Keystone Reset driver for 3.16

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Merge tag 'keystone-reset-driver' of git://git.kernel.org/pub/scm/linux/kernel/git/ssantosh/linux-keystone into next/drivers

Merge "Keystone Reset driver for 3.16" from Santosh Shilimkar:

* tag 'keystone-reset-driver' of git://git.kernel.org/pub/scm/linux/kernel/git/ssantosh/linux-keystone:
  power: reset: keystone-reset: introduce keystone reset driver
  Documentation: dt: add bindings for keystone pll control controller
  Documentation: dt: add bindings for keystone reset driver

Signed-off-by: Olof Johansson <olof@lixom.net>

Documentation/devicetree/bindings/clock/ti-keystone-pllctrl.txt

@@ -0,0 +1,20 @@
+* Device tree bindings for Texas Instruments keystone pll controller
+
+The main pll controller used to drive theC66x CorePacs, the switch fabric,
+and a majority of the peripheral clocks (all but the ARM CorePacs, DDR3 and
+the NETCP modules) requires a PLL Controller to manage the various clock
+divisions, gating, and synchronization.
+
+Required properties:
+
+- compatible:		"ti,keystone-pllctrl", "syscon"
+
+- reg:			contains offset/length value for pll controller
+			registers space.
+
+Example:
+
+pllctrl: pll-controller@0x02310000 {
+	compatible = "ti,keystone-pllctrl", "syscon";
+	reg = <0x02310000 0x200>;
+};

Documentation/devicetree/bindings/power/reset/keystone-reset.txt

@@ -0,0 +1,67 @@
+* Device tree bindings for Texas Instruments keystone reset
+
+This node is intended to allow SoC reset in case of software reset
+of selected watchdogs.
+
+The Keystone SoCs can contain up to 4 watchdog timers to reset
+SoC. Each watchdog timer event input is connected to the Reset Mux
+block. The Reset Mux block can be configured to cause reset or not.
+
+Additionally soft or hard reset can be configured.
+
+Required properties:
+
+- compatible:		ti,keystone-reset
+
+- ti,syscon-pll:	phandle/offset pair. The phandle to syscon used to
+			access pll controller registers and the offset to use
+			reset control registers.
+
+- ti,syscon-dev:	phandle/offset pair. The phandle to syscon used to
+			access device state control registers and the offset
+			in order to use mux block registers for all watchdogs.
+
+Optional properties:
+
+- ti,soft-reset:	Boolean option indicating soft reset.
+			By default hard reset is used.
+
+- ti,wdt-list:		WDT list that can cause SoC reset. It's not related
+			to WDT driver, it's just needed to enable a SoC related
+			reset that's triggered by one of WDTs. The list is
+			in format: <0>, <2>; It can be in random order and
+			begins from 0 to 3, as keystone can contain up to 4 SoC
+			reset watchdogs and can be in random order.
+
+Example 1:
+Setup keystone reset so that in case software reset or
+WDT0 is triggered it issues hard reset for SoC.
+
+pllctrl: pll-controller@02310000 {
+	compatible = "ti,keystone-pllctrl", "syscon";
+	reg = <0x02310000 0x200>;
+};
+
+devctrl: device-state-control@02620000 {
+	compatible = "ti,keystone-devctrl", "syscon";
+	reg = <0x02620000 0x1000>;
+};
+
+rstctrl: reset-controller {
+	compatible = "ti,keystone-reset";
+	ti,syscon-pll = <&pllctrl 0xe4>;
+	ti,syscon-dev = <&devctrl 0x328>;
+	ti,wdt-list = <0>;
+};
+
+Example 2:
+Setup keystone reset so that in case of software reset or
+WDT0 or WDT2 is triggered it issues soft reset for SoC.
+
+rstctrl: reset-controller {
+	compatible = "ti,keystone-reset";
+	ti,syscon-pll = <&pllctrl 0xe4>;
+	ti,syscon-dev = <&devctrl 0x328>;
+	ti,wdt-list = <0>, <2>;
+	ti,soft-reset;
+};

drivers/power/reset/Kconfig

@@ -64,3 +64,11 @@ config POWER_RESET_XGENE
 	depends on POWER_RESET
 	help
 	  Reboot support for the APM SoC X-Gene Eval boards.
+
+config POWER_RESET_KEYSTONE
+	bool "Keystone reset driver"
+	depends on ARCH_KEYSTONE
+	select MFD_SYSCON
+	help
+	  Reboot support for the KEYSTONE SoCs.
+

drivers/power/reset/Makefile

@@ -6,3 +6,4 @@ obj-$(CONFIG_POWER_RESET_RESTART) += restart-poweroff.o
 obj-$(CONFIG_POWER_RESET_SUN6I) += sun6i-reboot.o
 obj-$(CONFIG_POWER_RESET_VEXPRESS) += vexpress-poweroff.o
 obj-$(CONFIG_POWER_RESET_XGENE) += xgene-reboot.o
+obj-$(CONFIG_POWER_RESET_KEYSTONE) += keystone-reset.o

drivers/power/reset/keystone-reset.c

@@ -0,0 +1,166 @@
+/*
+ * TI keystone reboot driver
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated. http://www.ti.com/
+ *
+ * Author: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/reboot.h>
+#include <linux/regmap.h>
+#include <asm/system_misc.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of_platform.h>
+
+#define RSTYPE_RG			0x0
+#define RSCTRL_RG			0x4
+#define RSCFG_RG			0x8
+#define RSISO_RG			0xc
+
+#define RSCTRL_KEY_MASK			0x0000ffff
+#define RSCTRL_RESET_MASK		BIT(16)
+#define RSCTRL_KEY			0x5a69
+
+#define RSMUX_OMODE_MASK		0xe
+#define RSMUX_OMODE_RESET_ON		0xa
+#define RSMUX_OMODE_RESET_OFF		0x0
+#define RSMUX_LOCK_MASK			0x1
+#define RSMUX_LOCK_SET			0x1
+
+#define RSCFG_RSTYPE_SOFT		0x300f
+#define RSCFG_RSTYPE_HARD		0x0
+
+#define WDT_MUX_NUMBER			0x4
+
+static int rspll_offset;
+static struct regmap *pllctrl_regs;
+
+/**
+ * rsctrl_enable_rspll_write - enable access to RSCTRL, RSCFG
+ * To be able to access to RSCTRL, RSCFG registers
+ * we have to write a key before
+ */
+static inline int rsctrl_enable_rspll_write(void)
+{
+	return regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,
+				  RSCTRL_KEY_MASK, RSCTRL_KEY);
+}
+
+static void rsctrl_restart(enum reboot_mode mode, const char *cmd)
+{
+	/* enable write access to RSTCTRL */
+	rsctrl_enable_rspll_write();
+
+	/* reset the SOC */
+	regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,
+			   RSCTRL_RESET_MASK, 0);
+}
+
+static struct of_device_id rsctrl_of_match[] = {
+	{.compatible = "ti,keystone-reset", },
+	{},
+};
+
+static int rsctrl_probe(struct platform_device *pdev)
+{
+	int i;
+	int ret;
+	u32 val;
+	unsigned int rg;
+	u32 rsmux_offset;
+	struct regmap *devctrl_regs;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+
+	if (!np)
+		return -ENODEV;
+
+	/* get regmaps */
+	pllctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-pll");
+	if (IS_ERR(pllctrl_regs))
+		return PTR_ERR(pllctrl_regs);
+
+	devctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev");
+	if (IS_ERR(devctrl_regs))
+		return PTR_ERR(devctrl_regs);
+
+	ret = of_property_read_u32_index(np, "ti,syscon-pll", 1, &rspll_offset);
+	if (ret) {
+		dev_err(dev, "couldn't read the reset pll offset!\n");
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32_index(np, "ti,syscon-dev", 1, &rsmux_offset);
+	if (ret) {
+		dev_err(dev, "couldn't read the rsmux offset!\n");
+		return -EINVAL;
+	}
+
+	/* set soft/hard reset */
+	val = of_property_read_bool(np, "ti,soft-reset");
+	val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD;
+
+	ret = rsctrl_enable_rspll_write();
+	if (ret)
+		return ret;
+
+	ret = regmap_write(pllctrl_regs, rspll_offset + RSCFG_RG, val);
+	if (ret)
+		return ret;
+
+	arm_pm_restart = rsctrl_restart;
+
+	/* disable a reset isolation for all module clocks */
+	ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0);
+	if (ret)
+		return ret;
+
+	/* enable a reset for watchdogs from wdt-list */
+	for (i = 0; i < WDT_MUX_NUMBER; i++) {
+		ret = of_property_read_u32_index(np, "ti,wdt-list", i, &val);
+		if (ret == -EOVERFLOW && !i) {
+			dev_err(dev, "ti,wdt-list property has to contain at"
+				"least one entry\n");
+			return -EINVAL;
+		} else if (ret) {
+			break;
+		}
+
+		if (val >= WDT_MUX_NUMBER) {
+			dev_err(dev, "ti,wdt-list property can contain"
+				"only numbers < 4\n");
+			return -EINVAL;
+		}
+
+		rg = rsmux_offset + val * 4;
+
+		ret = regmap_update_bits(devctrl_regs, rg, RSMUX_OMODE_MASK,
+					 RSMUX_OMODE_RESET_ON |
+					 RSMUX_LOCK_SET);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static struct platform_driver rsctrl_driver = {
+	.probe = rsctrl_probe,
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = KBUILD_MODNAME,
+		.of_match_table = rsctrl_of_match,
+	},
+};
+module_platform_driver(rsctrl_driver);
+
+MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>");
+MODULE_DESCRIPTION("Texas Instruments keystone reset driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" KBUILD_MODNAME);