BeRTOS
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00001 00039 #include "hw/hw_i2c_bitbang.h" 00040 00041 #include "cfg/cfg_i2c.h" 00042 00043 #define LOG_LEVEL I2C_LOG_LEVEL 00044 #define LOG_FORMAT I2C_LOG_FORMAT 00045 00046 #include <cfg/log.h> 00047 #include <cfg/macros.h> 00048 #include <cfg/module.h> 00049 00050 #include <drv/timer.h> 00051 #include <drv/i2c.h> 00052 00053 #include <cpu/irq.h> 00054 00055 #include <cpu/attr.h> 00056 00057 #if !CONFIG_I2C_DISABLE_OLD_API 00058 00059 INLINE bool i2c_bitbang_start(void) 00060 { 00061 SDA_HI; 00062 SCL_HI; 00063 I2C_HALFBIT_DELAY(); 00064 SDA_LO; 00065 I2C_HALFBIT_DELAY(); 00066 00067 return !SDA_IN; 00068 } 00069 00070 void i2c_bitbang_stop(void) 00071 { 00072 SDA_LO; 00073 SCL_HI; 00074 I2C_HALFBIT_DELAY(); 00075 SDA_HI; 00076 } 00077 00078 bool i2c_bitbang_put(uint8_t _data) 00079 { 00080 /* Add ACK bit */ 00081 uint16_t data = (_data << 1) | 1; 00082 00083 for (uint16_t i = 0x100; i != 0; i >>= 1) 00084 { 00085 SCL_LO; 00086 if (data & i) 00087 SDA_HI; 00088 else 00089 SDA_LO; 00090 I2C_HALFBIT_DELAY(); 00091 00092 SCL_HI; 00093 I2C_HALFBIT_DELAY(); 00094 } 00095 00096 bool ack = !SDA_IN; 00097 SCL_LO; 00098 I2C_HALFBIT_DELAY(); 00099 return ack; 00100 } 00101 00102 bool i2c_bitbang_start_w(uint8_t id) 00103 { 00104 id &= ~I2C_READBIT; 00105 /* 00106 * Loop on the select write sequence: when the device is busy 00107 * writing previously sent data it will reply to the SLA_W 00108 * control byte with a NACK. In this case, we must 00109 * keep trying until the deveice responds with an ACK. 00110 */ 00111 ticks_t start = timer_clock(); 00112 while (i2c_bitbang_start()) 00113 { 00114 if (i2c_bitbang_put(id)) 00115 return true; 00116 else if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT)) 00117 { 00118 LOG_ERR("Timeout on I2C start write\n"); 00119 break; 00120 } 00121 //LOG_INFO("Rep start\n"); 00122 } 00123 00124 return false; 00125 } 00126 00127 bool i2c_bitbang_start_r(uint8_t id) 00128 { 00129 id |= I2C_READBIT; 00130 if (i2c_bitbang_start()) 00131 { 00132 if (i2c_bitbang_put(id)) 00133 return true; 00134 00135 LOG_ERR("NACK on I2c start read\n"); 00136 } 00137 00138 return false; 00139 } 00140 00141 int i2c_bitbang_get(bool ack) 00142 { 00143 uint8_t data = 0; 00144 for (uint8_t i = 0x80; i != 0; i >>= 1) 00145 { 00146 SCL_LO; 00147 I2C_HALFBIT_DELAY(); 00148 SCL_HI; 00149 if (SDA_IN) 00150 data |= i; 00151 else 00152 data &= ~i; 00153 00154 I2C_HALFBIT_DELAY(); 00155 } 00156 SCL_LO; 00157 00158 if (ack) 00159 SDA_LO; 00160 else 00161 SDA_HI; 00162 00163 I2C_HALFBIT_DELAY(); 00164 SCL_HI; 00165 I2C_HALFBIT_DELAY(); 00166 SCL_LO; 00167 SDA_HI; 00168 /* avoid sign extension */ 00169 return (int)(uint8_t)data; 00170 } 00171 00172 #endif /* !CONFIG_I2C_DISABLE_OLD_API */ 00173 00174 /* 00175 * New I2C API 00176 */ 00177 static bool old_api = false; 00178 #define I2C_DEV(i2c) ((int)((i2c)->hw)) 00179 00180 static void i2c_bitbang_stop_1(struct I2c *i2c) 00181 { 00182 if (old_api) 00183 { 00184 SDA_LO; 00185 SCL_HI; 00186 I2C_HALFBIT_DELAY(); 00187 SDA_HI; 00188 } 00189 else 00190 { 00191 i2c_sdaLo(I2C_DEV(i2c)); 00192 i2c_sclHi(I2C_DEV(i2c)); 00193 i2c_halfbitDelay(I2C_DEV(i2c)); 00194 i2c_sdaHi(I2C_DEV(i2c)); 00195 } 00196 } 00197 00198 INLINE bool i2c_bitbang_start_1(struct I2c *i2c) 00199 { 00200 bool ret; 00201 /* Clear all error, we restart */ 00202 i2c->errors &= ~(I2C_NO_ACK | I2C_ARB_LOST); 00203 00204 if (old_api) 00205 { 00206 SDA_HI; 00207 SCL_HI; 00208 I2C_HALFBIT_DELAY(); 00209 SDA_LO; 00210 I2C_HALFBIT_DELAY(); 00211 00212 ret = !SDA_IN; 00213 } 00214 else 00215 { 00216 i2c_sdaHi(I2C_DEV(i2c)); 00217 i2c_sclHi(I2C_DEV(i2c)); 00218 i2c_halfbitDelay(I2C_DEV(i2c)); 00219 i2c_sdaLo(I2C_DEV(i2c)); 00220 i2c_halfbitDelay(I2C_DEV(i2c)); 00221 00222 ret = !i2c_sdaIn(I2C_DEV(i2c)); 00223 } 00224 00225 return ret; 00226 } 00227 00228 00229 static uint8_t i2c_bitbang_getc(struct I2c *i2c) 00230 { 00231 uint8_t data = 0; 00232 if (old_api) 00233 { 00234 for (uint8_t i = 0x80; i != 0; i >>= 1) 00235 { 00236 SCL_LO; 00237 I2C_HALFBIT_DELAY(); 00238 SCL_HI; 00239 if (SDA_IN) 00240 data |= i; 00241 else 00242 data &= ~i; 00243 00244 I2C_HALFBIT_DELAY(); 00245 } 00246 SCL_LO; 00247 00248 /* Generate ACK/NACK */ 00249 if (i2c->xfer_size > 1) 00250 SDA_LO; 00251 else 00252 SDA_HI; 00253 00254 I2C_HALFBIT_DELAY(); 00255 SCL_HI; 00256 I2C_HALFBIT_DELAY(); 00257 SCL_LO; 00258 SDA_HI; 00259 } 00260 else 00261 { 00262 for (uint8_t i = 0x80; i != 0; i >>= 1) 00263 { 00264 i2c_sclLo(I2C_DEV(i2c)); 00265 i2c_halfbitDelay(I2C_DEV(i2c)); 00266 i2c_sclHi(I2C_DEV(i2c)); 00267 if (i2c_sdaIn(I2C_DEV(i2c))) 00268 data |= i; 00269 else 00270 data &= ~i; 00271 00272 i2c_halfbitDelay(I2C_DEV(i2c)); 00273 } 00274 i2c_sclLo(I2C_DEV(i2c)); 00275 00276 /* Generate ACK/NACK */ 00277 if (i2c->xfer_size > 1) 00278 i2c_sdaLo(I2C_DEV(i2c)); 00279 else 00280 i2c_sdaHi(I2C_DEV(i2c)); 00281 00282 i2c_halfbitDelay(I2C_DEV(i2c)); 00283 i2c_sclHi(I2C_DEV(i2c)); 00284 i2c_halfbitDelay(I2C_DEV(i2c)); 00285 i2c_sclLo(I2C_DEV(i2c)); 00286 i2c_sdaHi(I2C_DEV(i2c)); 00287 } 00288 00289 /* Generate stop condition (if requested) */ 00290 if ((i2c->xfer_size == 1) && (i2c->flags & I2C_STOP)) 00291 i2c_bitbang_stop_1(i2c); 00292 00293 return data; 00294 } 00295 00296 INLINE void i2c_bitbang_putcStop(struct I2c *i2c, uint8_t _data, bool stop) 00297 { 00298 /* Add ACK bit */ 00299 uint16_t data = (_data << 1) | 1; 00300 bool ack; 00301 00302 if (old_api) 00303 { 00304 for (uint16_t i = 0x100; i != 0; i >>= 1) 00305 { 00306 SCL_LO; 00307 if (data & i) 00308 SDA_HI; 00309 else 00310 SDA_LO; 00311 I2C_HALFBIT_DELAY(); 00312 00313 SCL_HI; 00314 I2C_HALFBIT_DELAY(); 00315 } 00316 00317 ack = !SDA_IN; 00318 SCL_LO; 00319 I2C_HALFBIT_DELAY(); 00320 } 00321 else 00322 { 00323 for (uint16_t i = 0x100; i != 0; i >>= 1) 00324 { 00325 i2c_sclLo(I2C_DEV(i2c)); 00326 if (data & i) 00327 i2c_sdaHi(I2C_DEV(i2c)); 00328 else 00329 i2c_sdaLo(I2C_DEV(i2c)); 00330 i2c_halfbitDelay(I2C_DEV(i2c)); 00331 00332 i2c_sclHi(I2C_DEV(i2c)); 00333 i2c_halfbitDelay(I2C_DEV(i2c)); 00334 } 00335 ack = !i2c_sdaIn(I2C_DEV(i2c)); 00336 00337 i2c_sclLo(I2C_DEV(i2c)); 00338 i2c_halfbitDelay(I2C_DEV(i2c)); 00339 } 00340 00341 if (!ack) 00342 i2c->errors |= I2C_NO_ACK; 00343 00344 /* Generate stop condition (if requested) */ 00345 if (stop || i2c->errors) 00346 i2c_bitbang_stop_1(i2c); 00347 } 00348 00349 static void i2c_bitbang_putc(struct I2c *i2c, uint8_t data) 00350 { 00351 i2c_bitbang_putcStop(i2c, data, 00352 (i2c->xfer_size == 1) && (i2c->flags & I2C_STOP)); 00353 } 00354 00355 static void i2c_bitbang_start_2(struct I2c *i2c, uint16_t slave_addr) 00356 { 00357 if (i2c->flags & I2C_START_R) 00358 slave_addr |= I2C_READBIT; 00359 else 00360 slave_addr &= ~I2C_READBIT; 00361 00362 /* 00363 * Loop on the select write sequence: when the device is busy 00364 * writing previously sent data it will reply to the SLA_W 00365 * control byte with a NACK. In this case, we must 00366 * keep trying until the device responds with an ACK. 00367 */ 00368 ticks_t start = timer_clock(); 00369 while (i2c_bitbang_start_1(i2c)) 00370 { 00371 i2c_bitbang_putcStop(i2c, slave_addr, false); 00372 00373 if (!(i2c->errors & I2C_NO_ACK)) 00374 return; 00375 else if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT)) 00376 { 00377 LOG_ERR("Timeout on I2C start\n"); 00378 i2c->errors |= I2C_START_TIMEOUT; 00379 i2c_bitbang_stop_1(i2c); 00380 return; 00381 } 00382 } 00383 00384 LOG_ERR("START arbitration lost\n"); 00385 i2c->errors |= I2C_ARB_LOST; 00386 i2c_bitbang_stop_1(i2c); 00387 return; 00388 } 00389 00390 00391 static const I2cVT i2c_bitbang_vt = 00392 { 00393 .start = i2c_bitbang_start_2, 00394 .getc = i2c_bitbang_getc, 00395 .putc = i2c_bitbang_putc, 00396 .write = i2c_genericWrite, 00397 .read = i2c_genericRead, 00398 }; 00399 00400 00404 void i2c_hw_bitbangInit(I2c *i2c, int dev) 00405 { 00406 MOD_CHECK(timer); 00407 if (dev == I2C_BITBANG_OLD) 00408 old_api = true; 00409 else 00410 i2c->hw = (struct I2cHardware *)(dev - I2C_BITBANG0); 00411 00412 i2c->vt = &i2c_bitbang_vt; 00413 00414 if (old_api) 00415 { 00416 I2C_BITBANG_HW_INIT; 00417 SDA_HI; 00418 SCL_HI; 00419 } 00420 else 00421 { 00422 i2c_bitbangInit(I2C_DEV(i2c)); 00423 i2c_sdaHi(I2C_DEV(i2c)); 00424 i2c_sclHi(I2C_DEV(i2c)); 00425 } 00426 } 00427