1 files changed, 77 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/hdq1w.c b/arch/arm/mach-omap2/hdq1w.c
new file mode 100644
index 000000000..2bc4db23c
--- /dev/null
+++ b/arch/arm/mach-omap2/hdq1w.c
@@ -0,0 +1,77 @@
+/*
+ * 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;
+}