[PATCH v4 5/8] i2c: i801: remove SMBNTFDDAT reads as they always seem to return 0
flat view
STALE3647d
From: Benjamin Tissoires <hidden>
Date: 2016-10-10 16:42:57
Also in:
linux-i2c, lkml
Subsystem:
i2c subsystem, i2c subsystem host drivers, i2c/smbus controller drivers for pc, the rest · Maintainers:
Andi Shyti, Jean Delvare, Linus Torvalds
Revision v4 of 5 in this series.
Revisions (5)
On the platform tested, reading SMBNTFDDAT always returns 0 (using 1 read of a word or 2 of 2 bytes). Given that we are not sure why and that we don't need to rely on the data parameter in the current users of Host Notify, remove this part of the code. If someone wants to re-enable it, just revert this commit and data should be available. Signed-off-by: Benjamin Tissoires <redacted> --- no changes in v4 no changes in v3 new in v2 --- drivers/i2c/busses/i2c-i801.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 88b2e31..42a6a89 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c@@ -117,7 +117,6 @@ #define SMBSLVSTS(p) (16 + (p)->smba) /* ICH3 and later */ #define SMBSLVCMD(p) (17 + (p)->smba) /* ICH3 and later */ #define SMBNTFDADD(p) (20 + (p)->smba) /* ICH3 and later */ -#define SMBNTFDDAT(p) (22 + (p)->smba) /* ICH3 and later */ /* PCI Address Constants */ #define SMBBAR 4
@@ -578,12 +577,15 @@ static void i801_isr_byte_done(struct i801_priv *priv) static irqreturn_t i801_host_notify_isr(struct i801_priv *priv) { unsigned short addr; - unsigned int data; addr = inb_p(SMBNTFDADD(priv)) >> 1; - data = inw_p(SMBNTFDDAT(priv)); - i2c_handle_smbus_host_notify(priv->host_notify, addr, data); + /* + * With the tested platforms, reading SMBNTFDDAT (22 + (p)->smba) + * always returns 0 and is safe to read. + * We just use 0 given we have no use of the data right now. + */ + i2c_handle_smbus_host_notify(priv->host_notify, addr, 0); /* clear Host Notify bit and return */ outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
--
2.7.4