From: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
As no platform defines an interface clock the SCI driver always falls
back to a clock named "peripheral_clk".
- On SH platforms that clock is the base clock for the SCI functional
clock and has the same frequency,
- On ARM platforms that clock doesn't exist, and clk_get() will return
the default clock for the device.
We can thus make the functional clock mandatory and drop the interface
clock.
EPROBE_DEFER is handled for clocks that may be referenced from DT (i.e.
"fck" and deprecated "sci_ick").
Cc: devicetree@xxxxxxxxxxxxxxx
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
Acked-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
[geert: Handle EPROBE_DEFER, reformat description, break long comment line]
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
v2:
- Add Acked-by,
- Amendment by geert.
---
.../bindings/serial/renesas,sci-serial.txt | 4 +-
drivers/tty/serial/sh-sci.c | 64 ++++++++++++++--------
2 files changed, 43 insertions(+), 25 deletions(-)
diff --git a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
index 73f825e5e6448815..2c9e6b8477e92792 100644
--- a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
+++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
@@ -42,7 +42,7 @@ Required properties:
- clocks: Must contain a phandle and clock-specifier pair for each entry
in clock-names.
- - clock-names: Must contain "sci_ick" for the SCIx UART interface clock.
+ - clock-names: Must contain "fck" for the SCIx UART functional clock.
Note: Each enabled SCIx UART should have an alias correctly numbered in the
"aliases" node.
@@ -63,7 +63,7 @@ Example:
interrupt-parent = <&gic>;
interrupts = <0 144 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&mstp2_clks R8A7790_CLK_SCIFA0>;
- clock-names = "sci_ick";
+ clock-names = "fck";
dmas = <&dmac0 0x21>, <&dmac0 0x22>;
dma-names = "tx", "rx";
};
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 51c7507b0444957b..3c908804cab1c88c 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -92,8 +92,6 @@ struct sci_port {
struct timer_list break_timer;
int break_flag;
- /* Interface clock */
- struct clk *iclk;
/* Function clock */
struct clk *fclk;
@@ -457,9 +455,8 @@ static void sci_port_enable(struct sci_port *sci_port)
pm_runtime_get_sync(sci_port->port.dev);
- clk_prepare_enable(sci_port->iclk);
- sci_port->port.uartclk = clk_get_rate(sci_port->iclk);
clk_prepare_enable(sci_port->fclk);
+ sci_port->port.uartclk = clk_get_rate(sci_port->fclk);
}
static void sci_port_disable(struct sci_port *sci_port)
@@ -476,7 +473,6 @@ static void sci_port_disable(struct sci_port *sci_port)
sci_port->break_flag = 0;
clk_disable_unprepare(sci_port->fclk);
- clk_disable_unprepare(sci_port->iclk);
pm_runtime_put_sync(sci_port->port.dev);
}
@@ -1622,7 +1618,7 @@ static int sci_notifier(struct notifier_block *self,
struct uart_port *port = &sci_port->port;
spin_lock_irqsave(&port->lock, flags);
- port->uartclk = clk_get_rate(sci_port->iclk);
+ port->uartclk = clk_get_rate(sci_port->fclk);
spin_unlock_irqrestore(&port->lock, flags);
}
@@ -2241,6 +2237,42 @@ static struct uart_ops sci_uart_ops = {
#endif
};
+static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
+{
+ /* Get the SCI functional clock. It's called "fck" on ARM. */
+ sci_port->fclk = clk_get(dev, "fck");
+ if (PTR_ERR(sci_port->fclk) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ if (!IS_ERR(sci_port->fclk))
+ return 0;
+
+ /*
+ * But it used to be called "sci_ick", and we need to maintain DT
+ * backward compatibility.
+ */
+ sci_port->fclk = clk_get(dev, "sci_ick");
+ if (PTR_ERR(sci_port->fclk) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ if (!IS_ERR(sci_port->fclk))
+ return 0;
+
+ /* SH has historically named the clock "sci_fck". */
+ sci_port->fclk = clk_get(dev, "sci_fck");
+ if (!IS_ERR(sci_port->fclk))
+ return 0;
+
+ /*
+ * Not all SH platforms declare a clock lookup entry for SCI devices,
+ * in which case we need to get the global "peripheral_clk" clock.
+ */
+ sci_port->fclk = clk_get(dev, "peripheral_clk");
+ if (!IS_ERR(sci_port->fclk))
+ return 0;
+
+ dev_err(dev, "failed to get functional clock\n");
+ return PTR_ERR(sci_port->fclk);
+}
+
static int sci_init_single(struct platform_device *dev,
struct sci_port *sci_port, unsigned int index,
struct plat_sci_port *p, bool early)
@@ -2333,22 +2365,9 @@ static int sci_init_single(struct platform_device *dev,
sci_port->sampling_rate = p->sampling_rate;
if (!early) {
- sci_port->iclk = clk_get(&dev->dev, "sci_ick");
- if (IS_ERR(sci_port->iclk)) {
- sci_port->iclk = clk_get(&dev->dev, "peripheral_clk");
- if (IS_ERR(sci_port->iclk)) {
- dev_err(&dev->dev, "can't get iclk\n");
- return PTR_ERR(sci_port->iclk);
- }
- }
-
- /*
- * The function clock is optional, ignore it if we can't
- * find it.
- */
- sci_port->fclk = clk_get(&dev->dev, "sci_fck");
- if (IS_ERR(sci_port->fclk))
- sci_port->fclk = NULL;
+ ret = sci_init_clocks(sci_port, &dev->dev);
+ if (ret < 0)
+ return ret;
port->dev = &dev->dev;
@@ -2405,7 +2424,6 @@ static int sci_init_single(struct platform_device *dev,
static void sci_cleanup_single(struct sci_port *port)
{
- clk_put(port->iclk);
clk_put(port->fclk);
pm_runtime_disable(port->port.dev);
--
1.9.1
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