mfd: Add ST Multi-Function eXpander (STMFX) core driver

STMicroelectronics Multi-Function eXpander (STMFX) is a slave controller
using I2C for communication with the main MCU. Main features are:
- 16 fast GPIOs individually configurable in input/output
- 8 alternate GPIOs individually configurable in input/output when other
STMFX functions are not used
- Main MCU IDD measurement
- Resistive touchscreen controller
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -1907,6 +1907,19 @@ config MFD_STPMIC1
 	  To compile this driver as a module, choose M here: the
 	  module will be called stpmic1.
 
+config MFD_STMFX
+	tristate "Support for STMicroelectronics Multi-Function eXpander (STMFX)"
+	depends on I2C
+	depends on OF || COMPILE_TEST
+	select MFD_CORE
+	select REGMAP_I2C
+	help
+	  Support for the STMicroelectronics Multi-Function eXpander.
+
+	  This driver provides common support for accessing the device,
+	  additional drivers must be enabled in order to use the functionality
+	  of the device.
+
 menu "Multimedia Capabilities Port drivers"
 	depends on ARCH_SA1100
 

drivers/mfd/Makefile

@@ -246,4 +246,4 @@ obj-$(CONFIG_MFD_MXS_LRADC)     += mxs-lradc.o
 obj-$(CONFIG_MFD_SC27XX_PMIC)	+= sprd-sc27xx-spi.o
 obj-$(CONFIG_RAVE_SP_CORE)	+= rave-sp.o
 obj-$(CONFIG_MFD_ROHM_BD718XX)	+= rohm-bd718x7.o
-
+obj-$(CONFIG_MFD_STMFX) 	+= stmfx.o

include/linux/mfd/stmfx.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 STMicroelectronics
+ * Author(s): Amelie Delaunay <amelie.delaunay@st.com>.
+ */
+
+#ifndef MFD_STMFX_H
+#define MFX_STMFX_H
+
+#include <linux/regmap.h>
+
+/* General */
+#define STMFX_REG_CHIP_ID		0x00 /* R */
+#define STMFX_REG_FW_VERSION_MSB	0x01 /* R */
+#define STMFX_REG_FW_VERSION_LSB	0x02 /* R */
+#define STMFX_REG_SYS_CTRL		0x40 /* RW */
+/* IRQ output management */
+#define STMFX_REG_IRQ_OUT_PIN		0x41 /* RW */
+#define STMFX_REG_IRQ_SRC_EN		0x42 /* RW */
+#define STMFX_REG_IRQ_PENDING		0x08 /* R */
+#define STMFX_REG_IRQ_ACK		0x44 /* RW */
+/* GPIO management */
+#define STMFX_REG_IRQ_GPI_PENDING1	0x0C /* R */
+#define STMFX_REG_IRQ_GPI_PENDING2	0x0D /* R */
+#define STMFX_REG_IRQ_GPI_PENDING3	0x0E /* R */
+#define STMFX_REG_GPIO_STATE1		0x10 /* R */
+#define STMFX_REG_GPIO_STATE2		0x11 /* R */
+#define STMFX_REG_GPIO_STATE3		0x12 /* R */
+#define STMFX_REG_IRQ_GPI_SRC1		0x48 /* RW */
+#define STMFX_REG_IRQ_GPI_SRC2		0x49 /* RW */
+#define STMFX_REG_IRQ_GPI_SRC3		0x4A /* RW */
+#define STMFX_REG_IRQ_GPI_EVT1		0x4C /* RW */
+#define STMFX_REG_IRQ_GPI_EVT2		0x4D /* RW */
+#define STMFX_REG_IRQ_GPI_EVT3		0x4E /* RW */
+#define STMFX_REG_IRQ_GPI_TYPE1		0x50 /* RW */
+#define STMFX_REG_IRQ_GPI_TYPE2		0x51 /* RW */
+#define STMFX_REG_IRQ_GPI_TYPE3		0x52 /* RW */
+#define STMFX_REG_IRQ_GPI_ACK1		0x54 /* RW */
+#define STMFX_REG_IRQ_GPI_ACK2		0x55 /* RW */
+#define STMFX_REG_IRQ_GPI_ACK3		0x56 /* RW */
+#define STMFX_REG_GPIO_DIR1		0x60 /* RW */
+#define STMFX_REG_GPIO_DIR2		0x61 /* RW */
+#define STMFX_REG_GPIO_DIR3		0x62 /* RW */
+#define STMFX_REG_GPIO_TYPE1		0x64 /* RW */
+#define STMFX_REG_GPIO_TYPE2		0x65 /* RW */
+#define STMFX_REG_GPIO_TYPE3		0x66 /* RW */
+#define STMFX_REG_GPIO_PUPD1		0x68 /* RW */
+#define STMFX_REG_GPIO_PUPD2		0x69 /* RW */
+#define STMFX_REG_GPIO_PUPD3		0x6A /* RW */
+#define STMFX_REG_GPO_SET1		0x6C /* RW */
+#define STMFX_REG_GPO_SET2		0x6D /* RW */
+#define STMFX_REG_GPO_SET3		0x6E /* RW */
+#define STMFX_REG_GPO_CLR1		0x70 /* RW */
+#define STMFX_REG_GPO_CLR2		0x71 /* RW */
+#define STMFX_REG_GPO_CLR3		0x72 /* RW */
+
+#define STMFX_REG_MAX			0xB0
+
+/* MFX boot time is around 10ms, so after reset, we have to wait this delay */
+#define STMFX_BOOT_TIME_MS 10
+
+/* STMFX_REG_CHIP_ID bitfields */
+#define STMFX_REG_CHIP_ID_MASK		GENMASK(7, 0)
+
+/* STMFX_REG_SYS_CTRL bitfields */
+#define STMFX_REG_SYS_CTRL_GPIO_EN	BIT(0)
+#define STMFX_REG_SYS_CTRL_TS_EN	BIT(1)
+#define STMFX_REG_SYS_CTRL_IDD_EN	BIT(2)
+#define STMFX_REG_SYS_CTRL_ALTGPIO_EN	BIT(3)
+#define STMFX_REG_SYS_CTRL_SWRST	BIT(7)
+
+/* STMFX_REG_IRQ_OUT_PIN bitfields */
+#define STMFX_REG_IRQ_OUT_PIN_TYPE	BIT(0) /* 0-OD 1-PP */
+#define STMFX_REG_IRQ_OUT_PIN_POL	BIT(1) /* 0-active LOW 1-active HIGH */
+
+/* STMFX_REG_IRQ_(SRC_EN/PENDING/ACK) bit shift */
+enum stmfx_irqs {
+	STMFX_REG_IRQ_SRC_EN_GPIO = 0,
+	STMFX_REG_IRQ_SRC_EN_IDD,
+	STMFX_REG_IRQ_SRC_EN_ERROR,
+	STMFX_REG_IRQ_SRC_EN_TS_DET,
+	STMFX_REG_IRQ_SRC_EN_TS_NE,
+	STMFX_REG_IRQ_SRC_EN_TS_TH,
+	STMFX_REG_IRQ_SRC_EN_TS_FULL,
+	STMFX_REG_IRQ_SRC_EN_TS_OVF,
+	STMFX_REG_IRQ_SRC_MAX,
+};
+
+enum stmfx_functions {
+	STMFX_FUNC_GPIO		= BIT(0), /* GPIO[15:0] */
+	STMFX_FUNC_ALTGPIO_LOW	= BIT(1), /* aGPIO[3:0] */
+	STMFX_FUNC_ALTGPIO_HIGH = BIT(2), /* aGPIO[7:4] */
+	STMFX_FUNC_TS		= BIT(3),
+	STMFX_FUNC_IDD		= BIT(4),
+};
+
+/**
+ * struct stmfx_ddata - STMFX MFD structure
+ * @device:		device reference used for logs
+ * @map:		register map
+ * @vdd:		STMFX power supply
+ * @irq_domain:		IRQ domain
+ * @lock:		IRQ bus lock
+ * @irq_src:		cache of IRQ_SRC_EN register for bus_lock
+ * @bkp_sysctrl:	backup of SYS_CTRL register for suspend/resume
+ * @bkp_irqoutpin:	backup of IRQ_OUT_PIN register for suspend/resume
+ */
+struct stmfx {
+	struct device *dev;
+	struct regmap *map;
+	struct regulator *vdd;
+	struct irq_domain *irq_domain;
+	struct mutex lock; /* IRQ bus lock */
+	u8 irq_src;
+#ifdef CONFIG_PM
+	u8 bkp_sysctrl;
+	u8 bkp_irqoutpin;
+#endif
+};
+
+int stmfx_function_enable(struct stmfx *stmfx, u32 func);
+int stmfx_function_disable(struct stmfx *stmfx, u32 func);
+#endif