[PATCH v8 7/9] i2c: rtl9300: use scoped guard instead of explicit lock/unlock

Jonas Jelonek
2025-09-27T10:19:59Z

Use the scoped guard infrastructure which unlocks a mutex automatically
when the guard goes out of scope, instead of explicit lock and unlock.
This simplifies the code and control flow in rtl9300_i2c_smbus_xfer and
removes the need of using goto in error cases to unlock before
returning.

Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Tested-by: Chris Packham <chris.packham@alliedtelesis.co.nz> # On RTL9302C based board
Tested-by: Markus Stockhausen <markus.stockhausen@gmx.de>
---
drivers/i2c/busses/i2c-rtl9300.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rtl9300.c b/drivers/i2c/busses/i2c-rtl9300.c
index fb3ebbd46a18..c67463228604 100644
--- a/drivers/i2c/busses/i2c-rtl9300.c
+++ b/drivers/i2c/busses/i2c-rtl9300.c
@@ -72,6 +72,8 @@ struct rtl9300_i2c {
struct mutex lock;
};

+DEFINE_GUARD(rtl9300_i2c, struct rtl9300_i2c *, mutex_lock(&_T->lock), mutex_unlock(&_T->lock))
+
enum rtl9300_i2c_xfer_type {
RTL9300_I2C_XFER_BYTE,
RTL9300_I2C_XFER_WORD,
@@ -283,11 +285,11 @@ static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned s
if (addr > 0x7f)
return -EINVAL;

- mutex_lock(&i2c->lock);
+ guard(rtl9300_i2c)(i2c);

ret = rtl9300_i2c_config_chan(i2c, chan);
if (ret)
- goto out_unlock;
+ return ret;

xfer.dev_addr = addr & 0x7f;
xfer.write = (read_write == I2C_SMBUS_WRITE);
@@ -324,20 +326,14 @@ static int rtl9300_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, unsigned s
break;
default:
dev_err(&adap->dev, "Unsupported transaction %d\n", size);
- ret = -EOPNOTSUPP;
- goto out_unlock;
+ return -EOPNOTSUPP;
}

ret = rtl9300_i2c_prepare_xfer(i2c, &xfer);
if (ret)
- goto out_unlock;
-
- ret = rtl9300_i2c_do_xfer(i2c, &xfer);
-
-out_unlock:
- mutex_unlock(&i2c->lock);
+ return ret;

- return ret;
+ return rtl9300_i2c_do_xfer(i2c, &xfer);
}

static u32 rtl9300_i2c_func(struct i2c_adapter *a)
--
2.48.1