reset: zx2967: add reset controller driver for ZTE's zx2967 family

This patch adds reset controller driver for ZTE's zx2967 family.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Reviewed-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

3 files changed, 113 insertions, 0 deletions

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 172dc966a01f..f4cdfe94b9ec 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -86,6 +86,12 @@ 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_ZX2967
+        bool "ZTE ZX2967 Reset Driver"
+        depends on ARCH_ZX || COMPILE_TEST
+        help
+          This enables the reset controller driver for ZTE's zx2967 family.
+
 config RESET_ZYNQ
         bool "ZYNQ Reset Driver" if COMPILE_TEST
         default ARCH_ZYNQ
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 13b346e03d84..2cd3f6c45165 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -13,4 +13,5 @@ obj-$(CONFIG_RESET_STM32) += reset-stm32.o
 obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
 obj-$(CONFIG_TI_SYSCON_RESET) += reset-ti-syscon.o
 obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
+obj-$(CONFIG_RESET_ZX2967) += reset-zx2967.o
 obj-$(CONFIG_RESET_ZYNQ) += reset-zynq.o
diff --git a/drivers/reset/reset-zx2967.c b/drivers/reset/reset-zx2967.c
new file mode 100644
index 000000000000..5d821513aa3e
--- /dev/null
+++ b/drivers/reset/reset-zx2967.c
@@ -0,0 +1,106 @@
+/*
+ * ZTE's zx2967 family reset controller driver
+ *
+ * Copyright (C) 2017 ZTE Ltd.
+ *
+ * Author: Baoyou Xie <baoyou.xie@linaro.org>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+struct zx2967_reset {
+        void __iomem                    *reg_base;
+        spinlock_t                      lock;
+        struct reset_controller_dev     rcdev;
+};
+
+static int zx2967_reset_act(struct reset_controller_dev *rcdev,
+                            unsigned long id, bool assert)
+{
+        struct zx2967_reset *reset = NULL;
+        int bank = id / 32;
+        int offset = id % 32;
+        u32 reg;
+        unsigned long flags;
+
+        reset = container_of(rcdev, struct zx2967_reset, rcdev);
+
+        spin_lock_irqsave(&reset->lock, flags);
+
+        reg = readl_relaxed(reset->reg_base + (bank * 4));
+        if (assert)
+                reg &= ~BIT(offset);
+        else
+                reg |= BIT(offset);
+        writel_relaxed(reg, reset->reg_base + (bank * 4));
+
+        spin_unlock_irqrestore(&reset->lock, flags);
+
+        return 0;
+}
+
+static int zx2967_reset_assert(struct reset_controller_dev *rcdev,
+                               unsigned long id)
+{
+        return zx2967_reset_act(rcdev, id, true);
+}
+
+static int zx2967_reset_deassert(struct reset_controller_dev *rcdev,
+                                 unsigned long id)
+{
+        return zx2967_reset_act(rcdev, id, false);
+}
+
+static struct reset_control_ops zx2967_reset_ops = {
+        .assert         = zx2967_reset_assert,
+        .deassert       = zx2967_reset_deassert,
+};
+
+static int zx2967_reset_probe(struct platform_device *pdev)
+{
+        struct zx2967_reset *reset;
+        struct resource *res;
+
+        reset = devm_kzalloc(&pdev->dev, sizeof(*reset), GFP_KERNEL);
+        if (!reset)
+                return -ENOMEM;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        reset->reg_base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(reset->reg_base))
+                return PTR_ERR(reset->reg_base);
+
+        spin_lock_init(&reset->lock);
+
+        reset->rcdev.owner = THIS_MODULE;
+        reset->rcdev.nr_resets = resource_size(res) * 8;
+        reset->rcdev.ops = &zx2967_reset_ops;
+        reset->rcdev.of_node = pdev->dev.of_node;
+
+        return devm_reset_controller_register(&pdev->dev, &reset->rcdev);
+}
+
+static const struct of_device_id zx2967_reset_dt_ids[] = {
+         { .compatible = "zte,zx296718-reset", },
+         {},
+};
+MODULE_DEVICE_TABLE(of, zx2967_reset_dt_ids);
+
+static struct platform_driver zx2967_reset_driver = {
+        .probe  = zx2967_reset_probe,
+        .driver = {
+                .name           = "zx2967-reset",
+                .of_match_table = zx2967_reset_dt_ids,
+        },
+};
+
+builtin_platform_driver(zx2967_reset_driver);
+
+MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
+MODULE_DESCRIPTION("ZTE zx2967 Reset Controller Driver");
+MODULE_LICENSE("GPL");