stk1160-i2c.c revision 0c0d06cac63ee327ceaab4b5ffe2206574ab86bd 
1/*
2 * STK1160 driver
3 *
4 * Copyright (C) 2012 Ezequiel Garcia
5 * <elezegarcia--a.t--gmail.com>
6 *
7 * Based on Easycap driver by R.M. Thomas
8 *	Copyright (C) 2010 R.M. Thomas
9 *	<rmthomas--a.t--sciolus.org>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19 * GNU General Public License for more details.
20 *
21 */
22
23#include <linux/module.h>
24#include <linux/usb.h>
25#include <linux/i2c.h>
26
27#include "stk1160.h"
28#include "stk1160-reg.h"
29
30static unsigned int i2c_debug;
31module_param(i2c_debug, int, 0644);
32MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
33
34#define dprintk_i2c(fmt, args...)				\
35do {								\
36	if (i2c_debug)						\
37		printk(KERN_DEBUG fmt, ##args);			\
38} while (0)
39
40static int stk1160_i2c_busy_wait(struct stk1160 *dev, u8 wait_bit_mask)
41{
42	unsigned long end;
43	u8 flag;
44
45	/* Wait until read/write finish bit is set */
46	end = jiffies + msecs_to_jiffies(STK1160_I2C_TIMEOUT);
47	while (time_is_after_jiffies(end)) {
48
49		stk1160_read_reg(dev, STK1160_SICTL+1, &flag);
50		/* read/write done? */
51		if (flag & wait_bit_mask)
52			goto done;
53
54		usleep_range(10 * USEC_PER_MSEC, 20 * USEC_PER_MSEC);
55	}
56
57	return -ETIMEDOUT;
58
59done:
60	return 0;
61}
62
63static int stk1160_i2c_write_reg(struct stk1160 *dev, u8 addr,
64		u8 reg, u8 value)
65{
66	int rc;
67
68	/* Set serial device address */
69	rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
70	if (rc < 0)
71		return rc;
72
73	/* Set i2c device register sub-address */
74	rc = stk1160_write_reg(dev, STK1160_SBUSW_WA, reg);
75	if (rc < 0)
76		return rc;
77
78	/* Set i2c device register value */
79	rc = stk1160_write_reg(dev, STK1160_SBUSW_WD, value);
80	if (rc < 0)
81		return rc;
82
83	/* Start write now */
84	rc = stk1160_write_reg(dev, STK1160_SICTL, 0x01);
85	if (rc < 0)
86		return rc;
87
88	rc = stk1160_i2c_busy_wait(dev, 0x04);
89	if (rc < 0)
90		return rc;
91
92	return 0;
93}
94
95static int stk1160_i2c_read_reg(struct stk1160 *dev, u8 addr,
96		u8 reg, u8 *value)
97{
98	int rc;
99
100	/* Set serial device address */
101	rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
102	if (rc < 0)
103		return rc;
104
105	/* Set i2c device register sub-address */
106	rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, reg);
107	if (rc < 0)
108		return rc;
109
110	/* Start read now */
111	rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
112	if (rc < 0)
113		return rc;
114
115	rc = stk1160_i2c_busy_wait(dev, 0x01);
116	if (rc < 0)
117		return rc;
118
119	stk1160_read_reg(dev, STK1160_SBUSR_RD, value);
120	if (rc < 0)
121		return rc;
122
123	return 0;
124}
125
126/*
127 * stk1160_i2c_check_for_device()
128 * check if there is a i2c_device at the supplied address
129 */
130static int stk1160_i2c_check_for_device(struct stk1160 *dev,
131		unsigned char addr)
132{
133	int rc;
134
135	/* Set serial device address */
136	rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, addr);
137	if (rc < 0)
138		return rc;
139
140	/* Set device sub-address, we'll chip version reg */
141	rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, 0x00);
142	if (rc < 0)
143		return rc;
144
145	/* Start read now */
146	rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
147	if (rc < 0)
148		return rc;
149
150	rc = stk1160_i2c_busy_wait(dev, 0x01);
151	if (rc < 0)
152		return -ENODEV;
153
154	return 0;
155}
156
157/*
158 * stk1160_i2c_xfer()
159 * the main i2c transfer function
160 */
161static int stk1160_i2c_xfer(struct i2c_adapter *i2c_adap,
162			   struct i2c_msg msgs[], int num)
163{
164	struct stk1160 *dev = i2c_adap->algo_data;
165	int addr, rc, i;
166
167	for (i = 0; i < num; i++) {
168		addr = msgs[i].addr << 1;
169		dprintk_i2c("%s: addr=%x", __func__, addr);
170
171		if (!msgs[i].len) {
172			/* no len: check only for device presence */
173			rc = stk1160_i2c_check_for_device(dev, addr);
174			if (rc < 0) {
175				dprintk_i2c(" no device\n");
176				return rc;
177			}
178
179		} else if (msgs[i].flags & I2C_M_RD) {
180			/* read request without preceding register selection */
181			dprintk_i2c(" subaddr not selected");
182			rc = -EOPNOTSUPP;
183			goto err;
184
185		} else if (i + 1 < num && msgs[i].len <= 2 &&
186			   (msgs[i + 1].flags & I2C_M_RD) &&
187			   msgs[i].addr == msgs[i + 1].addr) {
188
189			if (msgs[i].len != 1 || msgs[i + 1].len != 1) {
190				dprintk_i2c(" len not supported");
191				rc = -EOPNOTSUPP;
192				goto err;
193			}
194
195			dprintk_i2c(" subaddr=%x", msgs[i].buf[0]);
196
197			rc = stk1160_i2c_read_reg(dev, addr, msgs[i].buf[0],
198				msgs[i + 1].buf);
199
200			dprintk_i2c(" read=%x", *msgs[i + 1].buf);
201
202			/* consumed two msgs, so we skip one of them */
203			i++;
204
205		} else {
206			if (msgs[i].len != 2) {
207				dprintk_i2c(" len not supported");
208				rc = -EOPNOTSUPP;
209				goto err;
210			}
211
212			dprintk_i2c(" subaddr=%x write=%x",
213				msgs[i].buf[0],  msgs[i].buf[1]);
214
215			rc = stk1160_i2c_write_reg(dev, addr, msgs[i].buf[0],
216				msgs[i].buf[1]);
217		}
218
219		if (rc < 0)
220			goto err;
221		dprintk_i2c(" OK\n");
222	}
223
224	return num;
225err:
226	dprintk_i2c(" ERROR: %d\n", rc);
227	return num;
228}
229
230/*
231 * functionality(), what da heck is this?
232 */
233static u32 functionality(struct i2c_adapter *adap)
234{
235	return I2C_FUNC_SMBUS_EMUL;
236}
237
238static struct i2c_algorithm algo = {
239	.master_xfer   = stk1160_i2c_xfer,
240	.functionality = functionality,
241};
242
243static struct i2c_adapter adap_template = {
244	.owner = THIS_MODULE,
245	.name = "stk1160",
246	.algo = &algo,
247};
248
249static struct i2c_client client_template = {
250	.name = "stk1160 internal",
251};
252
253/*
254 * stk1160_i2c_register()
255 * register i2c bus
256 */
257int stk1160_i2c_register(struct stk1160 *dev)
258{
259	int rc;
260
261	dev->i2c_adap = adap_template;
262	dev->i2c_adap.dev.parent = dev->dev;
263	strcpy(dev->i2c_adap.name, "stk1160");
264	dev->i2c_adap.algo_data = dev;
265
266	i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
267
268	rc = i2c_add_adapter(&dev->i2c_adap);
269	if (rc < 0) {
270		stk1160_err("cannot add i2c adapter (%d)\n", rc);
271		return rc;
272	}
273
274	dev->i2c_client = client_template;
275	dev->i2c_client.adapter = &dev->i2c_adap;
276
277	/* Set i2c clock divider device address */
278	stk1160_write_reg(dev, STK1160_SICTL_CD,  0x0f);
279
280	/* ??? */
281	stk1160_write_reg(dev, STK1160_ASIC + 3,  0x00);
282
283	return 0;
284}
285
286/*
287 * stk1160_i2c_unregister()
288 * unregister i2c_bus
289 */
290int stk1160_i2c_unregister(struct stk1160 *dev)
291{
292	i2c_del_adapter(&dev->i2c_adap);
293	return 0;
294}
295