diff options
| -rw-r--r-- | Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt | 31 | ||||
| -rw-r--r-- | 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 f13f1c5be91c..095ac7172ffe 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 a1450ae6f9c1..c531fa42f838 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; }; @@ -359,10 +360,25 @@ 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; @@ -408,6 +424,9 @@ 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); @@ -445,6 +464,9 @@ 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; } @@ -452,6 +474,9 @@ 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); |
