Re: [PATCH] mfd: syscon: allow to register syscon with a device

[Pankaj Dubey]

+To: Arnd Bergmann

Hi Philipp,

On Friday 24 April 2015 02:02 PM, Philipp Zabel wrote:
> Am Dienstag, den 17.03.2015, 11:24 +0100 schrieb Philipp Zabel:
> > Commit bdb0066df96e ("mfd: syscon: Decouple syscon interface from platform devices")
> > added the possibility to register syscon devices without associated platform
> > device. This also removed regmap debugfs facilities, which don't work without a
> > device. Since there is no replacement, this patch allows again to register
> > syscon regions with an associated device where that this device exists anyway.
>
> Hi,
>
> any comments on this?

Verified patch on Exynos5250 based SMDK5250 board. Although it's not 
breaking Exynos PMU probing or S2R for me.
I am still not very sure about the approach, because as I mentioned 
earlier, Arnd was against [1] adding any such registration exported 
function in syscon. So including Arnd in this loop.

[1]: https://lkml.org/lkml/2014/6/18/311


> best regards
> Philipp
>
> > [fixed max_register parameter in case of device register]
> > Signed-off-by: Peter Seiderer <ps.report@xxxxxxx>
> > Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> > ---
> >   drivers/mfd/syscon.c       | 29 +++++++++++++++++++++--------
> >   include/linux/mfd/syscon.h | 10 ++++++++++
> >   2 files changed, 31 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> > index 176bf0f..af0f899 100644
> > --- a/drivers/mfd/syscon.c
> > +++ b/drivers/mfd/syscon.c
> > @@ -36,19 +36,20 @@ struct syscon {
> >   	struct list_head list;
> >   };
> >
> > -static struct regmap_config syscon_regmap_config = {
> > +static const struct regmap_config syscon_regmap_config = {
> >   	.reg_bits = 32,
> >   	.val_bits = 32,
> >   	.reg_stride = 4,
> >   };
> >
> > -static struct syscon *of_syscon_register(struct device_node *np)
> > +struct syscon *syscon_register(struct device *dev, struct device_node *np)
> >   {
> >   	struct syscon *syscon;
> >   	struct regmap *regmap;
> >   	void __iomem *base;
> >   	int ret;
> >   	struct regmap_config syscon_config = syscon_regmap_config;
> > +	struct resource res;
> >
> >   	if (!of_device_is_compatible(np, "syscon"))
> >   		return ERR_PTR(-EINVAL);
> > @@ -57,7 +58,12 @@ static struct syscon *of_syscon_register(struct device_node *np)
> >   	if (!syscon)
> >   		return ERR_PTR(-ENOMEM);
> >
> > -	base = of_iomap(np, 0);
> > +	if (of_address_to_resource(np, 0, &res)) {
> > +		ret = -ENOMEM;
> > +		goto err_map;
> > +	}
> > +
> > +	base = ioremap(res.start, resource_size(&res));
> >   	if (!base) {
> >   		ret = -ENOMEM;
> >   		goto err_map;
> > @@ -69,7 +75,8 @@ static struct syscon *of_syscon_register(struct device_node *np)
> >   	 else if (of_property_read_bool(np, "little-endian"))
> >   		syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE;
> >
> > -	regmap = regmap_init_mmio(NULL, base, &syscon_config);
> > +	syscon_config.max_register = res.end - res.start - 3;
> > +	regmap = regmap_init_mmio(dev, base, &syscon_config);
> >   	if (IS_ERR(regmap)) {
> >   		pr_err("regmap init failed\n");
> >   		ret = PTR_ERR(regmap);
> > @@ -91,6 +98,12 @@ err_map:
> >   	kfree(syscon);
> >   	return ERR_PTR(ret);
> >   }
> > +EXPORT_SYMBOL_GPL(syscon_register);
> > +
> > +static struct syscon *of_syscon_register(struct device_node *np)
> > +{
> > +	return syscon_register(NULL, np);
> > +}
> >
> >   struct regmap *syscon_node_to_regmap(struct device_node *np)
> >   {
> > @@ -179,6 +192,7 @@ static int syscon_probe(struct platform_device *pdev)
> >   	struct device *dev = &pdev->dev;
> >   	struct syscon_platform_data *pdata = dev_get_platdata(dev);
> >   	struct syscon *syscon;
> > +	struct regmap_config syscon_config = syscon_regmap_config;
> >   	struct resource *res;
> >   	void __iomem *base;
> >
> > @@ -194,11 +208,10 @@ static int syscon_probe(struct platform_device *pdev)
> >   	if (!base)
> >   		return -ENOMEM;
> >
> > -	syscon_regmap_config.max_register = res->end - res->start - 3;
> > +	syscon_config.max_register = res->end - res->start - 3;
> >   	if (pdata)
> > -		syscon_regmap_config.name = pdata->label;
> > -	syscon->regmap = devm_regmap_init_mmio(dev, base,
> > -					&syscon_regmap_config);
> > +		syscon_config.name = pdata->label;
> > +	syscon->regmap = devm_regmap_init_mmio(dev, base, &syscon_config);
> >   	if (IS_ERR(syscon->regmap)) {
> >   		dev_err(dev, "regmap init failed\n");
> >   		return PTR_ERR(syscon->regmap);
> > diff --git a/include/linux/mfd/syscon.h b/include/linux/mfd/syscon.h
> > index 75e543b..e0c4a86 100644
> > --- a/include/linux/mfd/syscon.h
> > +++ b/include/linux/mfd/syscon.h
> > @@ -17,10 +17,14 @@
> >
> >   #include <linux/err.h>
> >
> > +struct device;
> >   struct device_node;
> > +struct syscon;
> >
> >   #ifdef CONFIG_MFD_SYSCON
> >   extern struct regmap *syscon_node_to_regmap(struct device_node *np);
> > +extern struct syscon *syscon_register(struct device *dev,
> > +				      struct device_node *np);
> >   extern struct regmap *syscon_regmap_lookup_by_compatible(const char *s);
> >   extern struct regmap *syscon_regmap_lookup_by_pdevname(const char *s);
> >   extern struct regmap *syscon_regmap_lookup_by_phandle(
> > @@ -32,6 +36,12 @@ static inline struct regmap *syscon_node_to_regmap(struct device_node *np)
> >   	return ERR_PTR(-ENOSYS);
> >   }
> >
> > +static struct syscon *syscon_register(struct device *dev,
> > +				      struct device_node *np)
> > +{
> > +	return ERR_PTR(-ENOSYS);
> > +}
> > +
> >   static inline struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
> >   {
> >   	return ERR_PTR(-ENOSYS);


Thanks,
Pankaj Dubey
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