bertos/cpu/cortex-m3/drv/i2c_lm3s.c

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  25  * the GNU General Public License.  This exception does not however
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  27  * the GNU General Public License.
  28  *
  29  * Copyright 2010 Develer S.r.l. (http://www.develer.com/)
  30  *
  31  * -->
  32  *
  33  * \brief Driver for the LM3S I2C (implementation)
  34  *
  35  */
  36
  37 #include "cfg/cfg_i2c.h"
  38
  39 #define LOG_LEVEL  I2C_LOG_LEVEL
  40 #define LOG_FORMAT I2C_LOG_FORMAT
  41
  42 #include <cfg/log.h>
  43
  44 #include <cfg/debug.h>
  45 #include <cfg/macros.h> // BV()
  46 #include <cfg/module.h>
  47
  48 #include <cpu/detect.h>
  49 #include <cpu/irq.h>
  50 #include <cpu/types.h>
  51
  52 #include <io/lm3s.h>
  53
  54 #include <drv/timer.h>
  55 #include <drv/i2c.h>
  56 #include <drv/gpio_lm3s.h>
  57 #include <drv/clock_lm3s.h>
  58
  59
  60 struct I2cHardware
  61 {
  62         uint32_t base;
  63         uint32_t sys_cntl;
  64         uint32_t sys_gpio;
  65         uint32_t pin_mask;
  66         uint32_t gpio_base;
  67         bool first_send;
  68 };
  69
  70 static void i2c_lm3s_start(struct I2c *i2c, uint16_t slave_addr)
  71 {
  72         i2c->hw->first_send = true;
  73
  74         if (I2C_TEST_START(i2c->flags) == I2C_START_W)
  75                 HWREG(i2c->hw->base + I2C_O_MSA) = slave_addr & ~BV(0);
  76         else /* (I2C_TEST_START(i2c->flags) == I2C_START_R) */
  77                 HWREG(i2c->hw->base + I2C_O_MSA) = slave_addr | BV(0);
  78 }
  79
  80 INLINE bool wait_addrAck(I2c *i2c, uint32_t mode_mask)
  81 {
  82         ticks_t start = timer_clock();
  83         while (1)
  84         {
  85                 uint32_t status = HWREG(i2c->hw->base + I2C_O_MCS);
  86
  87                 if (timer_clock() - start > ms_to_ticks(CONFIG_I2C_START_TIMEOUT))
  88                         return false;
  89
  90                 if (status & I2C_MCS_ADRACK)
  91                 {
  92                         HWREG(i2c->hw->base + I2C_O_MCS) = mode_mask;
  93                         while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY);
  94                         continue;
  95                 }
  96                 else
  97                         break;
  98         }
  99         return true;
 100 }
 101
 102 static void i2c_lm3s_put(I2c *i2c, const uint8_t data)
 103 {
 104         if ((i2c->xfer_size == 1) && (i2c->hw->first_send))
 105         {
 106                 HWREG(i2c->hw->base + I2C_O_MDR) = data;
 107                 HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN | I2C_MCS_START;
 108                 while( HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 109
 110                 if (!wait_addrAck(i2c, I2C_MCS_RUN | I2C_MCS_START))
 111                 {
 112                         LOG_ERR("Start timeout\n");
 113                         i2c->errors |= I2C_START_TIMEOUT;
 114                         HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
 115                         while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY);
 116                         return;
 117                 }
 118
 119                 if (I2C_TEST_STOP(i2c->flags) == I2C_STOP)
 120                 {
 121                         HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
 122                         while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 123                 }
 124
 125                 i2c->hw->first_send = false;
 126                 return;
 127         }
 128         else
 129         {
 130                 HWREG(i2c->hw->base + I2C_O_MDR) = data;
 131                 if (i2c->hw->first_send)
 132                 {
 133                         HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN | I2C_MCS_START;
 134                         while( HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 135
 136                         if (!wait_addrAck(i2c, I2C_MCS_RUN | I2C_MCS_START))
 137                         {
 138                                 LOG_ERR("Start timeout\n");
 139                                 i2c->errors |= I2C_START_TIMEOUT;
 140                                 HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
 141                                 while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 142                                 return;
 143                         }
 144
 145                         i2c->hw->first_send = false;
 146                         return;
 147                 }
 148                 else
 149                 {
 150                         HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN;
 151                         while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 152
 153                         if ((i2c->xfer_size == 1) && (I2C_TEST_STOP(i2c->flags) == I2C_STOP))
 154                         {
 155                                 HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
 156                                 while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 157                         }
 158                 }
 159         }
 160 }
 161
 162 static uint8_t i2c_lm3s_get(I2c *i2c)
 163 {
 164         if ((i2c->xfer_size == 1) && (i2c->hw->first_send))
 165         {
 166                 HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN | I2C_MCS_START;
 167                 while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 168
 169
 170                 if (!wait_addrAck(i2c, I2C_MCS_RUN | I2C_MCS_START))
 171                 {
 172                         LOG_ERR("Start timeout\n");
 173                         i2c->errors |= I2C_START_TIMEOUT;
 174                         HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
 175                         return 0xFF;
 176                 }
 177
 178                 uint8_t data = HWREG(i2c->hw->base + I2C_O_MDR);
 179
 180                 if (I2C_TEST_STOP(i2c->flags) == I2C_STOP)
 181                 {
 182                         HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
 183                         while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 184                 }
 185
 186                 i2c->hw->first_send = false;
 187                 return data;
 188         }
 189         else
 190         {
 191                 if (i2c->hw->first_send)
 192                 {
 193                         HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_ACK | I2C_MCS_RUN | I2C_MCS_START;
 194                         while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY);
 195
 196                         if (!wait_addrAck(i2c, I2C_MCS_ACK | I2C_MCS_RUN | I2C_MCS_START))
 197                         {
 198                                 LOG_ERR("Start timeout\n");
 199                                 i2c->errors |= I2C_START_TIMEOUT;
 200                                 HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
 201                                 return 0xFF;
 202                         }
 203
 204                         i2c->hw->first_send = false;
 205                         return HWREG(i2c->hw->base + I2C_O_MDR);
 206                 }
 207                 else
 208                 {
 209                         if (i2c->xfer_size > 1)
 210                                 HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_ACK | I2C_MCS_RUN;
 211                         else
 212                                 HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_RUN;
 213
 214                         while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 215                         uint8_t data = HWREG(i2c->hw->base + I2C_O_MDR);
 216
 217                         if ((i2c->xfer_size == 1) && (I2C_TEST_STOP(i2c->flags) == I2C_STOP))
 218                         {
 219                                 HWREG(i2c->hw->base + I2C_O_MCS) = I2C_MCS_STOP;
 220                                 while (HWREG(i2c->hw->base + I2C_O_MCS) & I2C_MCS_BUSY );
 221                         }
 222
 223                         return data;
 224                 }
 225         }
 226         return 0xFF;
 227 }
 228
 229 MOD_DEFINE(i2c);
 230
 231 static const I2cVT i2c_lm3s_vt =
 232 {
 233         .start = i2c_lm3s_start,
 234         .get = i2c_lm3s_get,
 235         .put = i2c_lm3s_put,
 236         .send = i2c_swSend,
 237         .recv = i2c_swRecv,
 238 };
 239
 240 struct I2cHardware i2c_lm3s_hw[] =
 241 {
 242         { /* I2C0 */
 243                 .base = I2C0_MASTER_BASE,
 244                 .sys_cntl = SYSCTL_RCGC1_I2C0,
 245                 .sys_gpio = SYSCTL_RCGC2_GPIOB,
 246                 .pin_mask = (GPIO_I2C0_SCL_PIN | GPIO_I2C0_SDA_PIN),
 247                 .gpio_base = GPIO_PORTB_BASE,
 248         },
 249         { /* I2C1 */
 250                 .base = I2C1_MASTER_BASE,
 251                 .sys_cntl = SYSCTL_RCGC1_I2C1,
 252                 .sys_gpio = SYSCTL_RCGC2_GPIOA,
 253                 .pin_mask = (GPIO_I2C1_SCL_PIN | GPIO_I2C1_SDA_PIN),
 254                 .gpio_base = GPIO_PORTA_BASE,
 255         },
 256 };
 257
 258 /**
 259  * Initialize I2C module.
 260  */
 261 void i2c_hw_init(I2c *i2c, int dev, uint32_t clock)
 262 {
 263         i2c->hw = &i2c_lm3s_hw[dev];
 264         i2c->vt = &i2c_lm3s_vt;
 265
 266         /* Enable the peripheral clock */
 267         SYSCTL_RCGC1_R |= i2c->hw->sys_cntl;
 268         SYSCTL_RCGC2_R |= i2c->hw->sys_gpio;
 269
 270         /* Configure GPIO pins to work as I2C pins */
 271         lm3s_gpioPinConfig(i2c->hw->gpio_base, i2c->hw->pin_mask,
 272                 GPIO_DIR_MODE_HW, GPIO_STRENGTH_2MA, GPIO_PIN_TYPE_OD_WPU);
 273         /*
 274          * Note: to set correctly the i2c speed we shold before enable the i2c
 275          * device and then set in master time period the correct value
 276          */
 277
 278         /* Enable i2c device */
 279         HWREG(i2c->hw->base + I2C_O_MCR) |= I2C_MCR_MFE;
 280
 281     /*
 282          * Compute the clock divider that achieves the fastest speed less than or
 283      * equal to the desired speed.  The numerator is biased to favor a larger
 284      * clock divider so that the resulting clock is always less than or equal
 285      * to the desired clock, never greater.
 286          */
 287     HWREG(i2c->hw->base + I2C_O_MTPR) = ((CPU_FREQ + (2 * 10 * clock) - 1) / (2 * 10 * clock)) - 1;
 288
 289         MOD_INIT(i2c);
 290 }