18c2ecf20Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0-only
28c2ecf20Sopenharmony_ci/*
38c2ecf20Sopenharmony_ci * I2C multiplexer using GPIO API
48c2ecf20Sopenharmony_ci *
58c2ecf20Sopenharmony_ci * Peter Korsgaard <peter.korsgaard@barco.com>
68c2ecf20Sopenharmony_ci */
78c2ecf20Sopenharmony_ci
88c2ecf20Sopenharmony_ci#include <linux/i2c.h>
98c2ecf20Sopenharmony_ci#include <linux/i2c-mux.h>
108c2ecf20Sopenharmony_ci#include <linux/platform_data/i2c-mux-gpio.h>
118c2ecf20Sopenharmony_ci#include <linux/platform_device.h>
128c2ecf20Sopenharmony_ci#include <linux/module.h>
138c2ecf20Sopenharmony_ci#include <linux/slab.h>
148c2ecf20Sopenharmony_ci#include <linux/bits.h>
158c2ecf20Sopenharmony_ci#include <linux/gpio/consumer.h>
168c2ecf20Sopenharmony_ci/* FIXME: stop poking around inside gpiolib */
178c2ecf20Sopenharmony_ci#include "../../gpio/gpiolib.h"
188c2ecf20Sopenharmony_ci
198c2ecf20Sopenharmony_cistruct gpiomux {
208c2ecf20Sopenharmony_ci	struct i2c_mux_gpio_platform_data data;
218c2ecf20Sopenharmony_ci	int ngpios;
228c2ecf20Sopenharmony_ci	struct gpio_desc **gpios;
238c2ecf20Sopenharmony_ci};
248c2ecf20Sopenharmony_ci
258c2ecf20Sopenharmony_cistatic void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
268c2ecf20Sopenharmony_ci{
278c2ecf20Sopenharmony_ci	DECLARE_BITMAP(values, BITS_PER_TYPE(val));
288c2ecf20Sopenharmony_ci
298c2ecf20Sopenharmony_ci	values[0] = val;
308c2ecf20Sopenharmony_ci
318c2ecf20Sopenharmony_ci	gpiod_set_array_value_cansleep(mux->ngpios, mux->gpios, NULL, values);
328c2ecf20Sopenharmony_ci}
338c2ecf20Sopenharmony_ci
348c2ecf20Sopenharmony_cistatic int i2c_mux_gpio_select(struct i2c_mux_core *muxc, u32 chan)
358c2ecf20Sopenharmony_ci{
368c2ecf20Sopenharmony_ci	struct gpiomux *mux = i2c_mux_priv(muxc);
378c2ecf20Sopenharmony_ci
388c2ecf20Sopenharmony_ci	i2c_mux_gpio_set(mux, chan);
398c2ecf20Sopenharmony_ci
408c2ecf20Sopenharmony_ci	return 0;
418c2ecf20Sopenharmony_ci}
428c2ecf20Sopenharmony_ci
438c2ecf20Sopenharmony_cistatic int i2c_mux_gpio_deselect(struct i2c_mux_core *muxc, u32 chan)
448c2ecf20Sopenharmony_ci{
458c2ecf20Sopenharmony_ci	struct gpiomux *mux = i2c_mux_priv(muxc);
468c2ecf20Sopenharmony_ci
478c2ecf20Sopenharmony_ci	i2c_mux_gpio_set(mux, mux->data.idle);
488c2ecf20Sopenharmony_ci
498c2ecf20Sopenharmony_ci	return 0;
508c2ecf20Sopenharmony_ci}
518c2ecf20Sopenharmony_ci
528c2ecf20Sopenharmony_ci#ifdef CONFIG_OF
538c2ecf20Sopenharmony_cistatic int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
548c2ecf20Sopenharmony_ci					struct platform_device *pdev)
558c2ecf20Sopenharmony_ci{
568c2ecf20Sopenharmony_ci	struct device_node *np = pdev->dev.of_node;
578c2ecf20Sopenharmony_ci	struct device_node *adapter_np, *child;
588c2ecf20Sopenharmony_ci	struct i2c_adapter *adapter;
598c2ecf20Sopenharmony_ci	unsigned *values;
608c2ecf20Sopenharmony_ci	int i = 0;
618c2ecf20Sopenharmony_ci
628c2ecf20Sopenharmony_ci	if (!np)
638c2ecf20Sopenharmony_ci		return -ENODEV;
648c2ecf20Sopenharmony_ci
658c2ecf20Sopenharmony_ci	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
668c2ecf20Sopenharmony_ci	if (!adapter_np) {
678c2ecf20Sopenharmony_ci		dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
688c2ecf20Sopenharmony_ci		return -ENODEV;
698c2ecf20Sopenharmony_ci	}
708c2ecf20Sopenharmony_ci	adapter = of_find_i2c_adapter_by_node(adapter_np);
718c2ecf20Sopenharmony_ci	of_node_put(adapter_np);
728c2ecf20Sopenharmony_ci	if (!adapter)
738c2ecf20Sopenharmony_ci		return -EPROBE_DEFER;
748c2ecf20Sopenharmony_ci
758c2ecf20Sopenharmony_ci	mux->data.parent = i2c_adapter_id(adapter);
768c2ecf20Sopenharmony_ci	put_device(&adapter->dev);
778c2ecf20Sopenharmony_ci
788c2ecf20Sopenharmony_ci	mux->data.n_values = of_get_child_count(np);
798c2ecf20Sopenharmony_ci
808c2ecf20Sopenharmony_ci	values = devm_kcalloc(&pdev->dev,
818c2ecf20Sopenharmony_ci			      mux->data.n_values, sizeof(*mux->data.values),
828c2ecf20Sopenharmony_ci			      GFP_KERNEL);
838c2ecf20Sopenharmony_ci	if (!values) {
848c2ecf20Sopenharmony_ci		dev_err(&pdev->dev, "Cannot allocate values array");
858c2ecf20Sopenharmony_ci		return -ENOMEM;
868c2ecf20Sopenharmony_ci	}
878c2ecf20Sopenharmony_ci
888c2ecf20Sopenharmony_ci	for_each_child_of_node(np, child) {
898c2ecf20Sopenharmony_ci		of_property_read_u32(child, "reg", values + i);
908c2ecf20Sopenharmony_ci		i++;
918c2ecf20Sopenharmony_ci	}
928c2ecf20Sopenharmony_ci	mux->data.values = values;
938c2ecf20Sopenharmony_ci
948c2ecf20Sopenharmony_ci	if (of_property_read_u32(np, "idle-state", &mux->data.idle))
958c2ecf20Sopenharmony_ci		mux->data.idle = I2C_MUX_GPIO_NO_IDLE;
968c2ecf20Sopenharmony_ci
978c2ecf20Sopenharmony_ci	return 0;
988c2ecf20Sopenharmony_ci}
998c2ecf20Sopenharmony_ci#else
1008c2ecf20Sopenharmony_cistatic int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
1018c2ecf20Sopenharmony_ci					struct platform_device *pdev)
1028c2ecf20Sopenharmony_ci{
1038c2ecf20Sopenharmony_ci	return 0;
1048c2ecf20Sopenharmony_ci}
1058c2ecf20Sopenharmony_ci#endif
1068c2ecf20Sopenharmony_ci
1078c2ecf20Sopenharmony_cistatic int i2c_mux_gpio_probe(struct platform_device *pdev)
1088c2ecf20Sopenharmony_ci{
1098c2ecf20Sopenharmony_ci	struct i2c_mux_core *muxc;
1108c2ecf20Sopenharmony_ci	struct gpiomux *mux;
1118c2ecf20Sopenharmony_ci	struct i2c_adapter *parent;
1128c2ecf20Sopenharmony_ci	struct i2c_adapter *root;
1138c2ecf20Sopenharmony_ci	unsigned initial_state;
1148c2ecf20Sopenharmony_ci	int i, ngpios, ret;
1158c2ecf20Sopenharmony_ci
1168c2ecf20Sopenharmony_ci	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
1178c2ecf20Sopenharmony_ci	if (!mux)
1188c2ecf20Sopenharmony_ci		return -ENOMEM;
1198c2ecf20Sopenharmony_ci
1208c2ecf20Sopenharmony_ci	if (!dev_get_platdata(&pdev->dev)) {
1218c2ecf20Sopenharmony_ci		ret = i2c_mux_gpio_probe_dt(mux, pdev);
1228c2ecf20Sopenharmony_ci		if (ret < 0)
1238c2ecf20Sopenharmony_ci			return ret;
1248c2ecf20Sopenharmony_ci	} else {
1258c2ecf20Sopenharmony_ci		memcpy(&mux->data, dev_get_platdata(&pdev->dev),
1268c2ecf20Sopenharmony_ci			sizeof(mux->data));
1278c2ecf20Sopenharmony_ci	}
1288c2ecf20Sopenharmony_ci
1298c2ecf20Sopenharmony_ci	ngpios = gpiod_count(&pdev->dev, "mux");
1308c2ecf20Sopenharmony_ci	if (ngpios <= 0) {
1318c2ecf20Sopenharmony_ci		dev_err(&pdev->dev, "no valid gpios provided\n");
1328c2ecf20Sopenharmony_ci		return ngpios ?: -EINVAL;
1338c2ecf20Sopenharmony_ci	}
1348c2ecf20Sopenharmony_ci	mux->ngpios = ngpios;
1358c2ecf20Sopenharmony_ci
1368c2ecf20Sopenharmony_ci	parent = i2c_get_adapter(mux->data.parent);
1378c2ecf20Sopenharmony_ci	if (!parent)
1388c2ecf20Sopenharmony_ci		return -EPROBE_DEFER;
1398c2ecf20Sopenharmony_ci
1408c2ecf20Sopenharmony_ci	muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values,
1418c2ecf20Sopenharmony_ci			     ngpios * sizeof(*mux->gpios), 0,
1428c2ecf20Sopenharmony_ci			     i2c_mux_gpio_select, NULL);
1438c2ecf20Sopenharmony_ci	if (!muxc) {
1448c2ecf20Sopenharmony_ci		ret = -ENOMEM;
1458c2ecf20Sopenharmony_ci		goto alloc_failed;
1468c2ecf20Sopenharmony_ci	}
1478c2ecf20Sopenharmony_ci	mux->gpios = muxc->priv;
1488c2ecf20Sopenharmony_ci	muxc->priv = mux;
1498c2ecf20Sopenharmony_ci
1508c2ecf20Sopenharmony_ci	platform_set_drvdata(pdev, muxc);
1518c2ecf20Sopenharmony_ci
1528c2ecf20Sopenharmony_ci	root = i2c_root_adapter(&parent->dev);
1538c2ecf20Sopenharmony_ci
1548c2ecf20Sopenharmony_ci	muxc->mux_locked = true;
1558c2ecf20Sopenharmony_ci
1568c2ecf20Sopenharmony_ci	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
1578c2ecf20Sopenharmony_ci		initial_state = mux->data.idle;
1588c2ecf20Sopenharmony_ci		muxc->deselect = i2c_mux_gpio_deselect;
1598c2ecf20Sopenharmony_ci	} else {
1608c2ecf20Sopenharmony_ci		initial_state = mux->data.values[0];
1618c2ecf20Sopenharmony_ci	}
1628c2ecf20Sopenharmony_ci
1638c2ecf20Sopenharmony_ci	for (i = 0; i < ngpios; i++) {
1648c2ecf20Sopenharmony_ci		struct device *gpio_dev;
1658c2ecf20Sopenharmony_ci		struct gpio_desc *gpiod;
1668c2ecf20Sopenharmony_ci		enum gpiod_flags flag;
1678c2ecf20Sopenharmony_ci
1688c2ecf20Sopenharmony_ci		if (initial_state & BIT(i))
1698c2ecf20Sopenharmony_ci			flag = GPIOD_OUT_HIGH;
1708c2ecf20Sopenharmony_ci		else
1718c2ecf20Sopenharmony_ci			flag = GPIOD_OUT_LOW;
1728c2ecf20Sopenharmony_ci		gpiod = devm_gpiod_get_index(&pdev->dev, "mux", i, flag);
1738c2ecf20Sopenharmony_ci		if (IS_ERR(gpiod)) {
1748c2ecf20Sopenharmony_ci			ret = PTR_ERR(gpiod);
1758c2ecf20Sopenharmony_ci			goto alloc_failed;
1768c2ecf20Sopenharmony_ci		}
1778c2ecf20Sopenharmony_ci
1788c2ecf20Sopenharmony_ci		mux->gpios[i] = gpiod;
1798c2ecf20Sopenharmony_ci
1808c2ecf20Sopenharmony_ci		if (!muxc->mux_locked)
1818c2ecf20Sopenharmony_ci			continue;
1828c2ecf20Sopenharmony_ci
1838c2ecf20Sopenharmony_ci		/* FIXME: find a proper way to access the GPIO device */
1848c2ecf20Sopenharmony_ci		gpio_dev = &gpiod->gdev->dev;
1858c2ecf20Sopenharmony_ci		muxc->mux_locked = i2c_root_adapter(gpio_dev) == root;
1868c2ecf20Sopenharmony_ci	}
1878c2ecf20Sopenharmony_ci
1888c2ecf20Sopenharmony_ci	if (muxc->mux_locked)
1898c2ecf20Sopenharmony_ci		dev_info(&pdev->dev, "mux-locked i2c mux\n");
1908c2ecf20Sopenharmony_ci
1918c2ecf20Sopenharmony_ci	for (i = 0; i < mux->data.n_values; i++) {
1928c2ecf20Sopenharmony_ci		u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
1938c2ecf20Sopenharmony_ci		unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
1948c2ecf20Sopenharmony_ci
1958c2ecf20Sopenharmony_ci		ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class);
1968c2ecf20Sopenharmony_ci		if (ret)
1978c2ecf20Sopenharmony_ci			goto add_adapter_failed;
1988c2ecf20Sopenharmony_ci	}
1998c2ecf20Sopenharmony_ci
2008c2ecf20Sopenharmony_ci	dev_info(&pdev->dev, "%d port mux on %s adapter\n",
2018c2ecf20Sopenharmony_ci		 mux->data.n_values, parent->name);
2028c2ecf20Sopenharmony_ci
2038c2ecf20Sopenharmony_ci	return 0;
2048c2ecf20Sopenharmony_ci
2058c2ecf20Sopenharmony_ciadd_adapter_failed:
2068c2ecf20Sopenharmony_ci	i2c_mux_del_adapters(muxc);
2078c2ecf20Sopenharmony_cialloc_failed:
2088c2ecf20Sopenharmony_ci	i2c_put_adapter(parent);
2098c2ecf20Sopenharmony_ci
2108c2ecf20Sopenharmony_ci	return ret;
2118c2ecf20Sopenharmony_ci}
2128c2ecf20Sopenharmony_ci
2138c2ecf20Sopenharmony_cistatic int i2c_mux_gpio_remove(struct platform_device *pdev)
2148c2ecf20Sopenharmony_ci{
2158c2ecf20Sopenharmony_ci	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
2168c2ecf20Sopenharmony_ci
2178c2ecf20Sopenharmony_ci	i2c_mux_del_adapters(muxc);
2188c2ecf20Sopenharmony_ci	i2c_put_adapter(muxc->parent);
2198c2ecf20Sopenharmony_ci
2208c2ecf20Sopenharmony_ci	return 0;
2218c2ecf20Sopenharmony_ci}
2228c2ecf20Sopenharmony_ci
2238c2ecf20Sopenharmony_cistatic const struct of_device_id i2c_mux_gpio_of_match[] = {
2248c2ecf20Sopenharmony_ci	{ .compatible = "i2c-mux-gpio", },
2258c2ecf20Sopenharmony_ci	{},
2268c2ecf20Sopenharmony_ci};
2278c2ecf20Sopenharmony_ciMODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match);
2288c2ecf20Sopenharmony_ci
2298c2ecf20Sopenharmony_cistatic struct platform_driver i2c_mux_gpio_driver = {
2308c2ecf20Sopenharmony_ci	.probe	= i2c_mux_gpio_probe,
2318c2ecf20Sopenharmony_ci	.remove	= i2c_mux_gpio_remove,
2328c2ecf20Sopenharmony_ci	.driver	= {
2338c2ecf20Sopenharmony_ci		.name	= "i2c-mux-gpio",
2348c2ecf20Sopenharmony_ci		.of_match_table = i2c_mux_gpio_of_match,
2358c2ecf20Sopenharmony_ci	},
2368c2ecf20Sopenharmony_ci};
2378c2ecf20Sopenharmony_ci
2388c2ecf20Sopenharmony_cimodule_platform_driver(i2c_mux_gpio_driver);
2398c2ecf20Sopenharmony_ci
2408c2ecf20Sopenharmony_ciMODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
2418c2ecf20Sopenharmony_ciMODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
2428c2ecf20Sopenharmony_ciMODULE_LICENSE("GPL");
2438c2ecf20Sopenharmony_ciMODULE_ALIAS("platform:i2c-mux-gpio");
244