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   1 /*
   2  * Copyright © 2021 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; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  17  */
  18
  19 #include <ao.h>
  20 #include <ao_mmc5983.h>
  21 #include <ao_exti.h>
  22
  23 #if HAS_MMC5983
  24
  25 #define AO_MMC5983_SPI_SPEED    ao_spi_speed(10000000)
  26
  27 static void
  28 ao_mmc5983_start(void) {
  29         ao_spi_get_bit(AO_MMC5983_SPI_CS_PORT,
  30                        AO_MMC5983_SPI_CS_PIN,
  31                        AO_MMC5983_SPI_INDEX,
  32                        AO_MMC5983_SPI_SPEED);
  33 }
  34
  35 static void
  36 ao_mmc5983_stop(void) {
  37         ao_spi_put_bit(AO_MMC5983_SPI_CS_PORT,
  38                        AO_MMC5983_SPI_CS_PIN,
  39                        AO_MMC5983_SPI_INDEX);
  40 }
  41
  42 struct ao_mmc5983_sample        ao_mmc5983_current;
  43
  44 static uint8_t  ao_mmc5983_configured;
  45
  46 static void
  47 ao_mmc5983_reg_write(uint8_t addr, uint8_t data)
  48 {
  49         uint8_t d[2];
  50
  51         d[0] = addr;
  52         d[1] = data;
  53         ao_mmc5983_start();
  54         ao_spi_send(d, 2, AO_MMC5983_SPI_INDEX);
  55         ao_mmc5983_stop();
  56 }
  57
  58 static uint8_t
  59 ao_mmc5983_reg_read(uint8_t addr)
  60 {
  61         uint8_t d[2];
  62
  63         d[0] = addr | MMC5983_READ;
  64         ao_mmc5983_start();
  65         ao_spi_duplex(d, d, 2, AO_MMC5983_SPI_INDEX);
  66         ao_mmc5983_stop();
  67
  68         return d[1];
  69 }
  70
  71 static void
  72 ao_mmc5983_duplex(uint8_t *dst, uint8_t len)
  73 {
  74         ao_mmc5983_start();
  75         ao_spi_duplex(dst, dst, len, AO_MMC5983_SPI_INDEX);
  76         ao_mmc5983_stop();
  77 }
  78
  79 static void
  80 ao_mmc5983_sample(struct ao_mmc5983_sample *sample)
  81 {
  82         struct ao_mmc5983_raw   raw;
  83
  84         raw.addr = MMC5983_X_OUT_0 | MMC5983_READ;
  85         ao_mmc5983_duplex((uint8_t *) &raw, sizeof (raw));
  86
  87         sample->x = raw.x0 << 10 | raw.x1 << 2 | ((raw.xyz2 >> 6) & 3);
  88         sample->y = raw.y0 << 10 | raw.y1 << 2 | ((raw.xyz2 >> 4) & 3);
  89         sample->z = raw.z0 << 10 | raw.z1 << 2 | ((raw.xyz2 >> 2) & 3);
  90 }
  91
  92 static uint8_t
  93 ao_mmc5983_setup(void)
  94 {
  95         uint8_t product_id;
  96
  97         if (ao_mmc5983_configured)
  98                 return 1;
  99
 100         /* Place device in 3-wire mode */
 101         ao_mmc5983_reg_write(MMC5983_CONTROL_3,
 102                              1 << MMC5983_CONTROL_3_SPI_3W);
 103
 104         /* Check product ID */
 105         product_id = ao_mmc5983_reg_read(MMC5983_PRODUCT_ID);
 106         if (product_id != MMC5983_PRODUCT_ID_PRODUCT)
 107                 AO_SENSOR_ERROR(AO_DATA_MMC5983);
 108
 109         /* Set bandwidth to 200Hz */
 110         ao_mmc5983_reg_write(MMC5983_CONTROL_1,
 111                              MMC5983_CONTROL_1_BW_200 << MMC5983_CONTROL_1_BW);
 112
 113         /* Measure at 200Hz so we get recent samples by just reading
 114          * the registers
 115          */
 116         ao_mmc5983_reg_write(MMC5983_CONTROL_2,
 117                              (1 << MMC5983_CONTROL_2_CMM_EN) |
 118                              (MMC5983_CONTROL_2_CM_FREQ_200HZ << MMC5983_CONTROL_2_CM_FREQ));
 119
 120         ao_mmc5983_configured = 1;
 121         return 1;
 122 }
 123
 124 struct ao_mmc5983_sample ao_mmc5983_current;
 125
 126 static void
 127 ao_mmc5983(void)
 128 {
 129         struct ao_mmc5983_sample        sample;
 130         ao_mmc5983_setup();
 131         for (;;) {
 132                 ao_mmc5983_sample(&sample);
 133                 ao_arch_block_interrupts();
 134                 ao_mmc5983_current = sample;
 135                 AO_DATA_PRESENT(AO_DATA_MMC5983);
 136                 AO_DATA_WAIT();
 137                 ao_arch_release_interrupts();
 138         }
 139 }
 140
 141 static struct ao_task ao_mmc5983_task;
 142
 143 static void
 144 ao_mmc5983_show(void)
 145 {
 146         printf ("X: %d Z: %d Y: %d\n",
 147                 ao_mmc5983_current.x, ao_mmc5983_current.z, ao_mmc5983_current.y);
 148 }
 149
 150 static const struct ao_cmds ao_mmc5983_cmds[] = {
 151         { ao_mmc5983_show,      "M\0Show MMC5983 status" },
 152         { 0, NULL }
 153 };
 154
 155 void
 156 ao_mmc5983_init(void)
 157 {
 158         ao_mmc5983_configured = 0;
 159
 160         ao_spi_init_cs(AO_MMC5983_SPI_CS_PORT, (1 << AO_MMC5983_SPI_CS_PIN));
 161
 162         ao_add_task(&ao_mmc5983_task, ao_mmc5983, "mmc5983");
 163         ao_cmd_register(&ao_mmc5983_cmds[0]);
 164 }
 165
 166 #endif