serial: sh-sci: Drop the interface clock
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 the deprecated "sci_ick").
Cc: devicetree@vger.kernel.org
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
[geert: Handle EPROBE_DEFER, reformat description, break long comment line]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 960e50a..cc6fa55 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -92,8 +92,6 @@
struct timer_list break_timer;
int break_flag;
- /* Interface clock */
- struct clk *iclk;
/* Function clock */
struct clk *fclk;
@@ -457,9 +455,8 @@
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 @@
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 @@
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 @@
#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 @@
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 void sci_cleanup_single(struct sci_port *port)
{
- clk_put(port->iclk);
clk_put(port->fclk);
pm_runtime_disable(port->port.dev);