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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver to power on the Analogix ANX7428 USB Type-C crosspoint switch
* on MeeGoPad top-set boxes.
*
* The MeeGoPad T8 and T9 are Cherry Trail top-set boxes which
* use an ANX7428 to provide a Type-C port with USB3.1 Gen 1 and
* DisplayPort over Type-C alternate mode support.
*
* The ANX7428 has a microcontroller which takes care of the PD
* negotiation and automatically sets the builtin Crosspoint Switch
* to send the right signal to the 4 highspeed pairs of the Type-C
* connector. It also takes care of HPD and AUX channel routing for
* DP alternate mode.
*
* IOW the ANX7428 operates fully autonomous and to the x5-Z8350 SoC
* things look like there simply is a USB-3 Type-A connector and a
* separate DisplayPort connector. Except that the BIOS does not
* power on the ANX7428 at boot. This driver takes care of powering
* on the ANX7428.
*
* It should be possible to tell the micro-controller which data- and/or
* power-role to negotiate and to swap the role(s) after negotiation
* but the MeeGoPad top-set boxes always draw their power from a separate
* power-connector and they only support USB host-mode. So this functionality
* is unnecessary and due to lack of documentation this is tricky to support.
*
* For a more complete ANX7428 driver see drivers/usb/misc/anx7418/ of
* the LineageOS kernel for the LG G5 (International) aka the LG H850:
* https://github.com/LineageOS/android_kernel_lge_msm8996/
*
* (C) Copyright 2024 Hans de Goede <hansg@kernel.org>
*/
#include <linux/acpi.h>
#include <linux/bits.h>
#include <linux/delay.h>
#include <linux/dev_printk.h>
#include <linux/dmi.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/types.h>
/* Register addresses and fields */
#define VENDOR_ID 0x00
#define DEVICE_ID 0x02
#define TX_STATUS 0x16
#define STATUS_SUCCESS BIT(0)
#define STATUS_ERROR BIT(1)
#define OCM_STARTUP BIT(7)
static bool force;
module_param(force, bool, 0444);
MODULE_PARM_DESC(force, "Force the driver to probe on unknown boards");
static const struct acpi_gpio_params enable_gpio = { 0, 0, false };
static const struct acpi_gpio_params reset_gpio = { 1, 0, true };
static const struct acpi_gpio_mapping meegopad_anx7428_gpios[] = {
{ "enable-gpios", &enable_gpio, 1 },
{ "reset-gpios", &reset_gpio, 1 },
{ }
};
static const struct dmi_system_id meegopad_anx7428_ids[] = {
{
/* Meegopad T08 */
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Default string"),
DMI_MATCH(DMI_PRODUCT_NAME, "Default string"),
DMI_MATCH(DMI_BOARD_NAME, "T3 MRD"),
DMI_MATCH(DMI_BOARD_VERSION, "V1.1"),
},
},
{ }
};
static int anx7428_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct gpio_desc *gpio;
int ret, val;
if (!dmi_check_system(meegopad_anx7428_ids) && !force) {
dev_warn(dev, "Not probing unknown board, pass meegopad_anx7428.force=1 to probe");
return -ENODEV;
}
ret = devm_acpi_dev_add_driver_gpios(dev, meegopad_anx7428_gpios);
if (ret)
return ret;
/*
* Set GPIOs to desired values while getting them, they are not needed
* afterwards. Ordering and delays come from android_kernel_lge_msm8996.
*/
gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH);
if (IS_ERR(gpio))
return dev_err_probe(dev, PTR_ERR(gpio), "getting enable GPIO\n");
fsleep(10000);
gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
if (IS_ERR(gpio))
return dev_err_probe(dev, PTR_ERR(gpio), "getting reset GPIO\n");
/* Wait for the OCM (On Chip Microcontroller) to start */
ret = read_poll_timeout(i2c_smbus_read_byte_data, val,
val >= 0 && (val & OCM_STARTUP),
5000, 50000, true, client, TX_STATUS);
if (ret)
return dev_err_probe(dev, ret,
"On Chip Microcontroller did not start, status: 0x%02x\n",
val);
ret = i2c_smbus_read_word_data(client, VENDOR_ID);
if (ret < 0)
return dev_err_probe(dev, ret, "reading vendor-id register\n");
val = ret;
ret = i2c_smbus_read_word_data(client, DEVICE_ID);
if (ret < 0)
return dev_err_probe(dev, ret, "reading device-id register\n");
dev_dbg(dev, "Powered on ANX7428 id %04x:%04x\n", val, ret);
return 0;
}
static const struct acpi_device_id anx7428_acpi_match[] = {
{ "ANXO7418" }, /* ACPI says 7418 (max 2 DP lanes version) but HW is 7428 */
{ }
};
MODULE_DEVICE_TABLE(acpi, anx7428_acpi_match);
static struct i2c_driver anx7428_driver = {
.driver = {
.name = "meegopad_anx7428",
.acpi_match_table = anx7428_acpi_match,
},
.probe = anx7428_probe,
};
module_i2c_driver(anx7428_driver);
MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
MODULE_DESCRIPTION("MeeGoPad ANX7428 driver");
MODULE_LICENSE("GPL");
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