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authorSilvan Wicki <linux_wi@tinag.ch>2015-06-18 11:10:11 +0200
committerWolfram Sang <wsa@the-dreams.de>2015-06-23 19:55:19 +0200
commita294aba164389a3d2c40dfcf5f3989a3bbfe38a2 (patch)
tree079f75628fa91e1e19807aece7509912cb512b14 /drivers/i2c
parent365322fb32e82b20758e8a18e3aa94692ce2a3d1 (diff)
downloadlinux-a294aba164389a3d2c40dfcf5f3989a3bbfe38a2.tar.bz2
i2c: busses: i2c-bcm2835: limits cdiv to allowed values
Checks if the cdiv value is in between min (0x2) and max (0xFFFE) supported values by the bcm2835. If not, it returns -ENODEV. See page 33/34 of BCM2835-ARM-Peripherals.pdf for the DIV register. https://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf Signed-off-by: Silvan Wicki <linux_wi@tinag.ch> [wsa: resolved a merge conflict] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-bcm2835.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index aa06da17e30e..3032b89ac60b 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -52,6 +52,9 @@
#define BCM2835_I2C_BITMSK_S 0x03FF
+#define BCM2835_I2C_CDIV_MIN 0x0002
+#define BCM2835_I2C_CDIV_MAX 0xFFFE
+
#define BCM2835_I2C_TIMEOUT (msecs_to_jiffies(1000))
struct bcm2835_i2c_dev {
@@ -261,6 +264,11 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
*/
if (divider & 1)
divider++;
+ if ((divider < BCM2835_I2C_CDIV_MIN) ||
+ (divider > BCM2835_I2C_CDIV_MAX)) {
+ dev_err(&pdev->dev, "Invalid clock-frequency\n");
+ return -ENODEV;
+ }
bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DIV, divider);
irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);