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   1 /*
   2  * Copyright © 2012 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 #include <ao.h>
  19 #include <ao_hmc5883.h>
  20 #include <ao_exti.h>
  21
  22 uint8_t ao_hmc5883_valid;
  23
  24 static uint8_t  ao_hmc5883_configured;
  25
  26 static uint8_t  ao_hmc5883_addr;
  27
  28 static void
  29 ao_hmc5883_reg_write(uint8_t addr, uint8_t data)
  30 {
  31         uint8_t d[2];
  32
  33         d[0] = addr;
  34         d[1] = data;
  35         ao_i2c_get(AO_HMC5883_I2C_INDEX);
  36         ao_i2c_start(AO_HMC5883_I2C_INDEX, HMC5883_ADDR_WRITE);
  37         ao_i2c_send(d, 2, AO_HMC5883_I2C_INDEX, TRUE);
  38         ao_i2c_put(AO_HMC5883_I2C_INDEX);
  39         ao_hmc5883_addr = addr + 1;
  40 }
  41
  42 static void
  43 ao_hmc5883_read(uint8_t addr, uint8_t *data, uint8_t len)
  44 {
  45         ao_i2c_get(AO_HMC5883_I2C_INDEX);
  46         if (addr != ao_hmc5883_addr) {
  47                 ao_i2c_start(AO_HMC5883_I2C_INDEX, HMC5883_ADDR_WRITE);
  48                 ao_i2c_send(&addr, 1, AO_HMC5883_I2C_INDEX, FALSE);
  49         }
  50         ao_i2c_start(AO_HMC5883_I2C_INDEX, HMC5883_ADDR_READ);
  51         ao_i2c_recv(data, len, AO_HMC5883_I2C_INDEX, TRUE);
  52         ao_i2c_put(AO_HMC5883_I2C_INDEX);
  53         ao_hmc5883_addr = 0xff;
  54 }
  55
  56 static uint8_t ao_hmc5883_done;
  57
  58 static void
  59 ao_hmc5883_isr(void)
  60 {
  61         ao_exti_disable(&AO_HMC5883_INT_PORT, AO_HMC5883_INT_PIN);
  62         ao_hmc5883_done = 1;
  63         ao_wakeup(&ao_hmc5883_done);
  64 }
  65
  66 void
  67 ao_hmc5883_sample(struct ao_hmc5883_sample *sample)
  68 {
  69         uint16_t        *d = (uint16_t *) sample;
  70         int             i = sizeof (*sample) / 2;
  71         uint8_t         single = HMC5883_MODE_SINGLE;
  72
  73         ao_hmc5883_done = 0;
  74         ao_exti_enable(&AO_HMC5883_INT_PORT, AO_HMC5883_INT_PIN);
  75         ao_hmc5883_reg_write(HMC5883_MODE, HMC5883_MODE_SINGLE);
  76
  77         cli();
  78         while (!ao_hmc5883_done)
  79                 ao_sleep(&ao_hmc5883_done);
  80         sei();
  81
  82         ao_hmc5883_read(HMC5883_X_MSB, (uint8_t *) sample, sizeof (struct ao_hmc5883_sample));
  83 #if __BYTE_ORDER == __LITTLE_ENDIAN
  84         /* byte swap */
  85         while (i--) {
  86                 uint16_t        t = *d;
  87                 *d++ = (t >> 8) | (t << 8);
  88         }
  89 #endif
  90 }
  91
  92 static uint8_t
  93 ao_hmc5883_setup(void)
  94 {
  95         uint8_t d;
  96         uint8_t present;
  97
  98         if (ao_hmc5883_configured)
  99                 return 1;
 100
 101         ao_i2c_get(AO_HMC5883_I2C_INDEX);
 102         present = ao_i2c_start(AO_HMC5883_I2C_INDEX, HMC5883_ADDR_READ);
 103         ao_i2c_recv(&d, 1, AO_HMC5883_I2C_INDEX, TRUE);
 104         ao_i2c_put(AO_HMC5883_I2C_INDEX);
 105
 106         if (!present)
 107                 ao_panic(AO_PANIC_SELF_TEST);
 108
 109         ao_hmc5883_reg_write(HMC5883_CONFIG_A,
 110                              (HMC5883_CONFIG_A_MA_8 << HMC5883_CONFIG_A_MA) |
 111                              (HMC5883_CONFIG_A_DO_15 << HMC5883_CONFIG_A_DO) |
 112                              (HMC5883_CONFIG_A_MS_NORMAL << HMC5883_CONFIG_A_MS));
 113
 114         ao_hmc5883_reg_write(HMC5883_CONFIG_B,
 115                              (HMC5883_CONFIG_B_GN_1_3 << HMC5883_CONFIG_B_GN));
 116
 117         ao_hmc5883_configured = 1;
 118         return 1;
 119 }
 120
 121 struct ao_hmc5883_sample ao_hmc5883_current;
 122
 123 static void
 124 ao_hmc5883(void)
 125 {
 126         ao_hmc5883_setup();
 127         for (;;) {
 128                 struct ao_hmc5883_sample ao_hmc5883_next;
 129
 130                 ao_hmc5883_sample(&ao_hmc5883_next);
 131                 ao_arch_critical(
 132                         ao_hmc5883_current = ao_hmc5883_next;
 133                         ao_hmc5883_valid = 1;
 134                         );
 135                 ao_delay(0);
 136         }
 137 }
 138
 139 static struct ao_task ao_hmc5883_task;
 140
 141 static void
 142 ao_hmc5883_show(void)
 143 {
 144         struct ao_hmc5883_sample        sample;
 145
 146         sample = ao_hmc5883_current;
 147         printf ("X: %d Y: %d Z: %d\n", sample.x, sample.y, sample.z);
 148 }
 149
 150 static const struct ao_cmds ao_hmc5883_cmds[] = {
 151         { ao_hmc5883_show,      "M\0Show HMC5883 status" },
 152         { 0, NULL }
 153 };
 154
 155 void
 156 ao_hmc5883_init(void)
 157 {
 158         ao_hmc5883_configured = 0;
 159         ao_hmc5883_valid = 0;
 160
 161         ao_enable_port(AO_HMC5883_INT_PORT);
 162         ao_exti_setup(&AO_HMC5883_INT_PORT,
 163                       AO_HMC5883_INT_PIN,
 164                       AO_EXTI_MODE_FALLING | AO_EXTI_MODE_PULL_UP,
 165                       ao_hmc5883_isr);
 166
 167         ao_add_task(&ao_hmc5883_task, ao_hmc5883, "hmc5883");
 168         ao_cmd_register(&ao_hmc5883_cmds[0]);
 169 }