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[PATCH v6 2/8] mfd: simple-mfd-i2c: specify max_register

Alex Elder posted 8 patches 7 months, 2 weeks ago
There is a newer version of this series
[PATCH v6 2/8] mfd: simple-mfd-i2c: specify max_register
Posted by Alex Elder 7 months, 2 weeks 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 custome configuration, but no existing
device uses it.

Lee Jones suggested modifying the simple MFD implementation to
remove the generality of the full regmap configuration and add a
max_register value to the simple_mfd_data structure.  This can
be used in the regmap configuration to limit the valid register
addresses if desired.  It's simpler, and covers all existing and
anticipated device types.

Signed-off-by: Alex Elder <elder@riscstar.com>
Suggested-by: Lee Jones <lee@kernel.org>
---
v6: - New patch, changing the simple MFD functionality

 drivers/mfd/simple-mfd-i2c.c | 18 ++++++------------
 drivers/mfd/simple-mfd-i2c.h |  2 +-
 2 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
index 22159913bea03..c1dc315d44dcf 100644
--- a/drivers/mfd/simple-mfd-i2c.c
+++ b/drivers/mfd/simple-mfd-i2c.c
@@ -24,27 +24,21 @@
 
 #include "simple-mfd-i2c.h"
 
-static const struct regmap_config regmap_config_8r_8v = {
-	.reg_bits = 8,
-	.val_bits = 8,
-};
-
 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 regmap_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)
-		regmap_config = &regmap_config_8r_8v;
-	else
-		regmap_config = simple_mfd_data->regmap_config;
+	regmap_config.reg_bits = 8;
+	regmap_config.val_bits = 8;
+	if (simple_mfd_data)
+		regmap_config.max_register = simple_mfd_data->max_register;
 
-	regmap = devm_regmap_init_i2c(i2c, regmap_config);
+	regmap = devm_regmap_init_i2c(i2c, &regmap_config);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
 
diff --git a/drivers/mfd/simple-mfd-i2c.h b/drivers/mfd/simple-mfd-i2c.h
index 7cb2bdd347d97..4121fe1bc1d70 100644
--- a/drivers/mfd/simple-mfd-i2c.h
+++ b/drivers/mfd/simple-mfd-i2c.h
@@ -24,9 +24,9 @@
 #include <linux/regmap.h>
 
 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 v6 2/8] mfd: simple-mfd-i2c: specify max_register
Posted by Lee Jones 7 months, 1 week ago 
On Fri, 27 Jun 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 custome configuration, but no existing
> device uses it.
> 
> Lee Jones suggested modifying the simple MFD implementation to
> remove the generality of the full regmap configuration and add a
> max_register value to the simple_mfd_data structure.  This can
> be used in the regmap configuration to limit the valid register
> addresses if desired.  It's simpler, and covers all existing and
> anticipated device types.

Woah, not like this.  I wanted to make the framework _more_ flexible.

Just this should do what you want:

diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
index 22159913bea0..f43be10c0e60 100644
--- a/drivers/mfd/simple-mfd-i2c.c
+++ b/drivers/mfd/simple-mfd-i2c.c
@@ -44,6 +44,9 @@ static int simple_mfd_i2c_probe(struct i2c_client *i2c)
        else
                regmap_config = simple_mfd_data->regmap_config;
 
+       if (simple_mfd_data->max_register)
+               regmap_config->max_register = simple_mfd_data->max_register;
+
        regmap = devm_regmap_init_i2c(i2c, regmap_config);
        if (IS_ERR(regmap))
                return PTR_ERR(regmap);

Plus the one line change in drivers/mfd/simple-mfd-i2c.h.

> Signed-off-by: Alex Elder <elder@riscstar.com>
> Suggested-by: Lee Jones <lee@kernel.org>
> ---
> v6: - New patch, changing the simple MFD functionality
> 
>  drivers/mfd/simple-mfd-i2c.c | 18 ++++++------------
>  drivers/mfd/simple-mfd-i2c.h |  2 +-
>  2 files changed, 7 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
> index 22159913bea03..c1dc315d44dcf 100644
> --- a/drivers/mfd/simple-mfd-i2c.c
> +++ b/drivers/mfd/simple-mfd-i2c.c
> @@ -24,27 +24,21 @@
>  
>  #include "simple-mfd-i2c.h"
>  
> -static const struct regmap_config regmap_config_8r_8v = {
> -	.reg_bits = 8,
> -	.val_bits = 8,
> -};
> -
>  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 regmap_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)
> -		regmap_config = &regmap_config_8r_8v;
> -	else
> -		regmap_config = simple_mfd_data->regmap_config;
> +	regmap_config.reg_bits = 8;
> +	regmap_config.val_bits = 8;
> +	if (simple_mfd_data)
> +		regmap_config.max_register = simple_mfd_data->max_register;
>  
> -	regmap = devm_regmap_init_i2c(i2c, regmap_config);
> +	regmap = devm_regmap_init_i2c(i2c, &regmap_config);
>  	if (IS_ERR(regmap))
>  		return PTR_ERR(regmap);
>  
> diff --git a/drivers/mfd/simple-mfd-i2c.h b/drivers/mfd/simple-mfd-i2c.h
> index 7cb2bdd347d97..4121fe1bc1d70 100644
> --- a/drivers/mfd/simple-mfd-i2c.h
> +++ b/drivers/mfd/simple-mfd-i2c.h
> @@ -24,9 +24,9 @@
>  #include <linux/regmap.h>
>  
>  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 v6 2/8] mfd: simple-mfd-i2c: specify max_register
Posted by Alex Elder 7 months, 1 week ago 
On 7/2/25 10:26 AM, Lee Jones wrote:
> On Fri, 27 Jun 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 custome configuration, but no existing
>> device uses it.
>>
>> Lee Jones suggested modifying the simple MFD implementation to
>> remove the generality of the full regmap configuration and add a
>> max_register value to the simple_mfd_data structure.  This can
>> be used in the regmap configuration to limit the valid register
>> addresses if desired.  It's simpler, and covers all existing and
>> anticipated device types.
> 
> Woah, not like this.  I wanted to make the framework _more_ flexible.

OK, sorry I misunderstood.  I'll send another new version today
that does what you suggest.

Thanks a lot.

					-Alex

> Just this should do what you want:
> 
> diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
> index 22159913bea0..f43be10c0e60 100644
> --- a/drivers/mfd/simple-mfd-i2c.c
> +++ b/drivers/mfd/simple-mfd-i2c.c
> @@ -44,6 +44,9 @@ static int simple_mfd_i2c_probe(struct i2c_client *i2c)
>          else
>                  regmap_config = simple_mfd_data->regmap_config;
>   
> +       if (simple_mfd_data->max_register)
> +               regmap_config->max_register = simple_mfd_data->max_register;
> +
>          regmap = devm_regmap_init_i2c(i2c, regmap_config);
>          if (IS_ERR(regmap))
>                  return PTR_ERR(regmap);
> 
> Plus the one line change in drivers/mfd/simple-mfd-i2c.h.
> 
>> Signed-off-by: Alex Elder <elder@riscstar.com>
>> Suggested-by: Lee Jones <lee@kernel.org>
>> ---
>> v6: - New patch, changing the simple MFD functionality
>>
>>   drivers/mfd/simple-mfd-i2c.c | 18 ++++++------------
>>   drivers/mfd/simple-mfd-i2c.h |  2 +-
>>   2 files changed, 7 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/mfd/simple-mfd-i2c.c b/drivers/mfd/simple-mfd-i2c.c
>> index 22159913bea03..c1dc315d44dcf 100644
>> --- a/drivers/mfd/simple-mfd-i2c.c
>> +++ b/drivers/mfd/simple-mfd-i2c.c
>> @@ -24,27 +24,21 @@
>>   
>>   #include "simple-mfd-i2c.h"
>>   
>> -static const struct regmap_config regmap_config_8r_8v = {
>> -	.reg_bits = 8,
>> -	.val_bits = 8,
>> -};
>> -
>>   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 regmap_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)
>> -		regmap_config = &regmap_config_8r_8v;
>> -	else
>> -		regmap_config = simple_mfd_data->regmap_config;
>> +	regmap_config.reg_bits = 8;
>> +	regmap_config.val_bits = 8;
>> +	if (simple_mfd_data)
>> +		regmap_config.max_register = simple_mfd_data->max_register;
>>   
>> -	regmap = devm_regmap_init_i2c(i2c, regmap_config);
>> +	regmap = devm_regmap_init_i2c(i2c, &regmap_config);
>>   	if (IS_ERR(regmap))
>>   		return PTR_ERR(regmap);
>>   
>> diff --git a/drivers/mfd/simple-mfd-i2c.h b/drivers/mfd/simple-mfd-i2c.h
>> index 7cb2bdd347d97..4121fe1bc1d70 100644
>> --- a/drivers/mfd/simple-mfd-i2c.h
>> +++ b/drivers/mfd/simple-mfd-i2c.h
>> @@ -24,9 +24,9 @@
>>   #include <linux/regmap.h>
>>   
>>   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 v6 2/8] mfd: simple-mfd-i2c: specify max_register
Posted by Lee Jones 7 months, 1 week ago 
On Wed, 02 Jul 2025, Alex Elder wrote:

> On 7/2/25 10:26 AM, Lee Jones wrote:
> > On Fri, 27 Jun 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 custome configuration, but no existing
> > > device uses it.
> > > 
> > > Lee Jones suggested modifying the simple MFD implementation to
> > > remove the generality of the full regmap configuration and add a
> > > max_register value to the simple_mfd_data structure.  This can
> > > be used in the regmap configuration to limit the valid register
> > > addresses if desired.  It's simpler, and covers all existing and
> > > anticipated device types.
> > 
> > Woah, not like this.  I wanted to make the framework _more_ flexible.
> 
> OK, sorry I misunderstood.  I'll send another new version today
> that does what you suggest.

No worries.  Perhaps I wasn't clear enough.

-- 
Lee Jones [李琼斯]

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