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Commit ac8498f0 authored by Peter Rosin's avatar Peter Rosin Committed by Greg Kroah-Hartman
Browse files

i2c: i2c-mux-gpmux: new driver 



This is a general purpose i2c mux that uses a multiplexer controlled by
the multiplexer subsystem to do the muxing.

The user can select if the mux is to be mux-locked and parent-locked
as described in Documentation/i2c/i2c-topology.

Acked-by: default avatarJonathan Cameron <jic23@kernel.org>
Acked-by: default avatarWolfram Sang <wsa@the-dreams.de>
Signed-off-by: default avatarPeter Rosin <peda@axentia.se>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 18213551

drivers/i2c/muxes/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -30,6 +30,19 @@ config I2C_MUX_GPIO 
	  This driver can also be built as a module.  If so, the module

	  will be called i2c-mux-gpio.



config I2C_MUX_GPMUX

	tristate "General Purpose I2C multiplexer"

	select MULTIPLEXER

	depends on OF || COMPILE_TEST

	help

	  If you say yes to this option, support will be included for a

	  general purpose I2C multiplexer. This driver provides access to

	  I2C busses connected through a MUX, which in turn is controlled

	  by a MUX-controller from the MUX subsystem.



	  This driver can also be built as a module.  If so, the module

	  will be called i2c-mux-gpmux.



config I2C_MUX_LTC4306

	tristate "LTC LTC4306/5 I2C multiplexer"

	select GPIOLIB

drivers/i2c/muxes/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE) += i2c-arb-gpio-challenge.o 
obj-$(CONFIG_I2C_DEMUX_PINCTRL)		+= i2c-demux-pinctrl.o



obj-$(CONFIG_I2C_MUX_GPIO)	+= i2c-mux-gpio.o

obj-$(CONFIG_I2C_MUX_GPMUX)	+= i2c-mux-gpmux.o

obj-$(CONFIG_I2C_MUX_LTC4306)	+= i2c-mux-ltc4306.o

obj-$(CONFIG_I2C_MUX_MLXCPLD)	+= i2c-mux-mlxcpld.o

obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux-pca9541.o

drivers/i2c/muxes/i2c-mux-gpmux.c

0 → 100644
+173 −0
Original line number Diff line number Diff line 
/*

 * General Purpose I2C multiplexer

 *

 * Copyright (C) 2017 Axentia Technologies AB

 *

 * Author: Peter Rosin <peda@axentia.se>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */



#include <linux/i2c.h>

#include <linux/i2c-mux.h>

#include <linux/module.h>

#include <linux/mux/consumer.h>

#include <linux/of_device.h>

#include <linux/platform_device.h>



struct mux {

	struct mux_control *control;



	bool do_not_deselect;

};



static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)

{

	struct mux *mux = i2c_mux_priv(muxc);

	int ret;



	ret = mux_control_select(mux->control, chan);

	mux->do_not_deselect = ret < 0;



	return ret;

}



static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan)

{

	struct mux *mux = i2c_mux_priv(muxc);



	if (mux->do_not_deselect)

		return 0;



	return mux_control_deselect(mux->control);

}



static struct i2c_adapter *mux_parent_adapter(struct device *dev)

{

	struct device_node *np = dev->of_node;

	struct device_node *parent_np;

	struct i2c_adapter *parent;



	parent_np = of_parse_phandle(np, "i2c-parent", 0);

	if (!parent_np) {

		dev_err(dev, "Cannot parse i2c-parent\n");

		return ERR_PTR(-ENODEV);

	}

	parent = of_find_i2c_adapter_by_node(parent_np);

	of_node_put(parent_np);

	if (!parent)

		return ERR_PTR(-EPROBE_DEFER);



	return parent;

}



static const struct of_device_id i2c_mux_of_match[] = {

	{ .compatible = "i2c-mux", },

	{},

};

MODULE_DEVICE_TABLE(of, i2c_mux_of_match);



static int i2c_mux_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct device_node *np = dev->of_node;

	struct device_node *child;

	struct i2c_mux_core *muxc;

	struct mux *mux;

	struct i2c_adapter *parent;

	int children;

	int ret;



	if (!np)

		return -ENODEV;



	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);

	if (!mux)

		return -ENOMEM;



	mux->control = devm_mux_control_get(dev, NULL);

	if (IS_ERR(mux->control)) {

		if (PTR_ERR(mux->control) != -EPROBE_DEFER)

			dev_err(dev, "failed to get control-mux\n");

		return PTR_ERR(mux->control);

	}



	parent = mux_parent_adapter(dev);

	if (IS_ERR(parent)) {

		if (PTR_ERR(parent) != -EPROBE_DEFER)

			dev_err(dev, "failed to get i2c-parent adapter\n");

		return PTR_ERR(parent);

	}



	children = of_get_child_count(np);



	muxc = i2c_mux_alloc(parent, dev, children, 0, 0,

			     i2c_mux_select, i2c_mux_deselect);

	if (!muxc) {

		ret = -ENOMEM;

		goto err_parent;

	}

	muxc->priv = mux;



	platform_set_drvdata(pdev, muxc);



	muxc->mux_locked = of_property_read_bool(np, "mux-locked");



	for_each_child_of_node(np, child) {

		u32 chan;



		ret = of_property_read_u32(child, "reg", &chan);

		if (ret < 0) {

			dev_err(dev, "no reg property for node '%s'\n",

				child->name);

			goto err_children;

		}



		if (chan >= mux_control_states(mux->control)) {

			dev_err(dev, "invalid reg %u\n", chan);

			ret = -EINVAL;

			goto err_children;

		}



		ret = i2c_mux_add_adapter(muxc, 0, chan, 0);

		if (ret)

			goto err_children;

	}



	dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name);



	return 0;



err_children:

	i2c_mux_del_adapters(muxc);

err_parent:

	i2c_put_adapter(parent);



	return ret;

}



static int i2c_mux_remove(struct platform_device *pdev)

{

	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);



	i2c_mux_del_adapters(muxc);

	i2c_put_adapter(muxc->parent);



	return 0;

}



static struct platform_driver i2c_mux_driver = {

	.probe	= i2c_mux_probe,

	.remove	= i2c_mux_remove,

	.driver	= {

		.name	= "i2c-mux-gpmux",

		.of_match_table = i2c_mux_of_match,

	},

};

module_platform_driver(i2c_mux_driver);



MODULE_DESCRIPTION("General Purpose I2C multiplexer driver");

MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");

MODULE_LICENSE("GPL v2");