224 lines
7.2 KiB
C
224 lines
7.2 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2021 Scott Shawcroft for Adafruit Industries
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "py/mperrno.h"
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#include "py/mphal.h"
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#include "shared-bindings/busio/I2C.h"
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#include "py/runtime.h"
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#include "shared-bindings/microcontroller/__init__.h"
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#include "shared-bindings/bitbangio/I2C.h"
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#include "src/rp2_common/hardware_gpio/include/hardware/gpio.h"
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// Synopsys DW_apb_i2c (v2.01) IP
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#define NO_PIN 0xff
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// One second
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#define BUS_TIMEOUT_US 1000000
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STATIC bool never_reset_i2c[2];
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STATIC i2c_inst_t *i2c[2] = {i2c0, i2c1};
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void reset_i2c(void) {
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for (size_t i = 0; i < 2; i++) {
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if (never_reset_i2c[i]) {
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continue;
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}
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i2c_deinit(i2c[i]);
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}
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}
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void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
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const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
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self->peripheral = NULL;
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// I2C pins have a regular pattern. SCL is always odd and SDA is even. They match up in pairs
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// so we can divide by two to get the instance. This pattern repeats.
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if (scl->number % 2 == 1 && sda->number % 2 == 0 && scl->number / 2 == sda->number / 2) {
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size_t instance = (scl->number / 2) % 2;
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self->peripheral = i2c[instance];
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}
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if (self->peripheral == NULL) {
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mp_raise_ValueError(translate("Invalid pins"));
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}
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if ((i2c_get_hw(self->peripheral)->enable & I2C_IC_ENABLE_ENABLE_BITS) != 0) {
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mp_raise_ValueError(translate("I2C peripheral in use"));
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}
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if (frequency > 1000000) {
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mp_raise_ValueError(translate("Unsupported baudrate"));
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}
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#if CIRCUITPY_REQUIRE_I2C_PULLUPS
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// Test that the pins are in a high state. (Hopefully indicating they are pulled up.)
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gpio_set_function(sda->number, GPIO_FUNC_SIO);
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gpio_set_function(scl->number, GPIO_FUNC_SIO);
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gpio_set_dir(sda->number, GPIO_IN);
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gpio_set_dir(scl->number, GPIO_IN);
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gpio_set_pulls(sda->number, false, true);
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gpio_set_pulls(scl->number, false, true);
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common_hal_mcu_delay_us(10);
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gpio_set_pulls(sda->number, false, false);
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gpio_set_pulls(scl->number, false, false);
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// We must pull up within 3us to achieve 400khz.
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common_hal_mcu_delay_us(3);
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if (!gpio_get(sda->number) || !gpio_get(scl->number)) {
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reset_pin_number(sda->number);
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reset_pin_number(scl->number);
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mp_raise_RuntimeError(translate("No pull up found on SDA or SCL; check your wiring"));
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}
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#endif
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// Create a bitbangio.I2C object to do 0 byte writes.
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//
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// These are used to non-invasively detect I2C devices by sending
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// the address and confirming an ACK.
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// They are not supported by the RP2040 hardware.
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//
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// Must be done before setting up the I2C pins, since they will be
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// set up as GPIO by the bitbangio.I2C object.
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//
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// Sets pins to open drain, high, and input.
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shared_module_bitbangio_i2c_construct(&self->bitbangio_i2c, scl, sda,
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frequency, timeout);
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self->baudrate = i2c_init(self->peripheral, frequency);
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self->scl_pin = scl->number;
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self->sda_pin = sda->number;
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claim_pin(scl);
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claim_pin(sda);
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gpio_set_function(self->scl_pin, GPIO_FUNC_I2C);
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gpio_set_function(self->sda_pin, GPIO_FUNC_I2C);
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}
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bool common_hal_busio_i2c_deinited(busio_i2c_obj_t *self) {
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return self->sda_pin == NO_PIN;
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}
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void common_hal_busio_i2c_deinit(busio_i2c_obj_t *self) {
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if (common_hal_busio_i2c_deinited(self)) {
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return;
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}
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never_reset_i2c[i2c_hw_index(self->peripheral)] = false;
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i2c_deinit(self->peripheral);
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reset_pin_number(self->sda_pin);
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reset_pin_number(self->scl_pin);
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self->sda_pin = NO_PIN;
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self->scl_pin = NO_PIN;
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}
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bool common_hal_busio_i2c_probe(busio_i2c_obj_t *self, uint8_t addr) {
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return common_hal_busio_i2c_write(self, addr, NULL, 0, true) == 0;
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}
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bool common_hal_busio_i2c_try_lock(busio_i2c_obj_t *self) {
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bool grabbed_lock = false;
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if (!self->has_lock) {
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grabbed_lock = true;
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self->has_lock = true;
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}
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return grabbed_lock;
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}
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bool common_hal_busio_i2c_has_lock(busio_i2c_obj_t *self) {
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return self->has_lock;
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}
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void common_hal_busio_i2c_unlock(busio_i2c_obj_t *self) {
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self->has_lock = false;
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}
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uint8_t common_hal_busio_i2c_write(busio_i2c_obj_t *self, uint16_t addr,
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const uint8_t *data, size_t len, bool transmit_stop_bit) {
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if (len == 0) {
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// The RP2040 I2C peripheral will not perform 0 byte writes.
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// So use bitbangio.I2C to do the write.
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gpio_set_function(self->scl_pin, GPIO_FUNC_SIO);
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gpio_set_function(self->sda_pin, GPIO_FUNC_SIO);
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gpio_set_dir(self->scl_pin, GPIO_IN);
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gpio_set_dir(self->sda_pin, GPIO_IN);
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gpio_put(self->scl_pin, false);
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gpio_put(self->sda_pin, false);
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uint8_t status = shared_module_bitbangio_i2c_write(&self->bitbangio_i2c,
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addr, data, len, transmit_stop_bit);
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// The pins must be set back to GPIO_FUNC_I2C in the order given here,
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// SCL first, otherwise reads will hang.
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gpio_set_function(self->scl_pin, GPIO_FUNC_I2C);
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gpio_set_function(self->sda_pin, GPIO_FUNC_I2C);
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return status;
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}
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int result = i2c_write_timeout_us(self->peripheral, addr, data, len, !transmit_stop_bit, BUS_TIMEOUT_US);
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if (result == len) {
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return 0;
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}
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switch (result) {
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case PICO_ERROR_GENERIC:
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return MP_ENODEV;
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case PICO_ERROR_TIMEOUT:
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return MP_ETIMEDOUT;
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default:
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return MP_EIO;
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}
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}
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uint8_t common_hal_busio_i2c_read(busio_i2c_obj_t *self, uint16_t addr,
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uint8_t *data, size_t len) {
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int result = i2c_read_timeout_us(self->peripheral, addr, data, len, false, BUS_TIMEOUT_US);
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if (result == len) {
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return 0;
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}
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switch (result) {
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case PICO_ERROR_GENERIC:
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return MP_ENODEV;
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case PICO_ERROR_TIMEOUT:
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return MP_ETIMEDOUT;
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default:
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return MP_EIO;
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}
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}
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void common_hal_busio_i2c_never_reset(busio_i2c_obj_t *self) {
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never_reset_i2c[i2c_hw_index(self->peripheral)] = true;
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never_reset_pin_number(self->scl_pin);
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never_reset_pin_number(self->sda_pin);
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}
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