Message-Id: <20170213153338.13518-1-andrew.smirnov@gmail.com>
Date:   Mon, 13 Feb 2017 07:33:37 -0800
From:   Andrey Smirnov <andrew.smirnov@...il.com>
To:     Philipp Zabel <p.zabel@...gutronix.de>
Cc:     Andrey Smirnov <andrew.smirnov@...il.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v2] reset: Add i.MX7 SRC reset driver

This driver exposes various reset faculties, impelented by System Reset
Controller IP block, as a reset driver. Currently only PCIE related
reset lines are implemented.

Cc: Lucas Stach <l.stach@...gutronix.de>
Cc: Rob Herring <robh+dt@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: devicetree@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Cc: linux-arm-kernel@...ts.infradead.org
Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
---

Changes since v1 (see [v1]):

	- Various small DT bindings description fixes as per feedback
          from Rob Herring


[v1] https://lkml.org/lkml/2017/2/6/554

 .../devicetree/bindings/reset/fsl,imx7-src.txt     |  47 +++++++
 drivers/reset/Kconfig                              |   8 ++
 drivers/reset/Makefile                             |   1 +
 drivers/reset/reset-imx7.c                         | 149 +++++++++++++++++++++
 include/dt-bindings/reset/imx7-reset.h             |  28 ++++
 5 files changed, 233 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/reset/fsl,imx7-src.txt
 create mode 100644 drivers/reset/reset-imx7.c
 create mode 100644 include/dt-bindings/reset/imx7-reset.h

diff --git a/Documentation/devicetree/bindings/reset/fsl,imx7-src.txt b/Documentation/devicetree/bindings/reset/fsl,imx7-src.txt
new file mode 100644
index 0000000..c38f7f0
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/fsl,imx7-src.txt
@@ -0,0 +1,47 @@
+Freescale i.MX7 System Reset Controller
+======================================
+
+Please also refer to reset.txt in this directory for common reset
+controller binding usage.
+
+Required properties:
+- compatible: Should be "fsl,imx7-src", "syscon"
+- reg: should be register base and length as documented in the
+  datasheet
+- interrupts: Should contain SRC interrupt
+- #reset-cells: 1, see below
+
+example:
+
+src: reset-controller@...90000 {
+     compatible = "fsl,imx7d-src", "syscon";
+     reg = <0x30390000 0x2000>;
+     interrupts = <GIC_SPI 89 IRQ_TYPE_LEVEL_HIGH>;
+     #reset-cells = <1>;
+};
+
+
+Specifying reset lines connected to IP modules
+==============================================
+
+The system reset controller can be used to reset various set of
+peripherals. Device nodes that need access to reset lines should
+specify them as a reset phandle in their corresponding node as
+specified in reset.txt.
+
+Example:
+
+	pcie: pcie@...00000 {
+
+		...
+
+		resets = <&src IMX7_RESET_PCIEPHY>,
+			 <&src IMX7_RESET_PCIE_CTRL_APPS>;
+		reset-names = "pciephy", "apps";
+
+		...
+        };
+
+
+For list of all valid reset indicies see
+<dt-bindings/reset/imx7-reset.h>
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 172dc96..664a88b 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -92,6 +92,14 @@ config RESET_ZYNQ
 	help
 	  This enables the reset controller driver for Xilinx Zynq SoCs.
 
+config RESET_IMX7
+	bool "i.MX7 Reset Driver"
+	depends on SOC_IMX7D || COMPILE_TEST
+	select MFD_SYSCON
+	default SOC_IMX7D
+	help
+	  This enables the reset controller driver for i.MX7 SoCs.
+
 source "drivers/reset/sti/Kconfig"
 source "drivers/reset/hisilicon/Kconfig"
 source "drivers/reset/tegra/Kconfig"
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 13b346e..417c9d0 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -14,3 +14,4 @@ obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
 obj-$(CONFIG_TI_SYSCON_RESET) += reset-ti-syscon.o
 obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
 obj-$(CONFIG_RESET_ZYNQ) += reset-zynq.o
+obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
diff --git a/drivers/reset/reset-imx7.c b/drivers/reset/reset-imx7.c
new file mode 100644
index 0000000..6d90e57
--- /dev/null
+++ b/drivers/reset/reset-imx7.c
@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) 2017, Impinj, Inc.
+ *
+ * i.MX7 System Reset Controller (SRC) driver
+ *
+ * Author: Andrey Smirnov <andrew.smirnov@...il.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; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+#include <dt-bindings/reset/imx7-reset.h>
+
+struct imx7_src {
+	struct reset_controller_dev rcdev;
+	struct device *dev;
+	struct regmap *regmap;
+};
+
+enum imx7_src_registers {
+	SRC_PCIEPHY_RCR = 0x002c,
+	SRC_PCIEPHY_RCR_PCIEPHY_G_RST     = BIT(1),
+	SRC_PCIEPHY_RCR_PCIEPHY_BTN       = BIT(2),
+	SRC_PCIEPHY_RCR_PCIE_CTRL_APPS_EN = BIT(6),
+};
+
+static struct imx7_src *to_imx7_src(struct reset_controller_dev *rcdev)
+{
+	return container_of(rcdev, struct imx7_src, rcdev);
+}
+
+static int imx7_reset_assert(struct reset_controller_dev *rcdev,
+			     unsigned long id)
+{
+	struct imx7_src *imx7src = to_imx7_src(rcdev);
+
+	switch (id) {
+	case IMX7_RESET_PCIE_CTRL_APPS:
+		regmap_update_bits(imx7src->regmap,
+				   SRC_PCIEPHY_RCR,
+				   SRC_PCIEPHY_RCR_PCIE_CTRL_APPS_EN, 0);
+		return 0;
+
+	case IMX7_RESET_PCIEPHY:
+		regmap_update_bits(imx7src->regmap,
+				   SRC_PCIEPHY_RCR,
+				   SRC_PCIEPHY_RCR_PCIEPHY_G_RST,
+				   SRC_PCIEPHY_RCR_PCIEPHY_G_RST);
+		regmap_update_bits(imx7src->regmap,
+				   SRC_PCIEPHY_RCR,
+				   SRC_PCIEPHY_RCR_PCIEPHY_BTN,
+				   SRC_PCIEPHY_RCR_PCIEPHY_BTN);
+		return 0;
+	default:
+		dev_err(imx7src->dev, "Unknown reset ID %lu\n", id);
+		break;
+	}
+
+	return -EINVAL;
+}
+
+static int imx7_reset_deassert(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	struct imx7_src *imx7src = to_imx7_src(rcdev);
+
+	switch (id) {
+	case IMX7_RESET_PCIE_CTRL_APPS:
+		regmap_update_bits(imx7src->regmap,
+				   SRC_PCIEPHY_RCR,
+				   SRC_PCIEPHY_RCR_PCIE_CTRL_APPS_EN,
+				   SRC_PCIEPHY_RCR_PCIE_CTRL_APPS_EN);
+		return 0;
+
+	case IMX7_RESET_PCIEPHY:
+		/* wait for more than 10us to release phy g_rst and btnrst */
+		udelay(10);
+		regmap_update_bits(imx7src->regmap,
+				   SRC_PCIEPHY_RCR,
+				   SRC_PCIEPHY_RCR_PCIEPHY_G_RST, 0);
+		regmap_update_bits(imx7src->regmap,
+				   SRC_PCIEPHY_RCR,
+				   SRC_PCIEPHY_RCR_PCIEPHY_BTN, 0);
+		return 0;
+	default:
+		dev_err(imx7src->dev, "Unknown reset ID %lu\n", id);
+		break;
+	};
+
+	return -EINVAL;
+}
+
+static const struct reset_control_ops imx7_reset_ops = {
+	.assert		= imx7_reset_assert,
+	.deassert	= imx7_reset_deassert,
+};
+
+static int imx7_reset_probe(struct platform_device *pdev)
+{
+	struct imx7_src *imx7src;
+	struct device *dev = &pdev->dev;
+
+	imx7src = devm_kzalloc(dev, sizeof(*imx7src), GFP_KERNEL);
+	if (!imx7src)
+		return -ENOMEM;
+
+	imx7src->dev = dev;
+	imx7src->regmap = syscon_node_to_regmap(dev->of_node);
+	if (IS_ERR(imx7src->regmap)) {
+		dev_err(dev, "Unable to get imx7-src regmap");
+		return PTR_ERR(imx7src->regmap);
+	}
+
+	imx7src->rcdev.owner     = THIS_MODULE;
+	imx7src->rcdev.nr_resets = IMX7_RESET_NUM;
+	imx7src->rcdev.ops       = &imx7_reset_ops;
+	imx7src->rcdev.of_node   = dev->of_node;
+
+	return devm_reset_controller_register(dev, &imx7src->rcdev);
+}
+
+static const struct of_device_id imx7_reset_dt_ids[] = {
+	{ .compatible = "fsl,imx7d-src", },
+	{ /* sentinel */ },
+};
+
+static struct platform_driver imx7_reset_driver = {
+	.probe	= imx7_reset_probe,
+	.driver = {
+		.name		= KBUILD_MODNAME,
+		.of_match_table	= imx7_reset_dt_ids,
+	},
+};
+builtin_platform_driver(imx7_reset_driver);
diff --git a/include/dt-bindings/reset/imx7-reset.h b/include/dt-bindings/reset/imx7-reset.h
new file mode 100644
index 0000000..e20f2db
--- /dev/null
+++ b/include/dt-bindings/reset/imx7-reset.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2017 Impinj, Inc.
+ *
+ * Author: Andrey Smirnov <andrew.smirnov@...il.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DT_BINDING_RESET_IMX7_H
+#define DT_BINDING_RESET_IMX7_H
+
+#define IMX7_RESET_PCIE_CTRL_APPS	0
+#define IMX7_RESET_PCIEPHY		1
+
+#define IMX7_RESET_NUM			2
+
+#endif
+
-- 
2.9.3

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