[PATCH v2 1/7] mfd: add syscon driver based on regmap

[Dong Aisheng]

On Tue, Aug 28, 2012 at 06:08:32AM +0800, Shawn Guo wrote:
> On Mon, Aug 27, 2012 at 03:24:39PM +0800, Dong Aisheng wrote:
> > From: Dong Aisheng <dong.aisheng at 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.
> > 
> > Reviwed-by: Mark Brown <broonie at opensource.wolfsonmicro.com>
> > Signed-off-by: Dong Aisheng <dong.aisheng at linaro.org>
> > ---
> > ChangeLog:
> > 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.
> > ---
> >  .../devicetree/bindings/mfd/imx-syscon.txt         |   11 ++
> 
> So, this file should be renamed as well.
> 
Correct.
I missed it, thanks for reminder.

> >  drivers/mfd/Kconfig                                |    7 +
> >  drivers/mfd/Makefile                               |    1 +
> >  drivers/mfd/syscon.c                               |  169 ++++++++++++++++++++
> >  include/linux/mfd/syscon.h                         |   22 +++
> >  5 files changed, 210 insertions(+), 0 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/mfd/imx-syscon.txt b/Documentation/devicetree/bindings/mfd/imx-syscon.txt
> > new file mode 100644
> > index 0000000..c1a13b4
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mfd/imx-syscon.txt
> > @@ -0,0 +1,11 @@
> > +* System Controller Registers R/W driver
> > +
> > +Required properties:
> > +- compatible: Should contain "syscon".
> > +- reg: the register range can be access from syscon
> > +
> > +Examples:
> > +gpr: iomuxc-gpr at 020e0000 {
> > +	compatible = "fsl,imx6q-iomuxc", "syscon";
> > +	reg = <0x020e0000 0x38>;
> > +};
> > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > index b1a1462..4a6c48e 100644
> > --- a/drivers/mfd/Kconfig
> > +++ b/drivers/mfd/Kconfig
> > @@ -993,6 +993,13 @@ 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"
> > +        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..da2464f
> > --- /dev/null
> > +++ b/drivers/mfd/syscon.c
> > @@ -0,0 +1,169 @@
> > +/*
> > + * System Control Driver
> > + *
> > + * Copyright (C) 2012 Freescale Semiconductor, Inc.
> > + * Copyright (C) 2012 Linaro Ltd.
> > + *
> > + * Author: Dong Aisheng <dong.aisheng at 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;
> > +}
> > +
> > +static 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);
> > +	of_node_put(np);
> > +
> > +	if (!dev)
> > +		return ERR_PTR(-EPROBE_DEFER);
> > +
> > +	syscon = dev_get_drvdata(dev);
> > +
> > +	return syscon->regmap;
> > +}
> > +
> > +struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
> > +{
> > +	struct device_node *syscon_np;
> > +
> > +	syscon_np = of_find_compatible_node(NULL, NULL, s);
> > +	if (!syscon_np)
> > +		return ERR_PTR(-ENODEV);
> > +
> > +	return syscon_node_to_regmap(syscon_np);
> > +}
> > +
> > +struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
> > +					const char *property)
> > +{
> > +	struct device_node *syscon_np;
> > +
> > +	syscon_np = of_parse_phandle(np, property, 0);
> > +	if (!syscon_np)
> > +		return ERR_PTR(-ENODEV);
> > +
> > +	return syscon_node_to_regmap(syscon_np);
> > +}
> 
> The above two APIs are all about finding the device_node for syscon,
> and can be done by clients in whatever way that is easy for them.
> Then we can save these APIs and export syscon_node_to_regmap directly.
> 
Yes, we probably should also export syscon_node_to_regmap.
For other two, since they're common to be used, i prefer to keep them too
for user to choose to use, it saves client to write duplicate code.

> > +
> > +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(&pdev->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(&pdev->dev, syscon->base,
> > +					&syscon_regmap_config);
> > +	if (IS_ERR(syscon->regmap)) {
> > +		dev_err(&pdev->dev, "regmap init failed\n");
> > +		return PTR_ERR(syscon->regmap);
> > +	}
> > +
> > +	regcache_cache_only(syscon->regmap, false);
> > +
> > +	syscon->dev = &pdev->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		= syscon_remove,
> > +};
> > +
> > +static int __init syscon_init(void)
> > +{
> > +	return platform_driver_register(&syscon_driver);
> > +}
> > +postcore_initcall(syscon_init);
> > +
> > +static void __exit anatop_exit(void)
> 
> s/anatop_exit/syscon_exit
> 
> > +{
> > +	platform_driver_unregister(&syscon_driver);
> > +}
> > +module_exit(anatop_exit);
> 
> Ditto.
> 
Correct, Thanks.
Will fix those typo in updated patches.

Regards
Dong Aisheng
> > +
> > +MODULE_AUTHOR("Dong Aisheng <dong.aisheng at 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..990d7cf
> > --- /dev/null
> > +++ b/include/linux/mfd/syscon.h
> > @@ -0,0 +1,22 @@
> > +/*
> > + * System Control Driver
> > + *
> > + * Copyright (C) 2012 Freescale Semiconductor, Inc.
> > + * Copyright (C) 2012 Linaro Ltd.
> > + *
> > + * Author: Dong Aisheng <dong.aisheng at 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_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
> > 
> > 
>