cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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i2c.c (1729B)

      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 */
     36int 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}