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Diffstat (limited to 'drivers/sensors/pmw3320.c')
| -rw-r--r-- | drivers/sensors/pmw3320.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/sensors/pmw3320.c b/drivers/sensors/pmw3320.c new file mode 100644 index 0000000000..a4648ef425 --- /dev/null +++ b/drivers/sensors/pmw3320.c @@ -0,0 +1,192 @@ +/* Copyright 2021 Colin Lam (Ploopy Corporation) + * Copyright 2020 Christopher Courtney, aka Drashna Jael're (@drashna) <drashna@live.com> + * Copyright 2019 Sunjun Kim + * Copyright 2019 Hiroyuki Okada + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include "pmw3320.h" +#include "wait.h" +#include "debug.h" +#include "gpio.h" + +void pmw3320_init(void) { + // Initialize sensor serial pins. + setPinOutput(PMW3320_SCLK_PIN); + setPinOutput(PMW3320_SDIO_PIN); + setPinOutput(PMW3320_CS_PIN); + + // reboot the sensor. + pmw3320_write_reg(REG_Power_Up_Reset, 0x5a); + + // wait maximum time before sensor is ready. + // this ensures that the sensor is actually ready after reset. + wait_ms(55); + + // read a burst from the sensor and then discard it. + // gets the sensor ready for write commands + // (for example, setting the dpi). + pmw3320_read_burst(); + + // Pretty sure that this shouldn't be in the driver. + // Probably device specific? + // Set rest mode to default + pmw3320_write_reg(REG_Rest_Mode_Status, 0x00); + // Set LED to be always on + pmw3320_write_reg(REG_Led_Control, 0x4); + // Disable rest mode + pmw3320_write_reg(REG_Performance, 0x80); +} + +// Perform a synchronization with sensor. +// Just as with the serial protocol, this is used by the slave to send a +// synchronization signal to the master. +void pmw3320_sync(void) { + writePinLow(PMW3320_CS_PIN); + wait_us(1); + writePinHigh(PMW3320_CS_PIN); +} + +void pmw3320_cs_select(void) { + writePinLow(PMW3320_CS_PIN); +} + +void pmw3320_cs_deselect(void) { + writePinHigh(PMW3320_CS_PIN); +} + +uint8_t pmw3320_serial_read(void) { + setPinInput(PMW3320_SDIO_PIN); + uint8_t byte = 0; + + for (uint8_t i = 0; i < 8; ++i) { + writePinLow(PMW3320_SCLK_PIN); + wait_us(1); + + byte = (byte << 1) | readPin(PMW3320_SDIO_PIN); + + writePinHigh(PMW3320_SCLK_PIN); + wait_us(1); + } + + return byte; +} + +void pmw3320_serial_write(uint8_t data) { + setPinOutput(PMW3320_SDIO_PIN); + + for (int8_t b = 7; b >= 0; b--) { + writePinLow(PMW3320_SCLK_PIN); + + if (data & (1 << b)) + writePinHigh(PMW3320_SDIO_PIN); + else + writePinLow(PMW3320_SDIO_PIN); + + wait_us(2); + + writePinHigh(PMW3320_SCLK_PIN); + } + + // This was taken from ADNS5050 driver. + // There's no any info in PMW3320 datasheet about this... + // tSWR. See page 15 of the ADNS5050 spec sheet. + // Technically, this is only necessary if the next operation is an SDIO + // read. This is not guaranteed to be the case, but we're being lazy. + wait_us(4); + + // Note that tSWW is never necessary. All write operations require at + // least 32us, which exceeds tSWW, so there's never a need to wait for it. +} + +// Read a byte of data from a register on the sensor. +uint8_t pmw3320_read_reg(uint8_t reg_addr) { + pmw3320_cs_select(); + + pmw3320_serial_write(reg_addr); + + uint8_t byte = pmw3320_serial_read(); + + // This was taken directly from ADNS5050 driver... + // tSRW & tSRR. See page 15 of the ADNS5050 spec sheet. + // Technically, this is only necessary if the next operation is an SDIO + // read or write. This is not guaranteed to be the case. + // Honestly, this wait could probably be removed. + wait_us(1); + + pmw3320_cs_deselect(); + + return byte; +} + +void pmw3320_write_reg(uint8_t reg_addr, uint8_t data) { + pmw3320_cs_select(); + pmw3320_serial_write(0b10000000 | reg_addr); + pmw3320_serial_write(data); + pmw3320_cs_deselect(); +} + +report_pmw3320_t pmw3320_read_burst(void) { + pmw3320_cs_select(); + + report_pmw3320_t data; + data.dx = 0; + data.dy = 0; + + pmw3320_serial_write(REG_Motion_Burst); + + uint8_t x = pmw3320_serial_read(); + uint8_t y = pmw3320_serial_read(); + + // Probably burst mode may include contents of delta_xy register, + // which contain HI parts of x/y deltas, but I had no luck finding it. + // Probably it's required to activate 12-bit mode to access this data. + // So we end burst mode early to not read unneeded information. + pmw3320_cs_deselect(); + + data.dx = convert_twoscomp(x); + data.dy = convert_twoscomp(y); + + return data; +} + +// Convert a two's complement byte from an unsigned data type into a signed +// data type. +int8_t convert_twoscomp(uint8_t data) { + if ((data & 0x80) == 0x80) + return -128 + (data & 0x7F); + else + return data; +} + +uint16_t pmw3320_get_cpi(void) { + uint8_t cpival = pmw3320_read_reg(REG_Resolution); + // 0x1F is an inversion of 0x20 which is 0b100000 + return (uint16_t)((cpival & 0x1F) * PMW3320_CPI_STEP); +} + +void pmw3320_set_cpi(uint16_t cpi) { + uint8_t cpival = constrain((cpi / PMW3320_CPI_STEP) - 1U, 0, (PMW3320_CPI_MAX / PMW3320_CPI_STEP) - 1U); + // Fifth bit is probably a control bit. + // PMW3320 datasheet don't have any info on this, so this is a pure guess. + pmw3320_write_reg(REG_Resolution, 0x20 | cpival); +} + +bool pmw3320_check_signature(void) { + uint8_t pid = pmw3320_read_reg(REG_Product_ID); + uint8_t pid2 = pmw3320_read_reg(REG_Inverse_Product_ID); + + return (pid == 0x3b && pid2 == 0xc4); +} |