On 05/01/2012 12:23 PM, Stephen Warren wrote:
> From: Stephen Warren <swarren@xxxxxxxxxx>
>
> This is useful for SoCs whose I2C module's signals can be routed to
> different sets of pins at run-time, using the pinctrl API.
>
> +-----+ +-----+
> | dev | | dev |
> +------------------------+ +-----+ +-----+
> | SoC | | |
> | /----|------+--------+
> | +---+ +------+ | child bus A, on first set of pins
> | |I2C|---|Pinmux| |
> | +---+ +------+ | child bus B, on second set of pins
> | \----|------+--------+--------+
> | | | | |
> +------------------------+ +-----+ +-----+ +-----+
> | dev | | dev | | dev |
> +-----+ +-----+ +-----+
>
Such a pretty drawing, I think it deserves to be in the binding doc.
Otherwise, looks good to me:
Acked-by: Rob Herring <rob.herring@xxxxxxxxxxx>
Sorry for the delayed response.
Rob
> Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx>
> Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> v3: Renamed pinctrl-i2cmux.c to i2c-mux-pinctrl.c to match recent changes
> to other I2C mux files.
> v2: Rebase onto David Daney's i2c-mux OF support, including slight binding
> changes. Add more error messages.
>
> squash pinctrl i2c mux
> ---
> .../devicetree/bindings/i2c/i2c-mux-pinctrl.txt | 79 ++++++
> drivers/i2c/muxes/Kconfig | 12 +
> drivers/i2c/muxes/Makefile | 1 +
> drivers/i2c/muxes/i2c-mux-pinctrl.c | 279 ++++++++++++++++++++
> include/linux/i2c-mux-pinctrl.h | 41 +++
> 5 files changed, 412 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
> create mode 100644 drivers/i2c/muxes/i2c-mux-pinctrl.c
> create mode 100644 include/linux/i2c-mux-pinctrl.h
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
> new file mode 100644
> index 0000000..b10e268
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
> @@ -0,0 +1,79 @@
> +Pinctrl-based I2C Bus Mux
> +
> +This binding describes an I2C bus multiplexer that uses pin multiplexing to
> +route the I2C signals, and represents the pin multiplexing configuration
> +using the pinctrl device tree bindings.
> +
> +Required properties:
> +- compatible: i2c-mux-pinctrl
> +- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
> + port is connected to.
> +
> +Also required are:
> +
> +* Standard pinctrl properties that specify the pin mux state for each child
> + bus. See ../pinctrl/pinctrl-bindings.txt.
> +
> +* Standard I2C mux properties. See mux.txt in this directory.
> +
> +* I2C child bus nodes. See mux.txt in this directory.
> +
> +For each named state defined in the pinctrl-names property, an I2C child bus
> +will be created. I2C child bus numbers are assigned based on the index into
> +the pinctrl-names property.
> +
> +The only exception is that no bus will be created for a state named "idle". If
> +such a state is defined, it must be the last entry in pinctrl-names. For
> +example:
> +
> + pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1
> + pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last)
> + pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last)
> +
> +Whenever an access is made to a device on a child bus, the relevant pinctrl
> +state will be programmed into hardware.
> +
> +If an idle state is defined, whenever an access is not being made to a device
> +on a child bus, the idle pinctrl state will be programmed into hardware.
> +
> +If an idle state is not defined, the most recently used pinctrl state will be
> +left programmed into hardware whenever no access is being made of a device on
> +a child bus.
> +
> +Example:
> +
> + i2cmux {
> + compatible = "i2c-mux-pinctrl";
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + i2c-parent = <&i2c1>;
> +
> + pinctrl-names = "ddc", "pta", "idle";
> + pinctrl-0 = <&state_i2cmux_ddc>;
> + pinctrl-1 = <&state_i2cmux_pta>;
> + pinctrl-2 = <&state_i2cmux_idle>;
> +
> + i2c@0 {
> + reg = <0>;
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + eeprom {
> + compatible = "eeprom";
> + reg = <0x50>;
> + };
> + };
> +
> + i2c@1 {
> + reg = <1>;
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + eeprom {
> + compatible = "eeprom";
> + reg = <0x50>;
> + };
> + };
> + };
> +
> diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
> index e14a420..c237a1b 100644
> --- a/drivers/i2c/muxes/Kconfig
> +++ b/drivers/i2c/muxes/Kconfig
> @@ -37,4 +37,16 @@ config I2C_MUX_PCA954x
> This driver can also be built as a module. If so, the module
> will be called i2c-mux-pca954x.
>
> +config I2C_MUX_PINCTRL
> + tristate "pinctrl-based I2C multiplexer"
> + depends on PINCTRL
> + help
> + If you say yes to this option, support will be included for an I2C
> + multiplexer that uses the pinctrl subsystem, i.e. pin multiplexing.
> + This is useful for SoCs whose I2C module's signals can be routed to
> + different sets of pins at run-time.
> +
> + This driver can also be built as a module. If so, the module will be
> + called pinctrl-i2cmux.
> +
> endmenu
> diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
> index 0868335..0e2a3cd 100644
> --- a/drivers/i2c/muxes/Makefile
> +++ b/drivers/i2c/muxes/Makefile
> @@ -4,5 +4,6 @@
> obj-$(CONFIG_I2C_MUX_GPIO) += gpio-i2cmux.o
> obj-$(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
>
> ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
> diff --git a/drivers/i2c/muxes/i2c-mux-pinctrl.c b/drivers/i2c/muxes/i2c-mux-pinctrl.c
> new file mode 100644
> index 0000000..46a6697
> --- /dev/null
> +++ b/drivers/i2c/muxes/i2c-mux-pinctrl.c
> @@ -0,0 +1,279 @@
> +/*
> + * I2C multiplexer using pinctrl API
> + *
> + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/i2c-mux.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/of_i2c.h>
> +#include <linux/pinctrl/consumer.h>
> +#include <linux/i2c-mux-pinctrl.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +struct i2c_mux_pinctrl {
> + struct device *dev;
> + struct i2c_mux_pinctrl_platform_data *pdata;
> + struct pinctrl *pinctrl;
> + struct pinctrl_state **states;
> + struct pinctrl_state *state_idle;
> + struct i2c_adapter *parent;
> + struct i2c_adapter **busses;
> +};
> +
> +static int i2c_mux_pinctrl_select(struct i2c_adapter *adap, void *data,
> + u32 chan)
> +{
> + struct i2c_mux_pinctrl *mux = data;
> +
> + return pinctrl_select_state(mux->pinctrl, mux->states[chan]);
> +}
> +
> +static int i2c_mux_pinctrl_deselect(struct i2c_adapter *adap, void *data,
> + u32 chan)
> +{
> + struct i2c_mux_pinctrl *mux = data;
> +
> + return pinctrl_select_state(mux->pinctrl, mux->state_idle);
> +}
> +
> +#ifdef CONFIG_OF
> +static int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
> + struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + int num_names, i, ret;
> + struct device_node *adapter_np;
> + struct i2c_adapter *adapter;
> +
> + if (!np)
> + return 0;
> +
> + mux->pdata = devm_kzalloc(&pdev->dev, sizeof(*mux->pdata), GFP_KERNEL);
> + if (!mux->pdata) {
> + dev_err(mux->dev,
> + "Cannot allocate i2c_mux_pinctrl_platform_data\n");
> + return -ENOMEM;
> + }
> +
> + num_names = of_property_count_strings(np, "pinctrl-names");
> + if (num_names < 0) {
> + dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
> + num_names);
> + return num_names;
> + }
> +
> + mux->pdata->pinctrl_states = devm_kzalloc(&pdev->dev,
> + sizeof(*mux->pdata->pinctrl_states) * num_names,
> + GFP_KERNEL);
> + if (!mux->pdata->pinctrl_states) {
> + dev_err(mux->dev, "Cannot allocate pinctrl_states\n");
> + return -ENOMEM;
> + }
> +
> + for (i = 0; i < num_names; i++) {
> + ret = of_property_read_string_index(np, "pinctrl-names", i,
> + &mux->pdata->pinctrl_states[mux->pdata->bus_count]);
> + if (ret < 0) {
> + dev_err(mux->dev, "Cannot parse pinctrl-names: %d\n",
> + ret);
> + return ret;
> + }
> + if (!strcmp(mux->pdata->pinctrl_states[mux->pdata->bus_count],
> + "idle")) {
> + if (i != num_names - 1) {
> + dev_err(mux->dev, "idle state must be last\n");
> + return -EINVAL;
> + }
> + mux->pdata->pinctrl_state_idle = "idle";
> + } else {
> + mux->pdata->bus_count++;
> + }
> + }
> +
> + adapter_np = of_parse_phandle(np, "i2c-parent", 0);
> + if (!adapter_np) {
> + dev_err(mux->dev, "Cannot parse i2c-parent\n");
> + return -ENODEV;
> + }
> + adapter = of_find_i2c_adapter_by_node(adapter_np);
> + if (!adapter) {
> + dev_err(mux->dev, "Cannot find parent bus\n");
> + return -ENODEV;
> + }
> + mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
> + put_device(&adapter->dev);
> +
> + return 0;
> +}
> +#else
> +static inline int i2c_mux_pinctrl_parse_dt(struct i2c_mux_pinctrl *mux,
> + struct platform_device *pdev)
> +{
> + return 0;
> +}
> +#endif
> +
> +static int __devinit i2c_mux_pinctrl_probe(struct platform_device *pdev)
> +{
> + struct i2c_mux_pinctrl *mux;
> + int (*deselect)(struct i2c_adapter *, void *, u32);
> + int i, ret;
> +
> + mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
> + if (!mux) {
> + dev_err(&pdev->dev, "Cannot allocate i2c_mux_pinctrl\n");
> + ret = -ENOMEM;
> + goto err;
> + }
> + platform_set_drvdata(pdev, mux);
> +
> + mux->dev = &pdev->dev;
> +
> + mux->pdata = pdev->dev.platform_data;
> + if (!mux->pdata) {
> + ret = i2c_mux_pinctrl_parse_dt(mux, pdev);
> + if (ret < 0)
> + goto err;
> + }
> + if (!mux->pdata) {
> + dev_err(&pdev->dev, "Missing platform data\n");
> + ret = -ENODEV;
> + goto err;
> + }
> +
> + mux->states = devm_kzalloc(&pdev->dev,
> + sizeof(*mux->states) * mux->pdata->bus_count,
> + GFP_KERNEL);
> + if (!mux->states) {
> + dev_err(&pdev->dev, "Cannot allocate states\n");
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + mux->busses = devm_kzalloc(&pdev->dev,
> + sizeof(mux->busses) * mux->pdata->bus_count,
> + GFP_KERNEL);
> + if (!mux->states) {
> + dev_err(&pdev->dev, "Cannot allocate busses\n");
> + ret = -ENOMEM;
> + goto err;
> + }
> +
> + mux->pinctrl = devm_pinctrl_get(&pdev->dev);
> + if (IS_ERR(mux->pinctrl)) {
> + ret = PTR_ERR(mux->pinctrl);
> + dev_err(&pdev->dev, "Cannot get pinctrl: %d\n", ret);
> + goto err;
> + }
> + for (i = 0; i < mux->pdata->bus_count; i++) {
> + mux->states[i] = pinctrl_lookup_state(mux->pinctrl,
> + mux->pdata->pinctrl_states[i]);
> + if (IS_ERR(mux->states[i])) {
> + ret = PTR_ERR(mux->states[i]);
> + dev_err(&pdev->dev,
> + "Cannot look up pinctrl state %s: %d\n",
> + mux->pdata->pinctrl_states[i], ret);
> + goto err;
> + }
> + }
> + if (mux->pdata->pinctrl_state_idle) {
> + mux->state_idle = pinctrl_lookup_state(mux->pinctrl,
> + mux->pdata->pinctrl_state_idle);
> + if (IS_ERR(mux->state_idle)) {
> + ret = PTR_ERR(mux->state_idle);
> + dev_err(&pdev->dev,
> + "Cannot look up pinctrl state %s: %d\n",
> + mux->pdata->pinctrl_state_idle, ret);
> + goto err;
> + }
> +
> + deselect = i2c_mux_pinctrl_deselect;
> + } else {
> + deselect = NULL;
> + }
> +
> + mux->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
> + if (!mux->parent) {
> + dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
> + mux->pdata->parent_bus_num);
> + ret = -ENODEV;
> + goto err;
> + }
> +
> + for (i = 0; i < mux->pdata->bus_count; i++) {
> + u32 bus = mux->pdata->base_bus_num ?
> + (mux->pdata->base_bus_num + i) : 0;
> +
> + mux->busses[i] = i2c_add_mux_adapter(mux->parent, &pdev->dev,
> + mux, bus, i,
> + i2c_mux_pinctrl_select,
> + deselect);
> + if (!mux->busses[i]) {
> + ret = -ENODEV;
> + dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
> + goto err_del_adapter;
> + }
> + }
> +
> + return 0;
> +
> +err_del_adapter:
> + for (; i > 0; i--)
> + i2c_del_mux_adapter(mux->busses[i - 1]);
> + i2c_put_adapter(mux->parent);
> +err:
> + return ret;
> +}
> +
> +static int __devexit i2c_mux_pinctrl_remove(struct platform_device *pdev)
> +{
> + struct i2c_mux_pinctrl *mux = platform_get_drvdata(pdev);
> + int i;
> +
> + for (i = 0; i < mux->pdata->bus_count; i++)
> + i2c_del_mux_adapter(mux->busses[i]);
> +
> + i2c_put_adapter(mux->parent);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id i2c_mux_pinctrl_of_match[] __devinitconst = {
> + { .compatible = "i2c-mux-pinctrl", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, i2c_mux_pinctrl_of_match);
> +#endif
> +
> +static struct platform_driver i2c_mux_pinctrl_driver = {
> + .driver = {
> + .name = "i2c-mux-pinctrl",
> + .owner = THIS_MODULE,
> + .of_match_table = of_match_ptr(i2c_mux_pinctrl_of_match),
> + },
> + .probe = i2c_mux_pinctrl_probe,
> + .remove = __devexit_p(i2c_mux_pinctrl_remove),
> +};
> +module_platform_driver(i2c_mux_pinctrl_driver);
> +
> +MODULE_DESCRIPTION("pinctrl-based I2C multiplexer driver");
> +MODULE_AUTHOR("Stephen Warren <swarren@xxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:i2c-mux-pinctrl");
> diff --git a/include/linux/i2c-mux-pinctrl.h b/include/linux/i2c-mux-pinctrl.h
> new file mode 100644
> index 0000000..a65c864
> --- /dev/null
> +++ b/include/linux/i2c-mux-pinctrl.h
> @@ -0,0 +1,41 @@
> +/*
> + * i2c-mux-pinctrl platform data
> + *
> + * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef _LINUX_I2C_MUX_PINCTRL_H
> +#define _LINUX_I2C_MUX_PINCTRL_H
> +
> +/**
> + * struct i2c_mux_pinctrl_platform_data - Platform data for i2c-mux-pinctrl
> + * @parent_bus_num: Parent I2C bus number
> + * @base_bus_num: Base I2C bus number for the child busses. 0 for dynamic.
> + * @bus_count: Number of child busses. Also the number of elements in
> + * @pinctrl_states
> + * @pinctrl_states: The names of the pinctrl state to select for each child bus
> + * @pinctrl_state_idle: The pinctrl state to select when no child bus is being
> + * accessed. If NULL, the most recently used pinctrl state will be left
> + * selected.
> + */
> +struct i2c_mux_pinctrl_platform_data {
> + int parent_bus_num;
> + int base_bus_num;
> + int bus_count;
> + const char **pinctrl_states;
> + const char *pinctrl_state_idle;
> +};
> +
> +#endif
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