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-rw-r--r--drivers/sensors/pmw3320.c192
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/sensors/pmw3320.c b/drivers/sensors/pmw3320.c
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+++ b/drivers/sensors/pmw3320.c
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+/* 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);
+}