linux-kernel - Re: [PATCH RESEND] tps65023: Allow platforms to specify DCDC_2 and DCDC

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Date:	Sat, 04 Sep 2010 13:12:54 -0400
From:	Michael Williamson <michael.williamson@...ticallink.com>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
CC:	linux-kernel@...r.kernel.org, lrg@...mlogic.co.uk,
	broonie@...nsource.wolfsonmicro.com, gregkh@...e.de
Subject: Re: [PATCH RESEND] tps65023: Allow platforms to specify DCDC_2 and
 DCDC_3 value.

Hello Dmitry,

On 09/04/2010 01:01 PM, Dmitry Torokhov wrote:
> Hi Michael,
> 
> On Sat, Sep 04, 2010 at 12:04:31PM -0400, Michael Williamson wrote:
>> The TPS65023 regulator includes 5 regulators (3 DCDC and 2 LDO's).
>> 2 of the DCDC regulators are of fixed voltage and can only be
>> turned on or off via the I2C interface.  The current driver defaults
>> the values of the fixed DCDC regulators.  However, the actual
>> voltage of these regulators may be set differently for a board (via
>> voltage divider circuit, etc.).
>>
>> This patch allows a platform to pass in the actual voltage used
>> for these DCDC supplies such that they are reported correctly in
>> sysfs.
>>
>> Signed-off-by: Michael Williamson <michael.williamson@...ticallink.com>
>> ---
>> Previous submission said 1/3.  Should only be 1/1.
>>
>>  drivers/regulator/tps65023-regulator.c |   17 +++++++++++++----
>>  1 files changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/regulator/tps65023-regulator.c b/drivers/regulator/tps65023-regulator.c
>> index cd6d4fc..68cd7d3 100644
>> --- a/drivers/regulator/tps65023-regulator.c
>> +++ b/drivers/regulator/tps65023-regulator.c
>> @@ -124,7 +124,7 @@ struct tps_pmic {
>>  	struct regulator_desc desc[TPS65023_NUM_REGULATOR];
>>  	struct i2c_client *client;
>>  	struct regulator_dev *rdev[TPS65023_NUM_REGULATOR];
>> -	const struct tps_info *info[TPS65023_NUM_REGULATOR];
>> +	struct tps_info *info[TPS65023_NUM_REGULATOR];
>>  	struct mutex io_lock;
>>  };
>>  
>> @@ -462,9 +462,10 @@ static int __devinit tps_65023_probe(struct i2c_client *client,
>>  				     const struct i2c_device_id *id)
>>  {
>>  	static int desc_id;
>> -	const struct tps_info *info = (void *)id->driver_data;
>> +	struct tps_info *info = (void *)id->driver_data;
> 
> id is shared between multiple instances of the device and is constant.
> It is a bad idea to cast away constness and modify the data; you should
> move data that may be adjusted into tps_pmic structure.
> 
> Even if we expect to only a single instance of the device in question we
> should follow best practices.
> 
Yes of course.  Hadn't thought of multiple instances.  I will correct and resubmit.  
Thank you.

>>  	struct regulator_init_data *init_data;
> 
> This should probably be marked const too as it comes from platform code.
> 
>>  	struct regulator_dev *rdev;
>> +	struct regulation_constraints *c;
> 
> const as well?
> 
Right.

>>  	struct tps_pmic *tps;
>>  	int i;
>>  	int error;
>> @@ -501,6 +502,14 @@ static int __devinit tps_65023_probe(struct i2c_client *client,
>>  		tps->desc[i].type = REGULATOR_VOLTAGE;
>>  		tps->desc[i].owner = THIS_MODULE;
>>  
>> +		/* Override default DCDC2/3 values if provided */
>> +		c = &init_data->constraints;
>> +		if ((i == TPS65023_DCDC_2) || (i == TPS65023_DCDC_3)
>> +			&& c->min_uV && c->min_uV == c->max_uV) {
> 
> Min and max are the same? You sure you got the condition right? 
> 
These DCDC regulators are fixed in hardware, they cannot be controlled and should
only have one value (minus hardware tolerance, I suppose).  I thought that such a 
sanity check would be required.  What should the reported value be if a range is 
provided? 

>> +			info->min_uV = c->min_uV;
>> +			info->max_uV = c->max_uV;
>> +		}
>> +
>>  		/* Register the regulators */
>>  		rdev = regulator_register(&tps->desc[i], &client->dev,
>>  					  init_data, tps);
>> @@ -519,7 +528,7 @@ static int __devinit tps_65023_probe(struct i2c_client *client,
>>  
>>  	return 0;
>>  
>> - fail:
>> +fail:
>>  	while (--i >= 0)
>>  		regulator_unregister(tps->rdev[i]);
>>  
>> @@ -546,7 +555,7 @@ static int __devexit tps_65023_remove(struct i2c_client *client)
>>  	return 0;
>>  }
>>  
>> -static const struct tps_info tps65023_regs[] = {
>> +static struct tps_info tps65023_regs[] = {
>>  	{
>>  		.name = "VDCDC1",
>>  		.min_uV =  800000,
>> -- 
>> 1.7.0.4
>>
> 

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