mfd: smsc: Add support for smsc gpio io/keypad driver

smsc ece1099 is a keyboard scan or gpio expansion device.
The patch create keypad and gpio expander child for this
multi function smsc driver.

Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Sourav Poddar <sourav.poddar@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

Documentation/smsc_ece1099.txt

@@ -0,0 +1,56 @@
+What is smsc-ece1099?
+----------------------
+
+The ECE1099 is a 40-Pin 3.3V Keyboard Scan Expansion
+or GPIO Expansion device. The device supports a keyboard
+scan matrix of 23x8. The device is connected to a Master
+via the SMSC BC-Link interface or via the SMBus.
+Keypad scan Input(KSI) and Keypad Scan Output(KSO) signals
+are multiplexed with GPIOs.
+
+Interrupt generation
+--------------------
+
+Interrupts can be generated by an edge detection on a GPIO
+pin or an edge detection on one of the bus interface pins.
+Interrupts can also be detected on the keyboard scan interface.
+The bus interrupt pin (BC_INT# or SMBUS_INT#) is asserted if
+any bit in one of the Interrupt Status registers is 1 and
+the corresponding Interrupt Mask bit is also 1.
+
+In order for software to determine which device is the source
+of an interrupt, it should first read the Group Interrupt Status Register
+to determine which Status register group is a source for the interrupt.
+Software should read both the Status register and the associated Mask register,
+then AND the two values together. Bits that are 1 in the result of the AND
+are active interrupts. Software clears an interrupt by writing a 1 to the
+corresponding bit in the Status register.
+
+Communication Protocol
+----------------------
+
+- SMbus slave Interface
+	The host processor communicates with the ECE1099 device
+	through a series of read/write registers via the SMBus
+	interface. SMBus is a serial communication protocol between
+	a computer host and its peripheral devices. The SMBus data
+	rate is 10KHz minimum to 400 KHz maximum
+
+- Slave Bus Interface
+	The ECE1099 device SMBus implementation is a subset of the
+	SMBus interface to the host. The device is a slave-only SMBus device.
+	The implementation in the device is a subset of SMBus since it
+	only supports four protocols.
+
+	The Write Byte, Read Byte, Send Byte, and Receive Byte protocols are the
+	only valid SMBus protocols for the device.
+
+- BC-LinkTM Interface
+	The BC-Link is a proprietary bus that allows communication
+	between a Master device and a Companion device. The Master
+	device uses this serial bus to read and write registers
+	located on the Companion device. The bus comprises three signals,
+	BC_CLK, BC_DAT and BC_INT#. The Master device always provides the
+	clock, BC_CLK, and the Companion device is the source for an
+	independent asynchronous interrupt signal, BC_INT#. The ECE1099
+	supports BC-Link speeds up to 24MHz.

drivers/mfd/Kconfig

@@ -375,6 +375,18 @@ config MFD_T7L66XB
 	help
 	  Support for Toshiba Mobile IO Controller T7L66XB
 
+config MFD_SMSC
+       bool "Support for the SMSC ECE1099 series chips"
+       depends on I2C=y
+       select MFD_CORE
+       select REGMAP_I2C
+       help
+        If you say yes here you get support for the
+        ece1099 chips from SMSC.
+
+        To compile this driver as a module, choose M here: the
+        module will be called smsc.
+
 config MFD_TC6387XB
 	bool "Support Toshiba TC6387XB"
 	depends on ARM && HAVE_CLK

drivers/mfd/Makefile

@@ -76,6 +76,7 @@ obj-$(CONFIG_EZX_PCAP)		+= ezx-pcap.o
 obj-$(CONFIG_MCP)		+= mcp-core.o
 obj-$(CONFIG_MCP_SA11X0)	+= mcp-sa11x0.o
 obj-$(CONFIG_MCP_UCB1200)	+= ucb1x00-core.o
+obj-$(CONFIG_MFD_SMSC)        += smsc-ece1099.o
 obj-$(CONFIG_MCP_UCB1200_TS)	+= ucb1x00-ts.o
 
 ifeq ($(CONFIG_SA1100_ASSABET),y)

drivers/mfd/smsc-ece1099.c

@@ -0,0 +1,113 @@
+/*
+ * TI SMSC MFD Driver
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
+ *
+ * Author: Sourav Poddar <sourav.poddar@ti.com>
+ *
+ *  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;  GPL v2.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/workqueue.h>
+#include <linux/irq.h>
+#include <linux/regmap.h>
+#include <linux/err.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/smsc.h>
+#include <linux/of_platform.h>
+
+static struct regmap_config smsc_regmap_config = {
+		.reg_bits = 8,
+		.val_bits = 8,
+		.max_register = SMSC_VEN_ID_H,
+		.cache_type = REGCACHE_RBTREE,
+};
+
+static int smsc_i2c_probe(struct i2c_client *i2c,
+			const struct i2c_device_id *id)
+{
+	struct smsc *smsc;
+	int devid, rev, venid_l, venid_h;
+	int ret = 0;
+
+	smsc = devm_kzalloc(&i2c->dev, sizeof(struct smsc),
+				GFP_KERNEL);
+	if (!smsc) {
+		dev_err(&i2c->dev, "smsc mfd driver memory allocation failed\n");
+		return -ENOMEM;
+	}
+
+	smsc->regmap = devm_regmap_init_i2c(i2c, &smsc_regmap_config);
+	if (IS_ERR(smsc->regmap)) {
+		ret = PTR_ERR(smsc->regmap);
+		goto err;
+	}
+
+	i2c_set_clientdata(i2c, smsc);
+	smsc->dev = &i2c->dev;
+
+#ifdef CONFIG_OF
+	of_property_read_u32(i2c->dev.of_node, "clock", &smsc->clk);
+#endif
+
+	regmap_read(smsc->regmap, SMSC_DEV_ID, &devid);
+	regmap_read(smsc->regmap, SMSC_DEV_REV, &rev);
+	regmap_read(smsc->regmap, SMSC_VEN_ID_L, &venid_l);
+	regmap_read(smsc->regmap, SMSC_VEN_ID_H, &venid_h);
+
+	dev_info(&i2c->dev, "SMSCxxx devid: %02x rev: %02x venid: %02x\n",
+		devid, rev, (venid_h << 8) | venid_l);
+
+	ret = regmap_write(smsc->regmap, SMSC_CLK_CTRL, smsc->clk);
+	if (ret)
+		goto err;
+
+#ifdef CONFIG_OF
+	if (i2c->dev.of_node)
+		ret = of_platform_populate(i2c->dev.of_node,
+					   NULL, NULL, &i2c->dev);
+#endif
+
+err:
+	return ret;
+}
+
+static int smsc_i2c_remove(struct i2c_client *i2c)
+{
+	struct smsc *smsc = i2c_get_clientdata(i2c);
+
+	mfd_remove_devices(smsc->dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id smsc_i2c_id[] = {
+	{ "smscece1099", 0},
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, smsc_i2c_id);
+
+static struct i2c_driver smsc_i2c_driver = {
+	.driver = {
+		   .name = "smsc",
+		   .owner = THIS_MODULE,
+	},
+	.probe = smsc_i2c_probe,
+	.remove = smsc_i2c_remove,
+	.id_table = smsc_i2c_id,
+};
+
+module_i2c_driver(smsc_i2c_driver);
+
+MODULE_AUTHOR("Sourav Poddar <sourav.poddar@ti.com>");
+MODULE_DESCRIPTION("SMSC chip multi-function driver");
+MODULE_LICENSE("GPL v2");

include/linux/mfd/smsc.h

@@ -0,0 +1,109 @@
+/*
+ * SMSC ECE1099
+ *
+ * Copyright 2012 Texas Instruments Inc.
+ *
+ * Author: Sourav Poddar <sourav.poddar@ti.com>
+ *
+ *  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.
+ *
+ */
+
+#ifndef __LINUX_MFD_SMSC_H
+#define __LINUX_MFD_SMSC_H
+
+#include <linux/regmap.h>
+
+#define SMSC_ID_ECE1099			1
+#define SMSC_NUM_CLIENTS		2
+
+#define SMSC_BASE_ADDR			0x38
+#define OMAP_GPIO_SMSC_IRQ		151
+
+#define SMSC_MAXGPIO         32
+#define SMSC_BANK(offs)      ((offs) >> 3)
+#define SMSC_BIT(offs)       (1u << ((offs) & 0x7))
+
+struct smsc {
+	struct device *dev;
+	struct i2c_client *i2c_clients[SMSC_NUM_CLIENTS];
+	struct regmap *regmap;
+	int clk;
+	/* Stored chip id */
+	int id;
+};
+
+struct smsc_gpio;
+struct smsc_keypad;
+
+static inline int smsc_read(struct device *child, unsigned int reg,
+	unsigned int *dest)
+{
+	struct smsc     *smsc = dev_get_drvdata(child->parent);
+
+	return regmap_read(smsc->regmap, reg, dest);
+}
+
+static inline int smsc_write(struct device *child, unsigned int reg,
+	unsigned int value)
+{
+	struct smsc     *smsc = dev_get_drvdata(child->parent);
+
+	return regmap_write(smsc->regmap, reg, value);
+}
+
+/* Registers for SMSC */
+#define SMSC_RESET						0xF5
+#define SMSC_GRP_INT						0xF9
+#define SMSC_CLK_CTRL						0xFA
+#define SMSC_WKUP_CTRL						0xFB
+#define SMSC_DEV_ID						0xFC
+#define SMSC_DEV_REV						0xFD
+#define SMSC_VEN_ID_L						0xFE
+#define SMSC_VEN_ID_H						0xFF
+
+/* CLK VALUE */
+#define SMSC_CLK_VALUE						0x13
+
+/* Registers for function GPIO INPUT */
+#define SMSC_GPIO_DATA_IN_START					0x00
+
+/* Registers for function GPIO OUPUT */
+#define SMSC_GPIO_DATA_OUT_START                                       0x05
+
+/* Definitions for SMSC GPIO CONFIGURATION REGISTER*/
+#define SMSC_GPIO_INPUT_LOW					0x01
+#define SMSC_GPIO_INPUT_RISING					0x09
+#define SMSC_GPIO_INPUT_FALLING					0x11
+#define SMSC_GPIO_INPUT_BOTH_EDGE				0x19
+#define SMSC_GPIO_OUTPUT_PP					0x21
+#define SMSC_GPIO_OUTPUT_OP					0x31
+
+#define GRP_INT_STAT						0xf9
+#define	SMSC_GPI_INT						0x0f
+#define SMSC_CFG_START						0x0A
+
+/* Registers for SMSC GPIO INTERRUPT STATUS REGISTER*/
+#define SMSC_GPIO_INT_STAT_START                                  0x32
+
+/* Registers for SMSC GPIO INTERRUPT MASK REGISTER*/
+#define SMSC_GPIO_INT_MASK_START                               0x37
+
+/* Registers for SMSC function KEYPAD*/
+#define SMSC_KP_OUT						0x40
+#define SMSC_KP_IN						0x41
+#define SMSC_KP_INT_STAT					0x42
+#define SMSC_KP_INT_MASK					0x43
+
+/* Definitions for keypad */
+#define SMSC_KP_KSO           0x70
+#define SMSC_KP_KSI           0x51
+#define SMSC_KSO_ALL_LOW        0x20
+#define SMSC_KP_SET_LOW_PWR        0x0B
+#define SMSC_KP_SET_HIGH           0xFF
+#define SMSC_KSO_EVAL           0x00
+
+#endif /*  __LINUX_MFD_SMSC_H */