drivers/reset: support rockchip reset drivers

Create driver to support all Rockchip SoCs soft reset.
Example of usage:
i2c driver:
	ret = reset_get_by_name(dev, "i2c", &reset_ctl);
	if (ret) {
		error("reset_get_by_name() failed: %d\n", ret);
	}

	reset_assert(&reset_ctl);
	udelay(50);
	reset_deassert(&reset_ctl);

i2c dts node:
resets = <&cru SRST_P_I2C1>, <&cru SRST_I2C1>;
reset-names = "p_i2c", "i2c";

Change-Id: I7db97619e33447d6130e349e90799cd398e29d72
Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>

drivers/reset/Kconfig

@@ -67,4 +67,12 @@ config AST2500_RESET
 	  resets that are supported by watchdog. The main limitation though
 	  is that some reset signals, like I2C or MISC reset multiple devices.
 
+config RESET_ROCKCHIP
+	bool "Reset controller driver for Rockchip SoCs"
+	depends on DM_RESET && CLK
+	default y
+	help
+	  Support for reset controller on rockchip SoC. The main limitation though
+	  is that some reset signals, like I2C or MISC reset multiple devices.
+
 endmenu

drivers/reset/Makefile

@@ -11,3 +11,4 @@ obj-$(CONFIG_TEGRA186_RESET) += tegra186-reset.o
 obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
 obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
 obj-$(CONFIG_AST2500_RESET) += ast2500-reset.o
+obj-$(CONFIG_RESET_ROCKCHIP) += reset-rockchip.o

drivers/reset/reset-rockchip.c

@@ -0,0 +1,104 @@
+/*
+ * (C) Copyright 2017 Rockchip Electronics Co., Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <reset-uclass.h>
+#include <linux/io.h>
+
+struct rockchip_reset_priv {
+	void __iomem *base;
+	unsigned int sf_reset_offset;
+	unsigned int sf_reset_num;
+};
+
+static int rockchip_reset_request(struct reset_ctl *reset_ctl)
+{
+	struct rockchip_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+
+	debug("%s(reset_ctl=%p) (dev=%p, id=%lu) (sf_reset_num=%d)\n", __func__,
+	      reset_ctl, reset_ctl->dev, reset_ctl->id, priv->sf_reset_num);
+
+	if (reset_ctl->id / 16 >= priv->sf_reset_num)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int rockchip_reset_free(struct reset_ctl *reset_ctl)
+{
+	debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, reset_ctl,
+	      reset_ctl->dev, reset_ctl->id);
+
+	return 0;
+}
+
+static int rockchip_reset_assert(struct reset_ctl *reset_ctl)
+{
+	struct rockchip_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+	int bank =  reset_ctl->id / 16;
+	int offset =  reset_ctl->id % 16;
+
+	debug("%s(reset_ctl=%p) (dev=%p, id=%lu) (reg_addr=%p)\n", __func__,
+	      reset_ctl, reset_ctl->dev, reset_ctl->id,
+	      priv->base + (bank * 4));
+
+	writel(BIT(offset) | (BIT(offset) << 16), priv->base + (bank * 4));
+
+	return 0;
+}
+
+static int rockchip_reset_deassert(struct reset_ctl *reset_ctl)
+{
+	struct rockchip_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+	int bank =  reset_ctl->id / 16;
+	int offset =  reset_ctl->id % 16;
+
+	debug("%s(reset_ctl=%p) (dev=%p, id=%lu) (reg_addr=%p)\n", __func__,
+	      reset_ctl, reset_ctl->dev, reset_ctl->id,
+	      priv->base + (bank * 4));
+
+	writel((BIT(offset) << 16), priv->base + (bank * 4));
+
+	return 0;
+}
+
+struct reset_ops rockchip_reset_ops = {
+	.request = rockchip_reset_request,
+	.free = rockchip_reset_free,
+	.rst_assert = rockchip_reset_assert,
+	.rst_deassert = rockchip_reset_deassert,
+};
+
+static int rockchip_reset_probe(struct udevice *dev)
+{
+	struct rockchip_reset_priv *priv = dev_get_priv(dev);
+	fdt_addr_t addr;
+	fdt_size_t size;
+
+	addr = devfdt_get_addr_size_index(dev, 0, &size);
+	if (addr == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	if ((priv->sf_reset_offset == 0) && (priv->sf_reset_num == 0))
+		return -EINVAL;
+
+	addr += priv->sf_reset_offset;
+	priv->base = ioremap(addr, size);
+
+	debug("%s(base=%p) (sf_reset_offset=%x, sf_reset_num=%d)\n", __func__,
+	      priv->base, priv->sf_reset_offset, priv->sf_reset_num);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(rockchip_reset) = {
+	.name = "rockchip_reset",
+	.id = UCLASS_RESET,
+	.probe = rockchip_reset_probe,
+	.ops = &rockchip_reset_ops,
+	.priv_auto_alloc_size = sizeof(struct rockchip_reset_priv),
+};