i2c-algo-pca: Use timeout for checking the state machine

We now timeout also if the state machine does not change within the
given time. For that, the driver-specific completion-functions are
extended to return true or false depending on the timeout. This then
gets checked in the algorithm.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

3 files changed, 46 insertions, 33 deletions

diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
index 9e134fad7bda..f68e5f8e23ee 100644
--- a/drivers/i2c/algos/i2c-algo-pca.c
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -60,14 +60,14 @@ static void pca9665_reset(void *pd)
  *
  * returns after the start condition has occurred
  */
-static void pca_start(struct i2c_algo_pca_data *adap)
+static int pca_start(struct i2c_algo_pca_data *adap)
 {
         int sta = pca_get_con(adap);
         DEB2("=== START\n");
         sta |= I2C_PCA_CON_STA;
         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
         pca_set_con(adap, sta);
-        pca_wait(adap);
+        return pca_wait(adap);
 }
 
 /*
@@ -75,14 +75,14 @@ static void pca_start(struct i2c_algo_pca_data *adap)
  *
  * return after the repeated start condition has occurred
  */
-static void pca_repeated_start(struct i2c_algo_pca_data *adap)
+static int pca_repeated_start(struct i2c_algo_pca_data *adap)
 {
         int sta = pca_get_con(adap);
         DEB2("=== REPEATED START\n");
         sta |= I2C_PCA_CON_STA;
         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
         pca_set_con(adap, sta);
-        pca_wait(adap);
+        return pca_wait(adap);
 }
 
 /*
@@ -108,7 +108,7 @@ static void pca_stop(struct i2c_algo_pca_data *adap)
  *
  * returns after the address has been sent
  */
-static void pca_address(struct i2c_algo_pca_data *adap,
+static int pca_address(struct i2c_algo_pca_data *adap,
                         struct i2c_msg *msg)
 {
         int sta = pca_get_con(adap);
@@ -125,7 +125,7 @@ static void pca_address(struct i2c_algo_pca_data *adap,
         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
         pca_set_con(adap, sta);
 
-        pca_wait(adap);
+        return pca_wait(adap);
 }
 
 /*
@@ -133,7 +133,7 @@ static void pca_address(struct i2c_algo_pca_data *adap,
  *
  * Returns after the byte has been transmitted
  */
-static void pca_tx_byte(struct i2c_algo_pca_data *adap,
+static int pca_tx_byte(struct i2c_algo_pca_data *adap,
                         __u8 b)
 {
         int sta = pca_get_con(adap);
@@ -143,7 +143,7 @@ static void pca_tx_byte(struct i2c_algo_pca_data *adap,
         sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
         pca_set_con(adap, sta);
 
-        pca_wait(adap);
+        return pca_wait(adap);
 }
 
 /*
@@ -163,7 +163,7 @@ static void pca_rx_byte(struct i2c_algo_pca_data *adap,
  *
  * Returns after next byte has arrived.
  */
-static void pca_rx_ack(struct i2c_algo_pca_data *adap,
+static int pca_rx_ack(struct i2c_algo_pca_data *adap,
                        int ack)
 {
         int sta = pca_get_con(adap);
@@ -174,7 +174,7 @@ static void pca_rx_ack(struct i2c_algo_pca_data *adap,
                 sta |= I2C_PCA_CON_AA;
 
         pca_set_con(adap, sta);
-        pca_wait(adap);
+        return pca_wait(adap);
 }
 
 static int pca_xfer(struct i2c_adapter *i2c_adap,
@@ -187,6 +187,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
         int numbytes = 0;
         int state;
         int ret;
+        int completed = 1;
         unsigned long timeout = jiffies + i2c_adap->timeout;
 
         while (pca_status(adap) != 0xf8) {
@@ -232,18 +233,19 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
 
                 switch (state) {
                 case 0xf8: /* On reset or stop the bus is idle */
-                        pca_start(adap);
+                        completed = pca_start(adap);
                         break;
 
                 case 0x08: /* A START condition has been transmitted */
                 case 0x10: /* A repeated start condition has been transmitted */
-                        pca_address(adap, msg);
+                        completed = pca_address(adap, msg);
                         break;
 
                 case 0x18: /* SLA+W has been transmitted; ACK has been received */
                 case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
                         if (numbytes < msg->len) {
-                                pca_tx_byte(adap, msg->buf[numbytes]);
+                                completed = pca_tx_byte(adap,
+                                                        msg->buf[numbytes]);
                                 numbytes++;
                                 break;
                         }
@@ -251,7 +253,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
                         if (curmsg == num)
                                 pca_stop(adap);
                         else
-                                pca_repeated_start(adap);
+                                completed = pca_repeated_start(adap);
                         break;
 
                 case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
@@ -260,21 +262,22 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
                         goto out;
 
                 case 0x40: /* SLA+R has been transmitted; ACK has been received */
-                        pca_rx_ack(adap, msg->len > 1);
+                        completed = pca_rx_ack(adap, msg->len > 1);
                         break;
 
                 case 0x50: /* Data bytes has been received; ACK has been returned */
                         if (numbytes < msg->len) {
                                 pca_rx_byte(adap, &msg->buf[numbytes], 1);
                                 numbytes++;
-                                pca_rx_ack(adap, numbytes < msg->len - 1);
+                                completed = pca_rx_ack(adap,
+                                                       numbytes < msg->len - 1);
                                 break;
                         }
                         curmsg++; numbytes = 0;
                         if (curmsg == num)
                                 pca_stop(adap);
                         else
-                                pca_repeated_start(adap);
+                                completed = pca_repeated_start(adap);
                         break;
 
                 case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
@@ -297,7 +300,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
                                 if (curmsg == num)
                                         pca_stop(adap);
                                 else
-                                        pca_repeated_start(adap);
+                                        completed = pca_repeated_start(adap);
                         } else {
                                 DEB2("NOT ACK sent after data byte received. "
                                      "Not final byte. numbytes %d. len %d\n",
@@ -323,6 +326,8 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
                         break;
                 }
 
+                if (!completed)
+                        goto out;
         }
 
         ret = curmsg;
diff --git a/drivers/i2c/busses/i2c-pca-isa.c b/drivers/i2c/busses/i2c-pca-isa.c
index b9403fdfb6d8..0ed68e2ccd22 100644
--- a/drivers/i2c/busses/i2c-pca-isa.c
+++ b/drivers/i2c/busses/i2c-pca-isa.c
@@ -23,6 +23,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/delay.h>
+#include <linux/jiffies.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/wait.h>
@@ -43,6 +44,7 @@ static int irq = -1;
  * in the actual clock rate */
 static int clock  = 59000;
 
+static struct i2c_adapter pca_isa_ops;
 static wait_queue_head_t pca_wait;
 
 static void pca_isa_writebyte(void *pd, int reg, int val)
@@ -69,16 +71,22 @@ static int pca_isa_readbyte(void *pd, int reg)
 
 static int pca_isa_waitforcompletion(void *pd)
 {
-        int ret = 0;
+        long ret = ~0;
+        unsigned long timeout;
 
         if (irq > -1) {
-                ret = wait_event_interruptible(pca_wait,
-                                               pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI);
+                ret = wait_event_interruptible_timeout(pca_wait,
+                                pca_isa_readbyte(pd, I2C_PCA_CON)
+                                & I2C_PCA_CON_SI, pca_isa_ops.timeout);
         } else {
-                while ((pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
+                /* Do polling */
+                timeout = jiffies + pca_isa_ops.timeout;
+                while (((pca_isa_readbyte(pd, I2C_PCA_CON)
+                                & I2C_PCA_CON_SI) == 0)
+                                && (ret = time_before(jiffies, timeout)))
                         udelay(100);
         }
-        return ret;
+        return ret > 0;
 }
 
 static void pca_isa_resetchip(void *pd)
diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c
index 51d179bbddf9..df5e593a1d76 100644
--- a/drivers/i2c/busses/i2c-pca-platform.c
+++ b/drivers/i2c/busses/i2c-pca-platform.c
@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
+#include <linux/jiffies.h>
 #include <linux/errno.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
@@ -81,24 +82,23 @@ static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
 static int i2c_pca_pf_waitforcompletion(void *pd)
 {
         struct i2c_pca_pf_data *i2c = pd;
-        int ret = 0;
+        long ret = ~0;
+        unsigned long timeout;
 
         if (i2c->irq) {
-                ret = wait_event_interruptible(i2c->wait,
+                ret = wait_event_interruptible_timeout(i2c->wait,
                         i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
-                        & I2C_PCA_CON_SI);
+                        & I2C_PCA_CON_SI, i2c->adap.timeout);
         } else {
-                /*
-                 * Do polling...
-                 * XXX: Could get stuck in extreme cases!
-                 *      Maybe add timeout, but using irqs is preferred anyhow.
-                 */
-                while ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
+                /* Do polling */
+                timeout = jiffies + i2c->adap.timeout;
+                while (((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
                                 & I2C_PCA_CON_SI) == 0)
+                                && (ret = time_before(jiffies, timeout)))
                         udelay(100);
         }
 
-        return ret;
+        return ret > 0;
 }
 
 static void i2c_pca_pf_dummyreset(void *pd)