1/*
2 * ChromeOS EC multi-function device
3 *
4 * Copyright (C) 2012 Google, Inc
5 *
6 * This software is licensed under the terms of the GNU General Public
7 * License version 2, as published by the Free Software Foundation, and
8 * may be copied, distributed, and modified under those terms.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 */
15
16#ifndef __LINUX_MFD_CROS_EC_H
17#define __LINUX_MFD_CROS_EC_H
18
19#include <linux/cdev.h>
20#include <linux/notifier.h>
21#include <linux/mfd/cros_ec_commands.h>
22#include <linux/mutex.h>
23
24/*
25 * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
26 */
27enum {
28	EC_MSG_TX_HEADER_BYTES	= 3,
29	EC_MSG_TX_TRAILER_BYTES	= 1,
30	EC_MSG_TX_PROTO_BYTES	= EC_MSG_TX_HEADER_BYTES +
31					EC_MSG_TX_TRAILER_BYTES,
32	EC_MSG_RX_PROTO_BYTES	= 3,
33
34	/* Max length of messages */
35	EC_MSG_BYTES		= EC_PROTO2_MAX_PARAM_SIZE +
36					EC_MSG_TX_PROTO_BYTES,
37};
38
39/*
40 * @version: Command version number (often 0)
41 * @command: Command to send (EC_CMD_...)
42 * @outsize: Outgoing length in bytes
43 * @insize: Max number of bytes to accept from EC
44 * @result: EC's response to the command (separate from communication failure)
45 * @outdata: Outgoing data to EC
46 * @indata: Where to put the incoming data from EC
47 */
48struct cros_ec_command {
49	uint32_t version;
50	uint32_t command;
51	uint32_t outsize;
52	uint32_t insize;
53	uint32_t result;
54	uint8_t outdata[EC_PROTO2_MAX_PARAM_SIZE];
55	uint8_t indata[EC_PROTO2_MAX_PARAM_SIZE];
56};
57
58/**
59 * struct cros_ec_device - Information about a ChromeOS EC device
60 *
61 * @ec_name: name of EC device (e.g. 'chromeos-ec')
62 * @phys_name: name of physical comms layer (e.g. 'i2c-4')
63 * @dev: Device pointer for physical comms device
64 * @vdev: Device pointer for virtual comms device
65 * @cdev: Character device structure for virtual comms device
66 * @was_wake_device: true if this device was set to wake the system from
67 * sleep at the last suspend
68 * @cmd_readmem: direct read of the EC memory-mapped region, if supported
69 *     @offset is within EC_LPC_ADDR_MEMMAP region.
70 *     @bytes: number of bytes to read. zero means "read a string" (including
71 *     the trailing '\0'). At most only EC_MEMMAP_SIZE bytes can be read.
72 *     Caller must ensure that the buffer is large enough for the result when
73 *     reading a string.
74 *
75 * @priv: Private data
76 * @irq: Interrupt to use
77 * @din: input buffer (for data from EC)
78 * @dout: output buffer (for data to EC)
79 * \note
80 * These two buffers will always be dword-aligned and include enough
81 * space for up to 7 word-alignment bytes also, so we can ensure that
82 * the body of the message is always dword-aligned (64-bit).
83 * We use this alignment to keep ARM and x86 happy. Probably word
84 * alignment would be OK, there might be a small performance advantage
85 * to using dword.
86 * @din_size: size of din buffer to allocate (zero to use static din)
87 * @dout_size: size of dout buffer to allocate (zero to use static dout)
88 * @parent: pointer to parent device (e.g. i2c or spi device)
89 * @wake_enabled: true if this device can wake the system from sleep
90 * @cmd_xfer: send command to EC and get response
91 *     Returns the number of bytes received if the communication succeeded, but
92 *     that doesn't mean the EC was happy with the command. The caller
93 *     should check msg.result for the EC's result code.
94 * @lock: one transaction at a time
95 */
96struct cros_ec_device {
97
98	/* These are used by other drivers that want to talk to the EC */
99	const char *ec_name;
100	const char *phys_name;
101	struct device *dev;
102	struct device *vdev;
103	struct cdev cdev;
104	bool was_wake_device;
105	struct class *cros_class;
106	int (*cmd_readmem)(struct cros_ec_device *ec, unsigned int offset,
107			   unsigned int bytes, void *dest);
108
109	/* These are used to implement the platform-specific interface */
110	void *priv;
111	int irq;
112	uint8_t *din;
113	uint8_t *dout;
114	int din_size;
115	int dout_size;
116	struct device *parent;
117	bool wake_enabled;
118	int (*cmd_xfer)(struct cros_ec_device *ec,
119			struct cros_ec_command *msg);
120	struct mutex lock;
121};
122
123/**
124 * cros_ec_suspend - Handle a suspend operation for the ChromeOS EC device
125 *
126 * This can be called by drivers to handle a suspend event.
127 *
128 * ec_dev: Device to suspend
129 * @return 0 if ok, -ve on error
130 */
131int cros_ec_suspend(struct cros_ec_device *ec_dev);
132
133/**
134 * cros_ec_resume - Handle a resume operation for the ChromeOS EC device
135 *
136 * This can be called by drivers to handle a resume event.
137 *
138 * @ec_dev: Device to resume
139 * @return 0 if ok, -ve on error
140 */
141int cros_ec_resume(struct cros_ec_device *ec_dev);
142
143/**
144 * cros_ec_prepare_tx - Prepare an outgoing message in the output buffer
145 *
146 * This is intended to be used by all ChromeOS EC drivers, but at present
147 * only SPI uses it. Once LPC uses the same protocol it can start using it.
148 * I2C could use it now, with a refactor of the existing code.
149 *
150 * @ec_dev: Device to register
151 * @msg: Message to write
152 */
153int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
154		       struct cros_ec_command *msg);
155
156/**
157 * cros_ec_check_result - Check ec_msg->result
158 *
159 * This is used by ChromeOS EC drivers to check the ec_msg->result for
160 * errors and to warn about them.
161 *
162 * @ec_dev: EC device
163 * @msg: Message to check
164 */
165int cros_ec_check_result(struct cros_ec_device *ec_dev,
166			 struct cros_ec_command *msg);
167
168/**
169 * cros_ec_cmd_xfer - Send a command to the ChromeOS EC
170 *
171 * Call this to send a command to the ChromeOS EC.  This should be used
172 * instead of calling the EC's cmd_xfer() callback directly.
173 *
174 * @ec_dev: EC device
175 * @msg: Message to write
176 */
177int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
178		     struct cros_ec_command *msg);
179
180/**
181 * cros_ec_remove - Remove a ChromeOS EC
182 *
183 * Call this to deregister a ChromeOS EC, then clean up any private data.
184 *
185 * @ec_dev: Device to register
186 * @return 0 if ok, -ve on error
187 */
188int cros_ec_remove(struct cros_ec_device *ec_dev);
189
190/**
191 * cros_ec_register - Register a new ChromeOS EC, using the provided info
192 *
193 * Before calling this, allocate a pointer to a new device and then fill
194 * in all the fields up to the --private-- marker.
195 *
196 * @ec_dev: Device to register
197 * @return 0 if ok, -ve on error
198 */
199int cros_ec_register(struct cros_ec_device *ec_dev);
200
201#endif /* __LINUX_MFD_CROS_EC_H */
202