ARC: reset: introduce AXS10x reset driver

ARC AXS10x boards support custom IP-block which allows to control
reset signals of selected peripherals. For example DW GMAC, etc...
This block is controlled via memory-mapped register (AKA CREG) which
represents up-to 32 reset lines. This regiter is self-clearing so we
don't need to deassert line after reset.

As of today only the following lines are used:
 - DW GMAC - line 5

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

diff --git a/Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt b/Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt
new file mode 100644 (file)
index 0000000..32d8435
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt
@@ -0,0 +1,33 @@
+Binding for the AXS10x reset controller
+
+This binding describes the ARC AXS10x boards custom IP-block which allows
+to control reset signals of selected peripherals. For example DW GMAC, etc...
+This block is controlled via memory-mapped register (AKA CREG) which
+represents up-to 32 reset lines.
+
+As of today only the following lines are used:
+ - DW GMAC - line 5
+
+This binding uses the common reset binding[1].
+
+[1] Documentation/devicetree/bindings/reset/reset.txt
+
+Required properties:
+- compatible: should be "snps,axs10x-reset".
+- reg: should always contain pair address - length: for creg reset
+  bits register.
+- #reset-cells: from common reset binding; Should always be set to 1.
+
+Example:
+       reset: reset-controller@11220 {
+               compatible = "snps,axs10x-reset";
+               #reset-cells = <1>;
+               reg = <0x11220 0x4>;
+       };
+
+Specifying reset lines connected to IP modules:
+       ethernet@.... {
+               ....
+               resets = <&reset 5>;
+               ....
+       };

diff --git a/MAINTAINERS b/MAINTAINERS
index 2281af4b41b6ce2000be7f3305db98475fdd7df6..2cf502eeb774c69b5aff75186b3c201a3088e007 100644 (file)
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12883,6 +12883,12 @@ F:     arch/arc/plat-axs10x
 F:     arch/arc/boot/dts/ax*
 F:     Documentation/devicetree/bindings/arc/axs10*
 
+SYNOPSYS AXS10x RESET CONTROLLER DRIVER
+M:     Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
+S:     Supported
+F:     drivers/reset/reset-axs10x.c
+F:     Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt
+
 SYNOPSYS DESIGNWARE DMAC DRIVER
 M:     Viresh Kumar <vireshk@kernel.org>
 M:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index e0c393214264adad04a08fb6e48fc34266144e54..23ec43f99d9a3cac6bb9db5f0c8aef4e90a0d33f 100644 (file)
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -28,6 +28,12 @@ config RESET_ATH79
          This enables the ATH79 reset controller driver that supports the
          AR71xx SoC reset controller.
 
+config RESET_AXS10X
+       bool "AXS10x Reset Driver" if COMPILE_TEST
+       default ARC_PLAT_AXS10X
+       help
+         This enables the reset controller driver for AXS10x.
+
 config RESET_BERLIN
        bool "Berlin Reset Driver" if COMPILE_TEST
        default ARCH_BERLIN

diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index d368367110e55780c5154995011cd193c709ab49..7579dba7b185f809d598a125e577dca1752de4b8 100644 (file)
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_ARCH_STI) += sti/
 obj-$(CONFIG_ARCH_TEGRA) += tegra/
 obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
 obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
+obj-$(CONFIG_RESET_AXS10X) += reset-axs10x.o
 obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
 obj-$(CONFIG_RESET_HSDK_V1) += reset-hsdk-v1.o
 obj-$(CONFIG_RESET_IMX7) += reset-imx7.o

diff --git a/drivers/reset/reset-axs10x.c b/drivers/reset/reset-axs10x.c
new file mode 100644 (file)
index 0000000..afb298e
--- /dev/null
+++ b/drivers/reset/reset-axs10x.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2017 Synopsys.
+ *
+ * Synopsys AXS10x reset driver.
+ *
+ * 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/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+#define to_axs10x_rst(p)       container_of((p), struct axs10x_rst, rcdev)
+
+#define AXS10X_MAX_RESETS      32
+
+struct axs10x_rst {
+       void __iomem                    *regs_rst;
+       spinlock_t                      lock;
+       struct reset_controller_dev     rcdev;
+};
+
+static int axs10x_reset_reset(struct reset_controller_dev *rcdev,
+                             unsigned long id)
+{
+       struct axs10x_rst *rst = to_axs10x_rst(rcdev);
+       unsigned long flags;
+
+       spin_lock_irqsave(&rst->lock, flags);
+       writel(BIT(id), rst->regs_rst);
+       spin_unlock_irqrestore(&rst->lock, flags);
+
+       return 0;
+}
+
+static const struct reset_control_ops axs10x_reset_ops = {
+       .reset  = axs10x_reset_reset,
+};
+
+static int axs10x_reset_probe(struct platform_device *pdev)
+{
+       struct axs10x_rst *rst;
+       struct resource *mem;
+
+       rst = devm_kzalloc(&pdev->dev, sizeof(*rst), GFP_KERNEL);
+       if (!rst)
+               return -ENOMEM;
+
+       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       rst->regs_rst = devm_ioremap_resource(&pdev->dev, mem);
+       if (IS_ERR(rst->regs_rst))
+               return PTR_ERR(rst->regs_rst);
+
+       spin_lock_init(&rst->lock);
+
+       rst->rcdev.owner = THIS_MODULE;
+       rst->rcdev.ops = &axs10x_reset_ops;
+       rst->rcdev.of_node = pdev->dev.of_node;
+       rst->rcdev.nr_resets = AXS10X_MAX_RESETS;
+
+       return devm_reset_controller_register(&pdev->dev, &rst->rcdev);
+}
+
+static const struct of_device_id axs10x_reset_dt_match[] = {
+       { .compatible = "snps,axs10x-reset" },
+       { },
+};
+
+static struct platform_driver axs10x_reset_driver = {
+       .probe  = axs10x_reset_probe,
+       .driver = {
+               .name = "axs10x-reset",
+               .of_match_table = axs10x_reset_dt_match,
+       },
+};
+builtin_platform_driver(axs10x_reset_driver);
+
+MODULE_AUTHOR("Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>");
+MODULE_DESCRIPTION("Synopsys AXS10x reset driver");
+MODULE_LICENSE("GPL v2");