reset: add the Berlin reset controller driver

Add a reset controller for Marvell Berlin SoCs which is used by the
USB PHYs drivers (for now).

Signed-off-by: Antoine Ténart <antoine.tenart@free-electrons.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

2 files changed, 132 insertions, 0 deletions

diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 60fed3d7820b..157d421f755b 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_RESET_CONTROLLER) += core.o
 obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
+obj-$(CONFIG_ARCH_BERLIN) += reset-berlin.o
 obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o
 obj-$(CONFIG_ARCH_STI) += sti/
diff --git a/drivers/reset/reset-berlin.c b/drivers/reset/reset-berlin.c
new file mode 100644
index 000000000000..f8b48a13cf0b
--- /dev/null
+++ b/drivers/reset/reset-berlin.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2014 Marvell Technology Group Ltd.
+ *
+ * Antoine Tenart <antoine.tenart@free-electrons.com>
+ * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#define BERLIN_MAX_RESETS       32
+
+#define to_berlin_reset_priv(p)         \
+        container_of((p), struct berlin_reset_priv, rcdev)
+
+struct berlin_reset_priv {
+        void __iomem                    *base;
+        unsigned int                    size;
+        struct reset_controller_dev     rcdev;
+};
+
+static int berlin_reset_reset(struct reset_controller_dev *rcdev,
+                              unsigned long id)
+{
+        struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev);
+        int offset = id >> 8;
+        int mask = BIT(id & 0x1f);
+
+        writel(mask, priv->base + offset);
+
+        /* let the reset be effective */
+        udelay(10);
+
+        return 0;
+}
+
+static struct reset_control_ops berlin_reset_ops = {
+        .reset  = berlin_reset_reset,
+};
+
+static int berlin_reset_xlate(struct reset_controller_dev *rcdev,
+                              const struct of_phandle_args *reset_spec)
+{
+        struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev);
+        unsigned offset, bit;
+
+        if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
+                return -EINVAL;
+
+        offset = reset_spec->args[0];
+        bit = reset_spec->args[1];
+
+        if (offset >= priv->size)
+                return -EINVAL;
+
+        if (bit >= BERLIN_MAX_RESETS)
+                return -EINVAL;
+
+        return (offset << 8) | bit;
+}
+
+static int __berlin_reset_init(struct device_node *np)
+{
+        struct berlin_reset_priv *priv;
+        struct resource res;
+        resource_size_t size;
+        int ret;
+
+        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+        if (!priv)
+                return -ENOMEM;
+
+        ret = of_address_to_resource(np, 0, &res);
+        if (ret)
+                goto err;
+
+        size = resource_size(&res);
+        priv->base = ioremap(res.start, size);
+        if (!priv->base) {
+                ret = -ENOMEM;
+                goto err;
+        }
+        priv->size = size;
+
+        priv->rcdev.owner = THIS_MODULE;
+        priv->rcdev.ops = &berlin_reset_ops;
+        priv->rcdev.of_node = np;
+        priv->rcdev.of_reset_n_cells = 2;
+        priv->rcdev.of_xlate = berlin_reset_xlate;
+
+        reset_controller_register(&priv->rcdev);
+
+        return 0;
+
+err:
+        kfree(priv);
+        return ret;
+}
+
+static const struct of_device_id berlin_reset_of_match[] __initconst = {
+        { .compatible = "marvell,berlin2-chip-ctrl" },
+        { .compatible = "marvell,berlin2cd-chip-ctrl" },
+        { .compatible = "marvell,berlin2q-chip-ctrl" },
+        { },
+};
+
+static int __init berlin_reset_init(void)
+{
+        struct device_node *np;
+        int ret;
+
+        for_each_matching_node(np, berlin_reset_of_match) {
+                ret = __berlin_reset_init(np);
+                if (ret)
+                        return ret;
+        }
+
+        return 0;
+}
+arch_initcall(berlin_reset_init);