From mboxrd@z Thu Jan 1 00:00:00 1970 From: wens@csie.org (Chen-Yu Tsai) Date: Tue, 17 Jun 2014 22:52:38 +0800 Subject: [PATCH v2 01/20] serial: 8250_dw: Add optional reset control support In-Reply-To: <1403016777-15121-1-git-send-email-wens@csie.org> References: <1403016777-15121-1-git-send-email-wens@csie.org> Message-ID: <1403016777-15121-2-git-send-email-wens@csie.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- Documentation/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 f13f1c5..cb9af84 100644 --- a/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt +++ b/Documentation/devicetree/bindings/serial/snps-dw-apb-uart.txt @@ -7,6 +7,7 @@ Required properties: - clock-frequency : the input clock frequency for the UART. 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 51b307a..cb1b3dc 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 @@ -59,6 +60,7 @@ struct dw8250_data { int last_mcr; int line; struct clk *clk; + struct reset_control *rst; struct uart_8250_dma dma; }; @@ -408,6 +410,10 @@ static int dw8250_probe(struct platform_device *pdev) uart.port.uartclk = clk_get_rate(data->clk); } + 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; @@ -451,6 +457,9 @@ 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->clk)) clk_disable_unprepare(data->clk); -- 2.0.0