drivers: reset: Reset controller driver for STiH416

This patch adds a reset controller platform driver for the STiH416
SoC. This initial version provides a compatible driver for the
"st,stih416-powerdown" device, which registers a system configuration
register based reset controller that controls the powerdown state of
hardware such as the on-chip USB host controllers.

Signed-off-by: Stephen Gallimore <[email protected]>
Signed-off-by: Srinivas Kandagatla <[email protected]>
Acked-by: Philipp Zabel <[email protected]>

drivers/reset/sti/Kconfig

@@ -8,4 +8,8 @@ config STIH415_RESET
 	bool
 	select STI_RESET_SYSCFG
 
+config STIH416_RESET
+	bool
+	select STI_RESET_SYSCFG
+
 endif

drivers/reset/sti/Makefile

@@ -1,4 +1,4 @@
 obj-$(CONFIG_STI_RESET_SYSCFG) += reset-syscfg.o
 
-# SoC specific reset devices
 obj-$(CONFIG_STIH415_RESET) += reset-stih415.o
+obj-$(CONFIG_STIH416_RESET) += reset-stih416.o

drivers/reset/sti/reset-stih416.c

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2013 STMicroelectronics (R&D) Limited
+ * Author: Stephen Gallimore <[email protected]>
+ * Author: Srinivas Kandagatla <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include <dt-bindings/reset-controller/stih416-resets.h>
+
+#include "reset-syscfg.h"
+
+/*
+ * STiH416 Peripheral powerdown definitions.
+ */
+static const char stih416_front[] = "st,stih416-front-syscfg";
+static const char stih416_rear[] = "st,stih416-rear-syscfg";
+static const char stih416_sbc[] = "st,stih416-sbc-syscfg";
+static const char stih416_lpm[] = "st,stih416-lpm-syscfg";
+
+#define STIH416_PDN_FRONT(_bit) \
+	_SYSCFG_RST_CH(stih416_front, SYSCFG_1500, _bit, SYSSTAT_1578, _bit)
+
+#define STIH416_PDN_REAR(_cntl, _stat) \
+	_SYSCFG_RST_CH(stih416_rear, SYSCFG_2525, _cntl, SYSSTAT_2583, _stat)
+
+#define SYSCFG_1500	0x7d0 /* Powerdown request EMI/NAND/Keyscan */
+#define SYSSTAT_1578	0x908 /* Powerdown status EMI/NAND/Keyscan */
+
+#define SYSCFG_2525	0x834 /* Powerdown request USB/SATA/PCIe */
+#define SYSSTAT_2583	0x91c /* Powerdown status USB/SATA/PCIe */
+
+static const struct syscfg_reset_channel_data stih416_powerdowns[] = {
+	[STIH416_EMISS_POWERDOWN]	= STIH416_PDN_FRONT(0),
+	[STIH416_NAND_POWERDOWN]	= STIH416_PDN_FRONT(1),
+	[STIH416_KEYSCAN_POWERDOWN]	= STIH416_PDN_FRONT(2),
+	[STIH416_USB0_POWERDOWN]	= STIH416_PDN_REAR(0, 0),
+	[STIH416_USB1_POWERDOWN]	= STIH416_PDN_REAR(1, 1),
+	[STIH416_USB2_POWERDOWN]	= STIH416_PDN_REAR(2, 2),
+	[STIH416_USB3_POWERDOWN]	= STIH416_PDN_REAR(6, 5),
+	[STIH416_SATA0_POWERDOWN]	= STIH416_PDN_REAR(3, 3),
+	[STIH416_SATA1_POWERDOWN]	= STIH416_PDN_REAR(4, 4),
+	[STIH416_PCIE0_POWERDOWN]	= STIH416_PDN_REAR(7, 9),
+	[STIH416_PCIE1_POWERDOWN]	= STIH416_PDN_REAR(5, 8),
+};
+
+static struct syscfg_reset_controller_data stih416_powerdown_controller = {
+	.wait_for_ack	= true,
+	.nr_channels	= ARRAY_SIZE(stih416_powerdowns),
+	.channels	= stih416_powerdowns,
+};
+
+static struct of_device_id stih416_reset_match[] = {
+	{ .compatible = "st,stih416-powerdown",
+	  .data = &stih416_powerdown_controller, },
+	{},
+};
+
+static struct platform_driver stih416_reset_driver = {
+	.probe = syscfg_reset_probe,
+	.driver = {
+		.name = "reset-stih416",
+		.owner = THIS_MODULE,
+		.of_match_table = stih416_reset_match,
+	},
+};
+
+static int __init stih416_reset_init(void)
+{
+	return platform_driver_register(&stih416_reset_driver);
+}
+arch_initcall(stih416_reset_init);