1 /*
2 * Copyright (c) 2006-2022, RT-Thread Development Team
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 *
6 * Change Logs:
7 * Date Author Notes
8 * 2022-02-22 airm2m first version
9 */
10
11 #include <board.h>
12 #include "drv_soft_i2c.h"
13
14 #ifdef RT_USING_I2C
15
16 //#define DRV_DEBUG
17 #define LOG_TAG "drv.i2c"
18 #include <drv_log.h>
19
20 #if !defined(BSP_USING_I2C1) && !defined(BSP_USING_I2C2) && !defined(BSP_USING_I2C3) && !defined(BSP_USING_I2C4)
21 #error "Please define at least one BSP_USING_I2Cx"
22 /* this driver can be disabled at menuconfig -> RT-Thread Components -> Device Drivers */
23 #endif
24
25 static const struct air32_soft_i2c_config soft_i2c_config[] =
26 {
27 #ifdef BSP_USING_I2C1
28 I2C1_BUS_CONFIG,
29 #endif
30 #ifdef BSP_USING_I2C2
31 I2C2_BUS_CONFIG,
32 #endif
33 #ifdef BSP_USING_I2C3
34 I2C3_BUS_CONFIG,
35 #endif
36 #ifdef BSP_USING_I2C4
37 I2C4_BUS_CONFIG,
38 #endif
39 };
40
41 static struct air32_i2c i2c_obj[sizeof(soft_i2c_config) / sizeof(soft_i2c_config[0])];
42
43 /**
44 * This function initializes the i2c pin.
45 *
46 * @param air32 i2c dirver class.
47 */
air32_i2c_gpio_init(struct air32_i2c * i2c)48 static void air32_i2c_gpio_init(struct air32_i2c *i2c)
49 {
50 struct air32_soft_i2c_config* cfg = (struct air32_soft_i2c_config*)i2c->ops.data;
51
52 rt_pin_mode(cfg->scl, PIN_MODE_OUTPUT_OD);
53 rt_pin_mode(cfg->sda, PIN_MODE_OUTPUT_OD);
54
55 rt_pin_write(cfg->scl, PIN_HIGH);
56 rt_pin_write(cfg->sda, PIN_HIGH);
57 }
58
air32_i2c_pin_init(void)59 static void air32_i2c_pin_init(void)
60 {
61 rt_size_t obj_num = sizeof(i2c_obj) / sizeof(struct air32_i2c);
62
63 for(rt_size_t i = 0; i < obj_num; i++)
64 {
65 air32_i2c_gpio_init(&i2c_obj[i]);
66 }
67 }
68
69 /**
70 * This function sets the sda pin.
71 *
72 * @param air32 config class.
73 * @param The sda pin state.
74 */
air32_set_sda(void * data,rt_int32_t state)75 static void air32_set_sda(void *data, rt_int32_t state)
76 {
77 struct air32_soft_i2c_config* cfg = (struct air32_soft_i2c_config*)data;
78 if (state)
79 {
80 rt_pin_write(cfg->sda, PIN_HIGH);
81 }
82 else
83 {
84 rt_pin_write(cfg->sda, PIN_LOW);
85 }
86 }
87
88 /**
89 * This function sets the scl pin.
90 *
91 * @param air32 config class.
92 * @param The scl pin state.
93 */
air32_set_scl(void * data,rt_int32_t state)94 static void air32_set_scl(void *data, rt_int32_t state)
95 {
96 struct air32_soft_i2c_config* cfg = (struct air32_soft_i2c_config*)data;
97 if (state)
98 {
99 rt_pin_write(cfg->scl, PIN_HIGH);
100 }
101 else
102 {
103 rt_pin_write(cfg->scl, PIN_LOW);
104 }
105 }
106
107 /**
108 * This function gets the sda pin state.
109 *
110 * @param The sda pin state.
111 */
air32_get_sda(void * data)112 static rt_int32_t air32_get_sda(void *data)
113 {
114 struct air32_soft_i2c_config* cfg = (struct air32_soft_i2c_config*)data;
115 return rt_pin_read(cfg->sda);
116 }
117
118 /**
119 * This function gets the scl pin state.
120 *
121 * @param The scl pin state.
122 */
air32_get_scl(void * data)123 static rt_int32_t air32_get_scl(void *data)
124 {
125 struct air32_soft_i2c_config* cfg = (struct air32_soft_i2c_config*)data;
126 return rt_pin_read(cfg->scl);
127 }
128 /**
129 * The time delay function.
130 *
131 * @param microseconds.
132 */
air32_udelay(rt_uint32_t us)133 static void air32_udelay(rt_uint32_t us)
134 {
135 rt_uint32_t ticks;
136 rt_uint32_t told, tnow, tcnt = 0;
137 rt_uint32_t reload = SysTick->LOAD;
138
139 ticks = us * reload / (1000000 / RT_TICK_PER_SECOND);
140 told = SysTick->VAL;
141 while (1)
142 {
143 tnow = SysTick->VAL;
144 if (tnow != told)
145 {
146 if (tnow < told)
147 {
148 tcnt += told - tnow;
149 }
150 else
151 {
152 tcnt += reload - tnow + told;
153 }
154 told = tnow;
155 if (tcnt >= ticks)
156 {
157 break;
158 }
159 }
160 }
161 }
162
163 static const struct rt_i2c_bit_ops air32_bit_ops_default =
164 {
165 .data = RT_NULL,
166 .pin_init = air32_i2c_pin_init,
167 .set_sda = air32_set_sda,
168 .set_scl = air32_set_scl,
169 .get_sda = air32_get_sda,
170 .get_scl = air32_get_scl,
171 .udelay = air32_udelay,
172 .delay_us = 1,
173 .timeout = 100,
174 .i2c_pin_init_flag = RT_FALSE
175 };
176
177 /**
178 * if i2c is locked, this function will unlock it
179 *
180 * @param air32 config class
181 *
182 * @return RT_EOK indicates successful unlock.
183 */
air32_i2c_bus_unlock(const struct air32_soft_i2c_config * cfg)184 static rt_err_t air32_i2c_bus_unlock(const struct air32_soft_i2c_config *cfg)
185 {
186 rt_int32_t i = 0;
187
188 if (PIN_LOW == rt_pin_read(cfg->sda))
189 {
190 while (i++ < 9)
191 {
192 rt_pin_write(cfg->scl, PIN_HIGH);
193 air32_udelay(100);
194 rt_pin_write(cfg->scl, PIN_LOW);
195 air32_udelay(100);
196 }
197 }
198 if (PIN_LOW == rt_pin_read(cfg->sda))
199 {
200 return -RT_ERROR;
201 }
202
203 return RT_EOK;
204 }
205
206 /* I2C initialization function */
rt_sw_i2c_init(void)207 int rt_sw_i2c_init(void)
208 {
209 rt_err_t result;
210
211 for (rt_size_t i = 0; i < sizeof(i2c_obj) / sizeof(struct air32_i2c); i++)
212 {
213 i2c_obj[i].ops = air32_bit_ops_default;
214 i2c_obj[i].ops.data = (void*)&soft_i2c_config[i];
215 i2c_obj[i].i2c_bus.priv = &i2c_obj[i].ops;
216
217 result = rt_i2c_bit_add_bus(&i2c_obj[i].i2c_bus, soft_i2c_config[i].bus_name);
218 RT_ASSERT(result == RT_EOK);
219 air32_i2c_bus_unlock(&soft_i2c_config[i]);
220
221 LOG_D("software simulation %s init done, pin scl: %d, pin sda %d",
222 soft_i2c_config[i].bus_name,
223 soft_i2c_config[i].scl,
224 soft_i2c_config[i].sda);
225 }
226
227 return RT_EOK;
228 }
229 INIT_BOARD_EXPORT(rt_sw_i2c_init);
230
231 #endif /* RT_USING_I2C */
232