1 /*
2  * Copyright (c) 2019 - 2023, Nordic Semiconductor ASA
3  * All rights reserved.
4  *
5  * SPDX-License-Identifier: BSD-3-Clause
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright notice, this
11  *    list of conditions and the following disclaimer.
12  *
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * 3. Neither the name of the copyright holder nor the names of its
18  *    contributors may be used to endorse or promote products derived from this
19  *    software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
22  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31  * POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include <nrfx_twi_twim.h>
35 
36 #if NRFX_CHECK(NRFX_TWI_ENABLED) || NRFX_CHECK(NRFX_TWIM_ENABLED)
37 
38 #include <hal/nrf_gpio.h>
39 
40 #define TWI_TWIM_PIN_CONFIGURE(_pin) nrf_gpio_cfg((_pin),                     \
41                                                   NRF_GPIO_PIN_DIR_OUTPUT,    \
42                                                   NRF_GPIO_PIN_INPUT_CONNECT, \
43                                                   NRF_GPIO_PIN_PULLUP,        \
44                                                   NRF_GPIO_PIN_S0D1,          \
45                                                   NRF_GPIO_PIN_NOSENSE)
46 
nrfx_twi_twim_bus_recover(uint32_t scl_pin,uint32_t sda_pin)47 nrfx_err_t nrfx_twi_twim_bus_recover(uint32_t scl_pin, uint32_t sda_pin)
48 {
49     nrf_gpio_pin_set(scl_pin);
50     nrf_gpio_pin_set(sda_pin);
51 
52     TWI_TWIM_PIN_CONFIGURE(scl_pin);
53     TWI_TWIM_PIN_CONFIGURE(sda_pin);
54     NRFX_DELAY_US(4);
55 
56     for (uint8_t i = 0; i < 9; i++)
57     {
58         if (nrf_gpio_pin_read(sda_pin))
59         {
60             break;
61         }
62         else
63         {
64             // Pulse CLOCK signal
65             nrf_gpio_pin_clear(scl_pin);
66             NRFX_DELAY_US(4);
67             nrf_gpio_pin_set(scl_pin);
68             NRFX_DELAY_US(4);
69         }
70     }
71 
72     // Generate a STOP condition on the bus
73     nrf_gpio_pin_clear(sda_pin);
74     NRFX_DELAY_US(4);
75     nrf_gpio_pin_set(sda_pin);
76     NRFX_DELAY_US(4);
77 
78     if (nrf_gpio_pin_read(sda_pin))
79     {
80         return NRFX_SUCCESS;
81     }
82     else
83     {
84         return NRFX_ERROR_INTERNAL;
85     }
86 }
87 
88 #endif // NRFX_CHECK(NRFX_TWI_ENABLED) || NRFX_CHECK(NRFX_TWIM_ENABLED)
89