From 2378bc09b91b0702fac7823828a614fd8016a29f Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Sat, 28 Mar 2009 21:34:45 +0100 Subject: [PATCH] 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 Signed-off-by: Jean Delvare --- drivers/i2c/algos/i2c-algo-pca.c | 41 +++++++++++++++------------ drivers/i2c/busses/i2c-pca-isa.c | 18 ++++++++---- drivers/i2c/busses/i2c-pca-platform.c | 20 ++++++------- 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 #include #include +#include #include #include #include @@ -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 #include #include +#include #include #include #include @@ -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) -- 2.20.1