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authorMark Brown <broonie@opensource.wolfsonmicro.com>2011-03-18 00:40:51 +0300
committerSamuel Ortiz <sameo@linux.intel.com>2011-03-23 12:42:09 +0300
commit4c4d887822070410e3be519e1a4ff933fb899ba8 (patch)
tree0e7b58b1d53d42b745846c7456317c1e1e413da1 /drivers/mfd/wm831x-i2c.c
parentaad343107b4c153dd9f3ffc3d0f32558a25438e9 (diff)
downloadlinux-4c4d887822070410e3be519e1a4ff933fb899ba8.tar.xz
mfd: Remove copy from WM831x I2C write function
This saves us allocating an array on the stack, giving a meaningless performance improvement and ensuring that if drivers ever do large writes we'll not allocate large arrays on the stack. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Diffstat (limited to 'drivers/mfd/wm831x-i2c.c')
-rw-r--r--drivers/mfd/wm831x-i2c.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/drivers/mfd/wm831x-i2c.c b/drivers/mfd/wm831x-i2c.c
index 3853fa8e7cc2..a06cbc739716 100644
--- a/drivers/mfd/wm831x-i2c.c
+++ b/drivers/mfd/wm831x-i2c.c
@@ -51,17 +51,25 @@ static int wm831x_i2c_write_device(struct wm831x *wm831x, unsigned short reg,
int bytes, void *src)
{
struct i2c_client *i2c = wm831x->control_data;
- unsigned char msg[bytes + 2];
+ struct i2c_msg xfer[2];
int ret;
reg = cpu_to_be16(reg);
- memcpy(&msg[0], &reg, 2);
- memcpy(&msg[2], src, bytes);
- ret = i2c_master_send(i2c, msg, bytes + 2);
+ xfer[0].addr = i2c->addr;
+ xfer[0].flags = 0;
+ xfer[0].len = 2;
+ xfer[0].buf = (char *)&reg;
+
+ xfer[1].addr = i2c->addr;
+ xfer[1].flags = I2C_M_NOSTART;
+ xfer[1].len = bytes;
+ xfer[1].buf = (char *)src;
+
+ ret = i2c_transfer(i2c->adapter, xfer, 2);
if (ret < 0)
return ret;
- if (ret < bytes + 2)
+ if (ret != 2)
return -EIO;
return 0;