1 /* 2 * Copyright (C) 2012 Boundary Devices Inc. 3 * 4 * SPDX-License-Identifier: GPL-2.0+ 5 */ 6 #include <common.h> 7 #include <malloc.h> 8 #include <asm/arch/clock.h> 9 #include <asm/arch/imx-regs.h> 10 #include <linux/errno.h> 11 #include <asm/gpio.h> 12 #include <asm/mach-imx/mxc_i2c.h> 13 #include <watchdog.h> 14 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 */ 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 #ifndef CONFIG_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