1 /* 2 * Helper module for board specific I2C bus registration 3 * 4 * Copyright (C) 2009 Nokia Corporation. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, but 11 * WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 * General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 18 * 02110-1301 USA 19 * 20 */ 21 22 #include "soc.h" 23 #include "common.h" 24 #include "omap_hwmod.h" 25 #include "omap_device.h" 26 27 #include "mux.h" 28 #include "i2c.h" 29 30 /* In register I2C_CON, Bit 15 is the I2C enable bit */ 31 #define I2C_EN BIT(15) 32 #define OMAP2_I2C_CON_OFFSET 0x24 33 #define OMAP4_I2C_CON_OFFSET 0xA4 34 35 /* Maximum microseconds to wait for OMAP module to softreset */ 36 #define MAX_MODULE_SOFTRESET_WAIT 10000 37 38 #define MAX_OMAP_I2C_HWMOD_NAME_LEN 16 39 40 static void __init omap2_i2c_mux_pins(int bus_id) 41 { 42 char mux_name[sizeof("i2c2_scl.i2c2_scl")]; 43 44 /* First I2C bus is not muxable */ 45 if (bus_id == 1) 46 return; 47 48 sprintf(mux_name, "i2c%i_scl.i2c%i_scl", bus_id, bus_id); 49 omap_mux_init_signal(mux_name, OMAP_PIN_INPUT); 50 sprintf(mux_name, "i2c%i_sda.i2c%i_sda", bus_id, bus_id); 51 omap_mux_init_signal(mux_name, OMAP_PIN_INPUT); 52 } 53 54 /** 55 * omap_i2c_reset - reset the omap i2c module. 56 * @oh: struct omap_hwmod * 57 * 58 * The i2c moudle in omap2, omap3 had a special sequence to reset. The 59 * sequence is: 60 * - Disable the I2C. 61 * - Write to SOFTRESET bit. 62 * - Enable the I2C. 63 * - Poll on the RESETDONE bit. 64 * The sequence is implemented in below function. This is called for 2420, 65 * 2430 and omap3. 66 */ 67 int omap_i2c_reset(struct omap_hwmod *oh) 68 { 69 u32 v; 70 u16 i2c_con; 71 int c = 0; 72 73 if (oh->class->rev == OMAP_I2C_IP_VERSION_2) { 74 i2c_con = OMAP4_I2C_CON_OFFSET; 75 } else if (oh->class->rev == OMAP_I2C_IP_VERSION_1) { 76 i2c_con = OMAP2_I2C_CON_OFFSET; 77 } else { 78 WARN(1, "Cannot reset I2C block %s: unsupported revision\n", 79 oh->name); 80 return -EINVAL; 81 } 82 83 /* Disable I2C */ 84 v = omap_hwmod_read(oh, i2c_con); 85 v &= ~I2C_EN; 86 omap_hwmod_write(v, oh, i2c_con); 87 88 /* Write to the SOFTRESET bit */ 89 omap_hwmod_softreset(oh); 90 91 /* Enable I2C */ 92 v = omap_hwmod_read(oh, i2c_con); 93 v |= I2C_EN; 94 omap_hwmod_write(v, oh, i2c_con); 95 96 /* Poll on RESETDONE bit */ 97 omap_test_timeout((omap_hwmod_read(oh, 98 oh->class->sysc->syss_offs) 99 & SYSS_RESETDONE_MASK), 100 MAX_MODULE_SOFTRESET_WAIT, c); 101 102 if (c == MAX_MODULE_SOFTRESET_WAIT) 103 pr_warning("%s: %s: softreset failed (waited %d usec)\n", 104 __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT); 105 else 106 pr_debug("%s: %s: softreset in %d usec\n", __func__, 107 oh->name, c); 108 109 return 0; 110 } 111 112 static const char name[] = "omap_i2c"; 113 114 int __init omap_i2c_add_bus(struct omap_i2c_bus_platform_data *i2c_pdata, 115 int bus_id) 116 { 117 int l; 118 struct omap_hwmod *oh; 119 struct platform_device *pdev; 120 char oh_name[MAX_OMAP_I2C_HWMOD_NAME_LEN]; 121 struct omap_i2c_bus_platform_data *pdata; 122 struct omap_i2c_dev_attr *dev_attr; 123 124 omap2_i2c_mux_pins(bus_id); 125 126 l = snprintf(oh_name, MAX_OMAP_I2C_HWMOD_NAME_LEN, "i2c%d", bus_id); 127 WARN(l >= MAX_OMAP_I2C_HWMOD_NAME_LEN, 128 "String buffer overflow in I2C%d device setup\n", bus_id); 129 oh = omap_hwmod_lookup(oh_name); 130 if (!oh) { 131 pr_err("Could not look up %s\n", oh_name); 132 return -EEXIST; 133 } 134 135 pdata = i2c_pdata; 136 /* 137 * pass the hwmod class's CPU-specific knowledge of I2C IP revision in 138 * use, and functionality implementation flags, up to the OMAP I2C 139 * driver via platform data 140 */ 141 pdata->rev = oh->class->rev; 142 143 dev_attr = (struct omap_i2c_dev_attr *)oh->dev_attr; 144 pdata->flags = dev_attr->flags; 145 146 pdev = omap_device_build(name, bus_id, oh, pdata, 147 sizeof(struct omap_i2c_bus_platform_data), 148 NULL, 0, 0); 149 WARN(IS_ERR(pdev), "Could not build omap_device for %s\n", name); 150 151 return PTR_RET(pdev); 152 } 153 154