wilco-ec.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2/*
  3 * ChromeOS Wilco Embedded Controller
  4 *
  5 * Copyright 2018 Google LLC
  6 */
  7
  8#ifndef WILCO_EC_H
  9#define WILCO_EC_H
 10
 11#include <linux/mutex.h>
 12#include <linux/types.h>
 13
 14/* Message flags for using the mailbox() interface */
 15#define WILCO_EC_FLAG_NO_RESPONSE	BIT(0) /* EC does not respond */
 16
 17/* Normal commands have a maximum 32 bytes of data */
 18#define EC_MAILBOX_DATA_SIZE		32
 19
 20struct device;
 21struct resource;
 22struct platform_device;
 23
 24/**
 25 * struct wilco_ec_device - Wilco Embedded Controller handle.
 26 * @dev: Device handle.
 27 * @mailbox_lock: Mutex to ensure one mailbox command at a time.
 28 * @io_command: I/O port for mailbox command.  Provided by ACPI.
 29 * @io_data: I/O port for mailbox data.  Provided by ACPI.
 30 * @io_packet: I/O port for mailbox packet data.  Provided by ACPI.
 31 * @data_buffer: Buffer used for EC communication.  The same buffer
 32 *               is used to hold the request and the response.
 33 * @data_size: Size of the data buffer used for EC communication.
 34 * @debugfs_pdev: The child platform_device used by the debugfs sub-driver.
 35 * @rtc_pdev: The child platform_device used by the RTC sub-driver.
 36 * @charger_pdev: Child platform_device used by the charger config sub-driver.
 37 * @telem_pdev: The child platform_device used by the telemetry sub-driver.
 38 */
 39struct wilco_ec_device {
 40	struct device *dev;
 41	struct mutex mailbox_lock;
 42	struct resource *io_command;
 43	struct resource *io_data;
 44	struct resource *io_packet;
 45	void *data_buffer;
 46	size_t data_size;
 47	struct platform_device *debugfs_pdev;
 48	struct platform_device *rtc_pdev;
 49	struct platform_device *charger_pdev;
 50	struct platform_device *telem_pdev;
 51};
 52
 53/**
 54 * struct wilco_ec_request - Mailbox request message format.
 55 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
 56 * @checksum: Sum of all bytes must be 0.
 57 * @mailbox_id: Mailbox identifier, specifies the command set.
 58 * @mailbox_version: Mailbox interface version %EC_MAILBOX_VERSION
 59 * @reserved: Set to zero.
 60 * @data_size: Length of following data.
 61 */
 62struct wilco_ec_request {
 63	u8 struct_version;
 64	u8 checksum;
 65	u16 mailbox_id;
 66	u8 mailbox_version;
 67	u8 reserved;
 68	u16 data_size;
 69} __packed;
 70
 71/**
 72 * struct wilco_ec_response - Mailbox response message format.
 73 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
 74 * @checksum: Sum of all bytes must be 0.
 75 * @result: Result code from the EC.  Non-zero indicates an error.
 76 * @data_size: Length of the response data buffer.
 77 * @reserved: Set to zero.
 78 * @data: Response data buffer.  Max size is %EC_MAILBOX_DATA_SIZE_EXTENDED.
 79 */
 80struct wilco_ec_response {
 81	u8 struct_version;
 82	u8 checksum;
 83	u16 result;
 84	u16 data_size;
 85	u8 reserved[2];
 86	u8 data[];
 87} __packed;
 88
 89/**
 90 * enum wilco_ec_msg_type - Message type to select a set of command codes.
 91 * @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior.
 92 * @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property.
 93 * @WILCO_EC_MSG_TELEMETRY: Request telemetry data from the EC.
 94 */
 95enum wilco_ec_msg_type {
 96	WILCO_EC_MSG_LEGACY = 0x00f0,
 97	WILCO_EC_MSG_PROPERTY = 0x00f2,
 98	WILCO_EC_MSG_TELEMETRY = 0x00f5,
 99};
100
101/**
102 * struct wilco_ec_message - Request and response message.
103 * @type: Mailbox message type.
104 * @flags: Message flags, e.g. %WILCO_EC_FLAG_NO_RESPONSE.
105 * @request_size: Number of bytes to send to the EC.
106 * @request_data: Buffer containing the request data.
107 * @response_size: Number of bytes to read from EC.
108 * @response_data: Buffer containing the response data, should be
109 *                 response_size bytes and allocated by caller.
110 */
111struct wilco_ec_message {
112	enum wilco_ec_msg_type type;
113	u8 flags;
114	size_t request_size;
115	void *request_data;
116	size_t response_size;
117	void *response_data;
118};
119
120/**
121 * wilco_ec_mailbox() - Send request to the EC and receive the response.
122 * @ec: Wilco EC device.
123 * @msg: Wilco EC message.
124 *
125 * Return: Number of bytes received or negative error code on failure.
126 */
127int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
128
129/**
130 * wilco_keyboard_leds_init() - Set up the keyboard backlight LEDs.
131 * @ec: EC device to query.
132 *
133 * After this call, the keyboard backlight will be exposed through a an LED
134 * device at /sys/class/leds.
135 *
136 * This may sleep because it uses wilco_ec_mailbox().
137 *
138 * Return: 0 on success, negative error code on failure.
139 */
140int wilco_keyboard_leds_init(struct wilco_ec_device *ec);
141
142/*
143 * A Property is typically a data item that is stored to NVRAM
144 * by the EC. Each of these data items has an index associated
145 * with it, known as the Property ID (PID). Properties may have
146 * variable lengths, up to a max of WILCO_EC_PROPERTY_MAX_SIZE
147 * bytes. Properties can be simple integers, or they may be more
148 * complex binary data.
149 */
150
151#define WILCO_EC_PROPERTY_MAX_SIZE	4
152
153/**
154 * struct ec_property_set_msg - Message to get or set a property.
155 * @property_id: Which property to get or set.
156 * @length: Number of bytes of |data| that are used.
157 * @data: Actual property data.
158 */
159struct wilco_ec_property_msg {
160	u32 property_id;
161	int length;
162	u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
163};
164
165/**
166 * wilco_ec_get_property() - Retrieve a property from the EC.
167 * @ec: Embedded Controller device.
168 * @prop_msg: Message for request and response.
169 *
170 * The property_id field of |prop_msg| should be filled before calling this
171 * function. The result will be stored in the data and length fields.
172 *
173 * Return: 0 on success, negative error code on failure.
174 */
175int wilco_ec_get_property(struct wilco_ec_device *ec,
176			  struct wilco_ec_property_msg *prop_msg);
177
178/**
179 * wilco_ec_set_property() - Store a property on the EC.
180 * @ec: Embedded Controller device.
181 * @prop_msg: Message for request and response.
182 *
183 * The property_id, length, and data fields of |prop_msg| should be
184 * filled before calling this function.
185 *
186 * Return: 0 on success, negative error code on failure.
187 */
188int wilco_ec_set_property(struct wilco_ec_device *ec,
189			  struct wilco_ec_property_msg *prop_msg);
190
191/**
192 * wilco_ec_get_byte_property() - Retrieve a byte-size property from the EC.
193 * @ec: Embedded Controller device.
194 * @property_id: Which property to retrieve.
195 * @val: The result value, will be filled by this function.
196 *
197 * Return: 0 on success, negative error code on failure.
198 */
199int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,
200			       u8 *val);
201
202/**
203 * wilco_ec_get_byte_property() - Store a byte-size property on the EC.
204 * @ec: Embedded Controller device.
205 * @property_id: Which property to store.
206 * @val: Value to store.
207 *
208 * Return: 0 on success, negative error code on failure.
209 */
210int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,
211			       u8 val);
212
213/**
214 * wilco_ec_add_sysfs() - Create sysfs entries
215 * @ec: Wilco EC device
216 *
217 * wilco_ec_remove_sysfs() needs to be called afterwards
218 * to perform the necessary cleanup.
219 *
220 * Return: 0 on success or negative error code on failure.
221 */
222int wilco_ec_add_sysfs(struct wilco_ec_device *ec);
223void wilco_ec_remove_sysfs(struct wilco_ec_device *ec);
224
225#endif /* WILCO_EC_H */