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 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 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 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 */ 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 */ 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 */ 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 */ 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 */ 280 int stk1160_i2c_unregister(struct stk1160 *dev) 281 { 282 i2c_del_adapter(&dev->i2c_adap); 283 return 0; 284 } 285