Messages in this thread | | | From | Peter Korsgaard <> | Subject | Re: [PATCH] i2c-ocores: add common clock support | Date | Thu, 22 Jan 2015 16:21:27 +0100 |
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>>>>> "Wolfram" == Wolfram Sang <wsa@the-dreams.de> writes:
>> @@ -320,9 +322,23 @@ static int ocores_i2c_of_probe(struct platform_device *pdev, >> } >> >> if (of_property_read_u32(np, "clock-frequency", &val)) { >> - dev_err(&pdev->dev, >> - "Missing required parameter 'clock-frequency'\n"); >> - return -ENODEV; >> + struct clk *clk = devm_clk_get(&pdev->dev, NULL); >> + >> + if (!IS_ERR(clk)) { >> + int ret = clk_prepare_enable(clk); >> + >> + if (ret) { >> + dev_err(&pdev->dev, >> + "clk_prepare_enable failed: %d\n", ret); >> + return ret; >> + } >> + i2c->clk = clk; >> + val = clk_get_rate(clk); >> + } else { >> + dev_err(&pdev->dev, >> + "Missing required parameter 'clock-frequency'\n"); >> + return -ENODEV; >> + }
> Either NAK or I don't understand the logic here :) If a dts does NOT > have the bus-speed set by 'clock-frequency', then we take the value of > the clock assigned to this platform_device?
> The usual thing to do when 'clock-frequency' is not set is to default to > 100kHz.
The confusion comes from the fact that the device tree bindings uses clock-frequency for the clock frequency of the IP core and NOT for the i2c bus frequency. This dates back to when the bindings where added (049bb69d82e5f7f356) :/
The driver is currently hardcoded to use a 100KHz i2c bus clock (see ocoores_init()).
-- Bye, Peter Korsgaard
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