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Diffstat (limited to 'drivers/i2c/i2c-core-smbus.c')
-rw-r--r--drivers/i2c/i2c-core-smbus.c93
1 files changed, 55 insertions, 38 deletions
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index b34d2ff06931..71eb1ef56f0c 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -4,7 +4,7 @@
*
* This file contains the SMBus functions which are always included in the I2C
* core because they can be emulated via I2C. SMBus specific extensions
- * (e.g. smbalert) are handled in a seperate i2c-smbus module.
+ * (e.g. smbalert) are handled in a separate i2c-smbus module.
*
* All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
* SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
@@ -14,7 +14,9 @@
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/i2c-smbus.h>
+#include <linux/property.h>
#include <linux/slab.h>
+#include <linux/string_choices.h>
#include "i2c-core.h"
@@ -37,8 +39,15 @@ static u8 crc8(u16 data)
return (u8)(data >> 8);
}
-/* Incremental CRC8 over count bytes in the array pointed to by p */
-static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
+/**
+ * i2c_smbus_pec - Incremental CRC8 over the given input data array
+ * @crc: previous return crc8 value
+ * @p: pointer to data buffer.
+ * @count: number of bytes in data buffer.
+ *
+ * Incremental CRC8 over count bytes in the array pointed to by p
+ */
+u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
{
int i;
@@ -46,6 +55,7 @@ static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
crc = crc8((crc ^ p[i]) << 8);
return crc;
}
+EXPORT_SYMBOL(i2c_smbus_pec);
/* Assume a 7-bit address, which is reasonable for SMBus */
static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
@@ -113,7 +123,7 @@ EXPORT_SYMBOL(i2c_smbus_read_byte);
s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
{
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
- I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
+ I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
}
EXPORT_SYMBOL(i2c_smbus_write_byte);
@@ -323,8 +333,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
*/
unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
- int num = read_write == I2C_SMBUS_READ ? 2 : 1;
- int i;
+ int nmsgs = read_write == I2C_SMBUS_READ ? 2 : 1;
u8 partial_pec = 0;
int status;
struct i2c_msg msg[2] = {
@@ -340,6 +349,8 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
.buf = msgbuf1,
},
};
+ bool wants_pec = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
+ && size != I2C_SMBUS_I2C_BLOCK_DATA);
msgbuf0[0] = command;
switch (size) {
@@ -348,13 +359,13 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
/* Special case: The read/write field is used as data */
msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
I2C_M_RD : 0);
- num = 1;
+ nmsgs = 1;
break;
case I2C_SMBUS_BYTE:
if (read_write == I2C_SMBUS_READ) {
/* Special case: only a read! */
msg[0].flags = I2C_M_RD | flags;
- num = 1;
+ nmsgs = 1;
}
break;
case I2C_SMBUS_BYTE_DATA:
@@ -375,7 +386,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
}
break;
case I2C_SMBUS_PROC_CALL:
- num = 2; /* Special case */
+ nmsgs = 2; /* Special case */
read_write = I2C_SMBUS_READ;
msg[0].len = 3;
msg[1].len = 2;
@@ -398,12 +409,11 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
}
i2c_smbus_try_get_dmabuf(&msg[0], command);
- for (i = 1; i < msg[0].len; i++)
- msg[0].buf[i] = data->block[i - 1];
+ memcpy(msg[0].buf + 1, data->block, msg[0].len - 1);
}
break;
case I2C_SMBUS_BLOCK_PROC_CALL:
- num = 2; /* Another special case */
+ nmsgs = 2; /* Another special case */
read_write = I2C_SMBUS_READ;
if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
dev_err(&adapter->dev,
@@ -414,8 +424,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
msg[0].len = data->block[0] + 2;
i2c_smbus_try_get_dmabuf(&msg[0], command);
- for (i = 1; i < msg[0].len; i++)
- msg[0].buf[i] = data->block[i - 1];
+ memcpy(msg[0].buf + 1, data->block, msg[0].len - 1);
msg[1].flags |= I2C_M_RECV_LEN;
msg[1].len = 1; /* block length will be added by
@@ -425,7 +434,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
case I2C_SMBUS_I2C_BLOCK_DATA:
if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
dev_err(&adapter->dev, "Invalid block %s size %d\n",
- read_write == I2C_SMBUS_READ ? "read" : "write",
+ str_read_write(read_write == I2C_SMBUS_READ),
data->block[0]);
return -EINVAL;
}
@@ -437,8 +446,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
msg[0].len = data->block[0] + 1;
i2c_smbus_try_get_dmabuf(&msg[0], command);
- for (i = 1; i <= data->block[0]; i++)
- msg[0].buf[i] = data->block[i];
+ memcpy(msg[0].buf + 1, data->block + 1, data->block[0]);
}
break;
default:
@@ -446,33 +454,31 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
return -EOPNOTSUPP;
}
- i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
- && size != I2C_SMBUS_I2C_BLOCK_DATA);
- if (i) {
+ if (wants_pec) {
/* Compute PEC if first message is a write */
if (!(msg[0].flags & I2C_M_RD)) {
- if (num == 1) /* Write only */
+ if (nmsgs == 1) /* Write only */
i2c_smbus_add_pec(&msg[0]);
else /* Write followed by read */
partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
}
/* Ask for PEC if last message is a read */
- if (msg[num-1].flags & I2C_M_RD)
- msg[num-1].len++;
+ if (msg[nmsgs - 1].flags & I2C_M_RD)
+ msg[nmsgs - 1].len++;
}
- status = __i2c_transfer(adapter, msg, num);
+ status = __i2c_transfer(adapter, msg, nmsgs);
if (status < 0)
goto cleanup;
- if (status != num) {
+ if (status != nmsgs) {
status = -EIO;
goto cleanup;
}
status = 0;
/* Check PEC if last message is a read */
- if (i && (msg[num-1].flags & I2C_M_RD)) {
- status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
+ if (wants_pec && (msg[nmsgs - 1].flags & I2C_M_RD)) {
+ status = i2c_smbus_check_pec(partial_pec, &msg[nmsgs - 1]);
if (status < 0)
goto cleanup;
}
@@ -490,13 +496,18 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
data->word = msgbuf1[0] | (msgbuf1[1] << 8);
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
- for (i = 0; i < data->block[0]; i++)
- data->block[i + 1] = msg[1].buf[i];
+ memcpy(data->block + 1, msg[1].buf, data->block[0]);
break;
case I2C_SMBUS_BLOCK_DATA:
case I2C_SMBUS_BLOCK_PROC_CALL:
- for (i = 0; i < msg[1].buf[0] + 1; i++)
- data->block[i] = msg[1].buf[i];
+ if (msg[1].buf[0] > I2C_SMBUS_BLOCK_MAX) {
+ dev_err(&adapter->dev,
+ "Invalid block size returned: %d\n",
+ msg[1].buf[0]);
+ status = -EPROTO;
+ goto cleanup;
+ }
+ memcpy(data->block, msg[1].buf, msg[1].buf[0] + 1);
break;
}
@@ -692,19 +703,25 @@ struct i2c_client *i2c_new_smbus_alert_device(struct i2c_adapter *adapter,
}
EXPORT_SYMBOL_GPL(i2c_new_smbus_alert_device);
-#if IS_ENABLED(CONFIG_I2C_SMBUS) && IS_ENABLED(CONFIG_OF)
-int of_i2c_setup_smbus_alert(struct i2c_adapter *adapter)
+#if IS_ENABLED(CONFIG_I2C_SMBUS)
+int i2c_setup_smbus_alert(struct i2c_adapter *adapter)
{
+ struct device *parent = adapter->dev.parent;
int irq;
- irq = of_property_match_string(adapter->dev.of_node, "interrupt-names",
- "smbus_alert");
- if (irq == -EINVAL || irq == -ENODATA)
+ /* Adapter instantiated without parent, skip the SMBus alert setup */
+ if (!parent)
return 0;
- else if (irq < 0)
+
+ /* Report serious errors */
+ irq = device_property_match_string(parent, "interrupt-names", "smbus_alert");
+ if (irq < 0 && irq != -EINVAL && irq != -ENODATA)
return irq;
+ /* Skip setup when no irq was found */
+ if (irq < 0 && !device_property_present(parent, "smbalert-gpios"))
+ return 0;
+
return PTR_ERR_OR_ZERO(i2c_new_smbus_alert_device(adapter, NULL));
}
-EXPORT_SYMBOL_GPL(of_i2c_setup_smbus_alert);
#endif
generated by cgit (git 2.34.1) at 2025-12-25 14:04:01 +0000