via: Do not attempt I/O on inactive I2C adapters

If an adapter has been configured for GPIO (or off), we should not try to
use it as an I2C port.

Cc: ScottFang@viatech.com.cn
Cc: JosephChan@via.com.tw
Cc: Harald Welte <laforge@gnumonks.org>
Acked-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

2 files changed, 11 insertions, 4 deletions

diff --git a/drivers/video/via/via_i2c.c b/drivers/video/via/via_i2c.c
index 3ff60b280d88..c88450ee62ba 100644
--- a/drivers/video/via/via_i2c.c
+++ b/drivers/video/via/via_i2c.c
@@ -115,6 +115,8 @@ int viafb_i2c_readbyte(u8 adap, u8 slave_addr, u8 index, u8 *pdata)
         u8 mm1[] = {0x00};
         struct i2c_msg msgs[2];
 
+        if (!via_i2c_par[adap].is_active)
+                return -ENODEV;
         *pdata = 0;
         msgs[0].flags = 0;
         msgs[1].flags = I2C_M_RD;
@@ -130,6 +132,8 @@ int viafb_i2c_writebyte(u8 adap, u8 slave_addr, u8 index, u8 data)
         u8 msg[2] = { index, data };
         struct i2c_msg msgs;
 
+        if (!via_i2c_par[adap].is_active)
+                return -ENODEV;
         msgs.flags = 0;
         msgs.addr = slave_addr / 2;
         msgs.len = 2;
@@ -142,6 +146,8 @@ int viafb_i2c_readbytes(u8 adap, u8 slave_addr, u8 index, u8 *buff, int buff_len
         u8 mm1[] = {0x00};
         struct i2c_msg msgs[2];
 
+        if (!via_i2c_par[adap].is_active)
+                return -ENODEV;
         msgs[0].flags = 0;
         msgs[1].flags = I2C_M_RD;
         msgs[0].addr = msgs[1].addr = slave_addr / 2;
@@ -198,18 +204,18 @@ static int viafb_i2c_probe(struct platform_device *platdev)
                 struct via_port_cfg *adap_cfg = configs++;
                 struct via_i2c_stuff *i2c_stuff = &via_i2c_par[i];
 
+                i2c_stuff->is_active = 0;
                 if (adap_cfg->type == 0 || adap_cfg->mode != VIA_MODE_I2C)
                         continue;
-
                 ret = create_i2c_bus(&i2c_stuff->adapter,
                                      &i2c_stuff->algo, adap_cfg,
                                 NULL); /* FIXME: PCIDEV */
                 if (ret < 0) {
                         printk(KERN_ERR "viafb: cannot create i2c bus %u:%d\n",
                                 i, ret);
-                        /* FIXME: properly release previous busses */
-                        return ret;
+                        continue;  /* Still try to make the rest */
                 }
+                i2c_stuff->is_active = 1;
         }
 
         return 0;
@@ -225,7 +231,7 @@ static int viafb_i2c_remove(struct platform_device *platdev)
                  * Only remove those entries in the array that we've
                  * actually used (and thus initialized algo_data)
                  */
-                if (i2c_stuff->adapter.algo_data == &i2c_stuff->algo)
+                if (i2c_stuff->is_active)
                         i2c_del_adapter(&i2c_stuff->adapter);
         }
         return 0;
diff --git a/drivers/video/via/via_i2c.h b/drivers/video/via/via_i2c.h
index b2332cce9d18..1d18e7d57b7f 100644
--- a/drivers/video/via/via_i2c.h
+++ b/drivers/video/via/via_i2c.h
@@ -26,6 +26,7 @@
 
 struct via_i2c_stuff {
         u16 i2c_port;                   /* GPIO or I2C port */
+        u16 is_active;                  /* Being used as I2C? */
         struct i2c_adapter adapter;
         struct i2c_algo_bit_data algo;
 };