diff options
author | Maxime Ripard <maxime.ripard@free-electrons.com> | 2012-10-25 16:23:53 (GMT) |
---|---|---|
committer | Wolfram Sang <w.sang@pengutronix.de> | 2012-11-16 08:28:27 (GMT) |
commit | 9b7a0c40de6c5c04371f8cdb9153a0a5a0af5243 (patch) | |
tree | 02a02f2c3b38e8504d58a2eb4e4fa815804faf78 | |
parent | 29fb08c300b5cb626b8a803440aab25d0983cab7 (diff) | |
download | linux-9b7a0c40de6c5c04371f8cdb9153a0a5a0af5243.tar.xz |
i2c: mux: Add dt support to i2c-mux-gpio driver
Allow the i2c-mux-gpio to be used by a device tree enabled device. The
bindings are inspired by the one found in the i2c-mux-pinctrl driver.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Peter Korsgaard <peter.korsgaard@barco.com>
[wsa: fixed some whitespace]
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
-rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt | 81 | ||||
-rw-r--r-- | drivers/i2c/muxes/i2c-mux-gpio.c | 145 |
2 files changed, 195 insertions, 31 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt new file mode 100644 index 0000000..66709a8 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-mux-gpio.txt @@ -0,0 +1,81 @@ +GPIO-based I2C Bus Mux + +This binding describes an I2C bus multiplexer that uses GPIOs to +route the I2C signals. + + +-----+ +-----+ + | dev | | dev | + +------------+ +-----+ +-----+ + | SoC | | | + | | /--------+--------+ + | +------+ | +------+ child bus A, on GPIO value set to 0 + | | I2C |-|--| Mux | + | +------+ | +--+---+ child bus B, on GPIO value set to 1 + | | | \----------+--------+--------+ + | +------+ | | | | | + | | GPIO |-|-----+ +-----+ +-----+ +-----+ + | +------+ | | dev | | dev | | dev | + +------------+ +-----+ +-----+ +-----+ + +Required properties: +- compatible: i2c-mux-gpio +- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side + port is connected to. +- mux-gpios: list of gpios used to control the muxer +* Standard I2C mux properties. See mux.txt in this directory. +* I2C child bus nodes. See mux.txt in this directory. + +Optional properties: +- idle-state: value to set the muxer to when idle. When no value is + given, it defaults to the last value used. + +For each i2c child node, an I2C child bus will be created. They will +be numbered based on their order in the device tree. + +Whenever an access is made to a device on a child bus, the value set +in the revelant node's reg property will be output using the list of +GPIOs, the first in the list holding the least-significant value. + +If an idle state is defined, using the idle-state (optional) property, +whenever an access is not being made to a device on a child bus, the +GPIOs will be set according to the idle value. + +If an idle state is not defined, the most recently used value will be +left programmed into hardware whenever no access is being made to a +device on a child bus. + +Example: + i2cmux { + compatible = "i2c-mux-gpio"; + #address-cells = <1>; + #size-cells = <0>; + mux-gpios = <&gpio1 22 0 &gpio1 23 0>; + i2c-parent = <&i2c1>; + + i2c@1 { + reg = <1>; + #address-cells = <1>; + #size-cells = <0>; + + ssd1307: oled@3c { + compatible = "solomon,ssd1307fb-i2c"; + reg = <0x3c>; + pwms = <&pwm 4 3000>; + reset-gpios = <&gpio2 7 1>; + reset-active-low; + }; + }; + + i2c@3 { + reg = <3>; + #address-cells = <1>; + #size-cells = <0>; + + pca9555: pca9555@20 { + compatible = "nxp,pca9555"; + gpio-controller; + #gpio-cells = <2>; + reg = <0x20>; + }; + }; + }; diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c index 566a675..3b7bc06 100644 --- a/drivers/i2c/muxes/i2c-mux-gpio.c +++ b/drivers/i2c/muxes/i2c-mux-gpio.c @@ -16,6 +16,8 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/gpio.h> +#include <linux/of_i2c.h> +#include <linux/of_gpio.h> struct gpiomux { struct i2c_adapter *parent; @@ -57,29 +59,110 @@ static int __devinit match_gpio_chip_by_label(struct gpio_chip *chip, return !strcmp(chip->label, data); } +#ifdef CONFIG_OF +static int __devinit i2c_mux_gpio_probe_dt(struct gpiomux *mux, + struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct device_node *adapter_np, *child; + struct i2c_adapter *adapter; + unsigned *values, *gpios; + int i = 0; + + if (!np) + return -ENODEV; + + adapter_np = of_parse_phandle(np, "i2c-parent", 0); + if (!adapter_np) { + dev_err(&pdev->dev, "Cannot parse i2c-parent\n"); + return -ENODEV; + } + adapter = of_find_i2c_adapter_by_node(adapter_np); + if (!adapter) { + dev_err(&pdev->dev, "Cannot find parent bus\n"); + return -ENODEV; + } + mux->data.parent = i2c_adapter_id(adapter); + put_device(&adapter->dev); + + mux->data.n_values = of_get_child_count(np); + + values = devm_kzalloc(&pdev->dev, + sizeof(*mux->data.values) * mux->data.n_values, + GFP_KERNEL); + if (!values) { + dev_err(&pdev->dev, "Cannot allocate values array"); + return -ENOMEM; + } + + for_each_child_of_node(np, child) { + of_property_read_u32(child, "reg", values + i); + i++; + } + mux->data.values = values; + + if (of_property_read_u32(np, "idle-state", &mux->data.idle)) + mux->data.idle = I2C_MUX_GPIO_NO_IDLE; + + mux->data.n_gpios = of_gpio_named_count(np, "mux-gpios"); + if (mux->data.n_gpios < 0) { + dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n"); + return -EINVAL; + } + + gpios = devm_kzalloc(&pdev->dev, + sizeof(*mux->data.gpios) * mux->data.n_gpios, GFP_KERNEL); + if (!gpios) { + dev_err(&pdev->dev, "Cannot allocate gpios array"); + return -ENOMEM; + } + + for (i = 0; i < mux->data.n_gpios; i++) + gpios[i] = of_get_named_gpio(np, "mux-gpios", i); + + mux->data.gpios = gpios; + + return 0; +} +#else +static int __devinit i2c_mux_gpio_probe_dt(struct gpiomux *mux, + struct platform_device *pdev) +{ + return 0; +} +#endif + static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev) { struct gpiomux *mux; - struct i2c_mux_gpio_platform_data *pdata; struct i2c_adapter *parent; int (*deselect) (struct i2c_adapter *, void *, u32); unsigned initial_state, gpio_base; int i, ret; - pdata = pdev->dev.platform_data; - if (!pdata) { - dev_err(&pdev->dev, "Missing platform data\n"); - return -ENODEV; + mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL); + if (!mux) { + dev_err(&pdev->dev, "Cannot allocate gpiomux structure"); + return -ENOMEM; } + platform_set_drvdata(pdev, mux); + + if (!pdev->dev.platform_data) { + ret = i2c_mux_gpio_probe_dt(mux, pdev); + if (ret < 0) + return ret; + } else + memcpy(&mux->data, pdev->dev.platform_data, sizeof(mux->data)); + /* * If a GPIO chip name is provided, the GPIO pin numbers provided are * relative to its base GPIO number. Otherwise they are absolute. */ - if (pdata->gpio_chip) { + if (mux->data.gpio_chip) { struct gpio_chip *gpio; - gpio = gpiochip_find(pdata->gpio_chip, + gpio = gpiochip_find(mux->data.gpio_chip, match_gpio_chip_by_label); if (!gpio) return -EPROBE_DEFER; @@ -89,49 +172,44 @@ static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev) gpio_base = 0; } - parent = i2c_get_adapter(pdata->parent); + parent = i2c_get_adapter(mux->data.parent); if (!parent) { dev_err(&pdev->dev, "Parent adapter (%d) not found\n", - pdata->parent); + mux->data.parent); return -ENODEV; } - mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL); - if (!mux) { - ret = -ENOMEM; - goto alloc_failed; - } - mux->parent = parent; - mux->data = *pdata; mux->gpio_base = gpio_base; + mux->adap = devm_kzalloc(&pdev->dev, - sizeof(*mux->adap) * pdata->n_values, + sizeof(*mux->adap) * mux->data.n_values, GFP_KERNEL); if (!mux->adap) { + dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure"); ret = -ENOMEM; goto alloc_failed; } - if (pdata->idle != I2C_MUX_GPIO_NO_IDLE) { - initial_state = pdata->idle; + if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) { + initial_state = mux->data.idle; deselect = i2c_mux_gpio_deselect; } else { - initial_state = pdata->values[0]; + initial_state = mux->data.values[0]; deselect = NULL; } - for (i = 0; i < pdata->n_gpios; i++) { - ret = gpio_request(gpio_base + pdata->gpios[i], "i2c-mux-gpio"); + for (i = 0; i < mux->data.n_gpios; i++) { + ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio"); if (ret) goto err_request_gpio; - gpio_direction_output(gpio_base + pdata->gpios[i], + gpio_direction_output(gpio_base + mux->data.gpios[i], initial_state & (1 << i)); } - for (i = 0; i < pdata->n_values; i++) { - u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0; - unsigned int class = pdata->classes ? pdata->classes[i] : 0; + for (i = 0; i < mux->data.n_values; i++) { + u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0; + unsigned int class = mux->data.classes ? mux->data.classes[i] : 0; mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr, i, class, @@ -144,19 +222,17 @@ static int __devinit i2c_mux_gpio_probe(struct platform_device *pdev) } dev_info(&pdev->dev, "%d port mux on %s adapter\n", - pdata->n_values, parent->name); - - platform_set_drvdata(pdev, mux); + mux->data.n_values, parent->name); return 0; add_adapter_failed: for (; i > 0; i--) i2c_del_mux_adapter(mux->adap[i - 1]); - i = pdata->n_gpios; + i = mux->data.n_gpios; err_request_gpio: for (; i > 0; i--) - gpio_free(gpio_base + pdata->gpios[i - 1]); + gpio_free(gpio_base + mux->data.gpios[i - 1]); alloc_failed: i2c_put_adapter(parent); @@ -180,12 +256,19 @@ static int __devexit i2c_mux_gpio_remove(struct platform_device *pdev) return 0; } +static const struct of_device_id i2c_mux_gpio_of_match[] __devinitconst = { + { .compatible = "i2c-mux-gpio", }, + {}, +}; +MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match); + static struct platform_driver i2c_mux_gpio_driver = { .probe = i2c_mux_gpio_probe, .remove = __devexit_p(i2c_mux_gpio_remove), .driver = { .owner = THIS_MODULE, .name = "i2c-mux-gpio", + .of_match_table = of_match_ptr(i2c_mux_gpio_of_match), }, }; |