1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2012 Boundary Devices Inc.
4 */
5 #include <common.h>
6 #include <malloc.h>
7 #include <asm/arch/clock.h>
8 #include <asm/arch/imx-regs.h>
9 #include <linux/delay.h>
10 #include <linux/errno.h>
11 #include <asm/gpio.h>
12 #include <asm/mach-imx/mxc_i2c.h>
13 #include <watchdog.h>
14
force_idle_bus(void * priv)15 int force_idle_bus(void *priv)
16 {
17 int i;
18 int sda, scl;
19 ulong elapsed, start_time;
20 struct i2c_pads_info *p = (struct i2c_pads_info *)priv;
21 int ret = 0;
22
23 gpio_direction_input(p->sda.gp);
24 gpio_direction_input(p->scl.gp);
25
26 imx_iomux_v3_setup_pad(p->sda.gpio_mode);
27 imx_iomux_v3_setup_pad(p->scl.gpio_mode);
28
29 sda = gpio_get_value(p->sda.gp);
30 scl = gpio_get_value(p->scl.gp);
31 if ((sda & scl) == 1)
32 goto exit; /* Bus is idle already */
33
34 printf("%s: sda=%d scl=%d sda.gp=0x%x scl.gp=0x%x\n", __func__,
35 sda, scl, p->sda.gp, p->scl.gp);
36 /* Send high and low on the SCL line */
37 for (i = 0; i < 9; i++) {
38 gpio_direction_output(p->scl.gp, 0);
39 udelay(50);
40 gpio_direction_input(p->scl.gp);
41 udelay(50);
42 }
43 start_time = get_timer(0);
44 for (;;) {
45 sda = gpio_get_value(p->sda.gp);
46 scl = gpio_get_value(p->scl.gp);
47 if ((sda & scl) == 1)
48 break;
49 WATCHDOG_RESET();
50 elapsed = get_timer(start_time);
51 if (elapsed > (CONFIG_SYS_HZ / 5)) { /* .2 seconds */
52 ret = -EBUSY;
53 printf("%s: failed to clear bus, sda=%d scl=%d\n",
54 __func__, sda, scl);
55 break;
56 }
57 }
58 exit:
59 imx_iomux_v3_setup_pad(p->sda.i2c_mode);
60 imx_iomux_v3_setup_pad(p->scl.i2c_mode);
61 return ret;
62 }
63
64 static void * const i2c_bases[] = {
65 (void *)I2C1_BASE_ADDR,
66 (void *)I2C2_BASE_ADDR,
67 #ifdef I2C3_BASE_ADDR
68 (void *)I2C3_BASE_ADDR,
69 #endif
70 #ifdef I2C4_BASE_ADDR
71 (void *)I2C4_BASE_ADDR,
72 #endif
73 };
74
75 /* i2c_index can be from 0 - 3 */
setup_i2c(unsigned i2c_index,int speed,int slave_addr,struct i2c_pads_info * p)76 int setup_i2c(unsigned i2c_index, int speed, int slave_addr,
77 struct i2c_pads_info *p)
78 {
79 char name[9];
80 int ret;
81
82 if (i2c_index >= ARRAY_SIZE(i2c_bases))
83 return -EINVAL;
84
85 snprintf(name, sizeof(name), "i2c_sda%01d", i2c_index);
86 ret = gpio_request(p->sda.gp, name);
87 if (ret)
88 return ret;
89
90 snprintf(name, sizeof(name), "i2c_scl%01d", i2c_index);
91 ret = gpio_request(p->scl.gp, name);
92 if (ret)
93 goto err_req;
94
95 /* Enable i2c clock */
96 ret = enable_i2c_clk(1, i2c_index);
97 if (ret)
98 goto err_clk;
99
100 /* Make sure bus is idle */
101 ret = force_idle_bus(p);
102 if (ret)
103 goto err_idle;
104
105 #if !CONFIG_IS_ENABLED(DM_I2C)
106 bus_i2c_init(i2c_index, speed, slave_addr, force_idle_bus, p);
107 #endif
108
109 return 0;
110
111 err_idle:
112 err_clk:
113 gpio_free(p->scl.gp);
114 err_req:
115 gpio_free(p->sda.gp);
116
117 return ret;
118 }
119