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-rw-r--r--drivers/input/keyboard/cros_ec_keyb.c669
1 files changed, 669 insertions, 0 deletions
diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
new file mode 100644
index 000000000..1edf0e832
--- /dev/null
+++ b/drivers/input/keyboard/cros_ec_keyb.c
@@ -0,0 +1,669 @@
+// 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 <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/notifier.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sysrq.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+
+#include <asm/unaligned.h>
+
+/*
+ * @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;
+};
+
+
+/**
+ * cros_ec_bs_map - Struct mapping Linux keycodes to 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(ec_dev, msg);
+ if (ret < 0) {
+ dev_warn(ec_dev->dev, "Transfer error %d/%d: %d\n",
+ (int)info_type, (int)event_type, ret);
+ } else if (msg->result == EC_RES_INVALID_VERSION) {
+ /* With older ECs we just return 0 for everything */
+ memset(result, 0, result_size);
+ ret = 0;
+ } else if (msg->result != EC_RES_SUCCESS) {
+ dev_warn(ec_dev->dev, "Error getting info %d/%d: %d\n",
+ (int)info_type, (int)event_type, msg->result);
+ ret = -EPROTO;
+ } 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");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 01:37:09 +0000