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>
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@ -52,6 +52,9 @@
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#define BCM2835_I2C_BITMSK_S 0x03FF
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#define BCM2835_I2C_CDIV_MIN 0x0002
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#define BCM2835_I2C_CDIV_MAX 0xFFFE
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#define BCM2835_I2C_TIMEOUT (msecs_to_jiffies(1000))
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struct bcm2835_i2c_dev {
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@ -261,6 +264,11 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
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*/
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if (divider & 1)
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divider++;
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if ((divider < BCM2835_I2C_CDIV_MIN) ||
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(divider > BCM2835_I2C_CDIV_MAX)) {
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dev_err(&pdev->dev, "Invalid clock-frequency\n");
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return -ENODEV;
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}
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bcm2835_i2c_writel(i2c_dev, BCM2835_I2C_DIV, divider);
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irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
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