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/errno.h> 10 #include <asm/gpio.h> 11 #include <asm/mach-imx/mxc_i2c.h> 12 #include <watchdog.h> 13 14 int force_idle_bus(void *priv) 15 { 16 int i; 17 int sda, scl; 18 ulong elapsed, start_time; 19 struct i2c_pads_info *p = (struct i2c_pads_info *)priv; 20 int ret = 0; 21 22 gpio_direction_input(p->sda.gp); 23 gpio_direction_input(p->scl.gp); 24 25 imx_iomux_v3_setup_pad(p->sda.gpio_mode); 26 imx_iomux_v3_setup_pad(p->scl.gpio_mode); 27 28 sda = gpio_get_value(p->sda.gp); 29 scl = gpio_get_value(p->scl.gp); 30 if ((sda & scl) == 1) 31 goto exit; /* Bus is idle already */ 32 33 printf("%s: sda=%d scl=%d sda.gp=0x%x scl.gp=0x%x\n", __func__, 34 sda, scl, p->sda.gp, p->scl.gp); 35 /* Send high and low on the SCL line */ 36 for (i = 0; i < 9; i++) { 37 gpio_direction_output(p->scl.gp, 0); 38 udelay(50); 39 gpio_direction_input(p->scl.gp); 40 udelay(50); 41 } 42 start_time = get_timer(0); 43 for (;;) { 44 sda = gpio_get_value(p->sda.gp); 45 scl = gpio_get_value(p->scl.gp); 46 if ((sda & scl) == 1) 47 break; 48 WATCHDOG_RESET(); 49 elapsed = get_timer(start_time); 50 if (elapsed > (CONFIG_SYS_HZ / 5)) { /* .2 seconds */ 51 ret = -EBUSY; 52 printf("%s: failed to clear bus, sda=%d scl=%d\n", 53 __func__, sda, scl); 54 break; 55 } 56 } 57 exit: 58 imx_iomux_v3_setup_pad(p->sda.i2c_mode); 59 imx_iomux_v3_setup_pad(p->scl.i2c_mode); 60 return ret; 61 } 62 63 static void * const i2c_bases[] = { 64 (void *)I2C1_BASE_ADDR, 65 (void *)I2C2_BASE_ADDR, 66 #ifdef I2C3_BASE_ADDR 67 (void *)I2C3_BASE_ADDR, 68 #endif 69 #ifdef I2C4_BASE_ADDR 70 (void *)I2C4_BASE_ADDR, 71 #endif 72 }; 73 74 /* i2c_index can be from 0 - 3 */ 75 int setup_i2c(unsigned i2c_index, int speed, int slave_addr, 76 struct i2c_pads_info *p) 77 { 78 char name[9]; 79 int ret; 80 81 if (i2c_index >= ARRAY_SIZE(i2c_bases)) 82 return -EINVAL; 83 84 snprintf(name, sizeof(name), "i2c_sda%01d", i2c_index); 85 ret = gpio_request(p->sda.gp, name); 86 if (ret) 87 return ret; 88 89 snprintf(name, sizeof(name), "i2c_scl%01d", i2c_index); 90 ret = gpio_request(p->scl.gp, name); 91 if (ret) 92 goto err_req; 93 94 /* Enable i2c clock */ 95 ret = enable_i2c_clk(1, i2c_index); 96 if (ret) 97 goto err_clk; 98 99 /* Make sure bus is idle */ 100 ret = force_idle_bus(p); 101 if (ret) 102 goto err_idle; 103 104 #ifndef CONFIG_DM_I2C 105 bus_i2c_init(i2c_index, speed, slave_addr, force_idle_bus, p); 106 #endif 107 108 return 0; 109 110 err_idle: 111 err_clk: 112 gpio_free(p->scl.gp); 113 err_req: 114 gpio_free(p->sda.gp); 115 116 return ret; 117 } 118