Subject: [PATCHv2 1/4] mfd: smsc: Add support for smsc gpio io/keypad driver

From: [email-masked] (Vaibhav Hiremath)
Date: Wed, 5 Sep 2012 23:23:17 +0530

On 9/5/2012 5:06 PM, Sourav Poddar wrote:
> 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: Samuel Ortiz <[email-masked]>
> Cc: Benoit Cousson <[email-masked]>
> Cc: Felipe Balbi <[email-masked]>
> Cc: Santosh Shilimkar <[email-masked]>
> Signed-off-by: Sourav Poddar <[email-masked]>
> ---
> Changes since v1:
>  - Use Kconfig option correctly
>  - Add regmap_config paramters
>  - Modify formatting of logs for devid
>  - Move read/write function to headed file as an inline
>    function.
>  Documentation/smsc_ece1099.txt |   56 ++++++++++++++++++++
>  drivers/mfd/Kconfig            |   12 ++++
>  drivers/mfd/Makefile           |    1 +
>  drivers/mfd/smsc-ece1099.c     |  110 +++++++++++++++++++++++++++++++++++++++
>  include/linux/mfd/smsc.h       |  111 ++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 290 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/smsc_ece1099.txt
>  create mode 100644 drivers/mfd/smsc-ece1099.c
>  create mode 100644 include/linux/mfd/smsc.h
> 
> diff --git a/Documentation/smsc_ece1099.txt b/Documentation/smsc_ece1099.txt
> new file mode 100644
> index 0000000..6b492e8
> --- /dev/null
> +++ b/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.
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index d1facef..991ef15 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -385,6 +385,18 @@ 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
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 79dd22d..f587d91 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -77,6 +77,7 @@ 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-$(CONFIG_MFD_SMSC)        += smsc.o
>  obj-$(CONFIG_MCP_UCB1200_TS)	+= ucb1x00-ts.o
>  
>  ifeq ($(CONFIG_SA1100_ASSABET),y)
> diff --git a/drivers/mfd/smsc-ece1099.c b/drivers/mfd/smsc-ece1099.c
> new file mode 100644
> index 0000000..73a6cb7
> --- /dev/null
> +++ b/drivers/mfd/smsc-ece1099.c
> @@ -0,0 +1,110 @@
> +/*
> + * TI SMSC MFD Driver
> + *
> + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
> + *
> + * Author: Sourav Poddar <[email-masked]>
> + *
> + *  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_MAX_REGISTER - 1;
> +		.cache_type = REGCACHE_COMPRESSED,
> +};

You can remove one extra tab here.

> +
> +static const struct of_device_id of_smsc_match[] = {
> +	{ .compatible = "smsc,ece1099", },
> +	{ },
> +};
> +
> +static int smsc_i2c_probe(struct i2c_client *i2c,
> +			const struct i2c_device_id *id)
> +{
> +	struct device_node              *node = i2c->dev.of_node;
> +	struct smsc *smsc;
> +	int ret = 0;
> +
> +	smsc = devm_kzalloc(&i2c->dev, sizeof(struct smsc),
> +				GFP_KERNEL);
> +

You must check the return value here?

> +	smsc->regmap = devm_regmap_init_i2c(i2c, &smsc_regmap_config);
> +	if (IS_ERR(smsc->regmap)) {
> +		ret = PTR_ERR(smsc->regmap);
> +		goto err;

You can simply return from here right?

> +	}
> +
> +	i2c_set_clientdata(i2c, smsc);
> +	smsc->dev = &i2c->dev;
> +
> +#ifdef CONFIG_OF
> +	of_property_read_u32(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);
> +

You also want to check return value here.

> +	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;
> +
> +	if (node)
> +		ret = of_platform_populate(node, NULL, NULL, &i2c->dev);
> +

of_xxx above is encapsulated in CONFIG_OF macro, same is not done here.

> +	return ret;
> +

This return is not required, as next instruction. Infact I would suggest
you can simply return from each places above.

Thanks,
Vaibhav
> +err:
> +	return ret;
> +}
> +
> +static int smsc_i2c_remove(struct i2c_client *i2c)
> +{
> +	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",
> +		   .of_match_table = of_smsc_match,
> +		   .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 <[email-masked]>");
> +MODULE_DESCRIPTION("SMSC chip multi-function driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/smsc.h b/include/linux/mfd/smsc.h
> new file mode 100644
> index 0000000..adfaec2
> --- /dev/null
> +++ b/include/linux/mfd/smsc.h
> @@ -0,0 +1,111 @@
> +/*
> + * SMSC ECE1099
> + *
> + * Copyright 2012 Texas Instruments Inc.
> + *
> + * Author: Sourav Poddar <[email-masked]>
> + *
> + *  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
> +
> +#define SMSC_MAX_REG					 (SMSC_VEN_ID_H + 1)
> +
> +/* 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 */
>