i2c-designware: Check component type register

Designware component type register is checked before attaching to the device.

Signed-off-by: Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/i2c/busses/i2c-designware.c b/drivers/i2c/busses/i2c-designware.c
index 28335c3717d9..49386951f7fd 100644
--- a/drivers/i2c/busses/i2c-designware.c
+++ b/drivers/i2c/busses/i2c-designware.c
@@ -69,6 +69,7 @@
 #define DW_IC_TXFLR             0x74
 #define DW_IC_RXFLR             0x78
 #define DW_IC_COMP_PARAM_1      0xf4
+#define DW_IC_COMP_TYPE         0xfc
 #define DW_IC_TX_ABRT_SOURCE    0x80
 
 #define DW_IC_CON_MASTER                0x1
@@ -710,6 +711,7 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
         struct i2c_adapter *adap;
         struct resource *mem, *ioarea;
         int irq, r;
+        u32 reg;
 
         /* NOTE: driver uses the static register mapping */
         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -756,12 +758,19 @@ static int __devinit dw_i2c_probe(struct platform_device *pdev)
                 r = -EBUSY;
                 goto err_unuse_clocks;
         }
-        {
-                u32 param1 = dw_readl(dev, DW_IC_COMP_PARAM_1);
 
-                dev->tx_fifo_depth = ((param1 >> 16) & 0xff) + 1;
-                dev->rx_fifo_depth = ((param1 >> 8)  & 0xff) + 1;
+        reg = dw_readl(dev, DW_IC_COMP_TYPE);
+        if (reg != 0x44570140) {
+                dev_err(&pdev->dev, "Unknown Synopsys component type: "
+                                "0x%08x\n",     reg);
+                r = -ENODEV;
+                goto err_iounmap;
         }
+
+        reg = dw_readl(dev, DW_IC_COMP_PARAM_1);
+        dev->tx_fifo_depth = ((reg >> 16) & 0xff) + 1;
+        dev->rx_fifo_depth = ((reg >> 8)  & 0xff) + 1;
+
         i2c_dw_init(dev);
 
         dw_writel(dev, 0, DW_IC_INTR_MASK); /* disable IRQ */