diff options
Diffstat (limited to 'drivers/usb/misc/usb4604.c')
| -rw-r--r-- | drivers/usb/misc/usb4604.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/usb/misc/usb4604.c b/drivers/usb/misc/usb4604.c new file mode 100644 index 000000000000..e9f37fb746ac --- /dev/null +++ b/drivers/usb/misc/usb4604.c @@ -0,0 +1,175 @@ +/* + * 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. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#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, + const struct i2c_device_id *id) +{ + 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); +} + +#ifdef CONFIG_PM_SLEEP +static int 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 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; +} +#endif + +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 = &usb4604_i2c_pm_ops, + .of_match_table = of_match_ptr(usb4604_of_match), + }, + .probe = usb4604_i2c_probe, + .id_table = usb4604_id, +}; +module_i2c_driver(usb4604_i2c_driver); + +MODULE_DESCRIPTION("USB4604 USB HUB driver"); +MODULE_LICENSE("GPL v2"); |