1 /*
2 * Copyright (C) 2010-2013 Bluecherry, LLC <http://www.bluecherrydvr.com>
3 *
4 * Original author:
5 * Ben Collins <bcollins@ubuntu.com>
6 *
7 * Additional work by:
8 * John Brooks <john.brooks@bluecherry.net>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 */
20
21 /* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c
22 * channel. The bus can only handle one i2c event at a time. The below handles
23 * this all wrong. We should be using the status registers to see if the bus
24 * is in use, and have a global lock to check the status register. Also,
25 * the bulk of the work should be handled out-of-interrupt. The ugly loops
26 * that occur during interrupt scare me. The ISR should merely signal
27 * thread context, ACK the interrupt, and move on. -- BenC */
28
29 #include <linux/kernel.h>
30
31 #include "solo6x10.h"
32
solo_i2c_readbyte(struct solo_dev * solo_dev,int id,u8 addr,u8 off)33 u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)
34 {
35 struct i2c_msg msgs[2];
36 u8 data;
37
38 msgs[0].flags = 0;
39 msgs[0].addr = addr;
40 msgs[0].len = 1;
41 msgs[0].buf = &off;
42
43 msgs[1].flags = I2C_M_RD;
44 msgs[1].addr = addr;
45 msgs[1].len = 1;
46 msgs[1].buf = &data;
47
48 i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);
49
50 return data;
51 }
52
solo_i2c_writebyte(struct solo_dev * solo_dev,int id,u8 addr,u8 off,u8 data)53 void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,
54 u8 off, u8 data)
55 {
56 struct i2c_msg msgs;
57 u8 buf[2];
58
59 buf[0] = off;
60 buf[1] = data;
61 msgs.flags = 0;
62 msgs.addr = addr;
63 msgs.len = 2;
64 msgs.buf = buf;
65
66 i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);
67 }
68
solo_i2c_flush(struct solo_dev * solo_dev,int wr)69 static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)
70 {
71 u32 ctrl;
72
73 ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);
74
75 if (solo_dev->i2c_state == IIC_STATE_START)
76 ctrl |= SOLO_IIC_START;
77
78 if (wr) {
79 ctrl |= SOLO_IIC_WRITE;
80 } else {
81 ctrl |= SOLO_IIC_READ;
82 if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))
83 ctrl |= SOLO_IIC_ACK_EN;
84 }
85
86 if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)
87 ctrl |= SOLO_IIC_STOP;
88
89 solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);
90 }
91
solo_i2c_start(struct solo_dev * solo_dev)92 static void solo_i2c_start(struct solo_dev *solo_dev)
93 {
94 u32 addr = solo_dev->i2c_msg->addr << 1;
95
96 if (solo_dev->i2c_msg->flags & I2C_M_RD)
97 addr |= 1;
98
99 solo_dev->i2c_state = IIC_STATE_START;
100 solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);
101 solo_i2c_flush(solo_dev, 1);
102 }
103
solo_i2c_stop(struct solo_dev * solo_dev)104 static void solo_i2c_stop(struct solo_dev *solo_dev)
105 {
106 solo_irq_off(solo_dev, SOLO_IRQ_IIC);
107 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
108 solo_dev->i2c_state = IIC_STATE_STOP;
109 wake_up(&solo_dev->i2c_wait);
110 }
111
solo_i2c_handle_read(struct solo_dev * solo_dev)112 static int solo_i2c_handle_read(struct solo_dev *solo_dev)
113 {
114 prepare_read:
115 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
116 solo_i2c_flush(solo_dev, 0);
117 return 0;
118 }
119
120 solo_dev->i2c_msg_ptr = 0;
121 solo_dev->i2c_msg++;
122 solo_dev->i2c_msg_num--;
123
124 if (solo_dev->i2c_msg_num == 0) {
125 solo_i2c_stop(solo_dev);
126 return 0;
127 }
128
129 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
130 solo_i2c_start(solo_dev);
131 } else {
132 if (solo_dev->i2c_msg->flags & I2C_M_RD)
133 goto prepare_read;
134 else
135 solo_i2c_stop(solo_dev);
136 }
137
138 return 0;
139 }
140
solo_i2c_handle_write(struct solo_dev * solo_dev)141 static int solo_i2c_handle_write(struct solo_dev *solo_dev)
142 {
143 retry_write:
144 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
145 solo_reg_write(solo_dev, SOLO_IIC_TXD,
146 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);
147 solo_dev->i2c_msg_ptr++;
148 solo_i2c_flush(solo_dev, 1);
149 return 0;
150 }
151
152 solo_dev->i2c_msg_ptr = 0;
153 solo_dev->i2c_msg++;
154 solo_dev->i2c_msg_num--;
155
156 if (solo_dev->i2c_msg_num == 0) {
157 solo_i2c_stop(solo_dev);
158 return 0;
159 }
160
161 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
162 solo_i2c_start(solo_dev);
163 } else {
164 if (solo_dev->i2c_msg->flags & I2C_M_RD)
165 solo_i2c_stop(solo_dev);
166 else
167 goto retry_write;
168 }
169
170 return 0;
171 }
172
solo_i2c_isr(struct solo_dev * solo_dev)173 int solo_i2c_isr(struct solo_dev *solo_dev)
174 {
175 u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);
176 int ret = -EINVAL;
177
178
179 if (CHK_FLAGS(status, SOLO_IIC_STATE_TRNS | SOLO_IIC_STATE_SIG_ERR)
180 || solo_dev->i2c_id < 0) {
181 solo_i2c_stop(solo_dev);
182 return -ENXIO;
183 }
184
185 switch (solo_dev->i2c_state) {
186 case IIC_STATE_START:
187 if (solo_dev->i2c_msg->flags & I2C_M_RD) {
188 solo_dev->i2c_state = IIC_STATE_READ;
189 ret = solo_i2c_handle_read(solo_dev);
190 break;
191 }
192
193 solo_dev->i2c_state = IIC_STATE_WRITE;
194 case IIC_STATE_WRITE:
195 ret = solo_i2c_handle_write(solo_dev);
196 break;
197
198 case IIC_STATE_READ:
199 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =
200 solo_reg_read(solo_dev, SOLO_IIC_RXD);
201 solo_dev->i2c_msg_ptr++;
202
203 ret = solo_i2c_handle_read(solo_dev);
204 break;
205
206 default:
207 solo_i2c_stop(solo_dev);
208 }
209
210 return ret;
211 }
212
solo_i2c_master_xfer(struct i2c_adapter * adap,struct i2c_msg msgs[],int num)213 static int solo_i2c_master_xfer(struct i2c_adapter *adap,
214 struct i2c_msg msgs[], int num)
215 {
216 struct solo_dev *solo_dev = adap->algo_data;
217 unsigned long timeout;
218 int ret;
219 int i;
220 DEFINE_WAIT(wait);
221
222 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
223 if (&solo_dev->i2c_adap[i] == adap)
224 break;
225 }
226
227 if (i == SOLO_I2C_ADAPTERS)
228 return num; /* XXX Right return value for failure? */
229
230 mutex_lock(&solo_dev->i2c_mutex);
231 solo_dev->i2c_id = i;
232 solo_dev->i2c_msg = msgs;
233 solo_dev->i2c_msg_num = num;
234 solo_dev->i2c_msg_ptr = 0;
235
236 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
237 solo_irq_on(solo_dev, SOLO_IRQ_IIC);
238 solo_i2c_start(solo_dev);
239
240 timeout = HZ / 2;
241
242 for (;;) {
243 prepare_to_wait(&solo_dev->i2c_wait, &wait,
244 TASK_INTERRUPTIBLE);
245
246 if (solo_dev->i2c_state == IIC_STATE_STOP)
247 break;
248
249 timeout = schedule_timeout(timeout);
250 if (!timeout)
251 break;
252
253 if (signal_pending(current))
254 break;
255 }
256
257 finish_wait(&solo_dev->i2c_wait, &wait);
258 ret = num - solo_dev->i2c_msg_num;
259 solo_dev->i2c_state = IIC_STATE_IDLE;
260 solo_dev->i2c_id = -1;
261
262 mutex_unlock(&solo_dev->i2c_mutex);
263
264 return ret;
265 }
266
solo_i2c_functionality(struct i2c_adapter * adap)267 static u32 solo_i2c_functionality(struct i2c_adapter *adap)
268 {
269 return I2C_FUNC_I2C;
270 }
271
272 static const struct i2c_algorithm solo_i2c_algo = {
273 .master_xfer = solo_i2c_master_xfer,
274 .functionality = solo_i2c_functionality,
275 };
276
solo_i2c_init(struct solo_dev * solo_dev)277 int solo_i2c_init(struct solo_dev *solo_dev)
278 {
279 int i;
280 int ret;
281
282 solo_reg_write(solo_dev, SOLO_IIC_CFG,
283 SOLO_IIC_PRESCALE(8) | SOLO_IIC_ENABLE);
284
285 solo_dev->i2c_id = -1;
286 solo_dev->i2c_state = IIC_STATE_IDLE;
287 init_waitqueue_head(&solo_dev->i2c_wait);
288 mutex_init(&solo_dev->i2c_mutex);
289
290 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
291 struct i2c_adapter *adap = &solo_dev->i2c_adap[i];
292
293 snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d",
294 SOLO6X10_NAME, i);
295 adap->algo = &solo_i2c_algo;
296 adap->algo_data = solo_dev;
297 adap->retries = 1;
298 adap->dev.parent = &solo_dev->pdev->dev;
299
300 ret = i2c_add_adapter(adap);
301 if (ret) {
302 adap->algo_data = NULL;
303 break;
304 }
305 }
306
307 if (ret) {
308 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
309 if (!solo_dev->i2c_adap[i].algo_data)
310 break;
311 i2c_del_adapter(&solo_dev->i2c_adap[i]);
312 solo_dev->i2c_adap[i].algo_data = NULL;
313 }
314 return ret;
315 }
316
317 return 0;
318 }
319
solo_i2c_exit(struct solo_dev * solo_dev)320 void solo_i2c_exit(struct solo_dev *solo_dev)
321 {
322 int i;
323
324 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
325 if (!solo_dev->i2c_adap[i].algo_data)
326 continue;
327 i2c_del_adapter(&solo_dev->i2c_adap[i]);
328 solo_dev->i2c_adap[i].algo_data = NULL;
329 }
330 }
331