drivers: reset: Reset controller driver for STiH415

This patch adds a reset controller platform driver for the STiH415
SoC. This initial version provides a compatible driver for the
"st,stih415-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 <stephen.gallimore@st.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/reset/sti/Kconfig

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

drivers/reset/sti/Makefile

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

drivers/reset/sti/reset-stih415.c

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2013 STMicroelectronics (R&D) Limited
+ * Author: Stephen Gallimore <stephen.gallimore@st.com>
+ * Author: Srinivas Kandagatla <srinivas.kandagatla@st.com>
+ *
+ * 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/stih415-resets.h>
+
+#include "reset-syscfg.h"
+
+/*
+ * STiH415 Peripheral powerdown definitions.
+ */
+static const char stih415_front[] = "st,stih415-front-syscfg";
+static const char stih415_rear[] = "st,stih415-rear-syscfg";
+static const char stih415_sbc[] = "st,stih415-sbc-syscfg";
+static const char stih415_lpm[] = "st,stih415-lpm-syscfg";
+
+#define STIH415_PDN_FRONT(_bit) \
+	_SYSCFG_RST_CH(stih415_front, SYSCFG_114, _bit, SYSSTAT_187, _bit)
+
+#define STIH415_PDN_REAR(_cntl, _stat) \
+	_SYSCFG_RST_CH(stih415_rear, SYSCFG_336, _cntl, SYSSTAT_384, _stat)
+
+#define SYSCFG_114	0x38 /* Powerdown request EMI/NAND/Keyscan */
+#define SYSSTAT_187	0x15c /* Powerdown status EMI/NAND/Keyscan */
+
+#define SYSCFG_336	0x90 /* Powerdown request USB/SATA/PCIe */
+#define SYSSTAT_384	0x150 /* Powerdown status USB/SATA/PCIe */
+
+static const struct syscfg_reset_channel_data stih415_powerdowns[] = {
+	[STIH415_EMISS_POWERDOWN]	= STIH415_PDN_FRONT(0),
+	[STIH415_NAND_POWERDOWN]	= STIH415_PDN_FRONT(1),
+	[STIH415_KEYSCAN_POWERDOWN]	= STIH415_PDN_FRONT(2),
+	[STIH415_USB0_POWERDOWN]	= STIH415_PDN_REAR(0, 0),
+	[STIH415_USB1_POWERDOWN]	= STIH415_PDN_REAR(1, 1),
+	[STIH415_USB2_POWERDOWN]	= STIH415_PDN_REAR(2, 2),
+	[STIH415_SATA0_POWERDOWN]	= STIH415_PDN_REAR(3, 3),
+	[STIH415_SATA1_POWERDOWN]	= STIH415_PDN_REAR(4, 4),
+	[STIH415_PCIE_POWERDOWN]	= STIH415_PDN_REAR(5, 8),
+};
+
+static struct syscfg_reset_controller_data stih415_powerdown_controller = {
+	.wait_for_ack = true,
+	.nr_channels = ARRAY_SIZE(stih415_powerdowns),
+	.channels = stih415_powerdowns,
+};
+
+static struct of_device_id stih415_reset_match[] = {
+	{ .compatible = "st,stih415-powerdown",
+	  .data = &stih415_powerdown_controller, },
+	{},
+};
+
+static struct platform_driver stih415_reset_driver = {
+	.probe = syscfg_reset_probe,
+	.driver = {
+		.name = "reset-stih415",
+		.owner = THIS_MODULE,
+		.of_match_table = stih415_reset_match,
+	},
+};
+
+static int __init stih415_reset_init(void)
+{
+	return platform_driver_register(&stih415_reset_driver);
+}
+arch_initcall(stih415_reset_init);