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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 uint8_t ao_mmc5983_done;
  80
  81 static void
  82 ao_mmc5983_isr(void)
  83 {
  84         ao_exti_disable(AO_MMC5983_INT_PORT, AO_MMC5983_INT_PIN);
  85         ao_mmc5983_done = 1;
  86         ao_wakeup(&ao_mmc5983_done);
  87 }
  88
  89 static uint32_t ao_mmc5983_missed_irq;
  90
  91 static void
  92 ao_mmc5983_sample(struct ao_mmc5983_sample *sample)
  93 {
  94         struct ao_mmc5983_raw   raw;
  95
  96         ao_mmc5983_done = 0;
  97         ao_exti_enable(AO_MMC5983_INT_PORT, AO_MMC5983_INT_PIN);
  98         ao_mmc5983_reg_write(MMC5983_CONTROL_0,
  99                              (1 << MMC5983_CONTROL_0_INT_MEAS_DONE_EN) |
 100                              (1 << MMC5983_CONTROL_0_TM_M));
 101         ao_arch_block_interrupts();
 102         while (!ao_mmc5983_done)
 103                 if (ao_sleep_for(&ao_mmc5983_done, AO_MS_TO_TICKS(10)))
 104                         ++ao_mmc5983_missed_irq;
 105         ao_arch_release_interrupts();
 106         raw.addr = MMC5983_X_OUT_0 | MMC5983_READ;
 107         ao_mmc5983_duplex((uint8_t *) &raw, sizeof (raw));
 108
 109         sample->x = raw.x0 << 10 | raw.x1 << 2 | ((raw.xyz2 >> 6) & 3);
 110         sample->y = raw.y0 << 10 | raw.y1 << 2 | ((raw.xyz2 >> 4) & 3);
 111         sample->z = raw.z0 << 10 | raw.z1 << 2 | ((raw.xyz2 >> 2) & 3);
 112 }
 113
 114 static uint8_t
 115 ao_mmc5983_setup(void)
 116 {
 117         uint8_t product_id;
 118
 119         if (ao_mmc5983_configured)
 120                 return 1;
 121
 122         /* Place device in 3-wire mode */
 123         ao_mmc5983_reg_write(MMC5983_CONTROL_3,
 124                              1 << MMC5983_CONTROL_3_SPI_3W);
 125
 126         /* Check product ID */
 127         product_id = ao_mmc5983_reg_read(MMC5983_PRODUCT_ID);
 128         if (product_id != MMC5983_PRODUCT_ID_PRODUCT)
 129                 AO_SENSOR_ERROR(AO_DATA_MMC5983);
 130
 131         /* Set high bandwidth to reduce sample collection time */
 132         ao_mmc5983_reg_write(MMC5983_CONTROL_1,
 133                              MMC5983_CONTROL_1_BW_800 << MMC5983_CONTROL_1_BW);
 134
 135         /* Clear automatic measurement and 'set' operation */
 136         ao_mmc5983_reg_write(MMC5983_CONTROL_2,
 137                              0);
 138
 139         ao_mmc5983_configured = 1;
 140         return 1;
 141 }
 142
 143 struct ao_mmc5983_sample ao_mmc5983_current;
 144
 145 static void
 146 ao_mmc5983(void)
 147 {
 148         struct ao_mmc5983_sample        sample;
 149         ao_mmc5983_setup();
 150         for (;;) {
 151                 ao_mmc5983_sample(&sample);
 152                 ao_arch_block_interrupts();
 153                 ao_mmc5983_current = sample;
 154                 AO_DATA_PRESENT(AO_DATA_MMC5983);
 155                 AO_DATA_WAIT();
 156                 ao_arch_release_interrupts();
 157         }
 158 }
 159
 160 static struct ao_task ao_mmc5983_task;
 161
 162 static void
 163 ao_mmc5983_show(void)
 164 {
 165         printf ("X: %d Z: %d Y: %d missed irq: %lu\n",
 166                 ao_mmc5983_current.x, ao_mmc5983_current.z, ao_mmc5983_current.y, ao_mmc5983_missed_irq);
 167 }
 168
 169 static const struct ao_cmds ao_mmc5983_cmds[] = {
 170         { ao_mmc5983_show,      "M\0Show MMC5983 status" },
 171         { 0, NULL }
 172 };
 173
 174 void
 175 ao_mmc5983_init(void)
 176 {
 177         ao_mmc5983_configured = 0;
 178
 179         ao_spi_init_cs(AO_MMC5983_SPI_CS_PORT, (1 << AO_MMC5983_SPI_CS_PIN));
 180
 181         ao_enable_port(AO_MMC5983_INT_PORT);
 182         ao_exti_setup(AO_MMC5983_INT_PORT,
 183                       AO_MMC5983_INT_PIN,
 184                       AO_EXTI_MODE_RISING | AO_EXTI_MODE_PULL_NONE,
 185                       ao_mmc5983_isr);
 186
 187         ao_add_task(&ao_mmc5983_task, ao_mmc5983, "mmc5983");
 188         ao_cmd_register(&ao_mmc5983_cmds[0]);
 189 }
 190
 191 #endif