From c8f1e5025ca2fa8e6e037451f3d271e66745a19b Mon Sep 17 00:00:00 2001
From: Philipp Zabel <philipp.zabel@gmail.com>
Date: Thu, 28 May 2009 21:00:03 +0200
Subject: [PATCH] regulator/max1586: fix V3 gain calculation integer overflow
On Thu, May 28, 2009 at 10:59 AM, Mark Brown <broonie@opensource.wolfsonmicro.com> wrote:
> On Thu, May 28, 2009 at 07:15:16AM +0200, Philipp Zabel wrote:
>> The V3 regulator can be configured with an external resistor
>> connected to the feedback pin (R24 in the data sheet) to
>> increase the voltage range.
>>
>> For example, hx4700 has R24 = 3.32 kOhm to achieve a maximum
>> V3 voltage of 1.55 V which is needed for 624 MHz CPU frequency.
>>
>> Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
>
> Looks good.
>
> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Thanks, but it turns out I hit a 32 bit integer overflow in
the gain calculation. I'd like to mend that with the following
patch. Now max_uV could be increased up to 4.294 V, enough to
charge LiPo cells.
Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
---
drivers/regulator/max1586.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/regulator/max1586.c b/drivers/regulator/max1586.c
index 92799f40c864f..2c082d3ef4846 100644
--- a/drivers/regulator/max1586.c
+++ b/drivers/regulator/max1586.c
@@ -40,8 +40,8 @@ struct max1586_data {
struct i2c_client *client;
/* min/max V3 voltage */
- int min_uV;
- int max_uV;
+ unsigned int min_uV;
+ unsigned int max_uV;
struct regulator_dev *rdev[0];
};
@@ -199,8 +199,8 @@ static int max1586_pmic_probe(struct i2c_client *client,
ret = -EINVAL;
goto out_unmap;
}
- max1586->min_uV = MAX1586_V3_MIN_UV * pdata->v3_gain / 1000000;
- max1586->max_uV = MAX1586_V3_MAX_UV * pdata->v3_gain / 1000000;
+ max1586->min_uV = MAX1586_V3_MIN_UV / 1000 * pdata->v3_gain / 1000;
+ max1586->max_uV = MAX1586_V3_MAX_UV / 1000 * pdata->v3_gain / 1000;
rdev = max1586->rdev;
for (i = 0; i < pdata->num_subdevs && i <= MAX1586_V6; i++) {
--
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