SM501: Check SM501 ID register on initialisation
[sfrench/cifs-2.6.git] / drivers / mfd / sm501.c
index e14d70e074189624c86f5c2bce2f9a596cad19ae..8135e4c3bf47b7cff7f61d2ae9e236fcefd0baeb 100644 (file)
@@ -893,6 +893,7 @@ static int sm501_init_dev(struct sm501_devdata *sm)
 {
        resource_size_t mem_avail;
        unsigned long dramctrl;
+       unsigned long devid;
        int ret;
 
        mutex_init(&sm->clock_lock);
@@ -900,13 +901,18 @@ static int sm501_init_dev(struct sm501_devdata *sm)
 
        INIT_LIST_HEAD(&sm->devices);
 
-       dramctrl = readl(sm->regs + SM501_DRAM_CONTROL);
+       devid = readl(sm->regs + SM501_DEVICEID);
 
+       if ((devid & SM501_DEVICEID_IDMASK) != SM501_DEVICEID_SM501) {
+               dev_err(sm->dev, "incorrect device id %08lx\n", devid);
+               return -EINVAL;
+       }
+
+       dramctrl = readl(sm->regs + SM501_DRAM_CONTROL);
        mem_avail = sm501_mem_local[(dramctrl >> 13) & 0x7];
 
-       dev_info(sm->dev, "SM501 At %p: Version %08x, %ld Mb, IRQ %d\n",
-                sm->regs, readl(sm->regs + SM501_DEVICEID),
-                (unsigned long)mem_avail >> 20, sm->irq);
+       dev_info(sm->dev, "SM501 At %p: Version %08lx, %ld Mb, IRQ %d\n",
+                sm->regs, devid, (unsigned long)mem_avail >> 20, sm->irq);
 
        sm501_dump_gate(sm);