linux-kernel - RE: [patch] mfd/88pm860x: fix uninitialized variable and clean up

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Date:	Wed, 26 May 2010 19:08:25 -0700
From:	Haojian Zhuang <hzhuang1@...vell.com>
To:	Dan Carpenter <error27@...il.com>,
	Samuel Ortiz <sameo@...ux.intel.com>
CC:	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Liam Girdwood <lrg@...mlogic.co.uk>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject: RE: [patch] mfd/88pm860x: fix uninitialized variable and clean up

I'm OK on this patch.

Thanks
Haojian

-----Original Message-----
From: Dan Carpenter [mailto:error27@...il.com] 
Sent: 2010年5月27日 6:54 AM
To: Samuel Ortiz
Cc: Haojian Zhuang; Mark Brown; Liam Girdwood; linux-kernel@...r.kernel.org; kernel-janitors@...r.kernel.org
Subject: [patch] mfd/88pm860x: fix uninitialized variable and clean up

The original code had a compile warning:
drivers/mfd/88pm860x-core.c:431: warning: ‘ret’ may be used
	uninitialized in this function
It seems like the warning is valid if either pdata or pdata->touch is
NULL.

This patch checks pdata and pdata->touch at the beginning of the 
function.  That means everything can be pulled in one indent level.
Now all the statements fit within the 80 character limit.

Also at that point the "use_gpadc" variable isn't needed and removing
it simplifies the logic.

Signed-off-by: Dan Carpenter <error27@...il.com>

diff --git a/drivers/mfd/88pm860x-core.c b/drivers/mfd/88pm860x-core.c
index 405d2d5..f9ada69 100644
--- a/drivers/mfd/88pm860x-core.c
+++ b/drivers/mfd/88pm860x-core.c
@@ -428,52 +428,44 @@ static int __devinit device_gpadc_init(struct pm860x_chip *chip,
 {
 	struct i2c_client *i2c = (chip->id == CHIP_PM8607) ? chip->client \
 				: chip->companion;
-	int use_gpadc = 0, data, ret;
+	int data;
+	int ret;
 
 	/* initialize GPADC without activating it */
 
-	if (pdata && pdata->touch) {
-		/* set GPADC MISC1 register */
-		data = 0;
-		data |= (pdata->touch->gpadc_prebias << 1)
-			& PM8607_GPADC_PREBIAS_MASK;
-		data |= (pdata->touch->slot_cycle << 3)
-			& PM8607_GPADC_SLOT_CYCLE_MASK;
-		data |= (pdata->touch->off_scale << 5)
-			& PM8607_GPADC_OFF_SCALE_MASK;
-		data |= (pdata->touch->sw_cal << 7)
-			& PM8607_GPADC_SW_CAL_MASK;
-		if (data) {
-			ret = pm860x_reg_write(i2c, PM8607_GPADC_MISC1, data);
-			if (ret < 0)
-				goto out;
-		}
-		/* set tsi prebias time */
-		if (pdata->touch->tsi_prebias) {
-			data = pdata->touch->tsi_prebias;
-			ret = pm860x_reg_write(i2c, PM8607_TSI_PREBIAS, data);
-			if (ret < 0)
-				goto out;
-		}
-		/* set prebias & prechg time of pen detect */
-		data = 0;
-		data |= pdata->touch->pen_prebias & PM8607_PD_PREBIAS_MASK;
-		data |= (pdata->touch->pen_prechg << 5)
-			& PM8607_PD_PRECHG_MASK;
-		if (data) {
-			ret = pm860x_reg_write(i2c, PM8607_PD_PREBIAS, data);
-			if (ret < 0)
-				goto out;
-		}
+	if (!pdata || !pdata->touch)
+		return -EINVAL;
 
-		use_gpadc = 1;
+	/* set GPADC MISC1 register */
+	data = 0;
+	data |= (pdata->touch->gpadc_prebias << 1) & PM8607_GPADC_PREBIAS_MASK;
+	data |= (pdata->touch->slot_cycle << 3) & PM8607_GPADC_SLOT_CYCLE_MASK;
+	data |= (pdata->touch->off_scale << 5) & PM8607_GPADC_OFF_SCALE_MASK;
+	data |= (pdata->touch->sw_cal << 7) & PM8607_GPADC_SW_CAL_MASK;
+	if (data) {
+		ret = pm860x_reg_write(i2c, PM8607_GPADC_MISC1, data);
+		if (ret < 0)
+			goto out;
 	}
-
-	/* turn on GPADC */
-	if (use_gpadc) {
-		ret = pm860x_set_bits(i2c, PM8607_GPADC_MISC1,
-				      PM8607_GPADC_EN, PM8607_GPADC_EN);
+	/* set tsi prebias time */
+	if (pdata->touch->tsi_prebias) {
+		data = pdata->touch->tsi_prebias;
+		ret = pm860x_reg_write(i2c, PM8607_TSI_PREBIAS, data);
+		if (ret < 0)
+			goto out;
 	}
+	/* set prebias & prechg time of pen detect */
+	data = 0;
+	data |= pdata->touch->pen_prebias & PM8607_PD_PREBIAS_MASK;
+	data |= (pdata->touch->pen_prechg << 5) & PM8607_PD_PRECHG_MASK;
+	if (data) {
+		ret = pm860x_reg_write(i2c, PM8607_PD_PREBIAS, data);
+		if (ret < 0)
+			goto out;
+	}
+
+	ret = pm860x_set_bits(i2c, PM8607_GPADC_MISC1,
+			      PM8607_GPADC_EN, PM8607_GPADC_EN);
 out:
 	return ret;
 }