From 070ed82e32020dd9cc1ab3b5790b6b7d3f788e30 Mon Sep 17 00:00:00 2001
From: Sakari Ailus <sakari.ailus@linux.intel.com>
Date: Wed, 16 Aug 2017 03:28:16 -0400
Subject: [PATCH] media: et8ek8: Decrease stack usage
MIME-Version: 1.0
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The et8ek8 driver combines I²C register writes to a single array that it
passes to i2c_transfer(). The maximum number of writes is 48 at once,
decrease it to 8 and make more transfers if needed.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
---
drivers/media/i2c/et8ek8/et8ek8_driver.c | 26 ++++++++++++++++--------
1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/drivers/media/i2c/et8ek8/et8ek8_driver.c b/drivers/media/i2c/et8ek8/et8ek8_driver.c
index f39f5179dd95..c14f0fd6ded3 100644
--- a/drivers/media/i2c/et8ek8/et8ek8_driver.c
+++ b/drivers/media/i2c/et8ek8/et8ek8_driver.c
@@ -43,7 +43,7 @@
#define ET8EK8_NAME "et8ek8"
#define ET8EK8_PRIV_MEM_SIZE 128
-#define ET8EK8_MAX_MSG 48
+#define ET8EK8_MAX_MSG 8
struct et8ek8_sensor {
struct v4l2_subdev subdev;
@@ -220,7 +220,8 @@ static void et8ek8_i2c_create_msg(struct i2c_client *client, u16 len, u16 reg,
/*
* A buffered write method that puts the wanted register write
- * commands in a message list and passes the list to the i2c framework
+ * commands in smaller number of message lists and passes the lists to
+ * the i2c framework
*/
static int et8ek8_i2c_buffered_write_regs(struct i2c_client *client,
const struct et8ek8_reg *wnext,
@@ -231,11 +232,7 @@ static int et8ek8_i2c_buffered_write_regs(struct i2c_client *client,
int wcnt = 0;
u16 reg, data_length;
u32 val;
-
- if (WARN_ONCE(cnt > ET8EK8_MAX_MSG,
- ET8EK8_NAME ": %s: too many messages.\n", __func__)) {
- return -EINVAL;
- }
+ int rval;
/* Create new write messages for all writes */
while (wcnt < cnt) {
@@ -249,10 +246,21 @@ static int et8ek8_i2c_buffered_write_regs(struct i2c_client *client,
/* Update write count */
wcnt++;
+
+ if (wcnt < ET8EK8_MAX_MSG)
+ continue;
+
+ rval = i2c_transfer(client->adapter, msg, wcnt);
+ if (rval < 0)
+ return rval;
+
+ cnt -= wcnt;
+ wcnt = 0;
}
- /* Now we send everything ... */
- return i2c_transfer(client->adapter, msg, wcnt);
+ rval = i2c_transfer(client->adapter, msg, wcnt);
+
+ return rval < 0 ? rval : 0;
}
/*
--
2.30.9