// SPDX-License-Identifier: GPL-2.0 // ChromeOS EC keyboard driver // // Copyright (C) 2012 Google, Inc. // // This driver uses the ChromeOS EC byte-level message-based protocol for // communicating the keyboard state (which keys are pressed) from a keyboard EC // to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing, // but everything else (including deghosting) is done here. The main // motivation for this is to keep the EC firmware as simple as possible, since // it cannot be easily upgraded and EC flash/IRAM space is relatively // expensive. #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** * struct cros_ec_keyb - Structure representing EC keyboard device * * @rows: Number of rows in the keypad * @cols: Number of columns in the keypad * @row_shift: log2 or number of rows, rounded up * @keymap_data: Matrix keymap data used to convert to keyscan values * @ghost_filter: true to enable the matrix key-ghosting filter * @valid_keys: bitmap of existing keys for each matrix column * @old_kb_state: bitmap of keys pressed last scan * @dev: Device pointer * @ec: Top level ChromeOS device to use to talk to EC * @idev: The input device for the matrix keys. * @bs_idev: The input device for non-matrix buttons and switches (or NULL). * @notifier: interrupt event notifier for transport devices */ struct cros_ec_keyb { unsigned int rows; unsigned int cols; int row_shift; const struct matrix_keymap_data *keymap_data; bool ghost_filter; uint8_t *valid_keys; uint8_t *old_kb_state; struct device *dev; struct cros_ec_device *ec; struct input_dev *idev; struct input_dev *bs_idev; struct notifier_block notifier; }; /** * struct cros_ec_bs_map - Mapping between Linux keycodes and EC button/switch * bitmap #defines * * @ev_type: The type of the input event to generate (e.g., EV_KEY). * @code: A linux keycode * @bit: A #define like EC_MKBP_POWER_BUTTON or EC_MKBP_LID_OPEN * @inverted: If the #define and EV_SW have opposite meanings, this is true. * Only applicable to switches. */ struct cros_ec_bs_map { unsigned int ev_type; unsigned int code; u8 bit; bool inverted; }; /* cros_ec_keyb_bs - Map EC button/switch #defines into kernel ones */ static const struct cros_ec_bs_map cros_ec_keyb_bs[] = { /* Buttons */ { .ev_type = EV_KEY, .code = KEY_POWER, .bit = EC_MKBP_POWER_BUTTON, }, { .ev_type = EV_KEY, .code = KEY_VOLUMEUP, .bit = EC_MKBP_VOL_UP, }, { .ev_type = EV_KEY, .code = KEY_VOLUMEDOWN, .bit = EC_MKBP_VOL_DOWN, }, /* Switches */ { .ev_type = EV_SW, .code = SW_LID, .bit = EC_MKBP_LID_OPEN, .inverted = true, }, { .ev_type = EV_SW, .code = SW_TABLET_MODE, .bit = EC_MKBP_TABLET_MODE, }, }; /* * Returns true when there is at least one combination of pressed keys that * results in ghosting. */ static bool cros_ec_keyb_has_ghosting(struct cros_ec_keyb *ckdev, uint8_t *buf) { int col1, col2, buf1, buf2; struct device *dev = ckdev->dev; uint8_t *valid_keys = ckdev->valid_keys; /* * Ghosting happens if for any pressed key X there are other keys * pressed both in the same row and column of X as, for instance, * in the following diagram: * * . . Y . g . * . . . . . . * . . . . . . * . . X . Z . * * In this case only X, Y, and Z are pressed, but g appears to be * pressed too (see Wikipedia). */ for (col1 = 0; col1 < ckdev->cols; col1++) { buf1 = buf[col1] & valid_keys[col1]; for (col2 = col1 + 1; col2 < ckdev->cols; col2++) { buf2 = buf[col2] & valid_keys[col2]; if (hweight8(buf1 & buf2) > 1) { dev_dbg(dev, "ghost found at: B[%02d]:0x%02x & B[%02d]:0x%02x", col1, buf1, col2, buf2); return true; } } } return false; } /* * Compares the new keyboard state to the old one and produces key * press/release events accordingly. The keyboard state is 13 bytes (one byte * per column) */ static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev, uint8_t *kb_state, int len) { struct input_dev *idev = ckdev->idev; int col, row; int new_state; int old_state; if (ckdev->ghost_filter && cros_ec_keyb_has_ghosting(ckdev, kb_state)) { /* * Simple-minded solution: ignore this state. The obvious * improvement is to only ignore changes to keys involved in * the ghosting, but process the other changes. */ dev_dbg(ckdev->dev, "ghosting found\n"); return; } for (col = 0; col < ckdev->cols; col++) { for (row = 0; row < ckdev->rows; row++) { int pos = MATRIX_SCAN_CODE(row, col, ckdev->row_shift); const unsigned short *keycodes = idev->keycode; new_state = kb_state[col] & (1 << row); old_state = ckdev->old_kb_state[col] & (1 << row); if (new_state != old_state) { dev_dbg(ckdev->dev, "changed: [r%d c%d]: byte %02x\n", row, col, new_state); input_event(idev, EV_MSC, MSC_SCAN, pos); input_report_key(idev, keycodes[pos], new_state); } } ckdev->old_kb_state[col] = kb_state[col]; } input_sync(ckdev->idev); } /** * cros_ec_keyb_report_bs - Report non-matrixed buttons or switches * * This takes a bitmap of buttons or switches from the EC and reports events, * syncing at the end. * * @ckdev: The keyboard device. * @ev_type: The input event type (e.g., EV_KEY). * @mask: A bitmap of buttons from the EC. */ static void cros_ec_keyb_report_bs(struct cros_ec_keyb *ckdev, unsigned int ev_type, u32 mask) { struct input_dev *idev = ckdev->bs_idev; int i; for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) { const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i]; if (map->ev_type != ev_type) continue; input_event(idev, ev_type, map->code, !!(mask & BIT(map->bit)) ^ map->inverted); } input_sync(idev); } static int cros_ec_keyb_work(struct notifier_block *nb, unsigned long queued_during_suspend, void *_notify) { struct cros_ec_keyb *ckdev = container_of(nb, struct cros_ec_keyb, notifier); u32 val; unsigned int ev_type; /* * If not wake enabled, discard key state changes during * suspend. Switches will be re-checked in * cros_ec_keyb_resume() to be sure nothing is lost. */ if (queued_during_suspend && !device_may_wakeup(ckdev->dev)) return NOTIFY_OK; switch (ckdev->ec->event_data.event_type) { case EC_MKBP_EVENT_KEY_MATRIX: pm_wakeup_event(ckdev->dev, 0); if (ckdev->ec->event_size != ckdev->cols) { dev_err(ckdev->dev, "Discarded incomplete key matrix event.\n"); return NOTIFY_OK; } cros_ec_keyb_process(ckdev, ckdev->ec->event_data.data.key_matrix, ckdev->ec->event_size); break; case EC_MKBP_EVENT_SYSRQ: pm_wakeup_event(ckdev->dev, 0); val = get_unaligned_le32(&ckdev->ec->event_data.data.sysrq); dev_dbg(ckdev->dev, "sysrq code from EC: %#x\n", val); handle_sysrq(val); break; case EC_MKBP_EVENT_BUTTON: case EC_MKBP_EVENT_SWITCH: pm_wakeup_event(ckdev->dev, 0); if (ckdev->ec->event_data.event_type == EC_MKBP_EVENT_BUTTON) { val = get_unaligned_le32( &ckdev->ec->event_data.data.buttons); ev_type = EV_KEY; } else { val = get_unaligned_le32( &ckdev->ec->event_data.data.switches); ev_type = EV_SW; } cros_ec_keyb_report_bs(ckdev, ev_type, val); break; default: return NOTIFY_DONE; } return NOTIFY_OK; } /* * Walks keycodes flipping bit in buffer COLUMNS deep where bit is ROW. Used by * ghosting logic to ignore NULL or virtual keys. */ static void cros_ec_keyb_compute_valid_keys(struct cros_ec_keyb *ckdev) { int row, col; int row_shift = ckdev->row_shift; unsigned short *keymap = ckdev->idev->keycode; unsigned short code; BUG_ON(ckdev->idev->keycodesize != sizeof(*keymap)); for (col = 0; col < ckdev->cols; col++) { for (row = 0; row < ckdev->rows; row++) { code = keymap[MATRIX_SCAN_CODE(row, col, row_shift)]; if (code && (code != KEY_BATTERY)) ckdev->valid_keys[col] |= 1 << row; } dev_dbg(ckdev->dev, "valid_keys[%02d] = 0x%02x\n", col, ckdev->valid_keys[col]); } } /** * cros_ec_keyb_info - Wrap the EC command EC_CMD_MKBP_INFO * * This wraps the EC_CMD_MKBP_INFO, abstracting out all of the marshalling and * unmarshalling and different version nonsense into something simple. * * @ec_dev: The EC device * @info_type: Either EC_MKBP_INFO_SUPPORTED or EC_MKBP_INFO_CURRENT. * @event_type: Either EC_MKBP_EVENT_BUTTON or EC_MKBP_EVENT_SWITCH. Actually * in some cases this could be EC_MKBP_EVENT_KEY_MATRIX or * EC_MKBP_EVENT_HOST_EVENT too but we don't use in this driver. * @result: Where we'll store the result; a union * @result_size: The size of the result. Expected to be the size of one of * the elements in the union. * * Returns 0 if no error or -error upon error. */ static int cros_ec_keyb_info(struct cros_ec_device *ec_dev, enum ec_mkbp_info_type info_type, enum ec_mkbp_event event_type, union ec_response_get_next_data *result, size_t result_size) { struct ec_params_mkbp_info *params; struct cros_ec_command *msg; int ret; msg = kzalloc(sizeof(*msg) + max_t(size_t, result_size, sizeof(*params)), GFP_KERNEL); if (!msg) return -ENOMEM; msg->command = EC_CMD_MKBP_INFO; msg->version = 1; msg->outsize = sizeof(*params); msg->insize = result_size; params = (struct ec_params_mkbp_info *)msg->data; params->info_type = info_type; params->event_type = event_type; ret = cros_ec_cmd_xfer_status(ec_dev, msg); if (ret == -ENOPROTOOPT) { /* With older ECs we just return 0 for everything */ memset(result, 0, result_size); ret = 0; } else if (ret < 0) { dev_warn(ec_dev->dev, "Transfer error %d/%d: %d\n", (int)info_type, (int)event_type, ret); } else if (ret != result_size) { dev_warn(ec_dev->dev, "Wrong size %d/%d: %d != %zu\n", (int)info_type, (int)event_type, ret, result_size); ret = -EPROTO; } else { memcpy(result, msg->data, result_size); ret = 0; } kfree(msg); return ret; } /** * cros_ec_keyb_query_switches - Query the state of switches and report * * This will ask the EC about the current state of switches and report to the * kernel. Note that we don't query for buttons because they are more * transitory and we'll get an update on the next release / press. * * @ckdev: The keyboard device * * Returns 0 if no error or -error upon error. */ static int cros_ec_keyb_query_switches(struct cros_ec_keyb *ckdev) { struct cros_ec_device *ec_dev = ckdev->ec; union ec_response_get_next_data event_data = {}; int ret; ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_CURRENT, EC_MKBP_EVENT_SWITCH, &event_data, sizeof(event_data.switches)); if (ret) return ret; cros_ec_keyb_report_bs(ckdev, EV_SW, get_unaligned_le32(&event_data.switches)); return 0; } /** * cros_ec_keyb_resume - Resume the keyboard * * We use the resume notification as a chance to query the EC for switches. * * @dev: The keyboard device * * Returns 0 if no error or -error upon error. */ static __maybe_unused int cros_ec_keyb_resume(struct device *dev) { struct cros_ec_keyb *ckdev = dev_get_drvdata(dev); if (ckdev->bs_idev) return cros_ec_keyb_query_switches(ckdev); return 0; } /** * cros_ec_keyb_register_bs - Register non-matrix buttons/switches * * Handles all the bits of the keyboard driver related to non-matrix buttons * and switches, including asking the EC about which are present and telling * the kernel to expect them. * * If this device has no support for buttons and switches we'll return no error * but the ckdev->bs_idev will remain NULL when this function exits. * * @ckdev: The keyboard device * * Returns 0 if no error or -error upon error. */ static int cros_ec_keyb_register_bs(struct cros_ec_keyb *ckdev) { struct cros_ec_device *ec_dev = ckdev->ec; struct device *dev = ckdev->dev; struct input_dev *idev; union ec_response_get_next_data event_data = {}; const char *phys; u32 buttons; u32 switches; int ret; int i; ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED, EC_MKBP_EVENT_BUTTON, &event_data, sizeof(event_data.buttons)); if (ret) return ret; buttons = get_unaligned_le32(&event_data.buttons); ret = cros_ec_keyb_info(ec_dev, EC_MKBP_INFO_SUPPORTED, EC_MKBP_EVENT_SWITCH, &event_data, sizeof(event_data.switches)); if (ret) return ret; switches = get_unaligned_le32(&event_data.switches); if (!buttons && !switches) return 0; /* * We call the non-matrix buttons/switches 'input1', if present. * Allocate phys before input dev, to ensure correct tear-down * ordering. */ phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input1", ec_dev->phys_name); if (!phys) return -ENOMEM; idev = devm_input_allocate_device(dev); if (!idev) return -ENOMEM; idev->name = "cros_ec_buttons"; idev->phys = phys; __set_bit(EV_REP, idev->evbit); idev->id.bustype = BUS_VIRTUAL; idev->id.version = 1; idev->id.product = 0; idev->dev.parent = dev; input_set_drvdata(idev, ckdev); ckdev->bs_idev = idev; for (i = 0; i < ARRAY_SIZE(cros_ec_keyb_bs); i++) { const struct cros_ec_bs_map *map = &cros_ec_keyb_bs[i]; if ((map->ev_type == EV_KEY && (buttons & BIT(map->bit))) || (map->ev_type == EV_SW && (switches & BIT(map->bit)))) input_set_capability(idev, map->ev_type, map->code); } ret = cros_ec_keyb_query_switches(ckdev); if (ret) { dev_err(dev, "cannot query switches\n"); return ret; } ret = input_register_device(ckdev->bs_idev); if (ret) { dev_err(dev, "cannot register input device\n"); return ret; } return 0; } /** * cros_ec_keyb_register_bs - Register matrix keys * * Handles all the bits of the keyboard driver related to matrix keys. * * @ckdev: The keyboard device * * Returns 0 if no error or -error upon error. */ static int cros_ec_keyb_register_matrix(struct cros_ec_keyb *ckdev) { struct cros_ec_device *ec_dev = ckdev->ec; struct device *dev = ckdev->dev; struct input_dev *idev; const char *phys; int err; err = matrix_keypad_parse_properties(dev, &ckdev->rows, &ckdev->cols); if (err) return err; ckdev->valid_keys = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL); if (!ckdev->valid_keys) return -ENOMEM; ckdev->old_kb_state = devm_kzalloc(dev, ckdev->cols, GFP_KERNEL); if (!ckdev->old_kb_state) return -ENOMEM; /* * We call the keyboard matrix 'input0'. Allocate phys before input * dev, to ensure correct tear-down ordering. */ phys = devm_kasprintf(dev, GFP_KERNEL, "%s/input0", ec_dev->phys_name); if (!phys) return -ENOMEM; idev = devm_input_allocate_device(dev); if (!idev) return -ENOMEM; idev->name = CROS_EC_DEV_NAME; idev->phys = phys; __set_bit(EV_REP, idev->evbit); idev->id.bustype = BUS_VIRTUAL; idev->id.version = 1; idev->id.product = 0; idev->dev.parent = dev; ckdev->ghost_filter = of_property_read_bool(dev->of_node, "google,needs-ghost-filter"); err = matrix_keypad_build_keymap(NULL, NULL, ckdev->rows, ckdev->cols, NULL, idev); if (err) { dev_err(dev, "cannot build key matrix\n"); return err; } ckdev->row_shift = get_count_order(ckdev->cols); input_set_capability(idev, EV_MSC, MSC_SCAN); input_set_drvdata(idev, ckdev); ckdev->idev = idev; cros_ec_keyb_compute_valid_keys(ckdev); err = input_register_device(ckdev->idev); if (err) { dev_err(dev, "cannot register input device\n"); return err; } return 0; } static int cros_ec_keyb_probe(struct platform_device *pdev) { struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent); struct device *dev = &pdev->dev; struct cros_ec_keyb *ckdev; int err; if (!dev->of_node) return -ENODEV; ckdev = devm_kzalloc(dev, sizeof(*ckdev), GFP_KERNEL); if (!ckdev) return -ENOMEM; ckdev->ec = ec; ckdev->dev = dev; dev_set_drvdata(dev, ckdev); err = cros_ec_keyb_register_matrix(ckdev); if (err) { dev_err(dev, "cannot register matrix inputs: %d\n", err); return err; } err = cros_ec_keyb_register_bs(ckdev); if (err) { dev_err(dev, "cannot register non-matrix inputs: %d\n", err); return err; } ckdev->notifier.notifier_call = cros_ec_keyb_work; err = blocking_notifier_chain_register(&ckdev->ec->event_notifier, &ckdev->notifier); if (err) { dev_err(dev, "cannot register notifier: %d\n", err); return err; } device_init_wakeup(ckdev->dev, true); return 0; } static int cros_ec_keyb_remove(struct platform_device *pdev) { struct cros_ec_keyb *ckdev = dev_get_drvdata(&pdev->dev); blocking_notifier_chain_unregister(&ckdev->ec->event_notifier, &ckdev->notifier); return 0; } #ifdef CONFIG_OF static const struct of_device_id cros_ec_keyb_of_match[] = { { .compatible = "google,cros-ec-keyb" }, {}, }; MODULE_DEVICE_TABLE(of, cros_ec_keyb_of_match); #endif static SIMPLE_DEV_PM_OPS(cros_ec_keyb_pm_ops, NULL, cros_ec_keyb_resume); static struct platform_driver cros_ec_keyb_driver = { .probe = cros_ec_keyb_probe, .remove = cros_ec_keyb_remove, .driver = { .name = "cros-ec-keyb", .of_match_table = of_match_ptr(cros_ec_keyb_of_match), .pm = &cros_ec_keyb_pm_ops, }, }; module_platform_driver(cros_ec_keyb_driver); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("ChromeOS EC keyboard driver"); MODULE_ALIAS("platform:cros-ec-keyb");