xref: /openbmc/linux/drivers/staging/nvec/nvec.h (revision 40fbffd9)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * NVEC: NVIDIA compliant embedded controller interface
4  *
5  * Copyright (C) 2011 The AC100 Kernel Team <ac100@lists.launchpad.net>
6  *
7  * Authors:  Pierre-Hugues Husson <phhusson@free.fr>
8  *           Ilya Petrov <ilya.muromec@gmail.com>
9  *           Marc Dietrich <marvin24@gmx.de>
10  *           Julian Andres Klode <jak@jak-linux.org>
11  */
12 
13 #ifndef __LINUX_MFD_NVEC
14 #define __LINUX_MFD_NVEC
15 
16 #include <linux/atomic.h>
17 #include <linux/clk.h>
18 #include <linux/completion.h>
19 #include <linux/list.h>
20 #include <linux/mutex.h>
21 #include <linux/notifier.h>
22 #include <linux/reset.h>
23 #include <linux/spinlock.h>
24 #include <linux/workqueue.h>
25 
26 /* NVEC_POOL_SIZE - Size of the pool in &struct nvec_msg */
27 #define NVEC_POOL_SIZE	64
28 
29 /*
30  * NVEC_MSG_SIZE - Maximum size of the data field of &struct nvec_msg.
31  *
32  * A message must store up to a SMBus block operation which consists of
33  * one command byte, one count byte, and up to 32 payload bytes = 34
34  * byte.
35  */
36 #define NVEC_MSG_SIZE	34
37 
38 /**
39  * enum nvec_event_size - The size of an event message
40  * @NVEC_2BYTES: The message has one command byte and one data byte
41  * @NVEC_3BYTES: The message has one command byte and two data bytes
42  * @NVEC_VAR_SIZE: The message has one command byte, one count byte, and has
43  *                 up to as many bytes as the number in the count byte. The
44  *                 maximum is 32
45  *
46  * Events can be fixed or variable sized. This is useless on other message
47  * types, which are always variable sized.
48  */
49 enum nvec_event_size {
50 	NVEC_2BYTES,
51 	NVEC_3BYTES,
52 	NVEC_VAR_SIZE,
53 };
54 
55 /**
56  * enum nvec_msg_type - The type of a message
57  * @NVEC_SYS: A system request/response
58  * @NVEC_BAT: A battery request/response
59  * @NVEC_KBD: A keyboard request/response
60  * @NVEC_PS2: A mouse request/response
61  * @NVEC_CNTL: A EC control request/response
62  * @NVEC_KB_EVT: An event from the keyboard
63  * @NVEC_PS2_EVT: An event from the mouse
64  *
65  * Events can be fixed or variable sized. This is useless on other message
66  * types, which are always variable sized.
67  */
68 enum nvec_msg_type {
69 	NVEC_SYS = 1,
70 	NVEC_BAT,
71 	NVEC_GPIO,
72 	NVEC_SLEEP,
73 	NVEC_KBD,
74 	NVEC_PS2,
75 	NVEC_CNTL,
76 	NVEC_OEM0 = 0x0d,
77 	NVEC_KB_EVT = 0x80,
78 	NVEC_PS2_EVT,
79 };
80 
81 /**
82  * struct nvec_msg - A buffer for a single message
83  * @node: Messages are part of various lists in a &struct nvec_chip
84  * @data: The data of the message
85  * @size: For TX messages, the number of bytes used in @data
86  * @pos:  For RX messages, the current position to write to. For TX messages,
87  *        the position to read from.
88  * @used: Used for the message pool to mark a message as free/allocated.
89  *
90  * This structure is used to hold outgoing and incoming messages. Outgoing
91  * messages have a different format than incoming messages, and that is not
92  * documented yet.
93  */
94 struct nvec_msg {
95 	struct list_head node;
96 	unsigned char data[NVEC_MSG_SIZE];
97 	unsigned short size;
98 	unsigned short pos;
99 	atomic_t used;
100 };
101 
102 /**
103  * struct nvec_chip - A single connection to an NVIDIA Embedded controller
104  * @dev: The device
105  * @gpio: The same as for &struct nvec_platform_data
106  * @irq: The IRQ of the I2C device
107  * @i2c_addr: The address of the I2C slave
108  * @base: The base of the memory mapped region of the I2C device
109  * @i2c_clk: The clock of the I2C device
110  * @rst: The reset of the I2C device
111  * @notifier_list: Notifiers to be called on received messages, see
112  *                 nvec_register_notifier()
113  * @rx_data: Received messages that have to be processed
114  * @tx_data: Messages waiting to be sent to the controller
115  * @nvec_status_notifier: Internal notifier (see nvec_status_notifier())
116  * @rx_work: A work structure for the RX worker nvec_dispatch()
117  * @tx_work: A work structure for the TX worker nvec_request_master()
118  * @wq: The work queue in which @rx_work and @tx_work are executed
119  * @rx: The message currently being retrieved or %NULL
120  * @msg_pool: A pool of messages for allocation
121  * @tx: The message currently being transferred
122  * @tx_scratch: Used for building pseudo messages
123  * @ec_transfer: A completion that will be completed once a message has been
124  *               received (see nvec_rx_completed())
125  * @tx_lock: Spinlock for modifications on @tx_data
126  * @rx_lock: Spinlock for modifications on @rx_data
127  * @sync_write_mutex: A mutex for nvec_write_sync()
128  * @sync_write: A completion to signal that a synchronous message is complete
129  * @sync_write_pending: The first two bytes of the request (type and subtype)
130  * @last_sync_msg: The last synchronous message.
131  * @state: State of our finite state machine used in nvec_interrupt()
132  */
133 struct nvec_chip {
134 	struct device *dev;
135 	struct gpio_desc *gpiod;
136 	int irq;
137 	u32 i2c_addr;
138 	void __iomem *base;
139 	struct clk *i2c_clk;
140 	struct reset_control *rst;
141 	struct atomic_notifier_head notifier_list;
142 	struct list_head rx_data, tx_data;
143 	struct notifier_block nvec_status_notifier;
144 	struct work_struct rx_work, tx_work;
145 	struct workqueue_struct *wq;
146 	struct nvec_msg msg_pool[NVEC_POOL_SIZE];
147 	struct nvec_msg *rx;
148 
149 	struct nvec_msg *tx;
150 	struct nvec_msg tx_scratch;
151 	struct completion ec_transfer;
152 
153 	spinlock_t tx_lock, rx_lock;
154 
155 	/* sync write stuff */
156 	struct mutex sync_write_mutex;
157 	struct completion sync_write;
158 	u16 sync_write_pending;
159 	struct nvec_msg *last_sync_msg;
160 
161 	int state;
162 };
163 
164 int nvec_write_async(struct nvec_chip *nvec, const unsigned char *data,
165 		     short size);
166 
167 int nvec_write_sync(struct nvec_chip *nvec,
168 		    const unsigned char *data, short size,
169 		    struct nvec_msg **msg);
170 
171 int nvec_register_notifier(struct nvec_chip *nvec,
172 			   struct notifier_block *nb,
173 			   unsigned int events);
174 
175 int nvec_unregister_notifier(struct nvec_chip *dev, struct notifier_block *nb);
176 
177 void nvec_msg_free(struct nvec_chip *nvec, struct nvec_msg *msg);
178 
179 #endif
180