Commit 9dfee148 authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Wolfram Sang
Browse files

i2c: algo: bit: allow getsda to be NULL 



This is in preparation of supporting write-only SDA in i2c-gpio.

Signed-off-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent a00bb94c

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

+35 −42
Original line number Diff line number Diff line
@@ -184,8 +184,9 @@ static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) 


	/* read ack: SDA should be pulled down by slave, or it may

	 * NAK (usually to report problems with the data we wrote).

	 * Always report ACK if SDA is write-only.

	 */

	ack = !getsda(adap);    /* ack: sda is pulled low -> success */

	ack = !adap->getsda || !getsda(adap);    /* ack: sda is pulled low -> success */

	bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c,

		ack ? "A" : "NA");
@@ -238,71 +239,55 @@ static int test_bus(struct i2c_adapter *i2c_adap) 
			return -ENODEV;

	}



	if (adap->getsda == NULL)

		pr_info("%s: SDA is write-only, testing not possible\n", name);

	if (adap->getscl == NULL)

		pr_info("%s: Testing SDA only, SCL is not readable\n", name);

		pr_info("%s: SCL is write-only, testing not possible\n", name);



	sda = getsda(adap);

	scl = (adap->getscl == NULL) ? 1 : getscl(adap);

	sda = adap->getsda ? getsda(adap) : 1;

	scl = adap->getscl ? getscl(adap) : 1;

	if (!scl || !sda) {

		printk(KERN_WARNING

		       "%s: bus seems to be busy (scl=%d, sda=%d)\n",

		       name, scl, sda);

		pr_warn("%s: bus seems to be busy (scl=%d, sda=%d)\n", name, scl, sda);

		goto bailout;

	}



	sdalo(adap);

	sda = getsda(adap);

	scl = (adap->getscl == NULL) ? 1 : getscl(adap);

	if (sda) {

		printk(KERN_WARNING "%s: SDA stuck high!\n", name);

	if (adap->getsda && getsda(adap)) {

		pr_warn("%s: SDA stuck high!\n", name);

		goto bailout;

	}

	if (!scl) {

		printk(KERN_WARNING

		       "%s: SCL unexpected low while pulling SDA low!\n",

		       name);

	if (adap->getscl && !getscl(adap)) {

		pr_warn("%s: SCL unexpected low while pulling SDA low!\n", name);

		goto bailout;

	}



	sdahi(adap);

	sda = getsda(adap);

	scl = (adap->getscl == NULL) ? 1 : getscl(adap);

	if (!sda) {

		printk(KERN_WARNING "%s: SDA stuck low!\n", name);

	if (adap->getsda && !getsda(adap)) {

		pr_warn("%s: SDA stuck low!\n", name);

		goto bailout;

	}

	if (!scl) {

		printk(KERN_WARNING

		       "%s: SCL unexpected low while pulling SDA high!\n",

		       name);

	if (adap->getscl && !getscl(adap)) {

		pr_warn("%s: SCL unexpected low while pulling SDA high!\n", name);

		goto bailout;

	}



	scllo(adap);

	sda = getsda(adap);

	scl = (adap->getscl == NULL) ? 0 : getscl(adap);

	if (scl) {

		printk(KERN_WARNING "%s: SCL stuck high!\n", name);

	if (adap->getscl && getscl(adap)) {

		pr_warn("%s: SCL stuck high!\n", name);

		goto bailout;

	}

	if (!sda) {

		printk(KERN_WARNING

		       "%s: SDA unexpected low while pulling SCL low!\n",

		       name);

	if (adap->getsda && !getsda(adap)) {

		pr_warn("%s: SDA unexpected low while pulling SCL low!\n", name);

		goto bailout;

	}



	sclhi(adap);

	sda = getsda(adap);

	scl = (adap->getscl == NULL) ? 1 : getscl(adap);

	if (!scl) {

		printk(KERN_WARNING "%s: SCL stuck low!\n", name);

	if (adap->getscl && !getscl(adap)) {

		pr_warn("%s: SCL stuck low!\n", name);

		goto bailout;

	}

	if (!sda) {

		printk(KERN_WARNING

		       "%s: SDA unexpected low while pulling SCL high!\n",

		       name);

	if (adap->getsda && !getsda(adap)) {

		pr_warn("%s: SDA unexpected low while pulling SCL high!\n", name);

		goto bailout;

	}
@@ -420,6 +405,10 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) 
	unsigned char *temp = msg->buf;

	int count = msg->len;

	const unsigned flags = msg->flags;

	struct i2c_algo_bit_data *adap = i2c_adap->algo_data;



	if (!adap->getsda)

		return -EOPNOTSUPP;



	while (count > 0) {

		inval = i2c_inb(i2c_adap);
@@ -670,11 +659,15 @@ static int __i2c_bit_add_bus(struct i2c_adapter *adap, 
	if (ret < 0)

		return ret;



	/* Complain if SCL can't be read */

	if (bit_adap->getscl == NULL) {

	if (bit_adap->getsda == NULL)

		dev_warn(&adap->dev, "Not I2C compliant: can't read SDA\n");



	if (bit_adap->getscl == NULL)

		dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n");



	if (bit_adap->getsda == NULL || bit_adap->getscl == NULL)

		dev_warn(&adap->dev, "Bus may be unreliable\n");

	}



	return 0;

}