1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Driver to power on the Analogix ANX7428 USB Type-C crosspoint switch 4 * on MeeGoPad top-set boxes. 5 * 6 * The MeeGoPad T8 and T9 are Cherry Trail top-set boxes which 7 * use an ANX7428 to provide a Type-C port with USB3.1 Gen 1 and 8 * DisplayPort over Type-C alternate mode support. 9 * 10 * The ANX7428 has a microcontroller which takes care of the PD 11 * negotiation and automatically sets the builtin Crosspoint Switch 12 * to send the right signal to the 4 highspeed pairs of the Type-C 13 * connector. It also takes care of HPD and AUX channel routing for 14 * DP alternate mode. 15 * 16 * IOW the ANX7428 operates fully autonomous and to the x5-Z8350 SoC 17 * things look like there simply is a USB-3 Type-A connector and a 18 * separate DisplayPort connector. Except that the BIOS does not 19 * power on the ANX7428 at boot. This driver takes care of powering 20 * on the ANX7428. 21 * 22 * It should be possible to tell the micro-controller which data- and/or 23 * power-role to negotiate and to swap the role(s) after negotiation 24 * but the MeeGoPad top-set boxes always draw their power from a separate 25 * power-connector and they only support USB host-mode. So this functionality 26 * is unnecessary and due to lack of documentation this is tricky to support. 27 * 28 * For a more complete ANX7428 driver see drivers/usb/misc/anx7418/ of 29 * the LineageOS kernel for the LG G5 (International) aka the LG H850: 30 * https://github.com/LineageOS/android_kernel_lge_msm8996/ 31 * 32 * (C) Copyright 2024 Hans de Goede <hansg@kernel.org> 33 */ 34 35 #include <linux/acpi.h> 36 #include <linux/bits.h> 37 #include <linux/delay.h> 38 #include <linux/dev_printk.h> 39 #include <linux/dmi.h> 40 #include <linux/err.h> 41 #include <linux/gpio/consumer.h> 42 #include <linux/i2c.h> 43 #include <linux/iopoll.h> 44 #include <linux/module.h> 45 #include <linux/types.h> 46 47 /* Register addresses and fields */ 48 #define VENDOR_ID 0x00 49 #define DEVICE_ID 0x02 50 51 #define TX_STATUS 0x16 52 #define STATUS_SUCCESS BIT(0) 53 #define STATUS_ERROR BIT(1) 54 #define OCM_STARTUP BIT(7) 55 56 static bool force; 57 module_param(force, bool, 0444); 58 MODULE_PARM_DESC(force, "Force the driver to probe on unknown boards"); 59 60 static const struct acpi_gpio_params enable_gpio = { 0, 0, false }; 61 static const struct acpi_gpio_params reset_gpio = { 1, 0, true }; 62 63 static const struct acpi_gpio_mapping meegopad_anx7428_gpios[] = { 64 { "enable-gpios", &enable_gpio, 1 }, 65 { "reset-gpios", &reset_gpio, 1 }, 66 { } 67 }; 68 69 static const struct dmi_system_id meegopad_anx7428_ids[] = { 70 { 71 /* Meegopad T08 */ 72 .matches = { 73 DMI_MATCH(DMI_SYS_VENDOR, "Default string"), 74 DMI_MATCH(DMI_PRODUCT_NAME, "Default string"), 75 DMI_MATCH(DMI_BOARD_NAME, "T3 MRD"), 76 DMI_MATCH(DMI_BOARD_VERSION, "V1.1"), 77 }, 78 }, 79 { } 80 }; 81 82 static int anx7428_probe(struct i2c_client *client) 83 { 84 struct device *dev = &client->dev; 85 struct gpio_desc *gpio; 86 int ret, val; 87 88 if (!dmi_check_system(meegopad_anx7428_ids) && !force) { 89 dev_warn(dev, "Not probing unknown board, pass meegopad_anx7428.force=1 to probe"); 90 return -ENODEV; 91 } 92 93 ret = devm_acpi_dev_add_driver_gpios(dev, meegopad_anx7428_gpios); 94 if (ret) 95 return ret; 96 97 /* 98 * Set GPIOs to desired values while getting them, they are not needed 99 * afterwards. Ordering and delays come from android_kernel_lge_msm8996. 100 */ 101 gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_HIGH); 102 if (IS_ERR(gpio)) 103 return dev_err_probe(dev, PTR_ERR(gpio), "getting enable GPIO\n"); 104 105 fsleep(10000); 106 107 gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW); 108 if (IS_ERR(gpio)) 109 return dev_err_probe(dev, PTR_ERR(gpio), "getting reset GPIO\n"); 110 111 /* Wait for the OCM (On Chip Microcontroller) to start */ 112 ret = read_poll_timeout(i2c_smbus_read_byte_data, val, 113 val >= 0 && (val & OCM_STARTUP), 114 5000, 50000, true, client, TX_STATUS); 115 if (ret) 116 return dev_err_probe(dev, ret, 117 "On Chip Microcontroller did not start, status: 0x%02x\n", 118 val); 119 120 ret = i2c_smbus_read_word_data(client, VENDOR_ID); 121 if (ret < 0) 122 return dev_err_probe(dev, ret, "reading vendor-id register\n"); 123 val = ret; 124 125 ret = i2c_smbus_read_word_data(client, DEVICE_ID); 126 if (ret < 0) 127 return dev_err_probe(dev, ret, "reading device-id register\n"); 128 129 dev_dbg(dev, "Powered on ANX7428 id %04x:%04x\n", val, ret); 130 return 0; 131 } 132 133 static const struct acpi_device_id anx7428_acpi_match[] = { 134 { "ANXO7418" }, /* ACPI says 7418 (max 2 DP lanes version) but HW is 7428 */ 135 { } 136 }; 137 MODULE_DEVICE_TABLE(acpi, anx7428_acpi_match); 138 139 static struct i2c_driver anx7428_driver = { 140 .driver = { 141 .name = "meegopad_anx7428", 142 .acpi_match_table = anx7428_acpi_match, 143 }, 144 .probe = anx7428_probe, 145 }; 146 module_i2c_driver(anx7428_driver); 147 148 MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>"); 149 MODULE_DESCRIPTION("MeeGoPad ANX7428 driver"); 150 MODULE_LICENSE("GPL"); 151