[PATCH v2 2/6] drivers: reset: Reset controller driver for STiH415

From: srinivas.kandagatla
Date: Mon Feb 03 2014 - 09:37:53 EST

From: Stephen Gallimore <stephen.gallimore@xxxxxx>

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@xxxxxx>
---
.../devicetree/bindings/reset/st,sti-powerdown.txt | 47 ++++++++++++
arch/arm/boot/dts/stih415.dtsi | 6 ++
drivers/reset/sti/Kconfig | 4 +
drivers/reset/sti/Makefile | 3 +
drivers/reset/sti/reset-stih415.c | 77 ++++++++++++++++++++
.../dt-bindings/reset-controller/stih415-resets.h | 19 +++++
6 files changed, 156 insertions(+)
create mode 100644 Documentation/devicetree/bindings/reset/st,sti-powerdown.txt
create mode 100644 drivers/reset/sti/reset-stih415.c
create mode 100644 include/dt-bindings/reset-controller/stih415-resets.h

diff --git a/Documentation/devicetree/bindings/reset/st,sti-powerdown.txt b/Documentation/devicetree/bindings/reset/st,sti-powerdown.txt
new file mode 100644
index 0000000..5ab26b7
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/st,sti-powerdown.txt
@@ -0,0 +1,47 @@
+STMicroelectronics STi family Sysconfig Peripheral Powerdown Reset Controller
+=============================================================================
+
+This binding describes a reset controller device that is used to enable and
+disable on-chip peripheral controllers such as USB and SATA, using
+"powerdown" control bits found in the STi family SoC system configuration
+registers. These have been grouped together into a single reset controller
+device for convenience.
+
+The actual action taken when powerdown is asserted is hardware dependent.
+However, when asserted it may not be possible to access the hardware's
+registers and after an assert/deassert sequence the hardware's previous state
+may no longer be valid.
+
+Please refer to reset.txt in this directory for common reset
+controller binding usage.
+
+Required properties:
+- compatible: Should be "st,<chip>-powerdown"
+ ex: "st,stih415-powerdown", "st,stih416-powerdown"
+- #reset-cells: 1, see below
+
+example:
+
+ powerdown: powerdown-controller {
+ #reset-cells = <1>;
+ compatible = "st,stih415-powerdown";
+ };
+
+
+Specifying powerdown control of devices
+=======================================
+
+Device nodes should specify the reset channel required in their "resets"
+property, containing a phandle to the powerdown device node and an
+index specifying which channel to use, as described in reset.txt
+
+example:
+
+ usb1: usb@fe200000 {
+ resets = <&powerdown STIH41X_USB1_POWERDOWN>;
+ };
+
+Macro definitions for the supported reset channels can be found in:
+
+include/dt-bindings/reset-controller/stih415-resets.h
+include/dt-bindings/reset-controller/stih416-resets.h
diff --git a/arch/arm/boot/dts/stih415.dtsi b/arch/arm/boot/dts/stih415.dtsi
index d9c7dd1..19e29f4 100644
--- a/arch/arm/boot/dts/stih415.dtsi
+++ b/arch/arm/boot/dts/stih415.dtsi
@@ -10,6 +10,7 @@
#include "stih415-clock.dtsi"
#include "stih415-pinctrl.dtsi"
#include <dt-bindings/interrupt-controller/arm-gic.h>
+#include <dt-bindings/reset-controller/stih415-resets.h>
/ {

L2: cache-controller {
@@ -28,6 +29,11 @@
ranges;
compatible = "simple-bus";

+ powerdown: powerdown-controller {
+ #reset-cells = <1>;
+ compatible = "st,stih415-powerdown";
+ };
+
syscfg_sbc: sbc-syscfg@fe600000{
compatible = "st,stih415-sbc-syscfg", "syscon";
reg = <0xfe600000 0xb4>;
diff --git a/drivers/reset/sti/Kconfig b/drivers/reset/sti/Kconfig
index ba13796..ef6654a 100644
--- a/drivers/reset/sti/Kconfig
+++ b/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
diff --git a/drivers/reset/sti/Makefile b/drivers/reset/sti/Makefile
index c4a51d9..fce4433 100644
--- a/drivers/reset/sti/Makefile
+++ b/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
diff --git a/drivers/reset/sti/reset-stih415.c b/drivers/reset/sti/reset-stih415.c
new file mode 100644
index 0000000..56c2146
--- /dev/null
+++ b/drivers/reset/sti/reset-stih415.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2013 STMicroelectronics (R&D) Limited
+ * Author: Stephen Gallimore <stephen.gallimore@xxxxxx>
+ * Author: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
+ *
+ * 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);
diff --git a/include/dt-bindings/reset-controller/stih415-resets.h b/include/dt-bindings/reset-controller/stih415-resets.h
new file mode 100644
index 0000000..2d54e68
--- /dev/null
+++ b/include/dt-bindings/reset-controller/stih415-resets.h
@@ -0,0 +1,19 @@
+/*
+ * This header provides constants for the reset controller
+ * based peripheral powerdown requests on the STMicroelectronics
+ * STiH415 SoC.
+ */
+#ifndef _DT_BINDINGS_RESET_CONTROLLER_STIH415
+#define _DT_BINDINGS_RESET_CONTROLLER_STIH415
+
+#define STIH415_EMISS_POWERDOWN 0
+#define STIH415_NAND_POWERDOWN 1
+#define STIH415_KEYSCAN_POWERDOWN 2
+#define STIH415_USB0_POWERDOWN 3
+#define STIH415_USB1_POWERDOWN 4
+#define STIH415_USB2_POWERDOWN 5
+#define STIH415_SATA0_POWERDOWN 6
+#define STIH415_SATA1_POWERDOWN 7
+#define STIH415_PCIE_POWERDOWN 8
+
+#endif /* _DT_BINDINGS_RESET_CONTROLLER_STIH415 */
--
1.7.9.5

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