linux-kernel - [PATCH] mfd: wm8994: Return error when device ID mismatch is detected

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Date:	Wed, 22 Feb 2012 10:24:44 +0800
From:	Axel Lin <axel.lin@...il.com>
To:	linux-kernel@...r.kernel.org
Cc:	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Ian Lartey <ian@...nsource.wolfsonmicro.com>,
	Dimitris Papastamos <dp@...nsource.wolfsonmicro.com>,
	Samuel Ortiz <sameo@...ux.intel.com>
Subject: [PATCH] mfd: wm8994: Return error when device ID mismatch is
 detected

We base on wm8994->type to set wm8994->supplies and wm8994->num_supplies.
But in current code, wm8994->type may be changed when device ID mismatch is
detected. If we change wm8994->type, then the wm8994->supplies and
wm8994->num_supplies settings are wrong.

Fix it by return error immediately when device ID mismatch is detected.

Signed-off-by: Axel Lin <axel.lin@...il.com>
---
 drivers/mfd/wm8994-core.c |   32 +++++++-------------------------
 1 files changed, 7 insertions(+), 25 deletions(-)

diff --git a/drivers/mfd/wm8994-core.c b/drivers/mfd/wm8994-core.c
index 1599bba..6e4612e 100644
--- a/drivers/mfd/wm8994-core.c
+++ b/drivers/mfd/wm8994-core.c
@@ -415,14 +415,17 @@ static __devinit int wm8994_device_init(struct wm8994 *wm8994, int irq)
 
 	switch (wm8994->type) {
 	case WM1811:
+		devname = "WM1811";
 		for (i = 0; i < ARRAY_SIZE(wm1811_main_supplies); i++)
 			wm8994->supplies[i].supply = wm1811_main_supplies[i];
 		break;
 	case WM8994:
+		devname = "WM8994";
 		for (i = 0; i < ARRAY_SIZE(wm8994_main_supplies); i++)
 			wm8994->supplies[i].supply = wm8994_main_supplies[i];
 		break;
 	case WM8958:
+		devname = "WM8958";
 		for (i = 0; i < ARRAY_SIZE(wm8958_main_supplies); i++)
 			wm8994->supplies[i].supply = wm8958_main_supplies[i];
 		break;
@@ -450,31 +453,10 @@ static __devinit int wm8994_device_init(struct wm8994 *wm8994, int irq)
 		dev_err(wm8994->dev, "Failed to read ID register\n");
 		goto err_enable;
 	}
-	switch (ret) {
-	case 0x1811:
-		devname = "WM1811";
-		if (wm8994->type != WM1811)
-			dev_warn(wm8994->dev, "Device registered as type %d\n",
-				 wm8994->type);
-		wm8994->type = WM1811;
-		break;
-	case 0x8994:
-		devname = "WM8994";
-		if (wm8994->type != WM8994)
-			dev_warn(wm8994->dev, "Device registered as type %d\n",
-				 wm8994->type);
-		wm8994->type = WM8994;
-		break;
-	case 0x8958:
-		devname = "WM8958";
-		if (wm8994->type != WM8958)
-			dev_warn(wm8994->dev, "Device registered as type %d\n",
-				 wm8994->type);
-		wm8994->type = WM8958;
-		break;
-	default:
-		dev_err(wm8994->dev, "Device is not a WM8994, ID is %x\n",
-			ret);
+
+	if (ret != wm8994->type) {
+		dev_err(wm8994->dev, "Device ID mismatch: expect %x but we got %x\n",
+			wm8994->type, ret);
 		ret = -EINVAL;
 		goto err_enable;
 	}
-- 
1.7.5.4



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