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Diffstat (limited to 'src/sensor_angle.c')
| -rw-r--r-- | src/sensor_angle.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/src/sensor_angle.c b/src/sensor_angle.c new file mode 100644 index 00000000..c03cc957 --- /dev/null +++ b/src/sensor_angle.c @@ -0,0 +1,276 @@ +// Support for querying magnetic angle sensors via SPI +// +// Copyright (C) 2021 Kevin O'Connor <kevin@koconnor.net> +// +// This file may be distributed under the terms of the GNU GPLv3 license. + +#include "basecmd.h" // oid_alloc +#include "board/misc.h" // timer_read_time +#include "board/gpio.h" // gpio_out_write +#include "board/irq.h" // irq_disable +#include "command.h" // DECL_COMMAND +#include "sched.h" // DECL_TASK +#include "spicmds.h" // spidev_transfer + +enum { SA_CHIP_A1333, SA_CHIP_AS5047D, SA_CHIP_TLE5012B, SA_CHIP_MAX }; + +DECL_ENUMERATION("spi_angle_type", "a1333", SA_CHIP_A1333); +DECL_ENUMERATION("spi_angle_type", "as5047d", SA_CHIP_AS5047D); +DECL_ENUMERATION("spi_angle_type", "tle5012b", SA_CHIP_TLE5012B); + +enum { TCODE_ERROR = 0xff }; +enum { + SE_OVERFLOW, SE_SCHEDULE, SE_SPI_TIME, SE_CRC, SE_DUP, SE_NO_ANGLE +}; + +#define MAX_SPI_READ_TIME timer_from_us(50) + +struct spi_angle { + struct timer timer; + uint32_t rest_ticks; + struct spidev_s *spi; + uint16_t sequence; + uint8_t flags, chip_type, data_count, time_shift, overflow; + uint8_t data[48]; +}; + +enum { + SA_PENDING = 1<<2, +}; + +static struct task_wake angle_wake; + +// Event handler that wakes spi_angle_task() periodically +static uint_fast8_t +angle_event(struct timer *timer) +{ + struct spi_angle *sa = container_of(timer, struct spi_angle, timer); + uint8_t flags = sa->flags; + if (sa->flags & SA_PENDING) + sa->overflow++; + else + sa->flags = flags | SA_PENDING; + sched_wake_task(&angle_wake); + sa->timer.waketime += sa->rest_ticks; + return SF_RESCHEDULE; +} + +void +command_config_spi_angle(uint32_t *args) +{ + uint8_t chip_type = args[2]; + if (chip_type > SA_CHIP_MAX) + shutdown("Invalid spi_angle chip type"); + struct spi_angle *sa = oid_alloc(args[0], command_config_spi_angle + , sizeof(*sa)); + sa->timer.func = angle_event; + sa->spi = spidev_oid_lookup(args[1]); + if (!spidev_have_cs_pin(sa->spi)) + shutdown("angle sensor requires cs pin"); + sa->chip_type = chip_type; +} +DECL_COMMAND(command_config_spi_angle, + "config_spi_angle oid=%c spi_oid=%c spi_angle_type=%c"); + +// Report local measurement buffer +static void +angle_report(struct spi_angle *sa, uint8_t oid) +{ + sendf("spi_angle_data oid=%c sequence=%hu data=%*s" + , oid, sa->sequence, sa->data_count, sa->data); + sa->data_count = 0; + sa->sequence++; +} + +// Send spi_angle_data message if buffer is full +static void +angle_check_report(struct spi_angle *sa, uint8_t oid) +{ + if (sa->data_count + 3 > ARRAY_SIZE(sa->data)) + angle_report(sa, oid); +} + +// Add an error indicator to the measurement buffer +static void +angle_add_error(struct spi_angle *sa, uint_fast8_t error_code) +{ + sa->data[sa->data_count] = TCODE_ERROR; + sa->data[sa->data_count + 1] = error_code; + sa->data[sa->data_count + 2] = 0; + sa->data_count += 3; +} + +// Add a measurement to the buffer +static void +angle_add_data(struct spi_angle *sa, uint32_t stime, uint32_t mtime + , uint_fast16_t angle) +{ + uint32_t tdiff = mtime - stime; + if (sa->time_shift) + tdiff = (tdiff + (1<<(sa->time_shift - 1))) >> sa->time_shift; + if (tdiff >= TCODE_ERROR) { + angle_add_error(sa, SE_SCHEDULE); + return; + } + sa->data[sa->data_count] = tdiff; + sa->data[sa->data_count + 1] = angle; + sa->data[sa->data_count + 2] = angle >> 8; + sa->data_count += 3; +} + +// a1333 sensor query +static void +a1333_query(struct spi_angle *sa, uint32_t stime) +{ + uint8_t msg[2] = { 0x32, 0x00 }; + uint32_t mtime1 = timer_read_time(); + spidev_transfer(sa->spi, 1, sizeof(msg), msg); + uint32_t mtime2 = timer_read_time(); + // Data is latched on first sclk edge of response + if (mtime2 - mtime1 > MAX_SPI_READ_TIME) + angle_add_error(sa, SE_SPI_TIME); + else if (msg[0] & 0x80) + angle_add_error(sa, SE_CRC); + else + angle_add_data(sa, stime, mtime1, (msg[0] << 9) | (msg[1] << 1)); +} + +// as5047d sensor query +static void +as5047d_query(struct spi_angle *sa, uint32_t stime) +{ + uint8_t msg[2] = { 0x7F, 0xFE }; + uint32_t mtime1 = timer_read_time(); + spidev_transfer(sa->spi, 0, sizeof(msg), msg); + uint32_t mtime2 = timer_read_time(); + // Data is latched on CS pin rising after query request + if (mtime2 - mtime1 > MAX_SPI_READ_TIME) { + angle_add_error(sa, SE_SPI_TIME); + return; + } + msg[0] = 0xC0; + msg[1] = 0x00; + spidev_transfer(sa->spi, 1, sizeof(msg), msg); + uint_fast8_t parity = msg[0] ^ msg[1]; + parity ^= parity >> 4; + parity ^= parity >> 2; + parity ^= parity >> 1; + if (parity & 1) + angle_add_error(sa, SE_CRC); + else if (msg[0] & 0x40) + angle_add_error(sa, SE_NO_ANGLE); + else + angle_add_data(sa, stime, mtime2, (msg[0] << 10) | (msg[1] << 2)); +} + +#define TLE_READ 0x80 +#define TLE_READ_LATCH (TLE_READ | 0x04) +#define TLE_REG_AVAL 0x02 + +// crc8 "J1850" calculation for tle5012b messages +static uint8_t +crc8(uint8_t crc, uint8_t data) +{ + crc ^= data; + int i; + for (i=0; i<8; i++) + crc = crc & 0x80 ? (crc << 1) ^ 0x1d : crc << 1; + return crc; +} + +// microsecond delay helper +static inline void +udelay(uint32_t usecs) +{ + uint32_t end = timer_read_time() + timer_from_us(usecs); + while (!timer_is_before(end, timer_read_time())) + irq_poll(); +} + +// tle5012b sensor query +static void +tle5012b_query(struct spi_angle *sa, uint32_t stime) +{ + struct gpio_out cs_pin = spidev_get_cs_pin(sa->spi); + // Latch data (data is latched on rising CS of a NULL message) + gpio_out_write(cs_pin, 0); + udelay(1); + irq_disable(); + gpio_out_write(cs_pin, 1); + uint32_t mtime = timer_read_time(); + irq_enable(); + + uint8_t msg[6] = { TLE_READ_LATCH, (TLE_REG_AVAL << 4) | 0x01, 0, 0, 0, 0 }; + uint8_t start_crc = 0x3f; // 0x3f == crc8(crc8(0xff, msg[0]), msg[1]) + spidev_transfer(sa->spi, 1, sizeof(msg), msg); + uint8_t crc = ~crc8(crc8(start_crc, msg[2]), msg[3]); + if (crc != msg[5]) + angle_add_error(sa, SE_CRC); + else if (!(msg[4] & (1<<4))) + angle_add_error(sa, SE_NO_ANGLE); + else if (!(msg[2] & 0x80)) + angle_add_error(sa, SE_DUP); + else + angle_add_data(sa, stime, mtime, (msg[2] << 9) | (msg[3] << 1)); +} + +void +command_query_spi_angle(uint32_t *args) +{ + uint8_t oid = args[0]; + struct spi_angle *sa = oid_lookup(oid, command_config_spi_angle); + + sched_del_timer(&sa->timer); + sa->flags = 0; + if (!args[2]) { + // End measurements + if (sa->data_count) + angle_report(sa, oid); + sendf("spi_angle_end oid=%c sequence=%hu", oid, sa->sequence); + return; + } + // Start new measurements query + sa->timer.waketime = args[1]; + sa->rest_ticks = args[2]; + sa->sequence = 0; + sa->data_count = 0; + sa->time_shift = args[3]; + sched_add_timer(&sa->timer); +} +DECL_COMMAND(command_query_spi_angle, + "query_spi_angle oid=%c clock=%u rest_ticks=%u time_shift=%c"); + +// Background task that performs measurements +void +spi_angle_task(void) +{ + if (!sched_check_wake(&angle_wake)) + return; + uint8_t oid; + struct spi_angle *sa; + foreach_oid(oid, sa, command_config_spi_angle) { + uint_fast8_t flags = sa->flags; + if (!(flags & SA_PENDING)) + continue; + irq_disable(); + uint32_t stime = sa->timer.waketime; + uint_fast8_t overflow = sa->overflow; + sa->flags = 0; + sa->overflow = 0; + irq_enable(); + stime -= sa->rest_ticks; + while (overflow--) { + angle_add_error(sa, SE_OVERFLOW); + angle_check_report(sa, oid); + } + uint_fast8_t chip = sa->chip_type; + if (chip == SA_CHIP_A1333) + a1333_query(sa, stime); + else if (chip == SA_CHIP_AS5047D) + as5047d_query(sa, stime); + else if (chip == SA_CHIP_TLE5012B) + tle5012b_query(sa, stime); + angle_check_report(sa, oid); + } +} +DECL_TASK(spi_angle_task); |