From a294aba164389a3d2c40dfcf5f3989a3bbfe38a2 Mon Sep 17 00:00:00 2001 From: Silvan Wicki Date: Thu, 18 Jun 2015 11:10:11 +0200 Subject: [PATCH] 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 [wsa: resolved a merge conflict] Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-bcm2835.c | 8 ++++++++ 1 file changed, 8 insertions(+) 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);