Re: [PATCH v6 7/9] i2c: i2c-mux-simple: new driver

[Jonathan Cameron]

On 30/11/16 08:17, Peter Rosin wrote:
> This is a generic simple i2c mux that uses the generic 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.
> 
> Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>
Looks good to me though as I haven't really commented on it I'll give
an Ack rather than a reviewed by.

Acked-by: Jonathan Cameron <jic23@xxxxxxxxxx>
> ---
>  drivers/i2c/muxes/Kconfig          |  13 +++
>  drivers/i2c/muxes/Makefile         |   1 +
>  drivers/i2c/muxes/i2c-mux-simple.c | 179 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 193 insertions(+)
>  create mode 100644 drivers/i2c/muxes/i2c-mux-simple.c
> 
> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
> index 10b3d17ae3ea..565921e09a96 100644
> --- a/drivers/i2c/muxes/Kconfig
> +++ b/drivers/i2c/muxes/Kconfig
> @@ -73,6 +73,19 @@ config I2C_MUX_REG
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called i2c-mux-reg.
>  
> +config I2C_MUX_SIMPLE
> +	tristate "Simple I2C multiplexer"
> +	select MULTIPLEXER
> +	depends on OF
> +	help
> +	  If you say yes to this option, support will be included for a
> +	  simple generic I2C multiplexer. This driver provides access to
> +	  I2C busses connected through a MUX, which is controlled
> +	  by a generic MUX controller.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called i2c-mux-simple.
> +
>  config I2C_DEMUX_PINCTRL
>  	tristate "pinctrl-based I2C demultiplexer"
>  	depends on PINCTRL && OF
> diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
> index 9948fa45037f..6821d95c92a3 100644
> --- a/drivers/i2c/muxes/Makefile
> +++ b/drivers/i2c/muxes/Makefile
> @@ -11,5 +11,6 @@ obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux-pca9541.o
>  obj-$(CONFIG_I2C_MUX_PCA954x)	+= i2c-mux-pca954x.o
>  obj-$(CONFIG_I2C_MUX_PINCTRL)	+= i2c-mux-pinctrl.o
>  obj-$(CONFIG_I2C_MUX_REG)	+= i2c-mux-reg.o
> +obj-$(CONFIG_I2C_MUX_SIMPLE)	+= i2c-mux-simple.o
>  
>  ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
> diff --git a/drivers/i2c/muxes/i2c-mux-simple.c b/drivers/i2c/muxes/i2c-mux-simple.c
> new file mode 100644
> index 000000000000..4a03493e1ad7
> --- /dev/null
> +++ b/drivers/i2c/muxes/i2c-mux-simple.c
> @@ -0,0 +1,179 @@
> +/*
> + * Generic simple I2C multiplexer
> + *
> + * Copyright (C) 2016 Axentia Technologies AB
> + *
> + * Author: Peter Rosin <peda@xxxxxxxxxx>
> + *
> + * 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.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-simple,parent-locked",
> +	  .data = (void *)0, },
> +	{ .compatible = "i2c-mux-simple,mux-locked",
> +	  .data = (void *)1, },
> +	{},
> +};
> +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;
> +	const struct of_device_id *match;
> +	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);
> +
> +	match = of_match_device(of_match_ptr(i2c_mux_of_match), dev);
> +	if (match)
> +		muxc->mux_locked = !!of_device_get_match_data(dev);
> +
> +	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) {
> +			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-simple",
> +		.of_match_table = i2c_mux_of_match,
> +	},
> +};
> +module_platform_driver(i2c_mux_driver);
> +
> +MODULE_DESCRIPTION("Simple I2C multiplexer driver");
> +MODULE_AUTHOR("Peter Rosin <peda@xxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
>