Commit 3abee457 authored by Michael Walle's avatar Michael Walle Committed by Lee Jones
Browse files

mfd: Add simple regmap based I2C driver 



There are I2C devices which contain several different functions but
doesn't require any special access functions. For these kind of drivers
an I2C regmap should be enough.

Create an I2C driver which creates an I2C regmap and enumerates its
children. If a device wants to use this as its MFD core driver, it has
to add an individual compatible string. It may provide its own regmap
configuration.

Subdevices can use dev_get_regmap() on the parent to get their regmap
instance.

Signed-off-by: default avatarMichael Walle <michael@walle.cc>
Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
parent 9123e3a7

drivers/mfd/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -1162,6 +1162,18 @@ config MFD_SI476X_CORE 
	  To compile this driver as a module, choose M here: the

	  module will be called si476x-core.



config MFD_SIMPLE_MFD_I2C

	tristate

	depends on I2C

	select REGMAP_I2C

	help

	  This driver creates a single register map with the intention for it

	  to be shared by all sub-devices.



	  Once the register map has been successfully initialised, any

	  sub-devices represented by child nodes in Device Tree will be

	  subsequently registered.



config MFD_SM501

	tristate "Silicon Motion SM501"

	depends on HAS_DMA

drivers/mfd/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -264,3 +264,4 @@ obj-$(CONFIG_MFD_STMFX) += stmfx.o 
obj-$(CONFIG_MFD_KHADAS_MCU) 	+= khadas-mcu.o



obj-$(CONFIG_SGI_MFD_IOC3)	+= ioc3.o

obj-$(CONFIG_MFD_SIMPLE_MFD_I2C)	+= simple-mfd-i2c.o

drivers/mfd/simple-mfd-i2c.c

0 → 100644
+56 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Simple MFD - I2C

 *

 * This driver creates a single register map with the intention for it to be

 * shared by all sub-devices.  Children can use their parent's device structure

 * (dev.parent) in order to reference it.

 *

 * Once the register map has been successfully initialised, any sub-devices

 * represented by child nodes in Device Tree will be subsequently registered.

 */



#include <linux/i2c.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of_platform.h>

#include <linux/regmap.h>



static const struct regmap_config simple_regmap_config = {

	.reg_bits = 8,

	.val_bits = 8,

};



static int simple_mfd_i2c_probe(struct i2c_client *i2c)

{

	const struct regmap_config *config;

	struct regmap *regmap;



	config = device_get_match_data(&i2c->dev);

	if (!config)

		config = &simple_regmap_config;



	regmap = devm_regmap_init_i2c(i2c, config);

	if (IS_ERR(regmap))

		return PTR_ERR(regmap);



	return devm_of_platform_populate(&i2c->dev);

}



static const struct of_device_id simple_mfd_i2c_of_match[] = {

	{}

};

MODULE_DEVICE_TABLE(of, simple_mfd_i2c_of_match);



static struct i2c_driver simple_mfd_i2c_driver = {

	.probe_new = simple_mfd_i2c_probe,

	.driver = {

		.name = "simple-mfd-i2c",

		.of_match_table = simple_mfd_i2c_of_match,

	},

};

module_i2c_driver(simple_mfd_i2c_driver);



MODULE_AUTHOR("Michael Walle <michael@walle.cc>");

MODULE_DESCRIPTION("Simple MFD - I2C driver");

MODULE_LICENSE("GPL v2");

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