[PATCH] mfd: tps6586x: avoid burst writes

[PATCH] mfd: tps6586x: avoid burst writes

[vwadekar-DDmLM1+adcrQT0dZR+AlfA]

tps6586 does not support burst writes. i2c writes have to be
1 byte at a time.

Signed-off-by: Varun Wadekar <vwadekar-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 drivers/mfd/tps6586x.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/mfd/tps6586x.c b/drivers/mfd/tps6586x.c
index c937742..0aa9186 100644
--- a/drivers/mfd/tps6586x.c
+++ b/drivers/mfd/tps6586x.c
@@ -150,12 +150,12 @@ static inline int __tps6586x_write(struct i2c_client *client,
 static inline int __tps6586x_writes(struct i2c_client *client, int reg,
 				  int len, uint8_t *val)
 {
-	int ret;
+	int ret, i;
 
-	ret = i2c_smbus_write_i2c_block_data(client, reg, len, val);
-	if (ret < 0) {
-		dev_err(&client->dev, "failed writings to 0x%02x\n", reg);
-		return ret;
+	for (i = 0; i < len; i++) {
+		ret = __tps6586x_write(client, reg + i, *(val + i));
+		if (ret < 0)
+			return ret;
 	}
 
 	return 0;
-- 
1.7.1

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Re: [PATCH] mfd: tps6586x: avoid burst writes

[Mark Brown]

On Tue, Feb 15, 2011 at 03:33:42PM +0530, vwadekar-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org wrote:
> tps6586 does not support burst writes. i2c writes have to be
> 1 byte at a time.

Don't know if there's ever block writes big enough to care but
presumably some of the devices in this series do support this so perhaps
the fallback to byte at a time should be conditional to avoid hurting
those that can use block writes?
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Re: [PATCH] mfd: tps6586x: avoid burst writes

[Varun Wadekar]

> Don't know if there's ever block writes big enough to care but
> presumably some of the devices in this series do support this so perhaps
> the fallback to byte at a time should be conditional to avoid hurting
> those that can use block writes?
Mark, confirmed with TI and they say that the entire tps6586x family has
this behavior so this patch seems ok. The entire family has this
limitation and so we have to write one byte at a time.
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Re: [PATCH] mfd: tps6586x: avoid burst writes

[Mark Brown]

On Fri, Feb 18, 2011 at 10:15:39AM +0530, Varun Wadekar wrote:

> Mark, confirmed with TI and they say that the entire tps6586x family has
> this behavior so this patch seems ok. The entire family has this
> limitation and so we have to write one byte at a time.

OK, that's good to have confirmed - in that case this should go into
2.6.38 as a bugfix since clearly any device which tries to do a bulk
operation is broken at the minute.
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