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 <plat/i2c.h> 23 #include "common.h" 24 #include <plat/omap_hwmod.h> 25 26 #include "mux.h" 27 28 /* In register I2C_CON, Bit 15 is the I2C enable bit */ 29 #define I2C_EN BIT(15) 30 #define OMAP2_I2C_CON_OFFSET 0x24 31 #define OMAP4_I2C_CON_OFFSET 0xA4 32 33 /* Maximum microseconds to wait for OMAP module to softreset */ 34 #define MAX_MODULE_SOFTRESET_WAIT 10000 35 36 void __init omap2_i2c_mux_pins(int bus_id) 37 { 38 char mux_name[sizeof("i2c2_scl.i2c2_scl")]; 39 40 /* First I2C bus is not muxable */ 41 if (bus_id == 1) 42 return; 43 44 sprintf(mux_name, "i2c%i_scl.i2c%i_scl", bus_id, bus_id); 45 omap_mux_init_signal(mux_name, OMAP_PIN_INPUT); 46 sprintf(mux_name, "i2c%i_sda.i2c%i_sda", bus_id, bus_id); 47 omap_mux_init_signal(mux_name, OMAP_PIN_INPUT); 48 } 49 50 /** 51 * omap_i2c_reset - reset the omap i2c module. 52 * @oh: struct omap_hwmod * 53 * 54 * The i2c moudle in omap2, omap3 had a special sequence to reset. The 55 * sequence is: 56 * - Disable the I2C. 57 * - Write to SOFTRESET bit. 58 * - Enable the I2C. 59 * - Poll on the RESETDONE bit. 60 * The sequence is implemented in below function. This is called for 2420, 61 * 2430 and omap3. 62 */ 63 int omap_i2c_reset(struct omap_hwmod *oh) 64 { 65 u32 v; 66 u16 i2c_con; 67 int c = 0; 68 69 if (oh->class->rev == OMAP_I2C_IP_VERSION_2) { 70 i2c_con = OMAP4_I2C_CON_OFFSET; 71 } else if (oh->class->rev == OMAP_I2C_IP_VERSION_1) { 72 i2c_con = OMAP2_I2C_CON_OFFSET; 73 } else { 74 WARN(1, "Cannot reset I2C block %s: unsupported revision\n", 75 oh->name); 76 return -EINVAL; 77 } 78 79 /* Disable I2C */ 80 v = omap_hwmod_read(oh, i2c_con); 81 v &= ~I2C_EN; 82 omap_hwmod_write(v, oh, i2c_con); 83 84 /* Write to the SOFTRESET bit */ 85 omap_hwmod_softreset(oh); 86 87 /* Enable I2C */ 88 v = omap_hwmod_read(oh, i2c_con); 89 v |= I2C_EN; 90 omap_hwmod_write(v, oh, i2c_con); 91 92 /* Poll on RESETDONE bit */ 93 omap_test_timeout((omap_hwmod_read(oh, 94 oh->class->sysc->syss_offs) 95 & SYSS_RESETDONE_MASK), 96 MAX_MODULE_SOFTRESET_WAIT, c); 97 98 if (c == MAX_MODULE_SOFTRESET_WAIT) 99 pr_warning("%s: %s: softreset failed (waited %d usec)\n", 100 __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT); 101 else 102 pr_debug("%s: %s: softreset in %d usec\n", __func__, 103 oh->name, c); 104 105 return 0; 106 } 107