1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2010-2013 Bluecherry, LLC <https://www.bluecherrydvr.com>
4 *
5 * Original author:
6 * Ben Collins <bcollins@ubuntu.com>
7 *
8 * Additional work by:
9 * John Brooks <john.brooks@bluecherry.net>
10 */
11
12 /* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c
13 * channel. The bus can only handle one i2c event at a time. The below handles
14 * this all wrong. We should be using the status registers to see if the bus
15 * is in use, and have a global lock to check the status register. Also,
16 * the bulk of the work should be handled out-of-interrupt. The ugly loops
17 * that occur during interrupt scare me. The ISR should merely signal
18 * thread context, ACK the interrupt, and move on. -- BenC */
19
20 #include <linux/kernel.h>
21 #include <linux/sched/signal.h>
22
23 #include "solo6x10.h"
24
solo_i2c_readbyte(struct solo_dev * solo_dev,int id,u8 addr,u8 off)25 u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)
26 {
27 struct i2c_msg msgs[2];
28 u8 data;
29
30 msgs[0].flags = 0;
31 msgs[0].addr = addr;
32 msgs[0].len = 1;
33 msgs[0].buf = &off;
34
35 msgs[1].flags = I2C_M_RD;
36 msgs[1].addr = addr;
37 msgs[1].len = 1;
38 msgs[1].buf = &data;
39
40 i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);
41
42 return data;
43 }
44
solo_i2c_writebyte(struct solo_dev * solo_dev,int id,u8 addr,u8 off,u8 data)45 void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,
46 u8 off, u8 data)
47 {
48 struct i2c_msg msgs;
49 u8 buf[2];
50
51 buf[0] = off;
52 buf[1] = data;
53 msgs.flags = 0;
54 msgs.addr = addr;
55 msgs.len = 2;
56 msgs.buf = buf;
57
58 i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);
59 }
60
solo_i2c_flush(struct solo_dev * solo_dev,int wr)61 static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)
62 {
63 u32 ctrl;
64
65 ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);
66
67 if (solo_dev->i2c_state == IIC_STATE_START)
68 ctrl |= SOLO_IIC_START;
69
70 if (wr) {
71 ctrl |= SOLO_IIC_WRITE;
72 } else {
73 ctrl |= SOLO_IIC_READ;
74 if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))
75 ctrl |= SOLO_IIC_ACK_EN;
76 }
77
78 if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)
79 ctrl |= SOLO_IIC_STOP;
80
81 solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);
82 }
83
solo_i2c_start(struct solo_dev * solo_dev)84 static void solo_i2c_start(struct solo_dev *solo_dev)
85 {
86 u32 addr = solo_dev->i2c_msg->addr << 1;
87
88 if (solo_dev->i2c_msg->flags & I2C_M_RD)
89 addr |= 1;
90
91 solo_dev->i2c_state = IIC_STATE_START;
92 solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);
93 solo_i2c_flush(solo_dev, 1);
94 }
95
solo_i2c_stop(struct solo_dev * solo_dev)96 static void solo_i2c_stop(struct solo_dev *solo_dev)
97 {
98 solo_irq_off(solo_dev, SOLO_IRQ_IIC);
99 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
100 solo_dev->i2c_state = IIC_STATE_STOP;
101 wake_up(&solo_dev->i2c_wait);
102 }
103
solo_i2c_handle_read(struct solo_dev * solo_dev)104 static int solo_i2c_handle_read(struct solo_dev *solo_dev)
105 {
106 prepare_read:
107 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
108 solo_i2c_flush(solo_dev, 0);
109 return 0;
110 }
111
112 solo_dev->i2c_msg_ptr = 0;
113 solo_dev->i2c_msg++;
114 solo_dev->i2c_msg_num--;
115
116 if (solo_dev->i2c_msg_num == 0) {
117 solo_i2c_stop(solo_dev);
118 return 0;
119 }
120
121 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
122 solo_i2c_start(solo_dev);
123 } else {
124 if (solo_dev->i2c_msg->flags & I2C_M_RD)
125 goto prepare_read;
126 else
127 solo_i2c_stop(solo_dev);
128 }
129
130 return 0;
131 }
132
solo_i2c_handle_write(struct solo_dev * solo_dev)133 static int solo_i2c_handle_write(struct solo_dev *solo_dev)
134 {
135 retry_write:
136 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
137 solo_reg_write(solo_dev, SOLO_IIC_TXD,
138 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);
139 solo_dev->i2c_msg_ptr++;
140 solo_i2c_flush(solo_dev, 1);
141 return 0;
142 }
143
144 solo_dev->i2c_msg_ptr = 0;
145 solo_dev->i2c_msg++;
146 solo_dev->i2c_msg_num--;
147
148 if (solo_dev->i2c_msg_num == 0) {
149 solo_i2c_stop(solo_dev);
150 return 0;
151 }
152
153 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
154 solo_i2c_start(solo_dev);
155 } else {
156 if (solo_dev->i2c_msg->flags & I2C_M_RD)
157 solo_i2c_stop(solo_dev);
158 else
159 goto retry_write;
160 }
161
162 return 0;
163 }
164
solo_i2c_isr(struct solo_dev * solo_dev)165 int solo_i2c_isr(struct solo_dev *solo_dev)
166 {
167 u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);
168 int ret = -EINVAL;
169
170
171 if (CHK_FLAGS(status, SOLO_IIC_STATE_TRNS | SOLO_IIC_STATE_SIG_ERR)
172 || solo_dev->i2c_id < 0) {
173 solo_i2c_stop(solo_dev);
174 return -ENXIO;
175 }
176
177 switch (solo_dev->i2c_state) {
178 case IIC_STATE_START:
179 if (solo_dev->i2c_msg->flags & I2C_M_RD) {
180 solo_dev->i2c_state = IIC_STATE_READ;
181 ret = solo_i2c_handle_read(solo_dev);
182 break;
183 }
184
185 solo_dev->i2c_state = IIC_STATE_WRITE;
186 fallthrough;
187 case IIC_STATE_WRITE:
188 ret = solo_i2c_handle_write(solo_dev);
189 break;
190
191 case IIC_STATE_READ:
192 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =
193 solo_reg_read(solo_dev, SOLO_IIC_RXD);
194 solo_dev->i2c_msg_ptr++;
195
196 ret = solo_i2c_handle_read(solo_dev);
197 break;
198
199 default:
200 solo_i2c_stop(solo_dev);
201 }
202
203 return ret;
204 }
205
solo_i2c_master_xfer(struct i2c_adapter * adap,struct i2c_msg msgs[],int num)206 static int solo_i2c_master_xfer(struct i2c_adapter *adap,
207 struct i2c_msg msgs[], int num)
208 {
209 struct solo_dev *solo_dev = adap->algo_data;
210 unsigned long timeout;
211 int ret;
212 int i;
213 DEFINE_WAIT(wait);
214
215 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
216 if (&solo_dev->i2c_adap[i] == adap)
217 break;
218 }
219
220 if (i == SOLO_I2C_ADAPTERS)
221 return num; /* XXX Right return value for failure? */
222
223 mutex_lock(&solo_dev->i2c_mutex);
224 solo_dev->i2c_id = i;
225 solo_dev->i2c_msg = msgs;
226 solo_dev->i2c_msg_num = num;
227 solo_dev->i2c_msg_ptr = 0;
228
229 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
230 solo_irq_on(solo_dev, SOLO_IRQ_IIC);
231 solo_i2c_start(solo_dev);
232
233 timeout = HZ / 2;
234
235 for (;;) {
236 prepare_to_wait(&solo_dev->i2c_wait, &wait,
237 TASK_INTERRUPTIBLE);
238
239 if (solo_dev->i2c_state == IIC_STATE_STOP)
240 break;
241
242 timeout = schedule_timeout(timeout);
243 if (!timeout)
244 break;
245
246 if (signal_pending(current))
247 break;
248 }
249
250 finish_wait(&solo_dev->i2c_wait, &wait);
251 ret = num - solo_dev->i2c_msg_num;
252 solo_dev->i2c_state = IIC_STATE_IDLE;
253 solo_dev->i2c_id = -1;
254
255 mutex_unlock(&solo_dev->i2c_mutex);
256
257 return ret;
258 }
259
solo_i2c_functionality(struct i2c_adapter * adap)260 static u32 solo_i2c_functionality(struct i2c_adapter *adap)
261 {
262 return I2C_FUNC_I2C;
263 }
264
265 static const struct i2c_algorithm solo_i2c_algo = {
266 .master_xfer = solo_i2c_master_xfer,
267 .functionality = solo_i2c_functionality,
268 };
269
solo_i2c_init(struct solo_dev * solo_dev)270 int solo_i2c_init(struct solo_dev *solo_dev)
271 {
272 int i;
273 int ret;
274
275 solo_reg_write(solo_dev, SOLO_IIC_CFG,
276 SOLO_IIC_PRESCALE(8) | SOLO_IIC_ENABLE);
277
278 solo_dev->i2c_id = -1;
279 solo_dev->i2c_state = IIC_STATE_IDLE;
280 init_waitqueue_head(&solo_dev->i2c_wait);
281 mutex_init(&solo_dev->i2c_mutex);
282
283 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
284 struct i2c_adapter *adap = &solo_dev->i2c_adap[i];
285
286 snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d",
287 SOLO6X10_NAME, i);
288 adap->algo = &solo_i2c_algo;
289 adap->algo_data = solo_dev;
290 adap->retries = 1;
291 adap->dev.parent = &solo_dev->pdev->dev;
292
293 ret = i2c_add_adapter(adap);
294 if (ret) {
295 adap->algo_data = NULL;
296 break;
297 }
298 }
299
300 if (ret) {
301 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
302 if (!solo_dev->i2c_adap[i].algo_data)
303 break;
304 i2c_del_adapter(&solo_dev->i2c_adap[i]);
305 solo_dev->i2c_adap[i].algo_data = NULL;
306 }
307 return ret;
308 }
309
310 return 0;
311 }
312
solo_i2c_exit(struct solo_dev * solo_dev)313 void solo_i2c_exit(struct solo_dev *solo_dev)
314 {
315 int i;
316
317 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
318 if (!solo_dev->i2c_adap[i].algo_data)
319 continue;
320 i2c_del_adapter(&solo_dev->i2c_adap[i]);
321 solo_dev->i2c_adap[i].algo_data = NULL;
322 }
323 }
324