summaryrefslogtreecommitdiff
path: root/drivers/media/pci/solo6x10/solo6x10-i2c.c
blob: 7db785e9c997913010a29a769b68f7d30bd847b1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2010-2013 Bluecherry, LLC <https://www.bluecherrydvr.com>
 *
 * Original author:
 * Ben Collins <bcollins@ubuntu.com>
 *
 * Additional work by:
 * John Brooks <john.brooks@bluecherry.net>
 */

/* XXX: The SOLO6x10 i2c does not have separate interrupts for each i2c
 * channel. The bus can only handle one i2c event at a time. The below handles
 * this all wrong. We should be using the status registers to see if the bus
 * is in use, and have a global lock to check the status register. Also,
 * the bulk of the work should be handled out-of-interrupt. The ugly loops
 * that occur during interrupt scare me. The ISR should merely signal
 * thread context, ACK the interrupt, and move on. -- BenC */

#include <linux/kernel.h>
#include <linux/sched/signal.h>

#include "solo6x10.h"

u8 solo_i2c_readbyte(struct solo_dev *solo_dev, int id, u8 addr, u8 off)
{
	struct i2c_msg msgs[2];
	u8 data;

	msgs[0].flags = 0;
	msgs[0].addr = addr;
	msgs[0].len = 1;
	msgs[0].buf = &off;

	msgs[1].flags = I2C_M_RD;
	msgs[1].addr = addr;
	msgs[1].len = 1;
	msgs[1].buf = &data;

	i2c_transfer(&solo_dev->i2c_adap[id], msgs, 2);

	return data;
}

void solo_i2c_writebyte(struct solo_dev *solo_dev, int id, u8 addr,
			u8 off, u8 data)
{
	struct i2c_msg msgs;
	u8 buf[2];

	buf[0] = off;
	buf[1] = data;
	msgs.flags = 0;
	msgs.addr = addr;
	msgs.len = 2;
	msgs.buf = buf;

	i2c_transfer(&solo_dev->i2c_adap[id], &msgs, 1);
}

static void solo_i2c_flush(struct solo_dev *solo_dev, int wr)
{
	u32 ctrl;

	ctrl = SOLO_IIC_CH_SET(solo_dev->i2c_id);

	if (solo_dev->i2c_state == IIC_STATE_START)
		ctrl |= SOLO_IIC_START;

	if (wr) {
		ctrl |= SOLO_IIC_WRITE;
	} else {
		ctrl |= SOLO_IIC_READ;
		if (!(solo_dev->i2c_msg->flags & I2C_M_NO_RD_ACK))
			ctrl |= SOLO_IIC_ACK_EN;
	}

	if (solo_dev->i2c_msg_ptr == solo_dev->i2c_msg->len)
		ctrl |= SOLO_IIC_STOP;

	solo_reg_write(solo_dev, SOLO_IIC_CTRL, ctrl);
}

static void solo_i2c_start(struct solo_dev *solo_dev)
{
	u32 addr = solo_dev->i2c_msg->addr << 1;

	if (solo_dev->i2c_msg->flags & I2C_M_RD)
		addr |= 1;

	solo_dev->i2c_state = IIC_STATE_START;
	solo_reg_write(solo_dev, SOLO_IIC_TXD, addr);
	solo_i2c_flush(solo_dev, 1);
}

static void solo_i2c_stop(struct solo_dev *solo_dev)
{
	solo_irq_off(solo_dev, SOLO_IRQ_IIC);
	solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
	solo_dev->i2c_state = IIC_STATE_STOP;
	wake_up(&solo_dev->i2c_wait);
}

static int solo_i2c_handle_read(struct solo_dev *solo_dev)
{
prepare_read:
	if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
		solo_i2c_flush(solo_dev, 0);
		return 0;
	}

	solo_dev->i2c_msg_ptr = 0;
	solo_dev->i2c_msg++;
	solo_dev->i2c_msg_num--;

	if (solo_dev->i2c_msg_num == 0) {
		solo_i2c_stop(solo_dev);
		return 0;
	}

	if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
		solo_i2c_start(solo_dev);
	} else {
		if (solo_dev->i2c_msg->flags & I2C_M_RD)
			goto prepare_read;
		else
			solo_i2c_stop(solo_dev);
	}

	return 0;
}

static int solo_i2c_handle_write(struct solo_dev *solo_dev)
{
retry_write:
	if (solo_dev->i2c_msg_ptr != solo_dev->i2c_msg->len) {
		solo_reg_write(solo_dev, SOLO_IIC_TXD,
			       solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr]);
		solo_dev->i2c_msg_ptr++;
		solo_i2c_flush(solo_dev, 1);
		return 0;
	}

	solo_dev->i2c_msg_ptr = 0;
	solo_dev->i2c_msg++;
	solo_dev->i2c_msg_num--;

	if (solo_dev->i2c_msg_num == 0) {
		solo_i2c_stop(solo_dev);
		return 0;
	}

	if (!(solo_dev->i2c_msg->flags & I2C_M_NOSTART)) {
		solo_i2c_start(solo_dev);
	} else {
		if (solo_dev->i2c_msg->flags & I2C_M_RD)
			solo_i2c_stop(solo_dev);
		else
			goto retry_write;
	}

	return 0;
}

int solo_i2c_isr(struct solo_dev *solo_dev)
{
	u32 status = solo_reg_read(solo_dev, SOLO_IIC_CTRL);
	int ret = -EINVAL;


	if (CHK_FLAGS(status, SOLO_IIC_STATE_TRNS | SOLO_IIC_STATE_SIG_ERR)
	    || solo_dev->i2c_id < 0) {
		solo_i2c_stop(solo_dev);
		return -ENXIO;
	}

	switch (solo_dev->i2c_state) {
	case IIC_STATE_START:
		if (solo_dev->i2c_msg->flags & I2C_M_RD) {
			solo_dev->i2c_state = IIC_STATE_READ;
			ret = solo_i2c_handle_read(solo_dev);
			break;
		}

		solo_dev->i2c_state = IIC_STATE_WRITE;
		fallthrough;
	case IIC_STATE_WRITE:
		ret = solo_i2c_handle_write(solo_dev);
		break;

	case IIC_STATE_READ:
		solo_dev->i2c_msg->buf[solo_dev->i2c_msg_ptr] =
			solo_reg_read(solo_dev, SOLO_IIC_RXD);
		solo_dev->i2c_msg_ptr++;

		ret = solo_i2c_handle_read(solo_dev);
		break;

	default:
		solo_i2c_stop(solo_dev);
	}

	return ret;
}

static int solo_i2c_master_xfer(struct i2c_adapter *adap,
				struct i2c_msg msgs[], int num)
{
	struct solo_dev *solo_dev = adap->algo_data;
	unsigned long timeout;
	int ret;
	int i;
	DEFINE_WAIT(wait);

	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
		if (&solo_dev->i2c_adap[i] == adap)
			break;
	}

	if (i == SOLO_I2C_ADAPTERS)
		return num; /* XXX Right return value for failure? */

	mutex_lock(&solo_dev->i2c_mutex);
	solo_dev->i2c_id = i;
	solo_dev->i2c_msg = msgs;
	solo_dev->i2c_msg_num = num;
	solo_dev->i2c_msg_ptr = 0;

	solo_reg_write(solo_dev, SOLO_IIC_CTRL, 0);
	solo_irq_on(solo_dev, SOLO_IRQ_IIC);
	solo_i2c_start(solo_dev);

	timeout = HZ / 2;

	for (;;) {
		prepare_to_wait(&solo_dev->i2c_wait, &wait,
				TASK_INTERRUPTIBLE);

		if (solo_dev->i2c_state == IIC_STATE_STOP)
			break;

		timeout = schedule_timeout(timeout);
		if (!timeout)
			break;

		if (signal_pending(current))
			break;
	}

	finish_wait(&solo_dev->i2c_wait, &wait);
	ret = num - solo_dev->i2c_msg_num;
	solo_dev->i2c_state = IIC_STATE_IDLE;
	solo_dev->i2c_id = -1;

	mutex_unlock(&solo_dev->i2c_mutex);

	return ret;
}

static u32 solo_i2c_functionality(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C;
}

static const struct i2c_algorithm solo_i2c_algo = {
	.master_xfer	= solo_i2c_master_xfer,
	.functionality	= solo_i2c_functionality,
};

int solo_i2c_init(struct solo_dev *solo_dev)
{
	int i;
	int ret;

	solo_reg_write(solo_dev, SOLO_IIC_CFG,
		       SOLO_IIC_PRESCALE(8) | SOLO_IIC_ENABLE);

	solo_dev->i2c_id = -1;
	solo_dev->i2c_state = IIC_STATE_IDLE;
	init_waitqueue_head(&solo_dev->i2c_wait);
	mutex_init(&solo_dev->i2c_mutex);

	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
		struct i2c_adapter *adap = &solo_dev->i2c_adap[i];

		snprintf(adap->name, I2C_NAME_SIZE, "%s I2C %d",
			 SOLO6X10_NAME, i);
		adap->algo = &solo_i2c_algo;
		adap->algo_data = solo_dev;
		adap->retries = 1;
		adap->dev.parent = &solo_dev->pdev->dev;

		ret = i2c_add_adapter(adap);
		if (ret) {
			adap->algo_data = NULL;
			break;
		}
	}

	if (ret) {
		for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
			if (!solo_dev->i2c_adap[i].algo_data)
				break;
			i2c_del_adapter(&solo_dev->i2c_adap[i]);
			solo_dev->i2c_adap[i].algo_data = NULL;
		}
		return ret;
	}

	return 0;
}

void solo_i2c_exit(struct solo_dev *solo_dev)
{
	int i;

	for (i = 0; i < SOLO_I2C_ADAPTERS; i++) {
		if (!solo_dev->i2c_adap[i].algo_data)
			continue;
		i2c_del_adapter(&solo_dev->i2c_adap[i]);
		solo_dev->i2c_adap[i].algo_data = NULL;
	}
}