diff options
Diffstat (limited to 'drivers/platform/x86/meegopad_anx7428.c')
| -rw-r--r-- | drivers/platform/x86/meegopad_anx7428.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/drivers/platform/x86/meegopad_anx7428.c b/drivers/platform/x86/meegopad_anx7428.c new file mode 100644 index 000000000000..b2c4d4f526c4 --- /dev/null +++ b/drivers/platform/x86/meegopad_anx7428.c @@ -0,0 +1,150 @@ +// 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"); |