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
20 static unsigned int i2c_debug;
21 module_param(i2c_debug, int, 0644);
22 MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
23
24 #define dprintk_i2c(fmt, args...) \
25 do { \
26 if (i2c_debug) \
27 printk(KERN_DEBUG fmt, ##args); \
28 } while (0)
29
stk1160_i2c_busy_wait(struct stk1160 * dev,u8 wait_bit_mask)30 static 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, &flag);
40 /* read/write done? */
41 if (flag & wait_bit_mask)
42 goto done;
43
44 usleep_range(10 * USEC_PER_MSEC, 20 * USEC_PER_MSEC);
45 }
46
47 return -ETIMEDOUT;
48
49 done:
50 return 0;
51 }
52
stk1160_i2c_write_reg(struct stk1160 * dev,u8 addr,u8 reg,u8 value)53 static 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, 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, 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, 0x01);
75 if (rc < 0)
76 return rc;
77
78 rc = stk1160_i2c_busy_wait(dev, 0x04);
79 if (rc < 0)
80 return rc;
81
82 return 0;
83 }
84
stk1160_i2c_read_reg(struct stk1160 * dev,u8 addr,u8 reg,u8 * value)85 static 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, 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, reg);
97 if (rc < 0)
98 return rc;
99
100 /* Start read now */
101 rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
102 if (rc < 0)
103 return rc;
104
105 rc = stk1160_i2c_busy_wait(dev, 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 */
stk1160_i2c_check_for_device(struct stk1160 * dev,unsigned char addr)120 static 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, 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, 0x00);
132 if (rc < 0)
133 return rc;
134
135 /* Start read now */
136 rc = stk1160_write_reg(dev, STK1160_SICTL, 0x20);
137 if (rc < 0)
138 return rc;
139
140 rc = stk1160_i2c_busy_wait(dev, 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 */
stk1160_i2c_xfer(struct i2c_adapter * i2c_adap,struct i2c_msg msgs[],int num)151 static 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, msgs[i].buf[0],
188 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, msgs[i].buf[0],
206 msgs[i].buf[1]);
207 }
208
209 if (rc < 0)
210 goto err;
211 dprintk_i2c(" OK\n");
212 }
213
214 return num;
215 err:
216 dprintk_i2c(" ERROR: %d\n", rc);
217 return num;
218 }
219
220 /*
221 * functionality(), what da heck is this?
222 */
functionality(struct i2c_adapter * adap)223 static u32 functionality(struct i2c_adapter *adap)
224 {
225 return I2C_FUNC_SMBUS_EMUL;
226 }
227
228 static const struct i2c_algorithm algo = {
229 .master_xfer = stk1160_i2c_xfer,
230 .functionality = functionality,
231 };
232
233 static const struct i2c_adapter adap_template = {
234 .owner = THIS_MODULE,
235 .name = "stk1160",
236 .algo = &algo,
237 };
238
239 static const struct i2c_client client_template = {
240 .name = "stk1160 internal",
241 };
242
243 /*
244 * stk1160_i2c_register()
245 * register i2c bus
246 */
stk1160_i2c_register(struct stk1160 * dev)247 int 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(&dev->i2c_adap, &dev->v4l2_dev);
257
258 rc = i2c_add_adapter(&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, 0x0f);
269
270 /* ??? */
271 stk1160_write_reg(dev, STK1160_ASIC + 3, 0x00);
272
273 return 0;
274 }
275
276 /*
277 * stk1160_i2c_unregister()
278 * unregister i2c_bus
279 */
stk1160_i2c_unregister(struct stk1160 * dev)280 int stk1160_i2c_unregister(struct stk1160 *dev)
281 {
282 i2c_del_adapter(&dev->i2c_adap);
283 return 0;
284 }
285