From: Chen-Yu Tsai <wens@csie.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.cz>, Pawel Moll <pawel.moll@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
Rob Herring <robh+dt@kernel.org>
Cc: Chen-Yu Tsai <wens@csie.org>,
Maxime Ripard <maxime.ripard@free-electrons.com>,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v5 1/2] serial: 8250_dw: Add optional reset control support
Date: Wed, 23 Jul 2014 23:33:06 +0800 [thread overview]
Message-ID: <1406129587-24668-2-git-send-email-wens@csie.org> (raw)
In-Reply-To: <1406129587-24668-1-git-send-email-wens@csie.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 <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
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 095ac71..7f76214 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 affdcb1..501db2f 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -26,6 +26,7 @@
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/clk.h>
+#include <linux/reset.h>
#include <linux/pm_runtime.h>
#include <asm/byteorder.h>
@@ -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);
--
2.0.1
next prev parent reply other threads:[~2014-07-23 15:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-23 15:33 [PATCH v5 0/2] serial: 8250_dw: optional reset control and deferred probe support Chen-Yu Tsai
2014-07-23 15:33 ` Chen-Yu Tsai [this message]
2014-07-23 15:33 ` [PATCH v5 2/2] serial: 8250_dw: Add support for deferred probing Chen-Yu Tsai
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