef CONFIG_SPI_MASTER
@@ -158,30 +370,6 @@ static const struct regmap_bus mcp23sxx_spi_regmap = {
 
 #endif /* CONFIG_SPI_MASTER */
 
-static int mcp_read(struct mcp23s08 *mcp, unsigned int reg, unsigned int *val)
-{
-	return regmap_read(mcp->regmap, reg << mcp->reg_shift, val);
-}
-
-static int mcp_write(struct mcp23s08 *mcp, unsigned int reg, unsigned int val)
-{
-	return regmap_write(mcp->regmap, reg << mcp->reg_shift, val);
-}
-
-static int mcp_update_cache(struct mcp23s08 *mcp)
-{
-	int ret, reg, i;
-
-	for (i = 0; i < ARRAY_SIZE(mcp->cache); i++) {
-		ret = mcp_read(mcp, i, &reg);
-		if (ret < 0)
-			return ret;
-		mcp->cache[i] = reg;
-	}
-
-	return 0;
-}
-
 /*----------------------------------------------------------------------*/
 
 /* A given spi_device can represent up to eight mcp23sxx chips
@@ -202,9 +390,9 @@ static int mcp23s08_direction_input(struct gpio_chip *chip, unsigned offset)
 	int status;
 
 	mutex_lock(&mcp->lock);
-	mcp->cache[MCP_IODIR] |= (1 << offset);
-	status = mcp_write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
+	status = mcp_set_bit(mcp, MCP_IODIR, offset, true);
 	mutex_unlock(&mcp->lock);
+
 	return status;
 }
 
@@ -219,33 +407,27 @@ static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
 	ret = mcp_read(mcp, MCP_GPIO, &status);
 	if (ret < 0)
 		status = 0;
-	else {
-		mcp->cache[MCP_GPIO] = status;
+	else
 		status = !!(status & (1 << offset));
-	}
+
+	mcp->cached_gpio = status;
+
 	mutex_unlock(&mcp->lock);
 	return status;
 }
 
-static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, int value)
+static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, bool value)
 {
-	unsigned olat = mcp->cache[MCP_OLAT];
-
-	if (value)
-		olat |= mask;
-	else
-		olat &= ~mask;
-	mcp->cache[MCP_OLAT] = olat;
-	return mcp_write(mcp, MCP_OLAT, olat);
+	return mcp_set_mask(mcp, MCP_OLAT, mask, value);
 }
 
 static void mcp23s08_set(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct mcp23s08	*mcp = gpiochip_get_data(chip);
-	unsigned mask = 1 << offset;
+	unsigned mask = BIT(offset);
 
 	mutex_lock(&mcp->lock);
-	__mcp23s08_set(mcp, mask, value);
+	__mcp23s08_set(mcp, mask, !!value);
 	mutex_unlock(&mcp->lock);
 }
 
@@ -253,14 +435,13 @@ static int
 mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct mcp23s08	*mcp = gpiochip_get_data(chip);
-	unsigned mask = 1 << offset;
+	unsigned mask = BIT(offset);
 	int status;
 
 	mutex_lock(&mcp->lock);
 	status = __mcp23s08_set(mcp, mask, value);
 	if (status == 0) {
-		mcp->cache[MCP_IODIR] &= ~mask;
-		status = mcp_write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
+		status = mcp_set_mask(mcp, MCP_IODIR, mask, false);
 	}
 	mutex_unlock(&mcp->lock);
 	return status;
@@ -270,7 +451,7 @@ mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
 static irqreturn_t mcp23s08_irq(int irq, void *data)
 {
 	struct mcp23s08 *mcp = data;
-	int intcap, intf, i, gpio, gpio_orig, intcap_mask;
+	int intcap, intcon, intf, i, gpio, gpio_orig, intcap_mask, defval;
 	unsigned int child_irq;
 	bool intf_set, intcap_changed, gpio_bit_changed,
 		defval_changed, gpio_set;
@@ -281,25 +462,31 @@ static irqreturn_t mcp23s08_irq(int irq, void *data)
 		return IRQ_HANDLED;
 	}
 
-	mcp->cache[MCP_INTF] = intf;
-
 	if (mcp_read(mcp, MCP_INTCAP, &intcap) < 0) {
 		mutex_unlock(&mcp->lock);
 		return IRQ_HANDLED;
 	}
 
-	mcp->cache[MCP_INTCAP] = intcap;
+	if (mcp_read(mcp, MCP_INTCON, &intcon) < 0) {
+		mutex_unlock(&mcp->lock);
+		return IRQ_HANDLED;
+	}
+
+	if (mcp_read(mcp, MCP_DEFVAL, &defval) < 0) {
+		mutex_unlock(&mcp->lock);
+		return IRQ_HANDLED;
+	}
 
 	/* This clears the interrupt(configurable on S18) */
 	if (mcp_read(mcp, MCP_GPIO, &gpio) < 0) {
 		mutex_unlock(&mcp->lock);
 		return IRQ_HANDLED;
 	}
-	gpio_orig = mcp->cache[MCP_GPIO];
-	mcp->cache[MCP_GPIO] = gpio;
+	gpio_orig = mcp->cached_gpio;
+	mcp->cached_gpio = gpio;
 	mutex_unlock(&mcp->lock);
 
-	if (mcp->cache[MCP_INTF] == 0) {
+	if (intf == 0) {
 		/* There is no interrupt pending */
 		return IRQ_HANDLED;
 	}
@@ -327,7 +514,7 @@ static irqreturn_t mcp23s08_irq(int irq, void *data)
 		 * to see if the input has changed.
 		 */
 
-		intf_set = BIT(i) & mcp->cache[MCP_INTF];
+		intf_set = intf & BIT(i);
 		if (i < 8 && intf_set)
 			intcap_mask = 0x00FF;
 		else if (i >= 8 && intf_set)
@@ -336,14 +523,14 @@ static irqreturn_t mcp23s08_irq(int irq, void *data)
 			intcap_mask = 0x00;
 
 		intcap_changed = (intcap_mask &
-			(BIT(i) & mcp->cache[MCP_INTCAP])) !=
+			(intcap & BIT(i))) !=
 			(intcap_mask & (BIT(i) & gpio_orig));
-		gpio_set = BIT(i) & mcp->cache[MCP_GPIO];
+		gpio_set = BIT(i) & gpio;
 		gpio_bit_changed = (BIT(i) & gpio_orig) !=
-			(BIT(i) & mcp->cache[MCP_GPIO]);
-		defval_changed = (BIT(i) & mcp->cache[MCP_INTCON]) &&
-			((BIT(i) & mcp->cache[MCP_GPIO]) !=
-			(BIT(i) & mcp->cache[MCP_DEFVAL]));
+			(BIT(i) & gpio);
+		defval_changed = (BIT(i) & intcon) &&
+			((BIT(i) & gpio) !=
+			(BIT(i) & defval));
 
 		if (((gpio_bit_changed || intcap_changed) &&
 			(BIT(i) & mcp->irq_rise) && gpio_set) ||
@@ -364,7 +551,7 @@ static void mcp23s08_irq_mask(struct irq_data *data)
 	struct mcp23s08 *mcp = gpiochip_get_data(gc);
 	unsigned int pos = data->hwirq;
 
-	mcp->cache[MCP_GPINTEN] &= ~BIT(pos);
+	mcp_set_bit(mcp, MCP_GPINTEN, pos, false);
 }
 
 static void mcp23s08_irq_unmask(struct irq_data *data)
@@ -373,7 +560,7 @@ static void mcp23s08_irq_unmask(struct irq_data *data)
 	struct mcp23s08 *mcp = gpiochip_get_data(gc);
 	unsigned int pos = data->hwirq;
 
-	mcp->cache[MCP_GPINTEN] |= BIT(pos);
+	mcp_set_bit(mcp, MCP_GPINTEN, pos, true);
 }
 
 static int mcp23s08_irq_set_type(struct irq_data *data, unsigned int type)
@@ -384,23 +571,23 @@ static int mcp23s08_irq_set_type(struct irq_data *data, unsigned int type)
 	int status = 0;
 
 	if ((type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH) {
-		mcp->cache[MCP_INTCON] &= ~BIT(pos);
+		mcp_set_bit(mcp, MCP_INTCON, pos, false);
 		mcp->irq_rise |= BIT(pos);
 		mcp->irq_fall |= BIT(pos);
 	} else if (type & IRQ_TYPE_EDGE_RISING) {
-		mcp->cache[MCP_INTCON] &= ~BIT(pos);
+		mcp_set_bit(mcp, MCP_INTCON, pos, false);
 		mcp->irq_rise |= BIT(pos);
 		mcp->irq_fall &= ~BIT(pos);
 	} else if (type & IRQ_TYPE_EDGE_FALLING) {
-		mcp->cache[MCP_INTCON] &= ~BIT(pos);
+		mcp_set_bit(mcp, MCP_INTCON, pos, false);
 		mcp->irq_rise &= ~BIT(pos);
 		mcp->irq_fall |= BIT(pos);
 	} else if (type & IRQ_TYPE_LEVEL_HIGH) {
-		mcp->cache[MCP_INTCON] |= BIT(pos);
-		mcp->cache[MCP_DEFVAL] &= ~BIT(pos);
+		mcp_set_bit(mcp, MCP_INTCON, pos, true);
+		mcp_set_bit(mcp, MCP_DEFVAL, pos, false);
 	} else if (type & IRQ_TYPE_LEVEL_LOW) {
-		mcp->cache[MCP_INTCON] |= BIT(pos);
-		mcp->cache[MCP_DEFVAL] |= BIT(pos);
+		mcp_set_bit(mcp, MCP_INTCON, pos, true);
+		mcp_set_bit(mcp, MCP_DEFVAL, pos, true);
 	} else
 		return -EINVAL;
 
@@ -412,7 +599,8 @@ static void mcp23s08_irq_bus_lock(struct irq_data *data)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
 	struct mcp23s08 *mcp = gpiochip_get_data(gc);
 
-	mutex_lock(&mcp->irq_lock);
+	mutex_lock(&mcp->lock);
+	regcache_cache_only(mcp->regmap, true);
 }
 
 static void mcp23s08_irq_bus_unlock(struct irq_data *data)
@@ -420,12 +608,10 @@ static void mcp23s08_irq_bus_unlock(struct irq_data *data)
 	struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
 	struct mcp23s08 *mcp = gpiochip_get_data(gc);
 
-	mutex_lock(&mcp->lock);
-	mcp_write(mcp, MCP_GPINTEN, mcp->cache[MCP_GPINTEN]);
-	mcp_write(mcp, MCP_DEFVAL, mcp->cache[MCP_DEFVAL]);
-	mcp_write(mcp, MCP_INTCON, mcp->cache[MCP_INTCON]);
+	regcache_cache_only(mcp->regmap, false);
+	regcache_sync(mcp->regmap);
+
 	mutex_unlock(&mcp->lock);
-	mutex_unlock(&mcp->irq_lock);
 }
 
 static struct irq_chip mcp23s08_irq_chip = {
@@ -443,8 +629,6 @@ static int mcp23s08_irq_setup(struct mcp23s08 *mcp)
 	int err;
 	unsigned long irqflags = IRQF_ONESHOT | IRQF_SHARED;
 
-	mutex_init(&mcp->irq_lock);
-
 	if (mcp->irq_active_high)
 		irqflags |= IRQF_TRIGGER_HIGH;
 	else
@@ -484,6 +668,47 @@ static int mcp23s08_irq_setup(struct mcp23s08 *mcp)
 #include <linux/seq_file.h>
 
 /*
+ * This compares the chip's registers with the register
+ * cache and corrects any incorrectly set register. This
+ * can be used to fix state for MCP23xxx, that temporary
+ * lost its power supply.
+ */
+#define MCP23S08_CONFIG_REGS 8
+static int __check_mcp23s08_reg_cache(struct mcp23s08 *mcp)
+{
+	int cached[MCP23S08_CONFIG_REGS];
+	int err = 0, i;
+
+	/* read cached config registers */
+	for (i = 0; i < MCP23S08_CONFIG_REGS; i++) {
+		err = mcp_read(mcp, i, &cached[i]);
+		if (err)
+			goto out;
+	}
+
+	regcache_cache_bypass(mcp->regmap, true);
+
+	for (i = 0; i < MCP23S08_CONFIG_REGS; i++) {
+		int uncached;
+		err = mcp_read(mcp, i, &uncached);
+		if (err)
+			goto out;
+
+		if (uncached != cached[i]) {
+			dev_err(mcp->dev, "restoring reg 0x%02x from 0x%04x to 0x%04x (power-loss?)\n",
+				i, uncached, cached[i]);
+			mcp_write(mcp, i, cached[i]);
+		}
+	}
+
+out:
+	if (err)
+		dev_err(mcp->dev, "read error: reg=%02x, err=%d", i, err);
+	regcache_cache_bypass(mcp->regmap, false);
+	return err;
+}
+
+/*
  * This shows more info than the generic gpio dump code:
  * pullups, deglitching, open drain drive.
  */
@@ -493,6 +718,7 @@ static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 	char		bank;
 	int		t;
 	unsigned	mask;
+	int iodir, gpio, gppu;
 
 	mcp = gpiochip_get_data(chip);
 
@@ -500,14 +726,30 @@ static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 	bank = '0' + ((mcp->addr >> 1) & 0x7);
 
 	mutex_lock(&mcp->lock);
-	t = mcp_update_cache(mcp);
-	if (t < 0) {
-		seq_printf(s, " I/O ERROR %d\n", t);
+
+	t = __check_mcp23s08_reg_cache(mcp);
+	if (t) {
+		seq_printf(s, " I/O Error\n");
+		goto done;
+	}
+	t = mcp_read(mcp, MCP_IODIR, &iodir);
+	if (t) {
+		seq_printf(s, " I/O Error\n");
+		goto done;
+	}
+	t = mcp_read(mcp, MCP_GPIO, &gpio);
+	if (t) {
+		seq_printf(s, " I/O Error\n");
+		goto done;
+	}
+	t = mcp_read(mcp, MCP_GPPU, &gppu);
+	if (t) {
+		seq_printf(s, " I/O Error\n");
 		goto done;
 	}
 
-	for (t = 0, mask = 1; t < chip->ngpio; t++, mask <<= 1) {
-		const char	*label;
+	for (t = 0, mask = BIT(0); t < chip->ngpio; t++, mask <<= 1) {
+		const char *label;
 
 		label = gpiochip_is_requested(chip, t);
 		if (!label)
@@ -515,9 +757,9 @@ static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 
 		seq_printf(s, " gpio-%-3d P%c.%d (%-12s) %s %s %s",
 			chip->base + t, bank, t, label,
-			(mcp->cache[MCP_IODIR] & mask) ? "in " : "out",
-			(mcp->cache[MCP_GPIO] & mask) ? "hi" : "lo",
-			(mcp->cache[MCP_GPPU] & mask) ? "up" : "  ");
+			(iodir & mask) ? "in " : "out",
+			(gpio & mask) ? "hi" : "lo",
+			(gppu & mask) ? "up" : "  ");
 		/* NOTE:  ignoring the irq-related registers */
 		seq_puts(s, "\n");
 	}
@@ -533,7 +775,7 @@ done:
 
 static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
 			      void *data, unsigned addr, unsigned type,
-			      struct mcp23s08_platform_data *pdata, int cs)
+			      unsigned int base, int cs)
 {
 	int status, ret;
 	bool mirror = false;
@@ -605,7 +847,7 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
 	if (IS_ERR(mcp->regmap))
 		return PTR_ERR(mcp->regmap);
 
-	mcp->chip.base = pdata->base;
+	mcp->chip.base = base;
 	mcp->chip.can_sleep = true;
 	mcp->chip.parent = dev;
 	mcp->chip.owner = THIS_MODULE;
@@ -618,13 +860,14 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
 	if (ret < 0)
 		goto fail;
 
-	mcp->irq_controller = pdata->irq_controller;
+	mcp->irq_controller =
+		device_property_read_bool(dev, "interrupt-controller");
 	if (mcp->irq && mcp->irq_controller) {
 		mcp->irq_active_high =
-			of_property_read_bool(mcp->chip.parent->of_node,
+			device_property_read_bool(dev,
 					      "microchip,irq-active-high");
 
-		mirror = pdata->mirror;
+		mirror = device_property_read_bool(dev, "microchip,irq-mirror");
 	}
 
 	if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN) || mirror ||
@@ -648,32 +891,7 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
 			goto fail;
 	}
 
-	/* configure ~100K pullups */
-	ret = mcp_write(mcp, MCP_GPPU, pdata->chip[cs].pullups);
-	if (ret < 0)
-		goto fail;
-
-	ret = mcp_update_cache(mcp);
-	if (ret < 0)
-		goto fail;
-
-	/* disable inverter on input */
-	if (mcp->cache[MCP_IPOL] != 0) {
-		mcp->cache[MCP_IPOL] = 0;
-		ret = mcp_write(mcp, MCP_IPOL, 0);
-		if (ret < 0)
-			goto fail;
-	}
-
-	/* disable irqs */
-	if (mcp->cache[MCP_GPINTEN] != 0) {
-		mcp->cache[MCP_GPINTEN] = 0;
-		ret = mcp_write(mcp, MCP_GPINTEN, 0);
-		if (ret < 0)
-			goto fail;
-	}
-
-	ret = gpiochip_add_data(&mcp->chip, mcp);
+	ret = devm_gpiochip_add_data(dev, &mcp->chip, mcp);
 	if (ret < 0)
 		goto fail;
 
@@ -682,6 +900,23 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
 		if (ret)
 			goto fail;
 	}
+
+	mcp->pinctrl_desc.name = "mcp23xxx-pinctrl";
+	mcp->pinctrl_desc.pctlops = &mcp_pinctrl_ops;
+	mcp->pinctrl_desc.confops = &mcp_pinconf_ops;
+	mcp->pinctrl_desc.npins = mcp->chip.ngpio;
+	if (mcp->pinctrl_desc.npins == 8)
+		mcp->pinctrl_desc.pins = mcp23x08_pins;
+	else if (mcp->pinctrl_desc.npins == 16)
+		mcp->pinctrl_desc.pins = mcp23x17_pins;
+	mcp->pinctrl_desc.owner = THIS_MODULE;
+
+	mcp->pctldev = devm_pinctrl_register(dev, &mcp->pinctrl_desc, mcp);
+	if (IS_ERR(mcp->pctldev)) {
+		ret = PTR_ERR(mcp->pctldev);
+		goto fail;
+	}
+
 fail:
 	if (ret < 0)
 		dev_dbg(dev, "can't setup chip %d, --> %d\n", addr, ret);
@@ -753,60 +988,26 @@ static int mcp230xx_probe(struct i2c_client *client,
 	struct mcp23s08_platform_data *pdata, local_pdata;
 	struct mcp23s08 *mcp;
 	int status;
-	const struct of_device_id *match;
 
-	match = of_match_device(of_match_ptr(mcp23s08_i2c_of_match),
-					&client->dev);
-	if (match) {
+	pdata = dev_get_platdata(&client->dev);
+	if (!pdata) {
 		pdata = &local_pdata;
 		pdata->base = -1;
-		pdata->chip[0].pullups = 0;
-		pdata->irq_controller =	of_property_read_bool(
-					client->dev.of_node,
-					"interrupt-controller");
-		pdata->mirror = of_property_read_bool(client->dev.of_node,
-						      "microchip,irq-mirror");
-		client->irq = irq_of_parse_and_map(client->dev.of_node, 0);
-	} else {
-		pdata = dev_get_platdata(&client->dev);
-		if (!pdata) {
-			pdata = devm_kzalloc(&client->dev,
-					sizeof(struct mcp23s08_platform_data),
-					GFP_KERNEL);
-			if (!pdata)
-				return -ENOMEM;
-			pdata->base = -1;
-		}
 	}
 
-	mcp = kzalloc(sizeof(*mcp), GFP_KERNEL);
+	mcp = devm_kzalloc(&client->dev, sizeof(*mcp), GFP_KERNEL);
 	if (!mcp)
 		return -ENOMEM;
 
 	mcp->irq = client->irq;
 	status = mcp23s08_probe_one(mcp, &client->dev, client, client->addr,
-				    id->driver_data, pdata, 0);
+				    id->driver_data, pdata->base, 0);
 	if (status)
-		goto fail;
+		return status;
 
 	i2c_set_clientdata(client, mcp);
 
 	return 0;
-
-fail:
-	kfree(mcp);
-
-	return status;
-}
-
-static int mcp230xx_remove(struct i2c_client *client)
-{
-	struct mcp23s08 *mcp = i2c_get_clientdata(client);
-
-	gpiochip_remove(&mcp->chip);
-	kfree(mcp);
-
-	return 0;
 }
 
 static const struct i2c_device_id mcp230xx_id[] = {
@@ -822,7 +1023,6 @@ static struct i2c_driver mcp230xx_driver = {
 		.of_match_table = of_match_ptr(mcp23s08_i2c_of_match),
 	},
 	.probe		= mcp230xx_probe,
-	.remove		= mcp230xx_remove,
 	.id_table	= mcp230xx_id,
 };
 
@@ -856,60 +1056,40 @@ static int mcp23s08_probe(struct spi_device *spi)
 	int				status, type;
 	unsigned			ngpio = 0;
 	const struct			of_device_id *match;
-	u32				spi_present_mask = 0;
 
 	match = of_match_device(of_match_ptr(mcp23s08_spi_of_match), &spi->dev);
-	if (match) {
+	if (match)
 		type = (int)(uintptr_t)match->data;
-		status = of_property_read_u32(spi->dev.of_node,
-			    "microchip,spi-present-mask", &spi_present_mask);
+	else
+		type = spi_get_device_id(spi)->driver_data;
+
+	pdata = dev_get_platdata(&spi->dev);
+	if (!pdata) {
+		pdata = &local_pdata;
+		pdata->base = -1;
+
+		status = device_property_read_u32(&spi->dev,
+			"microchip,spi-present-mask", &pdata->spi_present_mask);
 		if (status) {
-			status = of_property_read_u32(spi->dev.of_node,
-				    "mcp,spi-present-mask", &spi_present_mask);
+			status = device_property_read_u32(&spi->dev,
+				"mcp,spi-present-mask",
+				&pdata->spi_present_mask);
+
 			if (status) {
-				dev_err(&spi->dev,
-					"DT has no spi-present-mask\n");
+				dev_err(&spi->dev, "missing spi-present-mask");
 				return -ENODEV;
 			}
 		}
-		if ((spi_present_mask <= 0) || (spi_present_mask >= 256)) {
-			dev_err(&spi->dev, "invalid spi-present-mask\n");
-			return -ENODEV;
-		}
+	}
 
-		pdata = &local_pdata;
-		pdata->base = -1;
-		for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
-			pdata->chip[addr].pullups = 0;
-			if (spi_present_mask & (1 << addr))
-				chips++;
-		}
-		pdata->irq_controller =	of_property_read_bool(
-					spi->dev.of_node,
-					"interrupt-controller");
-		pdata->mirror = of_property_read_bool(spi->dev.of_node,
-						      "microchip,irq-mirror");
-	} else {
-		type = spi_get_device_id(spi)->driver_data;
-		pdata = dev_get_platdata(&spi->dev);
-		if (!pdata) {
-			pdata = devm_kzalloc(&spi->dev,
-					sizeof(struct mcp23s08_platform_data),
-					GFP_KERNEL);
-			pdata->base = -1;
-		}
+	if (!pdata->spi_present_mask || pdata->spi_present_mask > 0xff) {
+		dev_err(&spi->dev, "invalid spi-present-mask");
+		return -ENODEV;
+	}
 
-		for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
-			if (!pdata->chip[addr].is_present)
-				continue;
+	for (addr = 0; addr < MCP_MAX_DEV_PER_CS; addr++) {
+		if (pdata->spi_present_mask & BIT(addr))
 			chips++;
-			if ((type == MCP_TYPE_S08) && (addr > 3)) {
-				dev_err(&spi->dev,
-					"mcp23s08 only supports address 0..3\n");
-				return -EINVAL;
-			}
-			spi_present_mask |= 1 << addr;
-		}
 	}
 
 	if (!chips)
@@ -923,19 +1103,17 @@ static int mcp23s08_probe(struct spi_device *spi)
 
 	spi_set_drvdata(spi, data);
 
-	spi->irq = irq_of_parse_and_map(spi->dev.of_node, 0);
-
-	for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
-		if (!(spi_present_mask & (1 << addr)))
+	for (addr = 0; addr < MCP_MAX_DEV_PER_CS; addr++) {
+		if (!(pdata->spi_present_mask & BIT(addr)))
 			continue;
 		chips--;
 		data->mcp[addr] = &data->chip[chips];
 		data->mcp[addr]->irq = spi->irq;
 		status = mcp23s08_probe_one(data->mcp[addr], &spi->dev, spi,
-					    0x40 | (addr << 1), type, pdata,
-					    addr);
+					    0x40 | (addr << 1), type,
+					    pdata->base, addr);
 		if (status < 0)
-			goto fail;
+			return status;
 
 		if (pdata->base != -1)
 			pdata->base += data->mcp[addr]->chip.ngpio;
@@ -943,36 +1121,6 @@ static int mcp23s08_probe(struct spi_device *spi)
 	}
 	data->ngpio = ngpio;
 
-	/* NOTE:  these chips have a relatively sane IRQ framework, with
-	 * per-signal masking and level/edge triggering.  It's not yet
-	 * handled here...
-	 */
-
-	return 0;
-
-fail:
-	for (addr = 0; addr < ARRAY_SIZE(data->mcp); addr++) {
-
-		if (!data->mcp[addr])
-			continue;
-		gpiochip_remove(&data->mcp[addr]->chip);
-	}
-	return status;
-}
-
-static int mcp23s08_remove(struct spi_device *spi)
-{
-	struct mcp23s08_driver_data	*data = spi_get_drvdata(spi);
-	unsigned			addr;
-
-	for (addr = 0; addr < ARRAY_SIZE(data->mcp); addr++) {
-
-		if (!data->mcp[addr])
-			continue;
-
-		gpiochip_remove(&data->mcp[addr]->chip);
-	}
-
 	return 0;
 }
 
@@ -986,7 +1134,6 @@ MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
 
 static struct spi_driver mcp23s08_driver = {
 	.probe		= mcp23s08_probe,
-	.remove		= mcp23s08_remove,
 	.id_table	= mcp23s08_ids,
 	.driver = {
 		.name	= "mcp23s08",
diff --git a/include/linux/spi/mcp23s08.h b/include/linux/spi/mcp23s08.h
index aa07d7b..82d96a3 100644
--- a/include/linux/spi/mcp23s08.h
+++ b/include/linux/spi/mcp23s08.h
@@ -1,11 +1,3 @@
-
-/* FIXME driver should be able to handle IRQs...  */
-
-struct mcp23s08_chip_info {
-	bool		is_present;	/* true if populated */
-	unsigned	pullups;	/* BIT(x) means enable pullup x */
-};
-
 struct mcp23s08_platform_data {
 	/* For mcp23s08, up to 4 slaves (numbered 0..3) can share one SPI
 	 * chipselect, each providing 1 gpio_chip instance with 8 gpios.
@@ -13,31 +5,13 @@ struct mcp23s08_platform_data {
 	 * chipselect, each providing 1 gpio_chip (port A + port B) with
 	 * 16 gpios.
 	 */
-	struct mcp23s08_chip_info	chip[8];
+	u32 spi_present_mask;
 
-	/* "base" is the number of the first GPIO.  Dynamic assignment is
-	 * not currently supported, and even if there are gaps in chip
-	 * addressing the GPIO numbers are sequential .. so for example
-	 * if only slaves 0 and 3 are present, their GPIOs range from
-	 * base to base+15 (or base+31 for s17 variant).
+	/* "base" is the number of the first GPIO or -1 for dynamic
+	 * assignment. If there are gaps in chip addressing the GPIO
+	 * numbers are sequential .. so for example if only slaves 0
+	 * and 3 are present, their GPIOs range from base to base+15
+	 * (or base+31 for s17 variant).
 	 */
 	unsigned	base;
-	/* Marks the device as a interrupt controller.
-	 * NOTE: The interrupt functionality is only supported for i2c
-	 * versions of the chips. The spi chips can also do the interrupts,
-	 * but this is not supported by the linux driver yet.
-	 */
-	bool		irq_controller;
-
-	/* Sets the mirror flag in the IOCON register. Devices
-	 * with two interrupt outputs (these are the devices ending with 17 and
-	 * those that have 16 IOs) have two IO banks: IO 0-7 form bank 1 and
-	 * IO 8-15 are bank 2. These chips have two different interrupt outputs:
-	 * One for bank 1 and another for bank 2. If irq-mirror is set, both
-	 * interrupts are generated regardless of the bank that an input change
-	 * occurred on. If it is not set, the interrupt are only generated for
-	 * the bank they belong to.
-	 * On devices with only one interrupt output this property is useless.
-	 */
-	bool		mirror;
 };