| /* |
| * I2C multiplexer using GPIO API |
| * |
| * Peter Korsgaard <peter.korsgaard@barco.com> |
| * |
| * 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/i2c-mux-gpio.h> |
| #include <linux/platform_device.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/gpio.h> |
| #include "../../gpio/gpiolib.h" |
| #include <linux/of_gpio.h> |
| |
| struct gpiomux { |
| struct i2c_mux_gpio_platform_data data; |
| unsigned gpio_base; |
| struct gpio_desc **gpios; |
| int *values; |
| }; |
| |
| static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val) |
| { |
| int i; |
| |
| for (i = 0; i < mux->data.n_gpios; i++) |
| mux->values[i] = (val >> i) & 1; |
| |
| gpiod_set_array_value_cansleep(mux->data.n_gpios, |
| mux->gpios, mux->values); |
| } |
| |
| static int i2c_mux_gpio_select(struct i2c_mux_core *muxc, u32 chan) |
| { |
| struct gpiomux *mux = i2c_mux_priv(muxc); |
| |
| i2c_mux_gpio_set(mux, chan); |
| |
| return 0; |
| } |
| |
| static int i2c_mux_gpio_deselect(struct i2c_mux_core *muxc, u32 chan) |
| { |
| struct gpiomux *mux = i2c_mux_priv(muxc); |
| |
| i2c_mux_gpio_set(mux, mux->data.idle); |
| |
| return 0; |
| } |
| |
| static int match_gpio_chip_by_label(struct gpio_chip *chip, |
| void *data) |
| { |
| return !strcmp(chip->label, data); |
| } |
| |
| #ifdef CONFIG_OF |
| static int 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, ret; |
| |
| 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); |
| of_node_put(adapter_np); |
| if (!adapter) |
| return -EPROBE_DEFER; |
| |
| 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++) { |
| ret = of_get_named_gpio(np, "mux-gpios", i); |
| if (ret < 0) |
| return ret; |
| gpios[i] = ret; |
| } |
| |
| mux->data.gpios = gpios; |
| |
| return 0; |
| } |
| #else |
| static int i2c_mux_gpio_probe_dt(struct gpiomux *mux, |
| struct platform_device *pdev) |
| { |
| return 0; |
| } |
| #endif |
| |
| static int i2c_mux_gpio_probe(struct platform_device *pdev) |
| { |
| struct i2c_mux_core *muxc; |
| struct gpiomux *mux; |
| struct i2c_adapter *parent; |
| struct i2c_adapter *root; |
| unsigned initial_state, gpio_base; |
| int i, ret; |
| |
| mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL); |
| if (!mux) |
| return -ENOMEM; |
| |
| if (!dev_get_platdata(&pdev->dev)) { |
| ret = i2c_mux_gpio_probe_dt(mux, pdev); |
| if (ret < 0) |
| return ret; |
| } else { |
| memcpy(&mux->data, dev_get_platdata(&pdev->dev), |
| 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 (mux->data.gpio_chip) { |
| struct gpio_chip *gpio; |
| |
| gpio = gpiochip_find(mux->data.gpio_chip, |
| match_gpio_chip_by_label); |
| if (!gpio) |
| return -EPROBE_DEFER; |
| |
| gpio_base = gpio->base; |
| } else { |
| gpio_base = 0; |
| } |
| |
| parent = i2c_get_adapter(mux->data.parent); |
| if (!parent) |
| return -EPROBE_DEFER; |
| |
| muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, |
| mux->data.n_gpios * sizeof(*mux->gpios) + |
| mux->data.n_gpios * sizeof(*mux->values), 0, |
| i2c_mux_gpio_select, NULL); |
| if (!muxc) { |
| ret = -ENOMEM; |
| goto alloc_failed; |
| } |
| mux->gpios = muxc->priv; |
| mux->values = (int *)(mux->gpios + mux->data.n_gpios); |
| muxc->priv = mux; |
| |
| platform_set_drvdata(pdev, muxc); |
| |
| root = i2c_root_adapter(&parent->dev); |
| |
| muxc->mux_locked = true; |
| mux->gpio_base = gpio_base; |
| |
| if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) { |
| initial_state = mux->data.idle; |
| muxc->deselect = i2c_mux_gpio_deselect; |
| } else { |
| initial_state = mux->data.values[0]; |
| } |
| |
| for (i = 0; i < mux->data.n_gpios; i++) { |
| struct device *gpio_dev; |
| struct gpio_desc *gpio_desc; |
| |
| ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio"); |
| if (ret) { |
| dev_err(&pdev->dev, "Failed to request GPIO %d\n", |
| mux->data.gpios[i]); |
| goto err_request_gpio; |
| } |
| |
| ret = gpio_direction_output(gpio_base + mux->data.gpios[i], |
| initial_state & (1 << i)); |
| if (ret) { |
| dev_err(&pdev->dev, |
| "Failed to set direction of GPIO %d to output\n", |
| mux->data.gpios[i]); |
| i++; /* gpio_request above succeeded, so must free */ |
| goto err_request_gpio; |
| } |
| |
| gpio_desc = gpio_to_desc(gpio_base + mux->data.gpios[i]); |
| mux->gpios[i] = gpio_desc; |
| |
| if (!muxc->mux_locked) |
| continue; |
| |
| gpio_dev = &gpio_desc->gdev->dev; |
| muxc->mux_locked = i2c_root_adapter(gpio_dev) == root; |
| } |
| |
| if (muxc->mux_locked) |
| dev_info(&pdev->dev, "mux-locked i2c mux\n"); |
| |
| 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; |
| |
| ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class); |
| if (ret) { |
| dev_err(&pdev->dev, "Failed to add adapter %d\n", i); |
| goto add_adapter_failed; |
| } |
| } |
| |
| dev_info(&pdev->dev, "%d port mux on %s adapter\n", |
| mux->data.n_values, parent->name); |
| |
| return 0; |
| |
| add_adapter_failed: |
| i2c_mux_del_adapters(muxc); |
| i = mux->data.n_gpios; |
| err_request_gpio: |
| for (; i > 0; i--) |
| gpio_free(gpio_base + mux->data.gpios[i - 1]); |
| alloc_failed: |
| i2c_put_adapter(parent); |
| |
| return ret; |
| } |
| |
| static int i2c_mux_gpio_remove(struct platform_device *pdev) |
| { |
| struct i2c_mux_core *muxc = platform_get_drvdata(pdev); |
| struct gpiomux *mux = i2c_mux_priv(muxc); |
| int i; |
| |
| i2c_mux_del_adapters(muxc); |
| |
| for (i = 0; i < mux->data.n_gpios; i++) |
| gpio_free(mux->gpio_base + mux->data.gpios[i]); |
| |
| i2c_put_adapter(muxc->parent); |
| |
| return 0; |
| } |
| |
| static const struct of_device_id i2c_mux_gpio_of_match[] = { |
| { .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 = i2c_mux_gpio_remove, |
| .driver = { |
| .name = "i2c-mux-gpio", |
| .of_match_table = i2c_mux_gpio_of_match, |
| }, |
| }; |
| |
| module_platform_driver(i2c_mux_gpio_driver); |
| |
| MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver"); |
| MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS("platform:i2c-mux-gpio"); |