264 lines
7.4 KiB
C
264 lines
7.4 KiB
C
/*
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* Copyright (c) 2013 Google Inc.
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*
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* Use of this source code is governed by a MIT-style
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* license that can be found in the LICENSE file or at
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* https://opensource.org/licenses/MIT
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*/
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#include <assert.h>
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#include <lk/compiler.h>
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#include <lk/debug.h>
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#include <printf.h>
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#include <lk/err.h>
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#include <dev/gpio.h>
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#include <dev/gpio_i2c.h>
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#include <kernel/mutex.h>
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#if (!(defined(GPIO_I2C_BUS_COUNT)) || (GPIO_I2C_BUS_COUNT <= 0))
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#error ERROR: Must define GPIO_I2C_BUS_COUNT
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#endif
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#if GPIO_I2C_PULLUPS
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#define GPIO_I2C_INPUT (GPIO_INPUT | GPIO_PULLUP)
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#else
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#define GPIO_I2C_INPUT (GPIO_INPUT)
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#endif // GPIO_I2C_PULLUPS
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typedef struct gpio_i2c_state {
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mutex_t lock;
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const gpio_i2c_info_t *info;
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} gpio_i2c_state_t;
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static gpio_i2c_state_t gpio_i2c_states[GPIO_I2C_BUS_COUNT];
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/******************************************************************************
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*
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* Internal implementation.
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*
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******************************************************************************/
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static inline void send_start(const gpio_i2c_info_t *i) {
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gpio_config(i->sda, GPIO_OUTPUT);
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spin_cycles(i->qcd);
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gpio_config(i->scl, GPIO_OUTPUT);
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spin_cycles(i->hcd);
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}
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static inline void send_stop(const gpio_i2c_info_t *i) {
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gpio_config(i->sda, GPIO_OUTPUT);
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gpio_config(i->scl, GPIO_I2C_INPUT);
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spin_cycles(i->qcd);
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gpio_config(i->sda, GPIO_I2C_INPUT);
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}
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static inline void send_restart(const gpio_i2c_info_t *i) {
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gpio_config(i->scl, GPIO_I2C_INPUT);
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spin_cycles(i->qcd);
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send_start(i);
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}
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static inline void send_nack(const gpio_i2c_info_t *i) {
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spin_cycles(i->hcd);
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gpio_config(i->scl, GPIO_I2C_INPUT);
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spin_cycles(i->hcd);
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gpio_config(i->scl, GPIO_OUTPUT);
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gpio_config(i->sda, GPIO_I2C_INPUT);
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}
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static inline void send_ack(const gpio_i2c_info_t *i) {
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gpio_config(i->sda, GPIO_OUTPUT);
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send_nack(i);
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}
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static inline bool send_byte(const gpio_i2c_info_t *i, uint32_t b) {
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bool ret;
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for (size_t j = 0; j < 8; ++j) {
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if (b & 0x80)
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gpio_config(i->sda, GPIO_I2C_INPUT);
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else
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gpio_config(i->sda, GPIO_OUTPUT);
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b <<= 1;
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/* setup time for data (the time between when data becomes stable and
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* clock becomes a stable high) is spec'ed to be 250ns for 100KHz i2c
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* and 100nsec for 400KHz i2c. If any micro running LK needs to spin
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* here in order to hit that timing, they are welcome to add a spin
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* right here.
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*/
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spin_cycles(i->hcd);
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gpio_config(i->scl, GPIO_I2C_INPUT);
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spin_cycles(i->hcd);
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gpio_config(i->scl, GPIO_OUTPUT);
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}
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gpio_config(i->sda, GPIO_I2C_INPUT);
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spin_cycles(i->hcd);
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gpio_config(i->scl, GPIO_I2C_INPUT);
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spin_cycles(i->hcd);
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ret = (0 == gpio_get(i->sda));
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gpio_config(i->scl, GPIO_OUTPUT);
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spin_cycles(i->hcd);
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return ret;
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}
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static inline void recv_byte(const gpio_i2c_info_t *i, uint8_t *b) {
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uint32_t tmp = 0;
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for (size_t j = 0; j < 7; ++j) {
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gpio_config(i->scl, GPIO_I2C_INPUT);
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spin_cycles(i->hcd);
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if (gpio_get(i->sda))
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tmp |= 1;
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tmp <<= 1;
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gpio_config(i->scl, GPIO_OUTPUT);
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spin_cycles(i->hcd);
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}
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gpio_config(i->scl, GPIO_I2C_INPUT);
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spin_cycles(i->hcd);
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if (gpio_get(i->sda))
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tmp |= 1;
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gpio_config(i->scl, GPIO_OUTPUT);
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*b = (uint8_t)tmp;
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}
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static status_t gpio_i2c_tx_common(gpio_i2c_state_t *s,
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uint8_t address,
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const uint8_t *reg,
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const void *buf,
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size_t cnt) {
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const gpio_i2c_info_t *i = s->info;
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status_t ret = ERR_I2C_NACK;
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DEBUG_ASSERT(buf || !cnt);
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mutex_acquire(&s->lock);
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send_start(i);
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if (!send_byte(i, address << 1))
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goto finished;
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if ((NULL != reg) && !send_byte(i, *reg))
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goto finished;
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for (size_t j = 0; j < cnt; ++j)
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if (!send_byte(i, ((const uint8_t *)buf)[j]))
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goto finished;
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ret = NO_ERROR;
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finished:
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send_stop(i);
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mutex_release(&s->lock);
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return ret;
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}
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static status_t gpio_i2c_rx_common(gpio_i2c_state_t *s,
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uint8_t address,
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const uint8_t *reg,
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void *buf,
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size_t cnt) {
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const gpio_i2c_info_t *i = s->info;
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status_t ret = ERR_I2C_NACK;
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DEBUG_ASSERT(buf && cnt);
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address <<= 1;
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mutex_acquire(&s->lock);
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send_start(i);
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if (!send_byte(i, address | (!reg ? 0x1 : 0x0)))
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goto finished;
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if (NULL != reg) {
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if (!send_byte(i, *reg))
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goto finished;
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send_restart(i);
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if (!send_byte(i, address | 0x1))
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goto finished;
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}
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recv_byte(i, buf++);
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for (size_t j = 0; j < (cnt - 1); ++j) {
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send_ack(i);
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recv_byte(i, buf++);
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}
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send_nack(i);
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ret = NO_ERROR;
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finished:
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send_stop(i);
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mutex_release(&s->lock);
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return ret;
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}
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void gpio_i2c_add_bus(uint32_t bus_id, const gpio_i2c_info_t *info) {
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gpio_i2c_state_t *s = gpio_i2c_states + bus_id;
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DEBUG_ASSERT(info);
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DEBUG_ASSERT(bus_id < GPIO_I2C_BUS_COUNT);
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DEBUG_ASSERT(!s->info);
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gpio_config(info->scl, GPIO_I2C_INPUT);
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gpio_config(info->sda, GPIO_I2C_INPUT);
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gpio_set(info->scl, 0);
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gpio_set(info->sda, 0);
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mutex_init(&s->lock);
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s->info = info;
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}
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/******************************************************************************
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*
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* LK facing API
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*
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* *****************************************************************************/
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void gpio_i2c_init_early(void) { }
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void gpio_i2c_init(void) { }
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status_t gpio_i2c_transmit(int bus, uint8_t address, const void *buf, size_t cnt) {
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gpio_i2c_state_t *s = gpio_i2c_states + bus;
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if (((unsigned)bus >= countof(gpio_i2c_states)) || !s->info)
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return ERR_NOT_FOUND;
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return gpio_i2c_tx_common(s, address, NULL, buf, cnt);
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}
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status_t gpio_i2c_receive(int bus, uint8_t address, void *buf, size_t cnt) {
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gpio_i2c_state_t *s = gpio_i2c_states + bus;
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if (((unsigned)bus >= countof(gpio_i2c_states)) || !s->info)
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return ERR_NOT_FOUND;
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return gpio_i2c_rx_common(s, address, NULL, buf, cnt);
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}
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status_t gpio_i2c_write_reg_bytes(int bus, uint8_t address, uint8_t reg, const uint8_t *buf, size_t cnt) {
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gpio_i2c_state_t *s = gpio_i2c_states + bus;
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if (((unsigned)bus >= countof(gpio_i2c_states)) || !s->info)
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return ERR_NOT_FOUND;
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return gpio_i2c_tx_common(s, address, ®, buf, cnt);
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}
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status_t gpio_i2c_read_reg_bytes(int bus, uint8_t address, uint8_t reg, uint8_t *buf, size_t cnt) {
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gpio_i2c_state_t *s = gpio_i2c_states + bus;
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if (((unsigned)bus >= countof(gpio_i2c_states)) || !s->info) {
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return ERR_NOT_FOUND;
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}
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return gpio_i2c_rx_common(s, address, ®, buf, cnt);
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}
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void i2c_init_early(void) __WEAK_ALIAS("gpio_i2c_init_early");
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void i2c_init(void) __WEAK_ALIAS("gpio_i2c_init");
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status_t i2c_transmit(int, uint8_t, const void *, size_t) __WEAK_ALIAS("gpio_i2c_transmit");
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status_t i2c_receive(int, uint8_t, void *, size_t) __WEAK_ALIAS("gpio_i2c_receive");
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status_t i2c_write_reg_bytes(int, uint8_t, uint8_t,
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const uint8_t *, size_t) __WEAK_ALIAS("gpio_i2c_write_reg_bytes");
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status_t i2c_read_reg_bytes(int, uint8_t, uint8_t,
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uint8_t *, size_t) __WEAK_ALIAS("gpio_i2c_read_reg_bytes");
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