[PATCH 1/2] i2c: mux: Add dt support to i2c-mux-gpio driver
Peter Korsgaard
peter.korsgaard at barco.com
Tue Oct 23 15:51:56 EDT 2012
>>>>> "MR" == Maxime Ripard <maxime.ripard at free-electrons.com> writes:
Hi Maxime,
I'm fine with the idea, but a few comments:
MR> Allow the i2c-mux-gpio to be used by a device tree enabled device. The
MR> bindings are inspired by the one found in the i2c-mux-pinctrl driver.
MR> Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
MR> ---
MR> .../devicetree/bindings/i2c/i2c-mux-gpio.txt | 81 ++++++++++
MR> drivers/i2c/muxes/i2c-mux-gpio.c | 169 +++++++++++++++-----
MR> 2 files changed, 211 insertions(+), 39 deletions(-)
MR> create mode 100644 Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt
MR> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt
MR> new file mode 100644
MR> index 0000000..335fc4e
MR> --- /dev/null
MR> +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt
MR> @@ -0,0 +1,81 @@
MR> +GPIO-based I2C Bus Mux
MR> +
MR> +This binding describes an I2C bus multiplexer that uses GPIOs to
MR> +route the I2C signals.
MR> +
MR> + +-----+ +-----+
MR> + | dev | | dev |
MR> + +------------+ +-----+ +-----+
MR> + | SoC | | |
MR> + | | /--------+--------+
MR> + | +------+ | +------+ child bus A, on GPIO value set to 0
MR> + | | I2C |-|--| Mux |
MR> + | +------+ | +--+---+ child bus B, on GPIO value set to 1
MR> + | | | \----------+--------+--------+
MR> + | +------+ | | | | |
MR> + | | GPIO |-|-----+ +-----+ +-----+ +-----+
MR> + | +------+ | | dev | | dev | | dev |
MR> + +------------+ +-----+ +-----+ +-----+
MR> +
MR> +Required properties:
MR> +- compatible: i2c-mux-gpio
MR> +- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
MR> + port is connected to.
MR> +- mux-gpios: list of gpios to use to control the muxer
s/to use to/used to/
MR> +* Standard I2C mux properties. See mux.txt in this directory.
MR> +* I2C child bus nodes. See mux.txt in this directory.
MR> +
MR> +Optional properties:
MR> +- idle-state: value to set to the muxer when idle. When no value is
How about 'bitmask defining mux state when idle' instead?
MR> + given, it defaults to the last value used.
MR> +
MR> +For each i2c child node, an I2C child bus will be created. They will
MR> +be numbered based on the reg property of each node.
As far as I can see they are dynamically assigned numbers in the order
they are listed in the dt.
MR> +
MR> +Whenever an access is made to a device on a child bus, the value set
MR> +in the revelant node's reg property will be output using the list of
MR> +GPIOs, the first in the list holding the most-significant value.
Isn't it the other way around, E.G. first gpio in mux-gpios controlled
by LSB of reg property, next gpio by lsb+1, ..?
MR> +
MR> +If an idle state is defined, using the idle-state (optional) property,
MR> +whenever an access is not being made to a device on a child bus, the
MR> +idle value will be programmed into the GPIOs.
s/idle value will be programmed into the GPIOS/GPIOS set according to
the idle value bitmask/
MR> +
MR> +If an idle state is not defined, the most recently used value will be
MR> +left programmed into hardware whenever no access is being made of a
s/of a/to a/
MR> +device on a child bus.
MR> +
MR> +Example:
MR> + i2cmux {
MR> + compatible = "i2c-mux-gpio";
MR> + #address-cells = <1>;
MR> + #size-cells = <0>;
MR> + mux-gpios = <&gpio1 22 0 &gpio1 23 0>;
MR> + i2c-parent = <&i2c1>;
MR> +
MR> + i2c at 1 {
MR> + reg = <1>;
MR> + #address-cells = <1>;
MR> + #size-cells = <0>;
MR> +
MR> + ssd1307: oled at 3c {
MR> + compatible = "solomon,ssd1307fb-i2c";
MR> + reg = <0x3c>;
MR> + pwms = <&pwm 4 3000>;
MR> + reset-gpios = <&gpio2 7 1>;
MR> + reset-active-low;
MR> + };
MR> + };
MR> +
MR> + i2c at 3 {
MR> + reg = <3>;
MR> + #address-cells = <1>;
MR> + #size-cells = <0>;
MR> +
MR> + pca9555: pca9555 at 20 {
MR> + compatible = "nxp,pca9555";
MR> + gpio-controller;
MR> + #gpio-cells = <2>;
MR> + reg = <0x20>;
MR> + };
MR> + };
MR> + };
MR> diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c
MR> index 566a675..7ebef01 100644
MR> --- a/drivers/i2c/muxes/i2c-mux-gpio.c
MR> +++ b/drivers/i2c/muxes/i2c-mux-gpio.c
MR> @@ -16,11 +16,13 @@
MR> #include <linux/module.h>
MR> #include <linux/slab.h>
MR> #include <linux/gpio.h>
MR> +#include <linux/of_i2c.h>
MR> +#include <linux/of_gpio.h>
MR> struct gpiomux {
MR> struct i2c_adapter *parent;
MR> struct i2c_adapter **adap; /* child busses */
MR> - struct i2c_mux_gpio_platform_data data;
MR> + struct i2c_mux_gpio_platform_data *data;
Why this change? I don't see why it is needed and the patch would be a
lot easier to review without all the s/.data/->data/ noise.
MR> unsigned gpio_base;
MR> };
MR> @@ -28,8 +30,8 @@ static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
MR> {
MR> int i;
MR> - for (i = 0; i < mux->data.n_gpios; i++)
MR> - gpio_set_value(mux->gpio_base + mux->data.gpios[i],
MR> + for (i = 0; i < mux->data->n_gpios; i++)
MR> + gpio_set_value(mux->gpio_base + mux->data->gpios[i],
MR> val & (1 << i));
MR> }
MR> @@ -37,7 +39,7 @@ static int i2c_mux_gpio_select(struct i2c_adapter *adap, void *data, u32 chan)
MR> {
MR> struct gpiomux *mux = data;
MR> - i2c_mux_gpio_set(mux, mux->data.values[chan]);
MR> + i2c_mux_gpio_set(mux, mux->data->values[chan]);
MR> return 0;
MR> }
MR> @@ -46,7 +48,7 @@ static int i2c_mux_gpio_deselect(struct i2c_adapter *adap, void *data, u32 chan)
MR> {
MR> struct gpiomux *mux = data;
MR> - i2c_mux_gpio_set(mux, mux->data.idle);
MR> + i2c_mux_gpio_set(mux, mux->data->idle);
MR> return 0;
MR> }
MR> @@ -57,29 +59,118 @@ static int __devinit match_gpio_chip_by_label(struct gpio_chip *chip,
MR> return !strcmp(chip->label, data);
MR> }
MR> +#ifdef CONFIG_OF
MR> +static int __devinit i2c_mux_gpio_probe_dt(struct gpiomux *mux,
MR> + struct platform_device *pdev)
MR> +{
MR> + struct device_node *np = pdev->dev.of_node;
MR> + struct device_node *adapter_np, *child;
MR> + struct i2c_adapter *adapter;
MR> + unsigned *values, *gpios;
MR> + int i = 0;
MR> +
MR> + if (!np)
MR> + return 0;
MR> +
MR> + mux->data = devm_kzalloc(&pdev->dev, sizeof(*mux->data),
MR> + GFP_KERNEL);
MR> + if (!mux->data) {
MR> + dev_err(&pdev->dev, "Cannot allocate platform_data");
MR> + return -ENOMEM;
MR> + }
MR> +
MR> + adapter_np = of_parse_phandle(np, "i2c-parent", 0);
MR> + if (!adapter_np) {
MR> + dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
MR> + return -ENODEV;
MR> + }
MR> + adapter = of_find_i2c_adapter_by_node(adapter_np);
MR> + if (!adapter) {
MR> + dev_err(&pdev->dev, "Cannot find parent bus\n");
MR> + return -ENODEV;
MR> + }
MR> + mux->data->parent = i2c_adapter_id(adapter);
MR> + put_device(&adapter->dev);
MR> +
MR> + mux->data->n_values = of_get_child_count(np);
MR> +
MR> + values = devm_kzalloc(&pdev->dev,
MR> + sizeof(*mux->data->values) * mux->data->n_values,
MR> + GFP_KERNEL);
MR> + if (!values) {
MR> + dev_err(&pdev->dev, "Cannot allocate values array");
MR> + return -ENOMEM;
MR> + }
MR> +
MR> + for_each_child_of_node(np, child) {
MR> + of_property_read_u32(child, "reg", values + i);
MR> + i++;
MR> + }
MR> + mux->data->values = values;
MR> +
MR> + if (of_property_read_u32(np, "idle-state", &mux->data->idle))
MR> + mux->data->idle = I2C_MUX_GPIO_NO_IDLE;
MR> +
MR> + mux->data->n_gpios = of_gpio_named_count(np, "mux-gpios");
MR> + if (mux->data->n_gpios < 0) {
MR> + dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n");
MR> + return -EINVAL;
MR> + }
MR> +
MR> + gpios = devm_kzalloc(&pdev->dev,
MR> + sizeof(*mux->data->gpios) * mux->data->n_gpios,
MR> + GFP_KERNEL);
MR> + if (!gpios) {
MR> + dev_err(&pdev->dev, "Cannot allocate gpios array");
MR> + return -ENOMEM;
MR> + }
MR> +
MR> + for (i = 0; i < mux->data->n_gpios; i++)
MR> + gpios[i] = of_get_named_gpio(np, "mux-gpios", i);
MR> +
MR> + mux->data->gpios = gpios;
MR> +
MR> + return 0;
MR> +}
MR> +#else
MR> +static int __devinit i2c_mux_gpio_probe_dt(struct gpiomux *mux,
MR> + struct platform_device *pdev)
MR> +{
MR> + return 0;
MR> +}
MR> +#endif
MR> +
MR> static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev)
MR> {
MR> struct gpiomux *mux;
MR> - struct i2c_mux_gpio_platform_data *pdata;
MR> struct i2c_adapter *parent;
MR> int (*deselect) (struct i2c_adapter *, void *, u32);
MR> unsigned initial_state, gpio_base;
MR> int i, ret;
MR> - pdata = pdev->dev.platform_data;
MR> - if (!pdata) {
MR> - dev_err(&pdev->dev, "Missing platform data\n");
MR> - return -ENODEV;
MR> + mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
MR> + if (!mux) {
MR> + dev_err(&pdev->dev, "Cannot allocate gpiomux structure");
MR> + return -ENOMEM;
MR> + }
MR> +
MR> + platform_set_drvdata(pdev, mux);
MR> +
MR> + mux->data = pdev->dev.platform_data;
MR> + if (!mux->data) {
MR> + ret = i2c_mux_gpio_probe_dt(mux, pdev);
MR> + if (ret < 0)
MR> + return ret;
MR> }
MR> /*
MR> * If a GPIO chip name is provided, the GPIO pin numbers provided are
MR> * relative to its base GPIO number. Otherwise they are absolute.
MR> */
MR> - if (pdata->gpio_chip) {
MR> + if (mux->data->gpio_chip) {
MR> struct gpio_chip *gpio;
MR> - gpio = gpiochip_find(pdata->gpio_chip,
MR> + gpio = gpiochip_find(mux->data->gpio_chip,
MR> match_gpio_chip_by_label);
MR> if (!gpio)
MR> return -EPROBE_DEFER;
MR> @@ -89,49 +180,44 @@ static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev)
MR> gpio_base = 0;
MR> }
MR> - parent = i2c_get_adapter(pdata->parent);
MR> + parent = i2c_get_adapter(mux->data->parent);
MR> if (!parent) {
MR> dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
MR> - pdata->parent);
MR> + mux->data->parent);
MR> return -ENODEV;
MR> }
MR> - mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
MR> - if (!mux) {
MR> - ret = -ENOMEM;
MR> - goto alloc_failed;
MR> - }
MR> -
mux-> parent = parent;
MR> - mux->data = *pdata;
mux-> gpio_base = gpio_base;
MR> +
mux-> adap = devm_kzalloc(&pdev->dev,
MR> - sizeof(*mux->adap) * pdata->n_values,
MR> + sizeof(*mux->adap) * mux->data->n_values,
MR> GFP_KERNEL);
MR> if (!mux->adap) {
MR> + dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
MR> ret = -ENOMEM;
MR> goto alloc_failed;
MR> }
MR> - if (pdata->idle != I2C_MUX_GPIO_NO_IDLE) {
MR> - initial_state = pdata->idle;
MR> + if (mux->data->idle != I2C_MUX_GPIO_NO_IDLE) {
MR> + initial_state = mux->data->idle;
MR> deselect = i2c_mux_gpio_deselect;
MR> } else {
MR> - initial_state = pdata->values[0];
MR> + initial_state = mux->data->values[0];
MR> deselect = NULL;
MR> }
MR> - for (i = 0; i < pdata->n_gpios; i++) {
MR> - ret = gpio_request(gpio_base + pdata->gpios[i], "i2c-mux-gpio");
MR> + for (i = 0; i < mux->data->n_gpios; i++) {
MR> + ret = gpio_request(gpio_base + mux->data->gpios[i], "i2c-mux-gpio");
MR> if (ret)
MR> goto err_request_gpio;
MR> - gpio_direction_output(gpio_base + pdata->gpios[i],
MR> + gpio_direction_output(gpio_base + mux->data->gpios[i],
MR> initial_state & (1 << i));
MR> }
MR> - for (i = 0; i < pdata->n_values; i++) {
MR> - u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0;
MR> - unsigned int class = pdata->classes ? pdata->classes[i] : 0;
MR> + for (i = 0; i < mux->data->n_values; i++) {
MR> + u32 nr = mux->data->base_nr ? (mux->data->base_nr + i) : 0;
MR> + unsigned int class = mux->data->classes ? mux->data->classes[i] : 0;
mux-> adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
MR> i, class,
MR> @@ -144,19 +230,17 @@ static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev)
MR> }
MR> dev_info(&pdev->dev, "%d port mux on %s adapter\n",
MR> - pdata->n_values, parent->name);
MR> -
MR> - platform_set_drvdata(pdev, mux);
MR> + mux->data->n_values, parent->name);
MR> return 0;
MR> add_adapter_failed:
MR> for (; i > 0; i--)
MR> i2c_del_mux_adapter(mux->adap[i - 1]);
MR> - i = pdata->n_gpios;
MR> + i = mux->data->n_gpios;
MR> err_request_gpio:
MR> for (; i > 0; i--)
MR> - gpio_free(gpio_base + pdata->gpios[i - 1]);
MR> + gpio_free(gpio_base + mux->data->gpios[i - 1]);
MR> alloc_failed:
MR> i2c_put_adapter(parent);
MR> @@ -168,11 +252,11 @@ static int __devexit i2c_mux_gpio_remove(struct platform_device *pdev)
MR> struct gpiomux *mux = platform_get_drvdata(pdev);
MR> int i;
MR> - for (i = 0; i < mux->data.n_values; i++)
MR> + for (i = 0; i < mux->data->n_values; i++)
MR> i2c_del_mux_adapter(mux->adap[i]);
MR> - for (i = 0; i < mux->data.n_gpios; i++)
MR> - gpio_free(mux->gpio_base + mux->data.gpios[i]);
MR> + for (i = 0; i < mux->data->n_gpios; i++)
MR> + gpio_free(mux->gpio_base + mux->data->gpios[i]);
MR> platform_set_drvdata(pdev, NULL);
MR> i2c_put_adapter(mux->parent);
MR> @@ -180,12 +264,19 @@ static int __devexit i2c_mux_gpio_remove(struct platform_device *pdev)
MR> return 0;
MR> }
MR> +static const struct of_device_id i2c_mux_gpio_of_match[] __devinitconst = {
MR> + { .compatible = "i2c-mux-gpio", },
MR> + {},
MR> +};
MR> +MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match);
MR> +
MR> static struct platform_driver i2c_mux_gpio_driver = {
MR> .probe = i2c_mux_gpio_probe,
MR> .remove = __devexit_p(i2c_mux_gpio_remove),
MR> .driver = {
MR> .owner = THIS_MODULE,
MR> .name = "i2c-mux-gpio",
MR> + .of_match_table = of_match_ptr(i2c_mux_gpio_of_match),
MR> },
MR> };
MR> --
MR> 1.7.9.5
--
Sorry about disclaimer - It's out of my control.
Bye, Peter Korsgaard
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