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 30 static unsigned int i2c_debug; 31 module_param(i2c_debug, int, 0644); 32 MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]"); 33 34 #define dprintk_i2c(fmt, args...) \ 35 do { \ 36 if (i2c_debug) \ 37 printk(KERN_DEBUG fmt, ##args); \ 38 } while (0) 39 40 static 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 59 done: 60 return 0; 61 } 62 63 static 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 95 static 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 rc = 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 */ 130 static 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 */ 161 static 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; 225 err: 226 dprintk_i2c(" ERROR: %d\n", rc); 227 return num; 228 } 229 230 /* 231 * functionality(), what da heck is this? 232 */ 233 static u32 functionality(struct i2c_adapter *adap) 234 { 235 return I2C_FUNC_SMBUS_EMUL; 236 } 237 238 static const struct i2c_algorithm algo = { 239 .master_xfer = stk1160_i2c_xfer, 240 .functionality = functionality, 241 }; 242 243 static const struct i2c_adapter adap_template = { 244 .owner = THIS_MODULE, 245 .name = "stk1160", 246 .algo = &algo, 247 }; 248 249 static const struct i2c_client client_template = { 250 .name = "stk1160 internal", 251 }; 252 253 /* 254 * stk1160_i2c_register() 255 * register i2c bus 256 */ 257 int 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 */ 290 int stk1160_i2c_unregister(struct stk1160 *dev) 291 { 292 i2c_del_adapter(&dev->i2c_adap); 293 return 0; 294 } 295