Commit a294aba1 authored by Silvan Wicki's avatar Silvan Wicki Committed by Wolfram Sang

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.pdfSigned-off-by: default avatarSilvan Wicki <linux_wi@tinag.ch>
[wsa: resolved a merge conflict]
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 365322fb
...@@ -52,6 +52,9 @@ ...@@ -52,6 +52,9 @@
#define BCM2835_I2C_BITMSK_S 0x03FF #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)) #define BCM2835_I2C_TIMEOUT (msecs_to_jiffies(1000))
struct bcm2835_i2c_dev { struct bcm2835_i2c_dev {
...@@ -261,6 +264,11 @@ static int bcm2835_i2c_probe(struct platform_device *pdev) ...@@ -261,6 +264,11 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
*/ */
if (divider & 1) if (divider & 1)
divider++; 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); bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DIV, divider);
irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
......
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