| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * Driver for SMSC USB4604 USB HSIC 4-port 2.0 hub controller driver |
| * Based on usb3503 driver |
| * |
| * Copyright (c) 2012-2013 Dongjin Kim (tobetter@gmail.com) |
| * Copyright (c) 2016 Linaro Ltd. |
| */ |
| |
| #include <linux/i2c.h> |
| #include <linux/delay.h> |
| #include <linux/slab.h> |
| #include <linux/module.h> |
| #include <linux/gpio/consumer.h> |
| |
| enum usb4604_mode { |
| USB4604_MODE_UNKNOWN, |
| USB4604_MODE_HUB, |
| USB4604_MODE_STANDBY, |
| }; |
| |
| struct usb4604 { |
| enum usb4604_mode mode; |
| struct device *dev; |
| struct gpio_desc *gpio_reset; |
| }; |
| |
| static void usb4604_reset(struct usb4604 *hub, int state) |
| { |
| gpiod_set_value_cansleep(hub->gpio_reset, state); |
| |
| /* Wait for i2c logic to come up */ |
| if (state) |
| msleep(250); |
| } |
| |
| static int usb4604_connect(struct usb4604 *hub) |
| { |
| struct device *dev = hub->dev; |
| struct i2c_client *client = to_i2c_client(dev); |
| int err; |
| u8 connect_cmd[] = { 0xaa, 0x55, 0x00 }; |
| |
| usb4604_reset(hub, 1); |
| |
| err = i2c_master_send(client, connect_cmd, ARRAY_SIZE(connect_cmd)); |
| if (err < 0) { |
| usb4604_reset(hub, 0); |
| return err; |
| } |
| |
| hub->mode = USB4604_MODE_HUB; |
| dev_dbg(dev, "switched to HUB mode\n"); |
| |
| return 0; |
| } |
| |
| static int usb4604_switch_mode(struct usb4604 *hub, enum usb4604_mode mode) |
| { |
| struct device *dev = hub->dev; |
| int err = 0; |
| |
| switch (mode) { |
| case USB4604_MODE_HUB: |
| err = usb4604_connect(hub); |
| break; |
| |
| case USB4604_MODE_STANDBY: |
| usb4604_reset(hub, 0); |
| dev_dbg(dev, "switched to STANDBY mode\n"); |
| break; |
| |
| default: |
| dev_err(dev, "unknown mode is requested\n"); |
| err = -EINVAL; |
| break; |
| } |
| |
| return err; |
| } |
| |
| static int usb4604_probe(struct usb4604 *hub) |
| { |
| struct device *dev = hub->dev; |
| struct device_node *np = dev->of_node; |
| struct gpio_desc *gpio; |
| u32 mode = USB4604_MODE_HUB; |
| |
| gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); |
| if (IS_ERR(gpio)) |
| return PTR_ERR(gpio); |
| hub->gpio_reset = gpio; |
| |
| if (of_property_read_u32(np, "initial-mode", &hub->mode)) |
| hub->mode = mode; |
| |
| return usb4604_switch_mode(hub, hub->mode); |
| } |
| |
| static int usb4604_i2c_probe(struct i2c_client *i2c) |
| { |
| struct usb4604 *hub; |
| |
| hub = devm_kzalloc(&i2c->dev, sizeof(*hub), GFP_KERNEL); |
| if (!hub) |
| return -ENOMEM; |
| |
| i2c_set_clientdata(i2c, hub); |
| hub->dev = &i2c->dev; |
| |
| return usb4604_probe(hub); |
| } |
| |
| static int __maybe_unused usb4604_i2c_suspend(struct device *dev) |
| { |
| struct i2c_client *client = to_i2c_client(dev); |
| struct usb4604 *hub = i2c_get_clientdata(client); |
| |
| usb4604_switch_mode(hub, USB4604_MODE_STANDBY); |
| |
| return 0; |
| } |
| |
| static int __maybe_unused usb4604_i2c_resume(struct device *dev) |
| { |
| struct i2c_client *client = to_i2c_client(dev); |
| struct usb4604 *hub = i2c_get_clientdata(client); |
| |
| usb4604_switch_mode(hub, hub->mode); |
| |
| return 0; |
| } |
| |
| static SIMPLE_DEV_PM_OPS(usb4604_i2c_pm_ops, usb4604_i2c_suspend, |
| usb4604_i2c_resume); |
| |
| static const struct i2c_device_id usb4604_id[] = { |
| { "usb4604", 0 }, |
| { } |
| }; |
| MODULE_DEVICE_TABLE(i2c, usb4604_id); |
| |
| #ifdef CONFIG_OF |
| static const struct of_device_id usb4604_of_match[] = { |
| { .compatible = "smsc,usb4604" }, |
| {} |
| }; |
| MODULE_DEVICE_TABLE(of, usb4604_of_match); |
| #endif |
| |
| static struct i2c_driver usb4604_i2c_driver = { |
| .driver = { |
| .name = "usb4604", |
| .pm = pm_ptr(&usb4604_i2c_pm_ops), |
| .of_match_table = of_match_ptr(usb4604_of_match), |
| }, |
| .probe_new = usb4604_i2c_probe, |
| .id_table = usb4604_id, |
| }; |
| module_i2c_driver(usb4604_i2c_driver); |
| |
| MODULE_DESCRIPTION("USB4604 USB HUB driver"); |
| MODULE_LICENSE("GPL v2"); |