[PATCH v2] serial: 8250_of: Add reset support

From: Joel Stanley
Date: Thu May 25 2017 - 21:55:47 EST


This adds the hooks for an optional reset controller in the 8250 device
tree node.

Signed-off-by: Joel Stanley <joel@xxxxxxxxx>

---
v2:
Address Philipp's comments. Thanks for the review!
- use _shared variant
- remove unnecessary error handling

Documentation/devicetree/bindings/serial/8250.txt | 1 +
drivers/tty/serial/8250/8250_of.c | 10 ++++++++++
2 files changed, 11 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
index 10276a46ecef..63e32393f82b 100644
--- a/Documentation/devicetree/bindings/serial/8250.txt
+++ b/Documentation/devicetree/bindings/serial/8250.txt
@@ -45,6 +45,7 @@ Optional properties:
property.
- tx-threshold: Specify the TX FIFO low water indication for parts with
programmable TX FIFO thresholds.
+- resets : phandle + reset specifier pairs

Note:
* fsl,ns16550:
diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
index 1cbadafc6889..e95cc9698c32 100644
--- a/drivers/tty/serial/8250/8250_of.c
+++ b/drivers/tty/serial/8250/8250_of.c
@@ -19,11 +19,13 @@
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/clk.h>
+#include <linux/reset.h>

#include "8250.h"

struct of_serial_info {
struct clk *clk;
+ struct reset_control *rst;
int type;
int line;
};
@@ -132,6 +134,13 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
}
}

+ info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
+ if (IS_ERR(info->rst))
+ goto out;
+ ret = reset_control_deassert(info->rst);
+ if (ret)
+ goto out;
+
port->type = type;
port->uartclk = clk;
port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
@@ -231,6 +240,7 @@ static int of_platform_serial_remove(struct platform_device *ofdev)

if (info->clk)
clk_disable_unprepare(info->clk);
+ reset_control_assert(info->rst);
kfree(info);
return 0;
}
--
2.11.0