1 /*
2 * Copyright (c) 2019 Antmicro <www.antmicro.com>
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #define DT_DRV_COMPAT litex_i2c
8
9 #include <zephyr/device.h>
10 #include <zephyr/drivers/i2c.h>
11 #include "i2c_bitbang.h"
12
13 #define SCL_BIT_POS 0
14 #define SDA_DIR_BIT_POS 1
15 #define SDA_BIT_W_POS 2
16 #define SDA_BIT_R_POS 0
17
18 #define SDA_DIR_OUTPUT 1
19 #define SDA_DIR_INPUT 0
20
21 #define HIGH_STATE_ON_I2C_LINES 0x7
22
23 struct i2c_litex_cfg {
24 uint32_t write_addr;
25 uint32_t read_addr;
26 };
27
28 #define GET_I2C_CFG(dev) \
29 ((const struct i2c_litex_cfg *) dev->config)
30
31 #define GET_I2C_BITBANG(dev) \
32 ((struct i2c_bitbang *) dev->data)
33
set_bit(uint32_t addr,uint32_t bit,uint32_t val)34 static inline void set_bit(uint32_t addr, uint32_t bit, uint32_t val)
35 {
36 uint32_t mask = BIT(bit);
37
38 if (val) {
39 litex_write8(litex_read8(addr) | mask, addr);
40 } else {
41 litex_write8(litex_read8(addr) & ~mask, addr);
42 }
43 }
44
get_bit(uint32_t addr,uint32_t bit)45 static inline int get_bit(uint32_t addr, uint32_t bit)
46 {
47 uint32_t mask = BIT(bit);
48
49 return !!(litex_read8(addr) & mask);
50 }
51
i2c_litex_bitbang_set_scl(void * context,int state)52 static void i2c_litex_bitbang_set_scl(void *context, int state)
53 {
54 const struct i2c_litex_cfg *config =
55 (const struct i2c_litex_cfg *) context;
56
57 set_bit(config->write_addr, SCL_BIT_POS, state);
58 }
59
i2c_litex_bitbang_set_sda(void * context,int state)60 static void i2c_litex_bitbang_set_sda(void *context, int state)
61 {
62 const struct i2c_litex_cfg *config =
63 (const struct i2c_litex_cfg *) context;
64
65 set_bit(config->write_addr, SDA_DIR_BIT_POS, SDA_DIR_OUTPUT);
66 set_bit(config->write_addr, SDA_BIT_W_POS, state);
67 }
68
i2c_litex_bitbang_get_sda(void * context)69 static int i2c_litex_bitbang_get_sda(void *context)
70 {
71 const struct i2c_litex_cfg *config =
72 (const struct i2c_litex_cfg *) context;
73
74 set_bit(config->write_addr, SDA_DIR_BIT_POS, SDA_DIR_INPUT);
75 return get_bit(config->read_addr, SDA_BIT_R_POS);
76 }
77
78 static const struct i2c_bitbang_io i2c_litex_bitbang_io = {
79 .set_scl = i2c_litex_bitbang_set_scl,
80 .set_sda = i2c_litex_bitbang_set_sda,
81 .get_sda = i2c_litex_bitbang_get_sda,
82 };
83
i2c_litex_init(const struct device * dev)84 static int i2c_litex_init(const struct device *dev)
85 {
86 const struct i2c_litex_cfg *config = GET_I2C_CFG(dev);
87 struct i2c_bitbang *bitbang = GET_I2C_BITBANG(dev);
88
89 litex_write8(litex_read8(config->write_addr) | HIGH_STATE_ON_I2C_LINES, config->write_addr);
90 i2c_bitbang_init(bitbang, &i2c_litex_bitbang_io, (void *)config);
91
92 return 0;
93 }
94
i2c_litex_configure(const struct device * dev,uint32_t dev_config)95 static int i2c_litex_configure(const struct device *dev, uint32_t dev_config)
96 {
97 struct i2c_bitbang *bitbang = GET_I2C_BITBANG(dev);
98
99 return i2c_bitbang_configure(bitbang, dev_config);
100 }
101
i2c_litex_transfer(const struct device * dev,struct i2c_msg * msgs,uint8_t num_msgs,uint16_t addr)102 static int i2c_litex_transfer(const struct device *dev, struct i2c_msg *msgs,
103 uint8_t num_msgs, uint16_t addr)
104 {
105 struct i2c_bitbang *bitbang = GET_I2C_BITBANG(dev);
106
107 return i2c_bitbang_transfer(bitbang, msgs, num_msgs, addr);
108 }
109
110 static const struct i2c_driver_api i2c_litex_driver_api = {
111 .configure = i2c_litex_configure,
112 .transfer = i2c_litex_transfer,
113 };
114
115 /* Device Instantiation */
116
117 #define I2C_LITEX_INIT(n) \
118 static const struct i2c_litex_cfg i2c_litex_cfg_##n = { \
119 .write_addr = DT_INST_REG_ADDR_BY_NAME(n, write), \
120 .read_addr = DT_INST_REG_ADDR_BY_NAME(n, read), \
121 }; \
122 \
123 static struct i2c_bitbang i2c_bitbang_##n; \
124 \
125 I2C_DEVICE_DT_INST_DEFINE(n, \
126 i2c_litex_init, \
127 NULL, \
128 &i2c_bitbang_##n, \
129 &i2c_litex_cfg_##n, \
130 POST_KERNEL, \
131 CONFIG_I2C_INIT_PRIORITY, \
132 &i2c_litex_driver_api \
133 );
134
135 DT_INST_FOREACH_STATUS_OKAY(I2C_LITEX_INIT)
136
