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/*
* IP block integration code for the HDQ1W/1-wire IP block
*
* Copyright (C) 2012 Texas Instruments, Inc.
* Paul Walmsley
*
* Based on the I2C reset code in arch/arm/mach-omap2/i2c.c by
* Avinash.H.M <avinashhm@ti.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include <plat/omap_hwmod.h>
#include <plat/hdq1w.h>
#include "common.h"
/* Maximum microseconds to wait for OMAP module to softreset */
#define MAX_MODULE_SOFTRESET_WAIT 10000
/**
* omap_hdq1w_reset - reset the OMAP HDQ1W module
* @oh: struct omap_hwmod *
*
* OCP soft reset the HDQ1W IP block. Section 20.6.1.4 "HDQ1W/1-Wire
* Software Reset" of the OMAP34xx Technical Reference Manual Revision
* ZR (SWPU223R) does not include the rather important fact that, for
* the reset to succeed, the HDQ1W module's internal clock gate must be
* programmed to allow the clock to propagate to the rest of the
* module. In this sense, it's rather similar to the I2C custom reset
* function. Returns 0.
*/
int omap_hdq1w_reset(struct omap_hwmod *oh)
{
u32 v;
int c = 0;
/* Write to the SOFTRESET bit */
omap_hwmod_softreset(oh);
/* Enable the module's internal clocks */
v = omap_hwmod_read(oh, HDQ_CTRL_STATUS_OFFSET);
v |= 1 << HDQ_CTRL_STATUS_CLOCKENABLE_SHIFT;
omap_hwmod_write(v, oh, HDQ_CTRL_STATUS_OFFSET);
/* Poll on RESETDONE bit */
omap_test_timeout((omap_hwmod_read(oh,
oh->class->sysc->syss_offs)
& SYSS_RESETDONE_MASK),
MAX_MODULE_SOFTRESET_WAIT, c);
if (c == MAX_MODULE_SOFTRESET_WAIT)
pr_warning("%s: %s: softreset failed (waited %d usec)\n",
__func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
else
pr_debug("%s: %s: softreset in %d usec\n", __func__,
oh->name, c);
return 0;
}
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