@@ -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;
}
This is in preparation of supporting write-only SDA in i2c-gpio. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> --- v3: - check for adap->getsda in readbytes() - align warning message level for info on missing getscl/getsda v4: - handle SDA and SCL independently - properly handle case that SDA is NULL but SCL not --- drivers/i2c/algos/i2c-algo-bit.c | 77 +++++++++++++++----------------- 1 file changed, 35 insertions(+), 42 deletions(-)