altos: Change MMC5893 driver to avoid interrupts

Set the chip to sample at 200Hz and then simply read the results at
100Hz to get a reasonably recent sample. This avoids a delay at each
sample interval.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/drivers/ao_mmc5983.c b/src/drivers/ao_mmc5983.c
index 06d4e9c9eb76d707cb06d29486436bab0d0b4b61..81bf8f2ba9f50c4c64cf629c4f74c9d122760833 100644 (file)
--- a/src/drivers/ao_mmc5983.c
+++ b/src/drivers/ao_mmc5983.c
@@ -76,33 +76,11 @@ ao_mmc5983_duplex(uint8_t *dst, uint8_t len)
        ao_mmc5983_stop();
 }
 
-static uint8_t ao_mmc5983_done;
-
-static void
-ao_mmc5983_isr(void)
-{
-       ao_exti_disable(AO_MMC5983_INT_PORT, AO_MMC5983_INT_PIN);
-       ao_mmc5983_done = 1;
-       ao_wakeup(&ao_mmc5983_done);
-}
-
-static uint32_t        ao_mmc5983_missed_irq;
-
 static void
 ao_mmc5983_sample(struct ao_mmc5983_sample *sample)
 {
        struct ao_mmc5983_raw   raw;
 
-       ao_mmc5983_done = 0;
-       ao_exti_enable(AO_MMC5983_INT_PORT, AO_MMC5983_INT_PIN);
-       ao_mmc5983_reg_write(MMC5983_CONTROL_0,
-                            (1 << MMC5983_CONTROL_0_INT_MEAS_DONE_EN) |
-                            (1 << MMC5983_CONTROL_0_TM_M));
-       ao_arch_block_interrupts();
-       while (!ao_mmc5983_done)
-               if (ao_sleep_for(&ao_mmc5983_done, AO_MS_TO_TICKS(10)))
-                       ++ao_mmc5983_missed_irq;
-       ao_arch_release_interrupts();
        raw.addr = MMC5983_X_OUT_0 | MMC5983_READ;
        ao_mmc5983_duplex((uint8_t *) &raw, sizeof (raw));
 
@@ -128,13 +106,16 @@ ao_mmc5983_setup(void)
        if (product_id != MMC5983_PRODUCT_ID_PRODUCT)
                AO_SENSOR_ERROR(AO_DATA_MMC5983);
 
-       /* Set high bandwidth to reduce sample collection time */
+       /* Set bandwidth to 200Hz */
        ao_mmc5983_reg_write(MMC5983_CONTROL_1,
-                            MMC5983_CONTROL_1_BW_800 << MMC5983_CONTROL_1_BW);
+                            MMC5983_CONTROL_1_BW_200 << MMC5983_CONTROL_1_BW);
 
-       /* Clear automatic measurement and 'set' operation */
+       /* Measure at 200Hz so we get recent samples by just reading
+        * the registers
+        */
        ao_mmc5983_reg_write(MMC5983_CONTROL_2,
-                            0);
+                            (1 << MMC5983_CONTROL_2_CMM_EN) |
+                            (MMC5983_CONTROL_2_CM_FREQ_200HZ << MMC5983_CONTROL_2_CM_FREQ));
 
        ao_mmc5983_configured = 1;
        return 1;
@@ -162,8 +143,8 @@ static struct ao_task ao_mmc5983_task;
 static void
 ao_mmc5983_show(void)
 {
-       printf ("X: %d Z: %d Y: %d missed irq: %lu\n",
-               ao_mmc5983_current.x, ao_mmc5983_current.z, ao_mmc5983_current.y, ao_mmc5983_missed_irq);
+       printf ("X: %d Z: %d Y: %d\n",
+               ao_mmc5983_current.x, ao_mmc5983_current.z, ao_mmc5983_current.y);
 }
 
 static const struct ao_cmds ao_mmc5983_cmds[] = {
@@ -178,12 +159,6 @@ ao_mmc5983_init(void)
 
        ao_spi_init_cs(AO_MMC5983_SPI_CS_PORT, (1 << AO_MMC5983_SPI_CS_PIN));
 
-       ao_enable_port(AO_MMC5983_INT_PORT);
-       ao_exti_setup(AO_MMC5983_INT_PORT,
-                     AO_MMC5983_INT_PIN,
-                     AO_EXTI_MODE_RISING | AO_EXTI_MODE_PULL_NONE,
-                     ao_mmc5983_isr);
-
        ao_add_task(&ao_mmc5983_task, ao_mmc5983, "mmc5983");
        ao_cmd_register(&ao_mmc5983_cmds[0]);
 }