clk: qcom: Add reset controller support

Reset controllers and clock controllers are combined into one IP
block on Qualcomm chipsets. Usually a reset signal is associated
with each clock branch but sometimes a reset signal is associated
with a handful of clocks. Either way the register interface is
the same; set a bit to assert a reset and clear a bit to deassert
a reset. Add support for these types of resets signals.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/qcom/Kconfig

@@ -2,4 +2,4 @@ config COMMON_CLK_QCOM
 	tristate "Support for Qualcomm's clock controllers"
 	depends on OF
 	select REGMAP_MMIO
-
+	select RESET_CONTROLLER

drivers/clk/qcom/Makefile

@@ -5,3 +5,4 @@ clk-qcom-$(CONFIG_COMMON_CLK_QCOM) += clk-pll.o
 clk-qcom-$(CONFIG_COMMON_CLK_QCOM) += clk-rcg.o
 clk-qcom-$(CONFIG_COMMON_CLK_QCOM) += clk-rcg2.o
 clk-qcom-$(CONFIG_COMMON_CLK_QCOM) += clk-branch.o
+clk-qcom-$(CONFIG_COMMON_CLK_QCOM) += reset.o

drivers/clk/qcom/reset.c

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/export.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/delay.h>
+
+#include "reset.h"
+
+static int qcom_reset(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	rcdev->ops->assert(rcdev, id);
+	udelay(1);
+	rcdev->ops->deassert(rcdev, id);
+	return 0;
+}
+
+static int
+qcom_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	struct qcom_reset_controller *rst;
+	const struct qcom_reset_map *map;
+	u32 mask;
+
+	rst = to_qcom_reset_controller(rcdev);
+	map = &rst->reset_map[id];
+	mask = BIT(map->bit);
+
+	return regmap_update_bits(rst->regmap, map->reg, mask, mask);
+}
+
+static int
+qcom_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	struct qcom_reset_controller *rst;
+	const struct qcom_reset_map *map;
+	u32 mask;
+
+	rst = to_qcom_reset_controller(rcdev);
+	map = &rst->reset_map[id];
+	mask = BIT(map->bit);
+
+	return regmap_update_bits(rst->regmap, map->reg, mask, 0);
+}
+
+struct reset_control_ops qcom_reset_ops = {
+	.reset = qcom_reset,
+	.assert = qcom_reset_assert,
+	.deassert = qcom_reset_deassert,
+};
+EXPORT_SYMBOL_GPL(qcom_reset_ops);

drivers/clk/qcom/reset.h

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#ifndef __QCOM_CLK_RESET_H__
+#define __QCOM_CLK_RESET_H__
+
+#include <linux/reset-controller.h>
+
+struct qcom_reset_map {
+	unsigned int reg;
+	u8 bit;
+};
+
+struct regmap;
+
+struct qcom_reset_controller {
+	const struct qcom_reset_map *reset_map;
+	struct regmap *regmap;
+	struct reset_controller_dev rcdev;
+};
+
+#define to_qcom_reset_controller(r) \
+	container_of(r, struct qcom_reset_controller, rcdev);
+
+extern struct reset_control_ops qcom_reset_ops;
+
+#endif