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[PATCH v7 2/8] mfd: simple-mfd-i2c: specify max_register

Alex Elder posted 8 patches 7 months, 1 week ago
There is a newer version of this series
[PATCH v7 2/8] mfd: simple-mfd-i2c: specify max_register
Posted by Alex Elder 7 months, 1 week ago 
All devices supported by simple MFD use the same 8-bit register
8-bit value regmap configuration.  There is an option available
for a device to specify a custom configuration, but no existing
device uses it.

Rather than specify a "full" regmap configuration to use this
option, Lee Jones suggested allowing just the max_register value
to be specified in the simple_mfd_data structure.

Signed-off-by: Alex Elder <elder@riscstar.com>
Suggested-by: Lee Jones <lee@kernel.org>
---
v2: - Allow max_register *and* regmap_config to be supplied

 drivers/mfd/simple-mfd-i2c.c | 15 ++++++++++++---
 drivers/mfd/simple-mfd-i2c.h |  1 +
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
index 22159913bea03..3f959f4f98261 100644
--- a/drivers/mfd/simple-mfd-i2c.c
+++ b/drivers/mfd/simple-mfd-i2c.c
@@ -33,16 +33,25 @@ static int simple_mfd_i2c_probe(struct i2c_client *i2c)
 {
 	const struct simple_mfd_data *simple_mfd_data;
 	const struct regmap_config *regmap_config;
+	struct regmap_config config;
 	struct regmap *regmap;
 	int ret;
 
 	simple_mfd_data = device_get_match_data(&i2c->dev);
 
 	/* If no regmap_config is specified, use the default 8reg and 8val bits */
-	if (!simple_mfd_data || !simple_mfd_data->regmap_config)
+	if (simple_mfd_data) {
+		if (simple_mfd_data->regmap_config)
+			config = *simple_mfd_data->regmap_config;
+		else
+			config = regmap_config_8r_8v;
+
+		if (simple_mfd_data->max_register)
+			config.max_register = simple_mfd_data->max_register;
+		regmap_config = &config;
+	} else {
 		regmap_config = &regmap_config_8r_8v;
-	else
-		regmap_config = simple_mfd_data->regmap_config;
+	}
 
 	regmap = devm_regmap_init_i2c(i2c, regmap_config);
 	if (IS_ERR(regmap))
diff --git a/drivers/mfd/simple-mfd-i2c.h b/drivers/mfd/simple-mfd-i2c.h
index 7cb2bdd347d97..706b6f53155ff 100644
--- a/drivers/mfd/simple-mfd-i2c.h
+++ b/drivers/mfd/simple-mfd-i2c.h
@@ -27,6 +27,7 @@ struct simple_mfd_data {
 	const struct regmap_config *regmap_config;
 	const struct mfd_cell *mfd_cell;
 	size_t mfd_cell_size;
+	unsigned int max_register;
 };
 
 #endif /* __MFD_SIMPLE_MFD_I2C_H */
-- 
2.45.2
Re: [PATCH v7 2/8] mfd: simple-mfd-i2c: specify max_register
Posted by Lee Jones 7 months ago 
On Wed, 02 Jul 2025, Alex Elder wrote:

> All devices supported by simple MFD use the same 8-bit register
> 8-bit value regmap configuration.  There is an option available
> for a device to specify a custom configuration, but no existing
> device uses it.
> 
> Rather than specify a "full" regmap configuration to use this
> option, Lee Jones suggested allowing just the max_register value
> to be specified in the simple_mfd_data structure.
> 
> Signed-off-by: Alex Elder <elder@riscstar.com>
> Suggested-by: Lee Jones <lee@kernel.org>
> ---
> v2: - Allow max_register *and* regmap_config to be supplied
> 
>  drivers/mfd/simple-mfd-i2c.c | 15 ++++++++++++---
>  drivers/mfd/simple-mfd-i2c.h |  1 +
>  2 files changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
> index 22159913bea03..3f959f4f98261 100644
> --- a/drivers/mfd/simple-mfd-i2c.c
> +++ b/drivers/mfd/simple-mfd-i2c.c
> @@ -33,16 +33,25 @@ static int simple_mfd_i2c_probe(struct i2c_client *i2c)
>  {
>  	const struct simple_mfd_data *simple_mfd_data;
>  	const struct regmap_config *regmap_config;

> +	struct regmap_config config;

Why do we need another regmap_config?

Can't we just remove the const and make use of the one above?

>  	struct regmap *regmap;
>  	int ret;
>  
>  	simple_mfd_data = device_get_match_data(&i2c->dev);
>  
>  	/* If no regmap_config is specified, use the default 8reg and 8val bits */
> -	if (!simple_mfd_data || !simple_mfd_data->regmap_config)
> +	if (simple_mfd_data) {
> +		if (simple_mfd_data->regmap_config)
> +			config = *simple_mfd_data->regmap_config;

			regmap_config = simple_mfd_data->regmap_config;

> +		else
> +			config = regmap_config_8r_8v;

			regmap_config = &regmap_config_8r_8v;
> +
> +		if (simple_mfd_data->max_register)
> +			config.max_register = simple_mfd_data->max_register;
> +		regmap_config = &config;
> +	} else {
>  		regmap_config = &regmap_config_8r_8v;

I suspect we don't need to have this line twice.

Either re-jig the if () above (I suspect this explains the existing
complexity [multiple conditions]) or pre-set regmap_config to
regmap_config_8r_8v and only over-write it if the conditions are met.

> -	else -		regmap_config = simple_mfd_data->regmap_config;
> +	}
>  
>  	regmap = devm_regmap_init_i2c(i2c, regmap_config); if
>  	(IS_ERR(regmap)) diff --git a/drivers/mfd/simple-mfd-i2c.h
>  	b/drivers/mfd/simple-mfd-i2c.h index
>  	7cb2bdd347d97..706b6f53155ff 100644 ---
>  	a/drivers/mfd/simple-mfd-i2c.h +++
>  	b/drivers/mfd/simple-mfd-i2c.h @@ -27,6 +27,7 @@ struct
>  	simple_mfd_data { const struct regmap_config *regmap_config;
>  	const struct mfd_cell *mfd_cell; size_t mfd_cell_size; +
>  	unsigned int max_register; };
>  
>  #endif /* __MFD_SIMPLE_MFD_I2C_H */ -- 2.45.2
> 

-- 
Lee Jones [李琼斯]
Re: [PATCH v7 2/8] mfd: simple-mfd-i2c: specify max_register
Posted by Alex Elder 7 months ago 
On 7/10/25 4:24 AM, Lee Jones wrote:
> On Wed, 02 Jul 2025, Alex Elder wrote:
> 
>> All devices supported by simple MFD use the same 8-bit register
>> 8-bit value regmap configuration.  There is an option available
>> for a device to specify a custom configuration, but no existing
>> device uses it.
>>
>> Rather than specify a "full" regmap configuration to use this
>> option, Lee Jones suggested allowing just the max_register value
>> to be specified in the simple_mfd_data structure.
>>
>> Signed-off-by: Alex Elder <elder@riscstar.com>
>> Suggested-by: Lee Jones <lee@kernel.org>
>> ---
>> v2: - Allow max_register *and* regmap_config to be supplied
>>
>>   drivers/mfd/simple-mfd-i2c.c | 15 ++++++++++++---
>>   drivers/mfd/simple-mfd-i2c.h |  1 +
>>   2 files changed, 13 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
>> index 22159913bea03..3f959f4f98261 100644
>> --- a/drivers/mfd/simple-mfd-i2c.c
>> +++ b/drivers/mfd/simple-mfd-i2c.c
>> @@ -33,16 +33,25 @@ static int simple_mfd_i2c_probe(struct i2c_client *i2c)
>>   {
>>   	const struct simple_mfd_data *simple_mfd_data;
>>   	const struct regmap_config *regmap_config;
> 
>> +	struct regmap_config config;
> 
> Why do we need another regmap_config?
> 
> Can't we just remove the const and make use of the one above?

If we change the global one, it changes for all users.

In my next version I will modify the global one temporarily and
zero the max_register field again after the devm_regmap_init_i2c()
call.  That doesn't protect against concurrent probes but I don't
think that's a problem.

>>   	struct regmap *regmap;
>>   	int ret;
>>   
>>   	simple_mfd_data = device_get_match_data(&i2c->dev);
>>   
>>   	/* If no regmap_config is specified, use the default 8reg and 8val bits */
>> -	if (!simple_mfd_data || !simple_mfd_data->regmap_config)
>> +	if (simple_mfd_data) {
>> +		if (simple_mfd_data->regmap_config)
>> +			config = *simple_mfd_data->regmap_config;
> 
> 			regmap_config = simple_mfd_data->regmap_config;
> 
>> +		else
>> +			config = regmap_config_8r_8v;
> 
> 			regmap_config = &regmap_config_8r_8v;
>> +
>> +		if (simple_mfd_data->max_register)
>> +			config.max_register = simple_mfd_data->max_register;
>> +		regmap_config = &config;
>> +	} else {
>>   		regmap_config = &regmap_config_8r_8v;
> 
> I suspect we don't need to have this line twice.
> 
> Either re-jig the if () above (I suspect this explains the existing
> complexity [multiple conditions]) or pre-set regmap_config to
> regmap_config_8r_8v and only over-write it if the conditions are met.

Sure, that would work, but it won't be needed if I just use
the (non-const) global config.

Thanks for the review.

					-Alex
		
> 
>> -	else -		regmap_config = simple_mfd_data->regmap_config;
>> +	}
>>   
>>   	regmap = devm_regmap_init_i2c(i2c, regmap_config); if
>>   	(IS_ERR(regmap)) diff --git a/drivers/mfd/simple-mfd-i2c.h
>>   	b/drivers/mfd/simple-mfd-i2c.h index
>>   	7cb2bdd347d97..706b6f53155ff 100644 ---
>>   	a/drivers/mfd/simple-mfd-i2c.h +++
>>   	b/drivers/mfd/simple-mfd-i2c.h @@ -27,6 +27,7 @@ struct
>>   	simple_mfd_data { const struct regmap_config *regmap_config;
>>   	const struct mfd_cell *mfd_cell; size_t mfd_cell_size; +
>>   	unsigned int max_register; };
>>   
>>   #endif /* __MFD_SIMPLE_MFD_I2C_H */ -- 2.45.2
>>
>
Re: [PATCH v7 2/8] mfd: simple-mfd-i2c: specify max_register
Posted by Lee Jones 7 months ago 
On Thu, 10 Jul 2025, Lee Jones wrote:

> On Wed, 02 Jul 2025, Alex Elder wrote:
> 
> > All devices supported by simple MFD use the same 8-bit register
> > 8-bit value regmap configuration.  There is an option available
> > for a device to specify a custom configuration, but no existing
> > device uses it.
> > 
> > Rather than specify a "full" regmap configuration to use this
> > option, Lee Jones suggested allowing just the max_register value
> > to be specified in the simple_mfd_data structure.
> > 
> > Signed-off-by: Alex Elder <elder@riscstar.com>
> > Suggested-by: Lee Jones <lee@kernel.org>
> > ---
> > v2: - Allow max_register *and* regmap_config to be supplied
> > 
> >  drivers/mfd/simple-mfd-i2c.c | 15 ++++++++++++---
> >  drivers/mfd/simple-mfd-i2c.h |  1 +
> >  2 files changed, 13 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
> > index 22159913bea03..3f959f4f98261 100644
> > --- a/drivers/mfd/simple-mfd-i2c.c
> > +++ b/drivers/mfd/simple-mfd-i2c.c
> > @@ -33,16 +33,25 @@ static int simple_mfd_i2c_probe(struct i2c_client *i2c)
> >  {
> >  	const struct simple_mfd_data *simple_mfd_data;
> >  	const struct regmap_config *regmap_config;
> 
> > +	struct regmap_config config;
> 
> Why do we need another regmap_config?
> 
> Can't we just remove the const and make use of the one above?
> 
> >  	struct regmap *regmap;
> >  	int ret;
> >  
> >  	simple_mfd_data = device_get_match_data(&i2c->dev);
> >  
> >  	/* If no regmap_config is specified, use the default 8reg and 8val bits */
> > -	if (!simple_mfd_data || !simple_mfd_data->regmap_config)
> > +	if (simple_mfd_data) {
> > +		if (simple_mfd_data->regmap_config)
> > +			config = *simple_mfd_data->regmap_config;
> 
> 			regmap_config = simple_mfd_data->regmap_config;
> 
> > +		else
> > +			config = regmap_config_8r_8v;
> 
> 			regmap_config = &regmap_config_8r_8v;
> > +
> > +		if (simple_mfd_data->max_register)
> > +			config.max_register = simple_mfd_data->max_register;
> > +		regmap_config = &config;
> > +	} else {
> >  		regmap_config = &regmap_config_8r_8v;
> 
> I suspect we don't need to have this line twice.
> 
> Either re-jig the if () above (I suspect this explains the existing
> complexity [multiple conditions]) or pre-set regmap_config to
> regmap_config_8r_8v and only over-write it if the conditions are met.

Not sure why this whole thing had to be reworked.

Why didn't the 2-liner I gave you work for you?

-- 
Lee Jones [李琼斯]

Patchew 2.1-devel-b67e4c2

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