[PATCH v6 1/4] mfd: add syscon driver based on regmap

Dong Aisheng
2012-09-05T03:19:52Z

From: Dong Aisheng <dong.aisheng@linaro.org>

Add regmap based syscon driver.
This is usually used for access misc bits in registers which does not belong
to a specific module, for example, IMX IOMUXC GPR and ANATOP.
With this driver, client can use generic regmap API to access registers
which are registered into syscon.

Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org>
---
ChangeLog:
v5->v6:
* using dev instead of &pdev->dev in probe
v4->v5:
* depends on OF
* do not call of_node_put in syscon_node_to_regmap
v3->v4:
* add more description about syscon(provided by Stephen Warren) in binding doc.
* fix a minor code indent error and remove set cache type code since the cache
is disabled by default.
v2->v3:
* export regmap lookup APIs including syscon_node_to_regmap
* fix a few typo
v1->v2:
* provide a way of retrieving the regmap, suggested by Mark Brown.
* delete imx-syscon io accessors and using generic regmap API for client drivers.
* change to a more generic name for other SoCs to use.
---
Documentation/devicetree/bindings/mfd/syscon.txt | 20 +++
drivers/mfd/Kconfig | 8 +
drivers/mfd/Makefile | 1 +
drivers/mfd/syscon.c | 176 ++++++++++++++++++++++
include/linux/mfd/syscon.h | 23 +++
5 files changed, 228 insertions(+), 0 deletions(-)

diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt
new file mode 100644
index 0000000..fe8150b
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/syscon.txt
@@ -0,0 +1,20 @@
+* System Controller Registers R/W driver
+
+System controller node represents a register region containing a set
+of miscellaneous registers. The registers are not cohesive enough to
+represent as any specific type of device. The typical use-case is for
+some other node's driver, or platform-specific code, to acquire a
+reference to the syscon node (e.g. by phandle, node path, or search
+using a specific compatible value), interrogate the node (or associated
+OS driver) to determine the location of the registers, and access the
+registers directly.
+
+Required properties:
+- compatible: Should contain "syscon".
+- reg: the register region can be accessed from syscon
+
+Examples:
+gpr: iomuxc-gpr@020e0000 {
+ compatible = "fsl,imx6q-iomuxc-gpr", "syscon";
+ reg = <0x020e0000 0x38>;
+};
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b1a1462..82247b7 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -993,6 +993,14 @@ config MFD_ANATOP
MFD controller. This controller embeds regulator and
thermal devices for Freescale i.MX platforms.

+config MFD_SYSCON
+ bool "System Controller Register R/W Based on Regmap"
+ depends on OF
+ select REGMAP_MMIO
+ help
+ Select this option to enable accessing system control registers
+ via regmap.
+
config MFD_PALMAS
bool "Support for the TI Palmas series chips"
select MFD_CORE
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 79dd22d..8384bc9 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -131,4 +131,5 @@ obj-$(CONFIG_MFD_PALMAS) += palmas.o
obj-$(CONFIG_MFD_RC5T583) += rc5t583.o rc5t583-irq.o
obj-$(CONFIG_MFD_SEC_CORE) += sec-core.o sec-irq.o
obj-$(CONFIG_MFD_ANATOP) += anatop-mfd.o
+obj-$(CONFIG_MFD_SYSCON) += syscon.o
obj-$(CONFIG_MFD_LM3533) += lm3533-core.o lm3533-ctrlbank.o
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
new file mode 100644
index 0000000..65fe609
--- /dev/null
+++ b/drivers/mfd/syscon.c
@@ -0,0 +1,176 @@
+/*
+ * System Control Driver
+ *
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ * Copyright (C) 2012 Linaro Ltd.
+ *
+ * Author: Dong Aisheng <dong.aisheng@linaro.org>
+ *
+ * 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/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+static struct platform_driver syscon_driver;
+
+struct syscon {
+ struct device *dev;
+ void __iomem *base;
+ struct regmap *regmap;
+};
+
+static int syscon_match(struct device *dev, void *data)
+{
+ struct syscon *syscon = dev_get_drvdata(dev);
+ struct device_node *dn = data;
+
+ return (syscon->dev->of_node == dn) ? 1 : 0;
+}
+
+struct regmap *syscon_node_to_regmap(struct device_node *np)
+{
+ struct syscon *syscon;
+ struct device *dev;
+
+ dev = driver_find_device(&syscon_driver.driver, NULL, np,
+ syscon_match);
+ if (!dev)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ syscon = dev_get_drvdata(dev);
+
+ return syscon->regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
+
+struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
+{
+ struct device_node *syscon_np;
+ struct regmap *regmap;
+
+ syscon_np = of_find_compatible_node(NULL, NULL, s);
+ if (!syscon_np)
+ return ERR_PTR(-ENODEV);
+
+ regmap = syscon_node_to_regmap(syscon_np);
+ of_node_put(syscon_np);
+
+ return regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);
+
+struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
+ const char *property)
+{
+ struct device_node *syscon_np;
+ struct regmap *regmap;
+
+ syscon_np = of_parse_phandle(np, property, 0);
+ if (!syscon_np)
+ return ERR_PTR(-ENODEV);
+
+ regmap = syscon_node_to_regmap(syscon_np);
+ of_node_put(syscon_np);
+
+ return regmap;
+}
+EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
+
+static const struct of_device_id of_syscon_match[] = {
+ { .compatible = "syscon", },
+ { },
+};
+
+static struct regmap_config syscon_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+};
+
+static int __devinit syscon_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct syscon *syscon;
+ struct resource res;
+ int ret;
+
+ if (!np)
+ return -ENOENT;
+
+ syscon = devm_kzalloc(dev, sizeof(struct syscon),
+ GFP_KERNEL);
+ if (!syscon)
+ return -ENOMEM;
+
+ syscon->base = of_iomap(np, 0);
+ if (!syscon->base)
+ return -EADDRNOTAVAIL;
+
+ ret = of_address_to_resource(np, 0, &res);
+ if (ret)
+ return ret;
+
+ syscon_regmap_config.max_register = res.end - res.start - 3;
+ syscon->regmap = devm_regmap_init_mmio(dev, syscon->base,
+ &syscon_regmap_config);
+ if (IS_ERR(syscon->regmap)) {
+ dev_err(dev, "regmap init failed\n");
+ return PTR_ERR(syscon->regmap);
+ }
+
+ syscon->dev = dev;
+ platform_set_drvdata(pdev, syscon);
+
+ dev_info(dev, "syscon regmap start 0x%x end 0x%x registered\n",
+ res.start, res.end);
+
+ return 0;
+}
+
+static int __devexit syscon_remove(struct platform_device *pdev)
+{
+ struct syscon *syscon;
+
+ syscon = platform_get_drvdata(pdev);
+ iounmap(syscon->base);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static struct platform_driver syscon_driver = {
+ .driver = {
+ .name = "syscon",
+ .owner = THIS_MODULE,
+ .of_match_table = of_syscon_match,
+ },
+ .probe = syscon_probe,
+ .remove = __devexit_p(syscon_remove),
+};
+
+static int __init syscon_init(void)
+{
+ return platform_driver_register(&syscon_driver);
+}
+postcore_initcall(syscon_init);
+
+static void __exit syscon_exit(void)
+{
+ platform_driver_unregister(&syscon_driver);
+}
+module_exit(syscon_exit);
+
+MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
+MODULE_DESCRIPTION("System Control driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
new file mode 100644
index 0000000..6aeb6b8
--- /dev/null
+++ b/include/linux/mfd/syscon.h
@@ -0,0 +1,23 @@
+/*
+ * System Control Driver
+ *
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ * Copyright (C) 2012 Linaro Ltd.
+ *
+ * Author: Dong Aisheng <dong.aisheng@linaro.org>
+ *
+ * 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.
+ */
+
+#ifndef __LINUX_MFD_SYSCON_H__
+#define __LINUX_MFD_SYSCON_H__
+
+extern struct regmap *syscon_node_to_regmap(struct device_node *np);
+extern struct regmap *syscon_regmap_lookup_by_compatible(const char *s);
+extern struct regmap *syscon_regmap_lookup_by_phandle(
+ struct device_node *np,
+ const char *property);
+#endif /* __LINUX_MFD_SYSCON_H__ */
--
1.7.0.4