board/trab/tsc2000.c

   1 /*
   2  * Functions to access the TSC2000 controller on TRAB board (used for scanning
   3  * thermo sensors)
   4  *
   5  * Copyright (C) 2003 Martin Krause, TQ-Systems GmbH, martin.krause@tqs.de
   6  *
   7  * Copyright (C) 2002 DENX Software Engineering, Wolfgang Denk, wd@denx.de
   8  *
   9  * See file CREDITS for list of people who contributed to this
  10  * project.
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of
  15  * the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  25  * MA 02111-1307 USA
  26  */
  27
  28 #include <common.h>
  29 #include <asm/arch/s3c24x0_cpu.h>
  30 #include <asm/io.h>
  31 #include <div64.h>
  32 #include "tsc2000.h"
  33
  34 #include "Pt1000_temp_data.h"
  35
  36 /* helper function */
  37 #define abs(value) (((value) < 0) ? ((value)*-1) : (value))
  38
  39 /*
  40  * Maximal allowed deviation between two immediate meassurments of an analog
  41  * thermo channel. 1 DIGIT = 0.0276 °C. This is used to filter sporadic
  42  * "jumps" in measurment.
  43  */
  44 #define MAX_DEVIATION   18      /* unit: DIGITs of adc; 18 DIGIT = 0.5 °C */
  45
  46 void tsc2000_spi_init(void)
  47 {
  48         struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();
  49         struct s3c24x0_spi * const spi = s3c24x0_get_base_spi();
  50         int i;
  51
  52         /* Configure I/O ports. */
  53         gpio->pdcon = (gpio->pdcon & 0xF3FFFF) | 0x040000;
  54         gpio->pgcon = (gpio->pgcon & 0x0F3FFF) | 0x008000;
  55         gpio->pgcon = (gpio->pgcon & 0x0CFFFF) | 0x020000;
  56         gpio->pgcon = (gpio->pgcon & 0x03FFFF) | 0x080000;
  57
  58         CLR_CS_TOUCH();
  59
  60         spi->ch[0].sppre = 0x1F; /* Baud-rate ca. 514kHz */
  61         spi->ch[0].sppin = 0x01; /* SPI-MOSI holds Level after last bit */
  62         spi->ch[0].spcon = 0x1A; /* Polling, Prescaler, Master, CPOL=0,
  63                                     CPHA=1 */
  64
  65         /* Dummy byte ensures clock to be low. */
  66         for (i = 0; i < 10; i++) {
  67                 spi->ch[0].sptdat = 0xFF;
  68         }
  69         spi_wait_transmit_done();
  70 }
  71
  72
  73 void spi_wait_transmit_done(void)
  74 {
  75         struct s3c24x0_spi * const spi = s3c24x0_get_base_spi();
  76
  77         while (!(spi->ch[0].spsta & 0x01)) /* wait until transfer is done */
  78                 ;
  79 }
  80
  81
  82 void tsc2000_write(unsigned short reg, unsigned short data)
  83 {
  84         struct s3c24x0_spi * const spi = s3c24x0_get_base_spi();
  85         unsigned int command;
  86
  87         SET_CS_TOUCH();
  88         command = reg;
  89         spi->ch[0].sptdat = (command & 0xFF00) >> 8;
  90         spi_wait_transmit_done();
  91         spi->ch[0].sptdat = (command & 0x00FF);
  92         spi_wait_transmit_done();
  93         spi->ch[0].sptdat = (data & 0xFF00) >> 8;
  94         spi_wait_transmit_done();
  95         spi->ch[0].sptdat = (data & 0x00FF);
  96         spi_wait_transmit_done();
  97
  98         CLR_CS_TOUCH();
  99 }
 100
 101
 102 unsigned short tsc2000_read (unsigned short reg)
 103 {
 104         unsigned short command, data;
 105         struct s3c24x0_spi * const spi = s3c24x0_get_base_spi();
 106
 107         SET_CS_TOUCH();
 108         command = 0x8000 | reg;
 109
 110         spi->ch[0].sptdat = (command & 0xFF00) >> 8;
 111         spi_wait_transmit_done();
 112         spi->ch[0].sptdat = (command & 0x00FF);
 113         spi_wait_transmit_done();
 114
 115         spi->ch[0].sptdat = 0xFF;
 116         spi_wait_transmit_done();
 117         data = spi->ch[0].sprdat;
 118         spi->ch[0].sptdat = 0xFF;
 119         spi_wait_transmit_done();
 120
 121         CLR_CS_TOUCH();
 122         return (spi->ch[0].sprdat & 0x0FF) | (data << 8);
 123 }
 124
 125
 126 void tsc2000_set_mux (unsigned int channel)
 127 {
 128         struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();
 129
 130         CLR_MUX1_ENABLE; CLR_MUX2_ENABLE;
 131         CLR_MUX3_ENABLE; CLR_MUX4_ENABLE;
 132         switch (channel) {
 133         case 0:
 134                 CLR_MUX0; CLR_MUX1;
 135                 SET_MUX1_ENABLE;
 136                 break;
 137         case 1:
 138                 SET_MUX0; CLR_MUX1;
 139                 SET_MUX1_ENABLE;
 140                 break;
 141         case 2:
 142                 CLR_MUX0; SET_MUX1;
 143                 SET_MUX1_ENABLE;
 144                 break;
 145         case 3:
 146                 SET_MUX0; SET_MUX1;
 147                 SET_MUX1_ENABLE;
 148                 break;
 149         case 4:
 150                 CLR_MUX0; CLR_MUX1;
 151                 SET_MUX2_ENABLE;
 152                 break;
 153         case 5:
 154                 SET_MUX0; CLR_MUX1;
 155                 SET_MUX2_ENABLE;
 156                 break;
 157         case 6:
 158                 CLR_MUX0; SET_MUX1;
 159                 SET_MUX2_ENABLE;
 160                 break;
 161         case 7:
 162                 SET_MUX0; SET_MUX1;
 163                 SET_MUX2_ENABLE;
 164                 break;
 165         case 8:
 166                 CLR_MUX0; CLR_MUX1;
 167                 SET_MUX3_ENABLE;
 168                 break;
 169         case 9:
 170                 SET_MUX0; CLR_MUX1;
 171                 SET_MUX3_ENABLE;
 172                 break;
 173         case 10:
 174                 CLR_MUX0; SET_MUX1;
 175                 SET_MUX3_ENABLE;
 176                 break;
 177         case 11:
 178                 SET_MUX0; SET_MUX1;
 179                 SET_MUX3_ENABLE;
 180                 break;
 181         case 12:
 182                 CLR_MUX0; CLR_MUX1;
 183                 SET_MUX4_ENABLE;
 184                 break;
 185         case 13:
 186                 SET_MUX0; CLR_MUX1;
 187                 SET_MUX4_ENABLE;
 188                 break;
 189         case 14:
 190                 CLR_MUX0; SET_MUX1;
 191                 SET_MUX4_ENABLE;
 192                 break;
 193         case 15:
 194                 SET_MUX0; SET_MUX1;
 195                 SET_MUX4_ENABLE;
 196                 break;
 197         default:
 198                 CLR_MUX0; CLR_MUX1;
 199         }
 200 }
 201
 202
 203 void tsc2000_set_range (unsigned int range)
 204 {
 205         struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();
 206
 207         switch (range) {
 208         case 1:
 209                 CLR_SEL_TEMP_V_0; SET_SEL_TEMP_V_1;
 210                 CLR_SEL_TEMP_V_2; CLR_SEL_TEMP_V_3;
 211                 break;
 212         case 2:
 213                 CLR_SEL_TEMP_V_0; CLR_SEL_TEMP_V_1;
 214                 CLR_SEL_TEMP_V_2; SET_SEL_TEMP_V_3;
 215                 break;
 216         case 3:
 217                 SET_SEL_TEMP_V_0; CLR_SEL_TEMP_V_1;
 218                 SET_SEL_TEMP_V_2; CLR_SEL_TEMP_V_3;
 219                 break;
 220         }
 221 }
 222
 223
 224 u16 tsc2000_read_channel (unsigned int channel)
 225 {
 226         u16 res;
 227
 228         tsc2000_set_mux(channel);
 229         udelay(20 * TSC2000_DELAY_BASE);
 230
 231         tsc2000_write(TSC2000_REG_ADC, 0x2036);
 232         adc_wait_conversion_done ();
 233         res = tsc2000_read(TSC2000_REG_AUX1);
 234         return res;
 235 }
 236
 237
 238 s32 tsc2000_contact_temp (void)
 239 {
 240         long adc_pt1000, offset;
 241         long u_pt1000;
 242         long contact_temp;
 243         long temp1, temp2;
 244
 245         tsc2000_reg_init ();
 246         tsc2000_set_range (3);
 247
 248         /*
 249          * Because of sporadic "jumps" in the measured adc values every
 250          * channel is read two times. If there is a significant difference
 251          * between the two measurements, then print an error and do a third
 252          * measurement, because it is very unlikely that a successive third
 253          * measurement goes also wrong.
 254          */
 255         temp1 = tsc2000_read_channel (14);
 256         temp2 = tsc2000_read_channel (14);
 257         if (abs(temp2 - temp1) < MAX_DEVIATION)
 258                 adc_pt1000 = temp2;
 259         else {
 260                 printf ("%s: read adc value (channel 14) exceeded max allowed "
 261                         "deviation: %d * 0.0276 °C\n",
 262                         __FUNCTION__, MAX_DEVIATION);
 263                 printf ("adc value 1: %ld DIGITs\nadc value 2: %ld DIGITs\n",
 264                         temp1, temp2);
 265                 adc_pt1000 = tsc2000_read_channel (14);
 266                 printf ("use (third read) adc value: adc_pt1000 = "
 267                         "%ld DIGITs\n", adc_pt1000);
 268         }
 269         debug ("read channel 14 (pt1000 adc value): %ld\n", adc_pt1000);
 270
 271         temp1 = tsc2000_read_channel (15);
 272         temp2 = tsc2000_read_channel (15);
 273         if (abs(temp2 - temp1) < MAX_DEVIATION)
 274                 offset = temp2;
 275         else {
 276                 printf ("%s: read adc value (channel 15) exceeded max allowed "
 277                         "deviation: %d * 0.0276 °C\n",
 278                         __FUNCTION__, MAX_DEVIATION);
 279                 printf ("adc value 1: %ld DIGITs\nadc value 2: %ld DIGITs\n",
 280                         temp1, temp2);
 281                 offset = tsc2000_read_channel (15);
 282                 printf ("use (third read) adc value: offset = %ld DIGITs\n",
 283                         offset);
 284         }
 285         debug ("read channel 15 (offset): %ld\n", offset);
 286
 287         /*
 288          * Formula for calculating voltage drop on PT1000 resistor: u_pt1000 =
 289          * x_range3 * (adc_raw - offset) / 10. Formula to calculate x_range3:
 290          * x_range3 = (2500 * (1000000 + err_vref + err_amp3)) / (4095*6). The
 291          * error correction Values err_vref and err_amp3 are assumed as 0 in
 292          * u-boot, because this could cause only a very small error (< 1%).
 293          */
 294         u_pt1000 = (101750 * (adc_pt1000 - offset)) / 10;
 295         debug ("u_pt1000: %ld\n", u_pt1000);
 296
 297         if (tsc2000_interpolate(u_pt1000, Pt1000_temp_table,
 298                                 &contact_temp) == -1) {
 299                 printf ("%s: error interpolating PT1000 vlaue\n",
 300                          __FUNCTION__);
 301                 return (-1000);
 302         }
 303         debug ("contact_temp: %ld\n", contact_temp);
 304
 305         return contact_temp;
 306 }
 307
 308
 309 void tsc2000_reg_init (void)
 310 {
 311         struct s3c24x0_gpio * const gpio = s3c24x0_get_base_gpio();
 312
 313         tsc2000_write(TSC2000_REG_ADC, 0x2036);
 314         tsc2000_write(TSC2000_REG_REF, 0x0011);
 315         tsc2000_write(TSC2000_REG_DACCTL, 0x0000);
 316
 317         CON_MUX0;
 318         CON_MUX1;
 319
 320         CON_MUX1_ENABLE;
 321         CON_MUX2_ENABLE;
 322         CON_MUX3_ENABLE;
 323         CON_MUX4_ENABLE;
 324
 325         CON_SEL_TEMP_V_0;
 326         CON_SEL_TEMP_V_1;
 327         CON_SEL_TEMP_V_2;
 328         CON_SEL_TEMP_V_3;
 329
 330         tsc2000_set_mux(0);
 331         tsc2000_set_range(0);
 332 }
 333
 334
 335 int tsc2000_interpolate(long value, long data[][2], long *result)
 336 {
 337         int i;
 338         unsigned long long val;
 339
 340         /* the data is sorted and the first element is upper
 341          * limit so we can easily check for out-of-band values
 342          */
 343         if (data[0][0] < value || data[1][0] > value)
 344                 return -1;
 345
 346         i = 1;
 347         while (data[i][0] < value)
 348                 i++;
 349
 350         /* To prevent overflow we have to store the intermediate
 351            result in 'long long'.
 352         */
 353
 354         val = ((unsigned long long)(data[i][1] - data[i-1][1])
 355                    * (unsigned long long)(value - data[i-1][0]));
 356         do_div(val, (data[i][0] - data[i-1][0]));
 357         *result = data[i-1][1] + val;
 358
 359         return 0;
 360 }
 361
 362
 363 void adc_wait_conversion_done(void)
 364 {
 365         while (!(tsc2000_read(TSC2000_REG_ADC) & (1 << 14)));
 366 }