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path: root/drivers/i2c/algos/i2c-algo-bit.c
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Diffstat (limited to 'drivers/i2c/algos/i2c-algo-bit.c')
-rw-r--r--drivers/i2c/algos/i2c-algo-bit.c128
1 files changed, 64 insertions, 64 deletions
diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index c33dcfb87993..6544d27e4419 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -1,21 +1,12 @@
-/* -------------------------------------------------------------------------
- * i2c-algo-bit.c i2c driver algorithms for bit-shift adapters
- * -------------------------------------------------------------------------
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * i2c-algo-bit.c: i2c driver algorithms for bit-shift adapters
+ *
* Copyright (C) 1995-2000 Simon G. Vogl
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- * ------------------------------------------------------------------------- */
-
-/* With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki
- <kmalkki@cc.hut.fi> and Jean Delvare <jdelvare@suse.de> */
+ *
+ * With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki
+ * <kmalkki@cc.hut.fi> and Jean Delvare <jdelvare@suse.de>
+ */
#include <linux/kernel.h>
#include <linux/module.h>
@@ -193,8 +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");
@@ -247,71 +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;
}
@@ -429,6 +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);
@@ -612,11 +592,26 @@ bailout:
return ret;
}
+/*
+ * We print a warning when we are not flagged to support atomic transfers but
+ * will try anyhow. That's what the I2C core would do as well. Sadly, we can't
+ * modify the algorithm struct at probe time because this struct is exported
+ * 'const'.
+ */
+static int bit_xfer_atomic(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[],
+ int num)
+{
+ struct i2c_algo_bit_data *adap = i2c_adap->algo_data;
+
+ if (!adap->can_do_atomic)
+ dev_warn(&i2c_adap->dev, "not flagged for atomic transfers\n");
+
+ return bit_xfer(i2c_adap, msgs, num);
+}
+
static u32 bit_func(struct i2c_adapter *adap)
{
- return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL |
- I2C_FUNC_SMBUS_READ_BLOCK_DATA |
- I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
+ return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL_ALL |
I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
}
@@ -624,8 +619,9 @@ static u32 bit_func(struct i2c_adapter *adap)
/* -----exported algorithm data: ------------------------------------- */
const struct i2c_algorithm i2c_bit_algo = {
- .master_xfer = bit_xfer,
- .functionality = bit_func,
+ .xfer = bit_xfer,
+ .xfer_atomic = bit_xfer_atomic,
+ .functionality = bit_func,
};
EXPORT_SYMBOL(i2c_bit_algo);
@@ -663,11 +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;
}
generated by cgit (git 2.34.1) at 2025-12-22 10:41:54 +0000