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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/device.h>
12#include <linux/kernel.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
20/**
21 * struct wilco_ec_device - Wilco Embedded Controller handle.
22 * @dev: Device handle.
23 * @mailbox_lock: Mutex to ensure one mailbox command at a time.
24 * @io_command: I/O port for mailbox command. Provided by ACPI.
25 * @io_data: I/O port for mailbox data. Provided by ACPI.
26 * @io_packet: I/O port for mailbox packet data. Provided by ACPI.
27 * @data_buffer: Buffer used for EC communication. The same buffer
28 * is used to hold the request and the response.
29 * @data_size: Size of the data buffer used for EC communication.
30 * @debugfs_pdev: The child platform_device used by the debugfs sub-driver.
31 * @rtc_pdev: The child platform_device used by the RTC sub-driver.
32 * @charger_pdev: Child platform_device used by the charger config sub-driver.
33 * @telem_pdev: The child platform_device used by the telemetry sub-driver.
34 */
35struct wilco_ec_device {
36 struct device *dev;
37 struct mutex mailbox_lock;
38 struct resource *io_command;
39 struct resource *io_data;
40 struct resource *io_packet;
41 void *data_buffer;
42 size_t data_size;
43 struct platform_device *debugfs_pdev;
44 struct platform_device *rtc_pdev;
45 struct platform_device *charger_pdev;
46 struct platform_device *telem_pdev;
47};
48
49/**
50 * struct wilco_ec_request - Mailbox request message format.
51 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
52 * @checksum: Sum of all bytes must be 0.
53 * @mailbox_id: Mailbox identifier, specifies the command set.
54 * @mailbox_version: Mailbox interface version %EC_MAILBOX_VERSION
55 * @reserved: Set to zero.
56 * @data_size: Length of following data.
57 */
58struct wilco_ec_request {
59 u8 struct_version;
60 u8 checksum;
61 u16 mailbox_id;
62 u8 mailbox_version;
63 u8 reserved;
64 u16 data_size;
65} __packed;
66
67/**
68 * struct wilco_ec_response - Mailbox response message format.
69 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
70 * @checksum: Sum of all bytes must be 0.
71 * @result: Result code from the EC. Non-zero indicates an error.
72 * @data_size: Length of the response data buffer.
73 * @reserved: Set to zero.
74 * @data: Response data buffer. Max size is %EC_MAILBOX_DATA_SIZE_EXTENDED.
75 */
76struct wilco_ec_response {
77 u8 struct_version;
78 u8 checksum;
79 u16 result;
80 u16 data_size;
81 u8 reserved[2];
82 u8 data[0];
83} __packed;
84
85/**
86 * enum wilco_ec_msg_type - Message type to select a set of command codes.
87 * @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior.
88 * @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property.
89 * @WILCO_EC_MSG_TELEMETRY: Request telemetry data from the EC.
90 */
91enum wilco_ec_msg_type {
92 WILCO_EC_MSG_LEGACY = 0x00f0,
93 WILCO_EC_MSG_PROPERTY = 0x00f2,
94 WILCO_EC_MSG_TELEMETRY = 0x00f5,
95};
96
97/**
98 * struct wilco_ec_message - Request and response message.
99 * @type: Mailbox message type.
100 * @flags: Message flags, e.g. %WILCO_EC_FLAG_NO_RESPONSE.
101 * @request_size: Number of bytes to send to the EC.
102 * @request_data: Buffer containing the request data.
103 * @response_size: Number of bytes to read from EC.
104 * @response_data: Buffer containing the response data, should be
105 * response_size bytes and allocated by caller.
106 */
107struct wilco_ec_message {
108 enum wilco_ec_msg_type type;
109 u8 flags;
110 size_t request_size;
111 void *request_data;
112 size_t response_size;
113 void *response_data;
114};
115
116/**
117 * wilco_ec_mailbox() - Send request to the EC and receive the response.
118 * @ec: Wilco EC device.
119 * @msg: Wilco EC message.
120 *
121 * Return: Number of bytes received or negative error code on failure.
122 */
123int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
124
125/**
126 * wilco_keyboard_leds_init() - Set up the keyboard backlight LEDs.
127 * @ec: EC device to query.
128 *
129 * After this call, the keyboard backlight will be exposed through a an LED
130 * device at /sys/class/leds.
131 *
132 * This may sleep because it uses wilco_ec_mailbox().
133 *
134 * Return: 0 on success, negative error code on failure.
135 */
136int wilco_keyboard_leds_init(struct wilco_ec_device *ec);
137
138/*
139 * A Property is typically a data item that is stored to NVRAM
140 * by the EC. Each of these data items has an index associated
141 * with it, known as the Property ID (PID). Properties may have
142 * variable lengths, up to a max of WILCO_EC_PROPERTY_MAX_SIZE
143 * bytes. Properties can be simple integers, or they may be more
144 * complex binary data.
145 */
146
147#define WILCO_EC_PROPERTY_MAX_SIZE 4
148
149/**
150 * struct ec_property_set_msg - Message to get or set a property.
151 * @property_id: Which property to get or set.
152 * @length: Number of bytes of |data| that are used.
153 * @data: Actual property data.
154 */
155struct wilco_ec_property_msg {
156 u32 property_id;
157 int length;
158 u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
159};
160
161/**
162 * wilco_ec_get_property() - Retrieve a property from the EC.
163 * @ec: Embedded Controller device.
164 * @prop_msg: Message for request and response.
165 *
166 * The property_id field of |prop_msg| should be filled before calling this
167 * function. The result will be stored in the data and length fields.
168 *
169 * Return: 0 on success, negative error code on failure.
170 */
171int wilco_ec_get_property(struct wilco_ec_device *ec,
172 struct wilco_ec_property_msg *prop_msg);
173
174/**
175 * wilco_ec_set_property() - Store a property on the EC.
176 * @ec: Embedded Controller device.
177 * @prop_msg: Message for request and response.
178 *
179 * The property_id, length, and data fields of |prop_msg| should be
180 * filled before calling this function.
181 *
182 * Return: 0 on success, negative error code on failure.
183 */
184int wilco_ec_set_property(struct wilco_ec_device *ec,
185 struct wilco_ec_property_msg *prop_msg);
186
187/**
188 * wilco_ec_get_byte_property() - Retrieve a byte-size property from the EC.
189 * @ec: Embedded Controller device.
190 * @property_id: Which property to retrieve.
191 * @val: The result value, will be filled by this function.
192 *
193 * Return: 0 on success, negative error code on failure.
194 */
195int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,
196 u8 *val);
197
198/**
199 * wilco_ec_get_byte_property() - Store a byte-size property on the EC.
200 * @ec: Embedded Controller device.
201 * @property_id: Which property to store.
202 * @val: Value to store.
203 *
204 * Return: 0 on success, negative error code on failure.
205 */
206int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,
207 u8 val);
208
209/**
210 * wilco_ec_add_sysfs() - Create sysfs entries
211 * @ec: Wilco EC device
212 *
213 * wilco_ec_remove_sysfs() needs to be called afterwards
214 * to perform the necessary cleanup.
215 *
216 * Return: 0 on success or negative error code on failure.
217 */
218int wilco_ec_add_sysfs(struct wilco_ec_device *ec);
219void wilco_ec_remove_sysfs(struct wilco_ec_device *ec);
220
221#endif /* WILCO_EC_H */