From 7fe090bf48b522de8cd6fe85e2b3252ed74e74f8 Mon Sep 17 00:00:00 2001 From: Chen-Yu Tsai Date: Wed, 23 Jul 2014 23:33:06 +0800 Subject: [PATCH] serial: 8250_dw: Add optional reset control support The Allwinner A31 and A23 SoCs have a reset controller maintaining the UART in reset by default. This patch adds optional reset support to the driver. Signed-off-by: Chen-Yu Tsai Acked-by: Maxime Ripard Signed-off-by: Greg Kroah-Hartman --- .../devicetree/bindings/serial/snps-dw-apb-uart.txt | 1 + drivers/tty/serial/8250/8250_dw.c | 9 +++++++++ 2 files changed, 10 insertions(+) diff --git a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt index 095ac7172ffe..7f76214f728a 100644 --- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt +++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt @@ -15,6 +15,7 @@ The supplying peripheral clock can also be handled, needing a second property Required elements: "baudclk", "apb_pclk" Optional properties: +- resets : phandle to the parent reset controller. - reg-shift : quantity to shift the register offsets by. If this property is not present then the register offsets are not shifted. - reg-io-width : the size (in bytes) of the IO accesses that should be diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index affdcb192aed..501db2f58fd2 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include @@ -60,6 +61,7 @@ struct dw8250_data { int line; struct clk *clk; struct clk *pclk; + struct reset_control *rst; struct uart_8250_dma dma; }; @@ -383,6 +385,10 @@ static int dw8250_probe(struct platform_device *pdev) } } + data->rst = devm_reset_control_get_optional(&pdev->dev, NULL); + if (!IS_ERR(data->rst)) + reset_control_deassert(data->rst); + data->dma.rx_chan_id = -1; data->dma.tx_chan_id = -1; data->dma.rx_param = data; @@ -426,6 +432,9 @@ static int dw8250_remove(struct platform_device *pdev) serial8250_unregister_port(data->line); + if (!IS_ERR(data->rst)) + reset_control_assert(data->rst); + if (!IS_ERR(data->pclk)) clk_disable_unprepare(data->pclk);