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

[Pankaj Dubey <pankaj.dubey@samsung.com>]

+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@gmx.net>
>> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
>> ---
>>   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