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mfd: Use bulk read to fill WM8350 register cache

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Some I2C controllers have high overheads for setting up I2C operations
which makes the register cache setup on startup excessively slow since
it does a lot of small transactions. Reduce this overhead by doing a
bulk read of the entire register bank and filtering out what we don't
need later.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>
This commit is contained in:
Mark Brown 2009-02-04 22:43:55 +01:00 committed by Samuel Ortiz
parent 22e2df7d5f
commit 9dfd338198
1 changed files with 12 additions and 9 deletions
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21
drivers/mfd/wm8350-core.c
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@ -1238,7 +1238,7 @@ static int wm8350_create_cache(struct wm8350 *wm8350, int type, int mode)
}
wm8350->reg_cache =
kzalloc(sizeof(u16) * (WM8350_MAX_REGISTER + 1), GFP_KERNEL);
kmalloc(sizeof(u16) * (WM8350_MAX_REGISTER + 1), GFP_KERNEL);
if (wm8350->reg_cache == NULL)
return -ENOMEM;
@ -1246,17 +1246,20 @@ static int wm8350_create_cache(struct wm8350 *wm8350, int type, int mode)
* a PMIC so the device many not be in a virgin state and we
* can't rely on the silicon values.
*/
ret = wm8350->read_dev(wm8350, 0,
sizeof(u16) * (WM8350_MAX_REGISTER + 1),
wm8350->reg_cache);
if (ret < 0) {
dev_err(wm8350->dev,
"failed to read initial cache values\n");
goto out;
}
/* Mask out uncacheable/unreadable bits and the audio. */
for (i = 0; i < WM8350_MAX_REGISTER; i++) {
/* audio register range */
if (wm8350_reg_io_map[i].readable &&
(i < WM8350_CLOCK_CONTROL_1 || i > WM8350_AIF_TEST)) {
ret = wm8350->read_dev(wm8350, i, 2, (char *)&value);
if (ret < 0) {
dev_err(wm8350->dev,
"failed to read initial cache value\n");
goto out;
}
value = be16_to_cpu(value);
value = be16_to_cpu(wm8350->reg_cache[i]);
value &= wm8350_reg_io_map[i].readable;
value &= ~wm8350_reg_io_map[i].vol;
wm8350->reg_cache[i] = value;