/* * 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 <linux/kernel.h> #include <linux/init.h> #include <linux/err.h> #include <linux/platform_device.h> #include "soc.h" #include "omap_hwmod.h" #include "omap_device.h" #include "hdq1w.h" #include "prm.h" #include "common.h" /** * 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_warn("%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; }