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

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Message-ID: <20100904170116.GA10918@core.coreip.homeip.net>
Date:	Sat, 4 Sep 2010 10:01:16 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Michael Williamson <michael.williamson@...ticallink.com>
Cc:	linux-kernel@...r.kernel.org, lrg@...mlogic.co.uk,
	broonie@...nsource.wolfsonmicro.com, khali@...ux-fr.org,
	gregkh@...e.de
Subject: Re: [PATCH RESEND] tps65023: Allow platforms to specify DCDC_2 and
 DCDC_3 value.

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.

>  	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?

>  	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? 

> +			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
> 

-- 
Dmitry
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