1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * STK1160 driver
4 *
5 * Copyright (C) 2012 Ezequiel Garcia
6 * <elezegarcia--a.t--gmail.com>
7 *
8 * Based on Easycap driver by R.M. Thomas
9 * Copyright (C) 2010 R.M. Thomas
10 * <rmthomas--a.t--sciolus.org>
11 */
12
13#include <linux/module.h>
14#include <linux/usb.h>
15#include <linux/i2c.h>
16
17#include "stk1160.h"
18#include "stk1160-reg.h"
19
20static unsigned int i2c_debug;
21module_param(i2c_debug, int, 0644);
22MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
23
24#define dprintk_i2c(fmt, args...) \
25do { \
26 if (i2c_debug) \
27 printk(KERN_DEBUG fmt, ##args); \
28} while (0)
29
30static int stk1160_i2c_busy_wait(struct stk1160 *dev, u8 wait_bit_mask)
31{
32 unsigned long end;
33 u8 flag;
34
35 /* Wait until read/write finish bit is set */
36 end = jiffies + msecs_to_jiffies(STK1160_I2C_TIMEOUT);
37 while (time_is_after_jiffies(end)) {
38
39 stk1160_read_reg(dev, STK1160_SICTL+1, value: &flag);
40 /* read/write done? */
41 if (flag & wait_bit_mask)
42 goto done;
43
44 usleep_range(min: 10 * USEC_PER_MSEC, max: 20 * USEC_PER_MSEC);
45 }
46
47 return -ETIMEDOUT;
48
49done:
50 return 0;
51}
52
53static int stk1160_i2c_write_reg(struct stk1160 *dev, u8 addr,
54 u8 reg, u8 value)
55{
56 int rc;
57
58 /* Set serial device address */
59 rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, value: addr);
60 if (rc < 0)
61 return rc;
62
63 /* Set i2c device register sub-address */
64 rc = stk1160_write_reg(dev, STK1160_SBUSW_WA, value: reg);
65 if (rc < 0)
66 return rc;
67
68 /* Set i2c device register value */
69 rc = stk1160_write_reg(dev, STK1160_SBUSW_WD, value);
70 if (rc < 0)
71 return rc;
72
73 /* Start write now */
74 rc = stk1160_write_reg(dev, STK1160_SICTL, value: 0x01);
75 if (rc < 0)
76 return rc;
77
78 rc = stk1160_i2c_busy_wait(dev, wait_bit_mask: 0x04);
79 if (rc < 0)
80 return rc;
81
82 return 0;
83}
84
85static int stk1160_i2c_read_reg(struct stk1160 *dev, u8 addr,
86 u8 reg, u8 *value)
87{
88 int rc;
89
90 /* Set serial device address */
91 rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, value: addr);
92 if (rc < 0)
93 return rc;
94
95 /* Set i2c device register sub-address */
96 rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, value: reg);
97 if (rc < 0)
98 return rc;
99
100 /* Start read now */
101 rc = stk1160_write_reg(dev, STK1160_SICTL, value: 0x20);
102 if (rc < 0)
103 return rc;
104
105 rc = stk1160_i2c_busy_wait(dev, wait_bit_mask: 0x01);
106 if (rc < 0)
107 return rc;
108
109 rc = stk1160_read_reg(dev, STK1160_SBUSR_RD, value);
110 if (rc < 0)
111 return rc;
112
113 return 0;
114}
115
116/*
117 * stk1160_i2c_check_for_device()
118 * check if there is a i2c_device at the supplied address
119 */
120static int stk1160_i2c_check_for_device(struct stk1160 *dev,
121 unsigned char addr)
122{
123 int rc;
124
125 /* Set serial device address */
126 rc = stk1160_write_reg(dev, STK1160_SICTL_SDA, value: addr);
127 if (rc < 0)
128 return rc;
129
130 /* Set device sub-address, we'll chip version reg */
131 rc = stk1160_write_reg(dev, STK1160_SBUSR_RA, value: 0x00);
132 if (rc < 0)
133 return rc;
134
135 /* Start read now */
136 rc = stk1160_write_reg(dev, STK1160_SICTL, value: 0x20);
137 if (rc < 0)
138 return rc;
139
140 rc = stk1160_i2c_busy_wait(dev, wait_bit_mask: 0x01);
141 if (rc < 0)
142 return -ENODEV;
143
144 return 0;
145}
146
147/*
148 * stk1160_i2c_xfer()
149 * the main i2c transfer function
150 */
151static int stk1160_i2c_xfer(struct i2c_adapter *i2c_adap,
152 struct i2c_msg msgs[], int num)
153{
154 struct stk1160 *dev = i2c_adap->algo_data;
155 int addr, rc, i;
156
157 for (i = 0; i < num; i++) {
158 addr = msgs[i].addr << 1;
159 dprintk_i2c("%s: addr=%x", __func__, addr);
160
161 if (!msgs[i].len) {
162 /* no len: check only for device presence */
163 rc = stk1160_i2c_check_for_device(dev, addr);
164 if (rc < 0) {
165 dprintk_i2c(" no device\n");
166 return rc;
167 }
168
169 } else if (msgs[i].flags & I2C_M_RD) {
170 /* read request without preceding register selection */
171 dprintk_i2c(" subaddr not selected");
172 rc = -EOPNOTSUPP;
173 goto err;
174
175 } else if (i + 1 < num && msgs[i].len <= 2 &&
176 (msgs[i + 1].flags & I2C_M_RD) &&
177 msgs[i].addr == msgs[i + 1].addr) {
178
179 if (msgs[i].len != 1 || msgs[i + 1].len != 1) {
180 dprintk_i2c(" len not supported");
181 rc = -EOPNOTSUPP;
182 goto err;
183 }
184
185 dprintk_i2c(" subaddr=%x", msgs[i].buf[0]);
186
187 rc = stk1160_i2c_read_reg(dev, addr, reg: msgs[i].buf[0],
188 value: msgs[i + 1].buf);
189
190 dprintk_i2c(" read=%x", *msgs[i + 1].buf);
191
192 /* consumed two msgs, so we skip one of them */
193 i++;
194
195 } else {
196 if (msgs[i].len != 2) {
197 dprintk_i2c(" len not supported");
198 rc = -EOPNOTSUPP;
199 goto err;
200 }
201
202 dprintk_i2c(" subaddr=%x write=%x",
203 msgs[i].buf[0], msgs[i].buf[1]);
204
205 rc = stk1160_i2c_write_reg(dev, addr, reg: msgs[i].buf[0],
206 value: msgs[i].buf[1]);
207 }
208
209 if (rc < 0)
210 goto err;
211 dprintk_i2c(" OK\n");
212 }
213
214 return num;
215err:
216 dprintk_i2c(" ERROR: %d\n", rc);
217 return num;
218}
219
220/*
221 * functionality(), what da heck is this?
222 */
223static u32 functionality(struct i2c_adapter *adap)
224{
225 return I2C_FUNC_SMBUS_EMUL;
226}
227
228static const struct i2c_algorithm algo = {
229 .master_xfer = stk1160_i2c_xfer,
230 .functionality = functionality,
231};
232
233static const struct i2c_adapter adap_template = {
234 .owner = THIS_MODULE,
235 .name = "stk1160",
236 .algo = &algo,
237};
238
239static const struct i2c_client client_template = {
240 .name = "stk1160 internal",
241};
242
243/*
244 * stk1160_i2c_register()
245 * register i2c bus
246 */
247int stk1160_i2c_register(struct stk1160 *dev)
248{
249 int rc;
250
251 dev->i2c_adap = adap_template;
252 dev->i2c_adap.dev.parent = dev->dev;
253 strscpy(dev->i2c_adap.name, "stk1160", sizeof(dev->i2c_adap.name));
254 dev->i2c_adap.algo_data = dev;
255
256 i2c_set_adapdata(adap: &dev->i2c_adap, data: &dev->v4l2_dev);
257
258 rc = i2c_add_adapter(adap: &dev->i2c_adap);
259 if (rc < 0) {
260 stk1160_err("cannot add i2c adapter (%d)\n", rc);
261 return rc;
262 }
263
264 dev->i2c_client = client_template;
265 dev->i2c_client.adapter = &dev->i2c_adap;
266
267 /* Set i2c clock divider device address */
268 stk1160_write_reg(dev, STK1160_SICTL_CD, value: 0x0f);
269
270 /* ??? */
271 stk1160_write_reg(dev, STK1160_ASIC + 3, value: 0x00);
272
273 return 0;
274}
275
276/*
277 * stk1160_i2c_unregister()
278 * unregister i2c_bus
279 */
280int stk1160_i2c_unregister(struct stk1160 *dev)
281{
282 i2c_del_adapter(adap: &dev->i2c_adap);
283 return 0;
284}
285

source code of linux/drivers/media/usb/stk1160/stk1160-i2c.c