i2c: algo: pca: Fix chip reset function for PCA9665

The parameter passed to pca9665_reset is adap->data (which is bus driver
specific), not i2c_algp_pca_data *adap. pca9665_reset expects it to be
i2c_algp_pca_data *adap. All other wrappers from the algo call back to
the bus driver, which knows to handle its custom data. Only pca9665_reset
resides inside the algorithm code and does not know how to handle a custom
data structure. This can result in a kernel crash.

Fix by re-factoring pca_reset() from a macro to a function handling chip
specific code, and only call adap->reset_chip() if the chip is not PCA9665.

Signed-off-by: Thomas Kavanagh <tkavanagh@juniper.net>
Signed-off-by: Guenter Roeck <groeck@juniper.net>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

1 files changed, 14 insertions, 13 deletions

diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
index 73133b1063f0..07ccbef6cc14 100644
--- a/drivers/i2c/algos/i2c-algo-pca.c
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -46,14 +46,19 @@ static int i2c_debug;
 #define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
 #define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
 #define pca_wait(adap) adap->wait_for_completion(adap->data)
-#define pca_reset(adap) adap->reset_chip(adap->data)
 
-static void pca9665_reset(void *pd)
+static void pca_reset(struct i2c_algo_pca_data *adap)
 {
-        struct i2c_algo_pca_data *adap = pd;
-        pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
-        pca_outw(adap, I2C_PCA_IND, 0xA5);
-        pca_outw(adap, I2C_PCA_IND, 0x5A);
+        if (adap->chip == I2C_PCA_CHIP_9665) {
+                /* Ignore the reset function from the module,
+                 * we can use the parallel bus reset.
+                 */
+                pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
+                pca_outw(adap, I2C_PCA_IND, 0xA5);
+                pca_outw(adap, I2C_PCA_IND, 0x5A);
+        } else {
+                adap->reset_chip(adap->data);
+        }
 }
 
 /*
@@ -378,11 +383,12 @@ static unsigned int pca_probe_chip(struct i2c_adapter *adap)
         pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
         if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {
                 printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);
-                return I2C_PCA_CHIP_9665;
+                pca_data->chip = I2C_PCA_CHIP_9665;
         } else {
                 printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
-                return I2C_PCA_CHIP_9564;
+                pca_data->chip = I2C_PCA_CHIP_9564;
         }
+        return pca_data->chip;
 }
 
 static int pca_init(struct i2c_adapter *adap)
@@ -456,11 +462,6 @@ static int pca_init(struct i2c_adapter *adap)
                  */
                 int raise_fall_time;
 
-                /* Ignore the reset function from the module,
-                 * we can use the parallel bus reset
-                 */
-                pca_data->reset_chip = pca9665_reset;
-
                 if (pca_data->i2c_clock > 1265800) {
                         printk(KERN_WARNING "%s: I2C clock speed too high."
                                 " Using 1265.8kHz.\n", adap->name);