Am Montag, 16. Juni 2014, 15:25:17 schrieb Heiko Stübner:
> First try to find the named clock variants then fall back to the already
> existing handling of a nameless declared baudclk.
>
> This also adds the missing documentation for this already existing variant.
>
> Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
any comments?
Thanks
Heiko
> ---
> .../bindings/serial/snps-dw-apb-uart.txt | 31
> ++++++++++++++++++++++ drivers/tty/serial/8250/8250_dw.c |
> 31 +++++++++++++++++++--- 2 files changed, 59 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt
> b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt index
> f13f1c5..3601399 100644
> --- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt
> +++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt
> @@ -4,7 +4,15 @@ Required properties:
> - compatible : "snps,dw-apb-uart"
> - reg : offset and length of the register set for the device.
> - interrupts : should contain uart interrupt.
> +
> +Clock handling:
> +The clock rate of the input clock needs to be supplied by one of
> - clock-frequency : the input clock frequency for the UART.
> +- clocks : phandle to the input clock
> +
> +The supplying peripheral clock can also be handled, needing a second
> property +- clock-names: tuple listing input clock names.
> + Required elements: "baudclk", "apb_pclk"
>
> Optional properties:
> - reg-shift : quantity to shift the register offsets by. If this property
> is @@ -23,3 +31,26 @@ Example:
> reg-shift = <2>;
> reg-io-width = <4>;
> };
> +
> +Example with one clock:
> +
> + uart@80230000 {
> + compatible = "snps,dw-apb-uart";
> + reg = <0x80230000 0x100>;
> + clocks = <&baudclk>;
> + interrupts = <10>;
> + reg-shift = <2>;
> + reg-io-width = <4>;
> + };
> +
> +Example with two clocks:
> +
> + uart@80230000 {
> + compatible = "snps,dw-apb-uart";
> + reg = <0x80230000 0x100>;
> + clocks = <&baudclk>, <&apb_pclk>;
> + clock-names = "baudclk", "apb_pclk";
> + interrupts = <10>;
> + reg-shift = <2>;
> + reg-io-width = <4>;
> + };
> diff --git a/drivers/tty/serial/8250/8250_dw.c
> b/drivers/tty/serial/8250/8250_dw.c index 51b307a..024cd58 100644
> --- a/drivers/tty/serial/8250/8250_dw.c
> +++ b/drivers/tty/serial/8250/8250_dw.c
> @@ -59,6 +59,7 @@ struct dw8250_data {
> int last_mcr;
> int line;
> struct clk *clk;
> + struct clk *pclk;
> struct uart_8250_dma dma;
> };
>
> @@ -402,10 +403,25 @@ static int dw8250_probe(struct platform_device *pdev)
> return -ENOMEM;
>
> data->usr_reg = DW_UART_USR;
> - data->clk = devm_clk_get(&pdev->dev, NULL);
> + data->clk = devm_clk_get(&pdev->dev, "baudclk");
> + if (IS_ERR(data->clk))
> + data->clk = devm_clk_get(&pdev->dev, NULL);
> if (!IS_ERR(data->clk)) {
> - clk_prepare_enable(data->clk);
> - uart.port.uartclk = clk_get_rate(data->clk);
> + err = clk_prepare_enable(data->clk);
> + if (err)
> + dev_warn(&pdev->dev, "could not enable optional baudclk: %d\n",
> + err);
> + else
> + uart.port.uartclk = clk_get_rate(data->clk);
> + }
> +
> + data->pclk = devm_clk_get(&pdev->dev, "apb_pclk");
> + if (!IS_ERR(data->pclk)) {
> + err = clk_prepare_enable(data->pclk);
> + if (err) {
> + dev_err(&pdev->dev, "could not enable apb_pclk\n");
> + return err;
> + }
> }
>
> data->dma.rx_chan_id = -1;
> @@ -451,6 +467,9 @@ static int dw8250_remove(struct platform_device *pdev)
>
> serial8250_unregister_port(data->line);
>
> + if (!IS_ERR(data->pclk))
> + clk_disable_unprepare(data->pclk);
> +
> if (!IS_ERR(data->clk))
> clk_disable_unprepare(data->clk);
>
> @@ -488,6 +507,9 @@ static int dw8250_runtime_suspend(struct device *dev)
> if (!IS_ERR(data->clk))
> clk_disable_unprepare(data->clk);
>
> + if (!IS_ERR(data->pclk))
> + clk_disable_unprepare(data->pclk);
> +
> return 0;
> }
>
> @@ -495,6 +517,9 @@ static int dw8250_runtime_resume(struct device *dev)
> {
> struct dw8250_data *data = dev_get_drvdata(dev);
>
> + if (!IS_ERR(data->pclk))
> + clk_prepare_enable(data->pclk);
> +
> if (!IS_ERR(data->clk))
> clk_prepare_enable(data->clk);
--
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