Subject: [PATCH 1/3] mfd: tps6586x: add version detection

From: [email-masked] (Stephen Warren)
Date: Wed, 27 Nov 2013 09:58:50 -0700

On 11/26/2013 04:45 PM, Stefan Agner wrote:
> Use the VERSIONCRC to determine the exact device version. According to
> the datasheet this register can be used as device identifier. The
> identification is needed since some tps6586x regulators use a different
> voltage table.

> diff --git a/drivers/mfd/tps6586x.c b/drivers/mfd/tps6586x.c

> @@ -477,6 +486,7 @@ static int tps6586x_i2c_probe(struct i2c_client *client,
>  {
>  	struct tps6586x_platform_data *pdata = dev_get_platdata(&client->dev);
>  	struct tps6586x *tps6586x;
> +	const char *name = "";

There's no need to assign any value here; the switch below always
assigns something over the top of the variable, so it doesn't need to be
pre-initialized.

> +	tps6586x = devm_kzalloc(&client->dev, sizeof(*tps6586x), GFP_KERNEL);
> +	if (tps6586x == NULL) {
> +		dev_err(&client->dev, "memory for tps6586x alloc failed\n");
> +		return -ENOMEM;
> +	}

> +	tps6586x->version = (enum tps6586x_version)ret;

Why not make the version variable an integer of some kind. Then, the
cast wouldn't be required. The values like TPS658621A can be #defines or
const u32.

> +	switch (ret) {

That should switch on tps6586x->version since that's been assigned;
it'll make the purpose a bit clearer.

> +	default:
> +		name = "TPS6586X";
> +		break;
>  	}

I hope the rest of the code deals with unknown values of
tps6586x->version OK.