| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * I2C multiplexer using GPIO API |
| * |
| * Peter Korsgaard <peter.korsgaard@barco.com> |
| */ |
| |
| #include <linux/i2c.h> |
| #include <linux/i2c-mux.h> |
| #include <linux/platform_data/i2c-mux-gpio.h> |
| #include <linux/platform_device.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/bits.h> |
| #include <linux/gpio/consumer.h> |
| /* FIXME: stop poking around inside gpiolib */ |
| #include "../../gpio/gpiolib.h" |
| |
| struct gpiomux { |
| struct i2c_mux_gpio_platform_data data; |
| int ngpios; |
| struct gpio_desc **gpios; |
| }; |
| |
| static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val) |
| { |
| DECLARE_BITMAP(values, BITS_PER_TYPE(val)); |
| |
| values[0] = val; |
| |
| gpiod_set_array_value_cansleep(mux->ngpios, mux->gpios, NULL, 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 i2c_mux_gpio_probe_fw(struct gpiomux *mux, |
| struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct device_node *np = dev->of_node; |
| struct device_node *adapter_np; |
| struct i2c_adapter *adapter = NULL; |
| struct fwnode_handle *child; |
| unsigned *values; |
| int rc, i = 0; |
| |
| if (is_of_node(dev->fwnode)) { |
| 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); |
| |
| } else if (is_acpi_node(dev->fwnode)) { |
| /* |
| * In ACPI land the mux should be a direct child of the i2c |
| * bus it muxes. |
| */ |
| acpi_handle dev_handle = ACPI_HANDLE(dev->parent); |
| |
| adapter = i2c_acpi_find_adapter_by_handle(dev_handle); |
| } |
| |
| if (!adapter) |
| return -EPROBE_DEFER; |
| |
| mux->data.parent = i2c_adapter_id(adapter); |
| put_device(&adapter->dev); |
| |
| mux->data.n_values = device_get_child_node_count(dev); |
| values = devm_kcalloc(dev, |
| mux->data.n_values, sizeof(*mux->data.values), |
| GFP_KERNEL); |
| if (!values) { |
| dev_err(dev, "Cannot allocate values array"); |
| return -ENOMEM; |
| } |
| |
| device_for_each_child_node(dev, child) { |
| if (is_of_node(child)) { |
| fwnode_property_read_u32(child, "reg", values + i); |
| |
| } else if (is_acpi_node(child)) { |
| rc = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), values + i); |
| if (rc) { |
| fwnode_handle_put(child); |
| return dev_err_probe(dev, rc, "Cannot get address\n"); |
| } |
| } |
| |
| i++; |
| } |
| mux->data.values = values; |
| |
| if (fwnode_property_read_u32(dev->fwnode, "idle-state", &mux->data.idle)) |
| mux->data.idle = I2C_MUX_GPIO_NO_IDLE; |
| |
| return 0; |
| } |
| |
| 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; |
| int i, ngpios, 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_fw(mux, pdev); |
| if (ret < 0) |
| return ret; |
| } else { |
| memcpy(&mux->data, dev_get_platdata(&pdev->dev), |
| sizeof(mux->data)); |
| } |
| |
| ngpios = gpiod_count(&pdev->dev, "mux"); |
| if (ngpios <= 0) { |
| dev_err(&pdev->dev, "no valid gpios provided\n"); |
| return ngpios ?: -EINVAL; |
| } |
| mux->ngpios = ngpios; |
| |
| parent = i2c_get_adapter(mux->data.parent); |
| if (!parent) |
| return -EPROBE_DEFER; |
| |
| muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, |
| ngpios * sizeof(*mux->gpios), 0, |
| i2c_mux_gpio_select, NULL); |
| if (!muxc) { |
| ret = -ENOMEM; |
| goto alloc_failed; |
| } |
| mux->gpios = muxc->priv; |
| muxc->priv = mux; |
| |
| platform_set_drvdata(pdev, muxc); |
| |
| root = i2c_root_adapter(&parent->dev); |
| |
| muxc->mux_locked = true; |
| |
| 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 < ngpios; i++) { |
| struct device *gpio_dev; |
| struct gpio_desc *gpiod; |
| enum gpiod_flags flag; |
| |
| if (initial_state & BIT(i)) |
| flag = GPIOD_OUT_HIGH; |
| else |
| flag = GPIOD_OUT_LOW; |
| gpiod = devm_gpiod_get_index(&pdev->dev, "mux", i, flag); |
| if (IS_ERR(gpiod)) { |
| ret = PTR_ERR(gpiod); |
| goto alloc_failed; |
| } |
| |
| mux->gpios[i] = gpiod; |
| |
| if (!muxc->mux_locked) |
| continue; |
| |
| /* FIXME: find a proper way to access the GPIO device */ |
| gpio_dev = &gpiod->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) |
| 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); |
| 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); |
| |
| i2c_mux_del_adapters(muxc); |
| 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"); |