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 <[email protected]> --- PATCH v5: instead of falling back to a supported clock speed, return an error. 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 c9336a3..6411bfa 100644 --- a/drivers/i2c/busses/i2c-bcm2835.c +++ b/drivers/i2c/busses/i2c-bcm2835.c @@ -50,6 +50,9 @@ #define BCM2835_I2C_S_CLKT BIT(9) #define BCM2835_I2C_S_LEN BIT(10) /* Fake bit for SW error reporting */ +#define BCM2835_I2C_CDIV_MIN 0x0002 +#define BCM2835_I2C_CDIV_MAX 0xFFFE + #define BCM2835_I2C_TIMEOUT (msecs_to_jiffies(1000)) struct bcm2835_i2c_dev { @@ -258,6 +261,11 @@ 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); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
