[U-Boot] [PATCH v1 05/11] sunxi: add module reset (UCLASS_RESET) support for sunxi

[Philipp Tomsich]

In order to have the device model describe the module reset bits
on sunxi (well, at least for anything newer than sun6i), we need
a (rather simple) driver for 'allwinner,sun6i-a31-clock-reset'
nodes.

Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
---
 drivers/reset/Kconfig       |   9 ++++
 drivers/reset/Makefile      |   1 +
 drivers/reset/reset-sunxi.c | 107 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 117 insertions(+)
 create mode 100644 drivers/reset/reset-sunxi.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index c42b0bc..8db25fc 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -43,4 +43,13 @@ config RESET_UNIPHIER
 	  Say Y if you want to control reset signals provided by System Control
 	  block, Media I/O block, Peripheral Block.
 
+config RESET_SUNXI
+        bool "Reset controller driver for Allwiner SoCs"
+	depends on DM_RESET && ARCH_SUNXI
+	default y
+	help
+	  Support for reset controllers on Allwinner SoCs.
+	  Say Y if you want to control reset signals provided by CCU (e.g. sun50i)
+	  or PRCM (e.g. sun6i, sun9i) blocks.
+
 endmenu
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 5c4305c..0086da9 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -1,10 +1,11 @@
 # Copyright (c) 2016, NVIDIA CORPORATION.
 #
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_DM_RESET) += reset-uclass.o
 obj-$(CONFIG_SANDBOX_MBOX) += sandbox-reset.o
 obj-$(CONFIG_SANDBOX_MBOX) += sandbox-reset-test.o
 obj-$(CONFIG_TEGRA_CAR_RESET) += tegra-car-reset.o
 obj-$(CONFIG_TEGRA186_RESET) += tegra186-reset.o
 obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
+obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
diff --git a/drivers/reset/reset-sunxi.c b/drivers/reset/reset-sunxi.c
new file mode 100644
index 0000000..b667ca1
--- /dev/null
+++ b/drivers/reset/reset-sunxi.c
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2017 Theobroma Systems Design und Consulting GmbH
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <reset-uclass.h>
+#include <dm/device.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+#include <linux/sizes.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct sunxi_reset_priv {
+	void __iomem *base;
+	size_t  size;
+};
+
+static int sunxi_reset_request(struct reset_ctl *reset_ctl)
+{
+	debug("%s (%s): id %ld\n",
+	      reset_ctl->dev->name, __func__, reset_ctl->id);
+	return 0;
+}
+
+static int sunxi_reset_free(struct reset_ctl *reset_ctl)
+{
+	debug("%s (%s): id %ld\n",
+	      reset_ctl->dev->name, __func__, reset_ctl->id);
+	return 0;
+}
+
+static int sunxi_reset_update(struct reset_ctl *reset_ctl, bool assert)
+{
+	struct sunxi_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+	unsigned long id = reset_ctl->id;
+	unsigned long offset = id / 32; /* TODO: symbolic name */
+	unsigned int bit = id % 32;
+
+	debug("%s (%s): id %ld base %p offset %lx bit %d assert %d size %ld\n",
+	      reset_ctl->dev->name, __func__, id, priv->base, offset,
+	      bit, assert, priv->size);
+
+	if (offset >= priv->size)
+		return -EINVAL;
+
+	if (assert)
+		clrbits_le32(priv->base + offset, BIT(bit));
+	else
+		setbits_le32(priv->base + offset, BIT(bit));
+
+	return 0;
+}
+
+static int sunxi_reset_assert(struct reset_ctl *reset_ctl)
+{
+	return sunxi_reset_update(reset_ctl, true);
+}
+
+static int sunxi_reset_deassert(struct reset_ctl *reset_ctl)
+{
+	return sunxi_reset_update(reset_ctl, false);
+}
+
+static const struct reset_ops sunxi_reset_ops = {
+	.request = sunxi_reset_request,
+	.free = sunxi_reset_free,
+	.rst_assert = sunxi_reset_assert,
+	.rst_deassert = sunxi_reset_deassert,
+};
+
+static int sunxi_reset_probe(struct udevice *dev)
+{
+	struct sunxi_reset_priv *priv = dev_get_priv(dev);
+	fdt_addr_t addr;
+	fdt_size_t size;
+
+	addr = fdtdec_get_addr_size_auto_noparent(gd->fdt_blob, dev->of_offset,
+						  "reg", 0, &size, false);
+	if (addr == FDT_ADDR_T_NONE) {
+		debug("%s: failed to find base address ('reg')\n", dev->name);
+		return -ENODEV;
+	}
+	priv->base = (void *)addr;
+	priv->size = size;
+
+	if (!priv->base)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static const struct udevice_id sunxi_reset_match[] = {
+	{ .compatible = "allwinner,sun6i-a31-clock-reset" },
+	{ }
+};
+
+U_BOOT_DRIVER(sunxi_reset) = {
+	.name = "sunxi-reset",
+	.id = UCLASS_RESET,
+	.of_match = sunxi_reset_match,
+	.ops = &sunxi_reset_ops,
+	.priv_auto_alloc_size = sizeof(struct sunxi_reset_priv),
+	.probe = sunxi_reset_probe,
+};
-- 
1.9.1