mfd: ab8500-sysctrl: Error check clean up

Add error checks to see if sysctrl was probed as it should.
If the sysctrl_dev is not set the return value is -EINVAL.
Signed-off-by: Marcus Danielsson <marcus.danielsson@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Mattias WALLIN <mattias.wallin@stericsson.com>
Tested-by: Per FORLIN <per.forlin@stericsson.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/ab8500-sysctrl.c

@@ -28,6 +28,11 @@ void ab8500_power_off(void)
 	struct power_supply *psy;
 	int ret;
 
+	if (sysctrl_dev == NULL) {
+		pr_err("%s: sysctrl not initialized\n", __func__);
+		return;
+	}
+
 	/*
 	 * If we have a charger connected and we're powering off,
 	 * reboot into charge-only mode.
@@ -85,7 +90,7 @@ int ab8500_sysctrl_read(u16 reg, u8 *value)
 	u8 bank;
 
 	if (sysctrl_dev == NULL)
-		return -EAGAIN;
+		return -EINVAL;
 
 	bank = (reg >> 8);
 	if (!valid_bank(bank))
@@ -101,7 +106,7 @@ int ab8500_sysctrl_write(u16 reg, u8 mask, u8 value)
 	u8 bank;
 
 	if (sysctrl_dev == NULL)
-		return -EAGAIN;
+		return -EINVAL;
 
 	bank = (reg >> 8);
 	if (!valid_bank(bank))
@@ -116,16 +121,18 @@ static int ab8500_sysctrl_probe(struct platform_device *pdev)
 {
 	struct ab8500_platform_data *plat;
 	struct ab8500_sysctrl_platform_data *pdata;
+	int ret, i, j;
 
-	sysctrl_dev = &pdev->dev;
 	plat = dev_get_platdata(pdev->dev.parent);
+
+	if (!(plat && plat->sysctrl))
+		return -EINVAL;
+
 	if (plat->pm_power_off)
 		pm_power_off = ab8500_power_off;
 
 	pdata = plat->sysctrl;
 
-	if (pdata) {
-		int ret, i, j;
 
 	for (i = AB8500_SYSCLKREQ1RFCLKBUF;
 	     i <= AB8500_SYSCLKREQ8RFCLKBUF; i++) {
@@ -142,7 +149,6 @@ static int ab8500_sysctrl_probe(struct platform_device *pdev)
 				"%d\n", j + 1, ret);
 		}
 	}
-	}
 
 	return 0;
 }