1 /*
2 * Copyright (C) 2010 Bluecherry, LLC www.bluecherrydvr.com
3 * Copyright (C) 2010 Ben Collins <bcollins@bluecherry.net>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
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 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 */
19
20 /* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c
21 * channel. The bus can only handle one i2c event at a time. The below handles
22 * this all wrong. We should be using the status registers to see if the bus
23 * is in use, and have a global lock to check the status register. Also,
24 * the bulk of the work should be handled out-of-interrupt. The ugly loops
25 * that occur during interrupt scare me. The ISR should merely signal
26 * thread context, ACK the interrupt, and move on. -- BenC */
27
28 #include <linux/kernel.h>
29 #include "solo6x10.h"
30
solo_i2c_readbyte(struct solo_dev * solo_dev,int id,u8 addr,u8 off)31 u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)
32 {
33 struct i2c_msg msgs[2];
34 u8 data;
35
36 msgs[0].flags = 0;
37 msgs[0].addr = addr;
38 msgs[0].len = 1;
39 msgs[0].buf = &off;
40
41 msgs[1].flags = I2C_M_RD;
42 msgs[1].addr = addr;
43 msgs[1].len = 1;
44 msgs[1].buf = &data;
45
46 i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);
47
48 return data;
49 }
50
solo_i2c_writebyte(struct solo_dev * solo_dev,int id,u8 addr,u8 off,u8 data)51 void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,
52 u8 off, u8 data)
53 {
54 struct i2c_msg msgs;
55 u8 buf[2];
56
57 buf[0] = off;
58 buf[1] = data;
59 msgs.flags = 0;
60 msgs.addr = addr;
61 msgs.len = 2;
62 msgs.buf = buf;
63
64 i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);
65 }
66
solo_i2c_flush(struct solo_dev * solo_dev,int wr)67 static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)
68 {
69 u32 ctrl;
70
71 ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);
72
73 if (solo_dev->i2c_state == IIC_STATE_START)
74 ctrl |= SOLO_IIC_START;
75
76 if (wr) {
77 ctrl |= SOLO_IIC_WRITE;
78 } else {
79 ctrl |= SOLO_IIC_READ;
80 if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))
81 ctrl |= SOLO_IIC_ACK_EN;
82 }
83
84 if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)
85 ctrl |= SOLO_IIC_STOP;
86
87 solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);
88 }
89
solo_i2c_start(struct solo_dev * solo_dev)90 static void solo_i2c_start(struct solo_dev *solo_dev)
91 {
92 u32 addr = solo_dev->i2c_msg->addr << 1;
93
94 if (solo_dev->i2c_msg->flags & I2C_M_RD)
95 addr |= 1;
96
97 solo_dev->i2c_state = IIC_STATE_START;
98 solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);
99 solo_i2c_flush(solo_dev, 1);
100 }
101
solo_i2c_stop(struct solo_dev * solo_dev)102 static void solo_i2c_stop(struct solo_dev *solo_dev)
103 {
104 solo_irq_off(solo_dev, SOLO_IRQ_IIC);
105 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
106 solo_dev->i2c_state = IIC_STATE_STOP;
107 wake_up(&solo_dev->i2c_wait);
108 }
109
solo_i2c_handle_read(struct solo_dev * solo_dev)110 static int solo_i2c_handle_read(struct solo_dev *solo_dev)
111 {
112 prepare_read:
113 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
114 solo_i2c_flush(solo_dev, 0);
115 return 0;
116 }
117
118 solo_dev->i2c_msg_ptr = 0;
119 solo_dev->i2c_msg++;
120 solo_dev->i2c_msg_num--;
121
122 if (solo_dev->i2c_msg_num == 0) {
123 solo_i2c_stop(solo_dev);
124 return 0;
125 }
126
127 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
128 solo_i2c_start(solo_dev);
129 } else {
130 if (solo_dev->i2c_msg->flags & I2C_M_RD)
131 goto prepare_read;
132 else
133 solo_i2c_stop(solo_dev);
134 }
135
136 return 0;
137 }
138
solo_i2c_handle_write(struct solo_dev * solo_dev)139 static int solo_i2c_handle_write(struct solo_dev *solo_dev)
140 {
141 retry_write:
142 if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
143 solo_reg_write(solo_dev, SOLO_IIC_TXD,
144 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);
145 solo_dev->i2c_msg_ptr++;
146 solo_i2c_flush(solo_dev, 1);
147 return 0;
148 }
149
150 solo_dev->i2c_msg_ptr = 0;
151 solo_dev->i2c_msg++;
152 solo_dev->i2c_msg_num--;
153
154 if (solo_dev->i2c_msg_num == 0) {
155 solo_i2c_stop(solo_dev);
156 return 0;
157 }
158
159 if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
160 solo_i2c_start(solo_dev);
161 } else {
162 if (solo_dev->i2c_msg->flags & I2C_M_RD)
163 solo_i2c_stop(solo_dev);
164 else
165 goto retry_write;
166 }
167
168 return 0;
169 }
170
solo_i2c_isr(struct solo_dev * solo_dev)171 int solo_i2c_isr(struct solo_dev *solo_dev)
172 {
173 u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);
174 int ret = -EINVAL;
175
176 solo_reg_write(solo_dev, SOLO_IRQ_STAT, SOLO_IRQ_IIC);
177
178 if (status & (SOLO_IIC_STATE_TRNS & SOLO_IIC_STATE_SIG_ERR) ||
179 solo_dev->i2c_id < 0) {
180 solo_i2c_stop(solo_dev);
181 return -ENXIO;
182 }
183
184 switch (solo_dev->i2c_state) {
185 case IIC_STATE_START:
186 if (solo_dev->i2c_msg->flags & I2C_M_RD) {
187 solo_dev->i2c_state = IIC_STATE_READ;
188 ret = solo_i2c_handle_read(solo_dev);
189 break;
190 }
191
192 solo_dev->i2c_state = IIC_STATE_WRITE;
193 case IIC_STATE_WRITE:
194 ret = solo_i2c_handle_write(solo_dev);
195 break;
196
197 case IIC_STATE_READ:
198 solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =
199 solo_reg_read(solo_dev, SOLO_IIC_RXD);
200 solo_dev->i2c_msg_ptr++;
201
202 ret = solo_i2c_handle_read(solo_dev);
203 break;
204
205 default:
206 solo_i2c_stop(solo_dev);
207 }
208
209 return ret;
210 }
211
solo_i2c_master_xfer(struct i2c_adapter * adap,struct i2c_msg msgs[],int num)212 static int solo_i2c_master_xfer(struct i2c_adapter *adap,
213 struct i2c_msg msgs[], int num)
214 {
215 struct solo_dev *solo_dev = adap->algo_data;
216 unsigned long timeout;
217 int ret;
218 int i;
219 DEFINE_WAIT(wait);
220
221 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
222 if (&solo_dev->i2c_adap[i] == adap)
223 break;
224 }
225
226 if (i == SOLO_I2C_ADAPTERS)
227 return num; /* XXX Right return value for failure? */
228
229 mutex_lock(&solo_dev->i2c_mutex);
230 solo_dev->i2c_id = i;
231 solo_dev->i2c_msg = msgs;
232 solo_dev->i2c_msg_num = num;
233 solo_dev->i2c_msg_ptr = 0;
234
235 solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
236 solo_irq_on(solo_dev, SOLO_IRQ_IIC);
237 solo_i2c_start(solo_dev);
238
239 timeout = HZ / 2;
240
241 for (;;) {
242 prepare_to_wait(&solo_dev->i2c_wait, &wait, TASK_INTERRUPTIBLE);
243
244 if (solo_dev->i2c_state == IIC_STATE_STOP)
245 break;
246
247 timeout = schedule_timeout(timeout);
248 if (!timeout)
249 break;
250
251 if (signal_pending(current))
252 break;
253 }
254
255 finish_wait(&solo_dev->i2c_wait, &wait);
256 ret = num - solo_dev->i2c_msg_num;
257 solo_dev->i2c_state = IIC_STATE_IDLE;
258 solo_dev->i2c_id = -1;
259
260 mutex_unlock(&solo_dev->i2c_mutex);
261
262 return ret;
263 }
264
solo_i2c_functionality(struct i2c_adapter * adap)265 static u32 solo_i2c_functionality(struct i2c_adapter *adap)
266 {
267 return I2C_FUNC_I2C;
268 }
269
270 static struct i2c_algorithm solo_i2c_algo = {
271 .master_xfer = solo_i2c_master_xfer,
272 .functionality = solo_i2c_functionality,
273 };
274
solo_i2c_init(struct solo_dev * solo_dev)275 int solo_i2c_init(struct solo_dev *solo_dev)
276 {
277 int i;
278 int ret;
279
280 solo_reg_write(solo_dev, SOLO_IIC_CFG,
281 SOLO_IIC_PRESCALE(8) | SOLO_IIC_ENABLE);
282
283 solo_dev->i2c_id = -1;
284 solo_dev->i2c_state = IIC_STATE_IDLE;
285 init_waitqueue_head(&solo_dev->i2c_wait);
286 mutex_init(&solo_dev->i2c_mutex);
287
288 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
289 struct i2c_adapter *adap = &solo_dev->i2c_adap[i];
290
291 snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d", SOLO6X10_NAME, i);
292 adap->algo = &solo_i2c_algo;
293 adap->algo_data = solo_dev;
294 adap->retries = 1;
295 adap->dev.parent = &solo_dev->pdev->dev;
296
297 ret = i2c_add_adapter(adap);
298 if (ret) {
299 adap->algo_data = NULL;
300 break;
301 }
302 }
303
304 if (ret) {
305 for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
306 if (!solo_dev->i2c_adap[i].algo_data)
307 break;
308 i2c_del_adapter(&solo_dev->i2c_adap[i]);
309 solo_dev->i2c_adap[i].algo_data = NULL;
310 }
311 return ret;
312 }
313
314 dev_info(&solo_dev->pdev->dev, "Enabled %d i2c adapters\n",
315 SOLO_I2C_ADAPTERS);
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