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| 1 | + |
| 2 | +#include <linux/acpi.h> |
| 3 | +#include <linux/platform_device.h> |
| 4 | +#include <linux/extcon-provider.h> |
| 5 | + |
| 6 | +#define ACPI_STEAMDECK_NOTIFY_STATUS 0x80 |
| 7 | + |
| 8 | +/* 0 - port connected, 1 -port disconnected */ |
| 9 | +#define ACPI_STEAMDECK_PORT_CONNECT BIT(0) |
| 10 | +/* 0 - Upstream Facing Port, 1 - Downdstream Facing Port */ |
| 11 | +#define ACPI_STEAMDECK_CUR_DATA_ROLE BIT(3) |
| 12 | +/* |
| 13 | + * Debouncing delay to allow negotiation process to settle. 2s value |
| 14 | + * was arrived at via trial and error. |
| 15 | + */ |
| 16 | +#define STEAMDECK_ROLE_SWITCH_DELAY (msecs_to_jiffies(2000)) |
| 17 | + |
| 18 | +struct steamdeck_extcon { |
| 19 | + struct acpi_device *adev; |
| 20 | + struct delayed_work role_work; |
| 21 | + struct extcon_dev *edev; |
| 22 | + struct device *dev; |
| 23 | +}; |
| 24 | + |
| 25 | +static int steamdeck_read_pdcs(struct steamdeck_extcon *sd, unsigned long long *pdcs) |
| 26 | +{ |
| 27 | + acpi_status status; |
| 28 | + |
| 29 | + status = acpi_evaluate_integer(sd->adev->handle, "PDCS", NULL, pdcs); |
| 30 | + if (ACPI_FAILURE(status)) { |
| 31 | + dev_err(sd->dev, "PDCS evaluation failed: %s\n", |
| 32 | + acpi_format_exception(status)); |
| 33 | + return -EIO; |
| 34 | + } |
| 35 | + |
| 36 | + return 0; |
| 37 | +} |
| 38 | + |
| 39 | +static void steamdeck_usb_role_work(struct work_struct *work) |
| 40 | +{ |
| 41 | + struct steamdeck_extcon *sd = |
| 42 | + container_of(work, struct steamdeck_extcon, role_work.work); |
| 43 | + unsigned long long pdcs; |
| 44 | + bool usb_host; |
| 45 | + |
| 46 | + if (steamdeck_read_pdcs(sd, &pdcs)) |
| 47 | + return; |
| 48 | + |
| 49 | + /* |
| 50 | + * We only care about these two |
| 51 | + */ |
| 52 | + pdcs &= ACPI_STEAMDECK_PORT_CONNECT | ACPI_STEAMDECK_CUR_DATA_ROLE; |
| 53 | + |
| 54 | + /* |
| 55 | + * For "connect" events our role is determined by a bit in |
| 56 | + * PDCS, for "disconnect" we switch to being a gadget |
| 57 | + * unconditionally. The thinking for the latter is we don't |
| 58 | + * want to start acting as a USB host until we get |
| 59 | + * confirmation from the firmware that we are a USB host |
| 60 | + */ |
| 61 | + usb_host = (pdcs & ACPI_STEAMDECK_PORT_CONNECT) ? |
| 62 | + pdcs & ACPI_STEAMDECK_CUR_DATA_ROLE : false; |
| 63 | + |
| 64 | + dev_dbg(sd->dev, "USB role is %s\n", usb_host ? "host" : "device"); |
| 65 | + WARN_ON(extcon_set_state_sync(sd->edev, EXTCON_USB_HOST, |
| 66 | + usb_host)); |
| 67 | + |
| 68 | +} |
| 69 | + |
| 70 | +static void steamdeck_notify(acpi_handle handle, u32 event, void *context) |
| 71 | +{ |
| 72 | + struct device *dev = context; |
| 73 | + struct steamdeck_extcon *sd = dev_get_drvdata(dev); |
| 74 | + unsigned long long pdcs; |
| 75 | + unsigned long delay; |
| 76 | + |
| 77 | + switch (event) { |
| 78 | + case ACPI_STEAMDECK_NOTIFY_STATUS: |
| 79 | + if (steamdeck_read_pdcs(sd, &pdcs)) |
| 80 | + return; |
| 81 | + /* |
| 82 | + * We process "disconnect" events immediately and |
| 83 | + * "connect" events with a delay to give the HW time |
| 84 | + * to settle. For example attaching USB hub (at least |
| 85 | + * for HW used for testing) will generate intermediary |
| 86 | + * event with "host" bit not set, followed by the one |
| 87 | + * that does have it set. |
| 88 | + */ |
| 89 | + delay = (pdcs & ACPI_STEAMDECK_PORT_CONNECT) ? |
| 90 | + STEAMDECK_ROLE_SWITCH_DELAY : 0; |
| 91 | + |
| 92 | + queue_delayed_work(system_long_wq, &sd->role_work, delay); |
| 93 | + break; |
| 94 | + default: |
| 95 | + dev_warn(dev, "Unsupported event [0x%x]\n", event); |
| 96 | + } |
| 97 | +} |
| 98 | + |
| 99 | +static void steamdeck_remove_notify_handler(void *data) |
| 100 | +{ |
| 101 | + struct steamdeck_extcon *sd = data; |
| 102 | + |
| 103 | + acpi_remove_notify_handler(sd->adev->handle, ACPI_DEVICE_NOTIFY, |
| 104 | + steamdeck_notify); |
| 105 | + cancel_delayed_work_sync(&sd->role_work); |
| 106 | +} |
| 107 | + |
| 108 | +static const unsigned int steamdeck_extcon_cable[] = { |
| 109 | + EXTCON_USB, |
| 110 | + EXTCON_USB_HOST, |
| 111 | + EXTCON_CHG_USB_SDP, |
| 112 | + EXTCON_CHG_USB_CDP, |
| 113 | + EXTCON_CHG_USB_DCP, |
| 114 | + EXTCON_CHG_USB_ACA, |
| 115 | + EXTCON_NONE, |
| 116 | +}; |
| 117 | + |
| 118 | +static int steamdeck_extcon_probe(struct platform_device *pdev) |
| 119 | +{ |
| 120 | + struct device *dev = &pdev->dev; |
| 121 | + struct steamdeck_extcon *sd; |
| 122 | + acpi_status status; |
| 123 | + int ret; |
| 124 | + |
| 125 | + sd = devm_kzalloc(dev, sizeof(*sd), GFP_KERNEL); |
| 126 | + if (!sd) |
| 127 | + return -ENOMEM; |
| 128 | + |
| 129 | + INIT_DELAYED_WORK(&sd->role_work, steamdeck_usb_role_work); |
| 130 | + platform_set_drvdata(pdev, sd); |
| 131 | + sd->adev = ACPI_COMPANION(dev->parent); |
| 132 | + sd->dev = dev; |
| 133 | + sd->edev = devm_extcon_dev_allocate(dev, steamdeck_extcon_cable); |
| 134 | + if (IS_ERR(sd->edev)) |
| 135 | + return PTR_ERR(sd->edev); |
| 136 | + |
| 137 | + ret = devm_extcon_dev_register(dev, sd->edev); |
| 138 | + if (ret < 0) { |
| 139 | + dev_err(dev, "Failed to register extcon device: %d\n", ret); |
| 140 | + return ret; |
| 141 | + } |
| 142 | + |
| 143 | + /* |
| 144 | + * Set initial role value |
| 145 | + */ |
| 146 | + queue_delayed_work(system_long_wq, &sd->role_work, 0); |
| 147 | + flush_delayed_work(&sd->role_work); |
| 148 | + |
| 149 | + status = acpi_install_notify_handler(sd->adev->handle, |
| 150 | + ACPI_DEVICE_NOTIFY, |
| 151 | + steamdeck_notify, |
| 152 | + dev); |
| 153 | + if (ACPI_FAILURE(status)) { |
| 154 | + dev_err(dev, "Error installing ACPI notify handler\n"); |
| 155 | + return -EIO; |
| 156 | + } |
| 157 | + |
| 158 | + ret = devm_add_action_or_reset(dev, steamdeck_remove_notify_handler, |
| 159 | + sd); |
| 160 | + return ret; |
| 161 | +} |
| 162 | + |
| 163 | +static const struct platform_device_id steamdeck_extcon_id_table[] = { |
| 164 | + { .name = "steamdeck-extcon" }, |
| 165 | + {} |
| 166 | +}; |
| 167 | +MODULE_DEVICE_TABLE(platform, steamdeck_extcon_id_table); |
| 168 | + |
| 169 | +static struct platform_driver steamdeck_extcon_driver = { |
| 170 | + .probe = steamdeck_extcon_probe, |
| 171 | + .driver = { |
| 172 | + .name = "steamdeck-extcon", |
| 173 | + }, |
| 174 | + .id_table = steamdeck_extcon_id_table, |
| 175 | +}; |
| 176 | +module_platform_driver(steamdeck_extcon_driver); |
| 177 | + |
| 178 | +MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>"); |
| 179 | +MODULE_DESCRIPTION("Steam Deck extcon driver"); |
| 180 | +MODULE_LICENSE("GPL"); |
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