Commit 2378bc09 authored by Wolfram Sang's avatar Wolfram Sang Committed by Jean Delvare
Browse files

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: default avatarWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: default avatarJean Delvare <khali@linux-fr.org>
parent 8e99ada8

drivers/i2c/algos/i2c-algo-pca.c

+23 −18
Original line number Diff line number Diff line
@@ -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;

drivers/i2c/busses/i2c-pca-isa.c

+13 −5
Original line number Diff line number Diff line
@@ -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)

drivers/i2c/busses/i2c-pca-platform.c

+10 −10
Original line number Diff line number Diff line
@@ -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)

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