1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Helper module for board specific I2C bus registration 4 * 5 * Copyright (C) 2009 Nokia Corporation. 6 */ 7 8 #include "soc.h" 9 #include "omap_hwmod.h" 10 #include "omap_device.h" 11 12 #include "prm.h" 13 #include "common.h" 14 #include "i2c.h" 15 16 /* In register I2C_CON, Bit 15 is the I2C enable bit */ 17 #define I2C_EN BIT(15) 18 #define OMAP2_I2C_CON_OFFSET 0x24 19 #define OMAP4_I2C_CON_OFFSET 0xA4 20 21 #define MAX_OMAP_I2C_HWMOD_NAME_LEN 16 22 23 /** 24 * omap_i2c_reset - reset the omap i2c module. 25 * @oh: struct omap_hwmod * 26 * 27 * The i2c moudle in omap2, omap3 had a special sequence to reset. The 28 * sequence is: 29 * - Disable the I2C. 30 * - Write to SOFTRESET bit. 31 * - Enable the I2C. 32 * - Poll on the RESETDONE bit. 33 * The sequence is implemented in below function. This is called for 2420, 34 * 2430 and omap3. 35 */ 36 int omap_i2c_reset(struct omap_hwmod *oh) 37 { 38 u32 v; 39 u16 i2c_con; 40 int c = 0; 41 42 if (soc_is_omap24xx() || soc_is_omap34xx() || soc_is_am35xx()) 43 i2c_con = OMAP2_I2C_CON_OFFSET; 44 else 45 i2c_con = OMAP4_I2C_CON_OFFSET; 46 47 /* Disable I2C */ 48 v = omap_hwmod_read(oh, i2c_con); 49 v &= ~I2C_EN; 50 omap_hwmod_write(v, oh, i2c_con); 51 52 /* Write to the SOFTRESET bit */ 53 omap_hwmod_softreset(oh); 54 55 /* Enable I2C */ 56 v = omap_hwmod_read(oh, i2c_con); 57 v |= I2C_EN; 58 omap_hwmod_write(v, oh, i2c_con); 59 60 /* Poll on RESETDONE bit */ 61 omap_test_timeout((omap_hwmod_read(oh, 62 oh->class->sysc->syss_offs) 63 & SYSS_RESETDONE_MASK), 64 MAX_MODULE_SOFTRESET_WAIT, c); 65 66 if (c == MAX_MODULE_SOFTRESET_WAIT) 67 pr_warn("%s: %s: softreset failed (waited %d usec)\n", 68 __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT); 69 else 70 pr_debug("%s: %s: softreset in %d usec\n", __func__, 71 oh->name, c); 72 73 return 0; 74 } 75