hdq1w.c

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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 <[email protected]>
 *
 * 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 <linux/kernel.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>

#include <plat/omap_hwmod.h>
#include <plat/omap_device.h>
#include "hdq1w.h"

#include "common.h"

/* Maximum microseconds to wait for OMAP module to softreset */
#define MAX_MODULE_SOFTRESET_WAIT   10000

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;
}

static int __init omap_init_hdq(void)
{
    int id = -1;
    struct platform_device *pdev;
    struct omap_hwmod *oh;
    char *oh_name = "hdq1w";
    char *devname = "omap_hdq";

    oh = omap_hwmod_lookup(oh_name);
    if (!oh)
        return 0;

    pdev = omap_device_build(devname, id, oh, NULL, 0, NULL, 0, 0);
    WARN(IS_ERR(pdev), "Can't build omap_device for %s:%s.\n",
         devname, oh->name);

    return 0;
}
arch_initcall(omap_init_hdq);