[PATCH v3 01/27] serial: sh-sci: Drop the interface clock

[PATCH v3 01/27] serial: sh-sci: Drop the interface clock

[Geert Uytterhoeven]

From: Laurent Pinchart <laurent.pinchart+renesas-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>

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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
Acked-by: Simon Horman <horms+renesas-/R6kz+dDXgpPR4JQBCEnsQ@public.gmane.org>
[geert: Handle EPROBE_DEFER, reformat description, break long comment line]
Signed-off-by: Geert Uytterhoeven <geert+renesas-gXvu3+zWzMSzQB+pC5nmwQ@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Acked-by: Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
---
v3:
  - Add Acked-by,

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 960e50a97558cff5..cc6fa55231ba3536 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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[PATCH v3 02/27] serial: sh-sci: Add fallback compatibility strings

[Geert Uytterhoeven]

Add fallback compatibility strings for R-Car Gen1, Gen2, and Gen3.
This is in keeping with the fallback scheme being adopted wherever
appropriate for drivers for Renesas SoCs.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: devicetree@vger.kernel.org
---
v3:
  - New.
---
 .../devicetree/bindings/serial/renesas,sci-serial.txt   | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
index 2c9e6b8477e92792..7091213f02513cda 100644
--- a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
+++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
@@ -2,7 +2,7 @@
 
 Required properties:
 
-  - compatible: Must contain one of the following:
+  - compatible: Must contain one or more of the following:
 
     - "renesas,scif-r7s72100" for R7S72100 (RZ/A1H) SCIF compatible UART.
     - "renesas,scifa-r8a73a4" for R8A73A4 (R-Mobile APE6) SCIFA compatible UART.
@@ -27,6 +27,14 @@ Required properties:
     - "renesas,hscif-r8a7795" for R8A7795 (R-Car H3) HSCIF compatible UART.
     - "renesas,scifa-sh73a0" for SH73A0 (SH-Mobile AG5) SCIFA compatible UART.
     - "renesas,scifb-sh73a0" for SH73A0 (SH-Mobile AG5) SCIFB compatible UART.
+    - "renesas,rcar-gen1-scif" for R-Car Gen1 SCIF compatible UART,
+    - "renesas,rcar-gen2-scif" for R-Car Gen2 SCIF compatible UART,
+    - "renesas,rcar-gen3-scif" for R-Car Gen3 SCIF compatible UART,
+    - "renesas,rcar-gen2-scifa" for R-Car Gen2 SCIFA compatible UART,
+    - "renesas,rcar-gen2-scifb" for R-Car Gen2 SCIFB compatible UART,
+    - "renesas,rcar-gen1-hscif" for R-Car Gen1 HSCIF compatible UART,
+    - "renesas,rcar-gen2-hscif" for R-Car Gen2 HSCIF compatible UART,
+    - "renesas,rcar-gen3-hscif" for R-Car Gen3 HSCIF compatible UART,
     - "renesas,scif" for generic SCIF compatible UART.
     - "renesas,scifa" for generic SCIFA compatible UART.
     - "renesas,scifb" for generic SCIFB compatible UART.
@@ -34,8 +42,8 @@ Required properties:
     - "renesas,sci" for generic SCI compatible UART.
 
     When compatible with the generic version, nodes must list the
-    SoC-specific version corresponding to the platform first followed by the
-    generic version.
+    SoC-specific version corresponding to the platform first, followed by the
+    family-specific and/or generic versions.
 
   - reg: Base address and length of the I/O registers used by the UART.
   - interrupts: Must contain an interrupt-specifier for the SCIx interrupt.
@@ -58,7 +66,8 @@ Example:
 	};
 
 	scifa0: serial@e6c40000 {
-		compatible = "renesas,scifa-r8a7790", "renesas,scifa";
+		compatible = "renesas,scifa-r8a7790",
+			     "renesas,rcar-gen2-scifa", "renesas,scifa";
 		reg = <0 0xe6c40000 0 64>;
 		interrupt-parent = <&gic>;
 		interrupts = <0 144 IRQ_TYPE_LEVEL_HIGH>;
-- 
1.9.1

[PATCH v3 03/27] serial: sh-sci: Update DT binding documentation for external clock input

[Geert Uytterhoeven]

Amend the DT bindings to include the optional external clock on
(H)SCI(F) and some SCIFA, where this pin can serve as a clock input,
depending on board wiring.

Clarify the use of the divided functional clock as a source for the
sampling clock.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: devicetree@vger.kernel.org
---
v3:
  - Add Acked-by,
  - Clarify the use of the divided functional clock.
---
 Documentation/devicetree/bindings/serial/renesas,sci-serial.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
index 7091213f02513cda..31cc0631ef7ca22d 100644
--- a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
+++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
@@ -51,6 +51,11 @@ Required properties:
   - clocks: Must contain a phandle and clock-specifier pair for each entry
     in clock-names.
   - clock-names: Must contain "fck" for the SCIx UART functional clock.
+    Apart from the divided functional clock, there may be other possible
+    sources for the sampling clock, depending on SCIx variant.
+    On (H)SCI(F) and some SCIFA, an additional clock may be specified:
+      - "hsck" for the optional external clock input (on HSCIF),
+      - "sck" for the optional external clock input (on other variants).
 
 Note: Each enabled SCIx UART should have an alias correctly numbered in the
 "aliases" node.
-- 
1.9.1

[PATCH v3 04/27] serial: sh-sci: Update DT binding documentation for BRG support

[Geert Uytterhoeven]

Amend the DT bindings to include the optional clock sources for the Baud
Rate Generator for External Clock (BRG), as found on some SCIF variants
and on HSCIF.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: devicetree@vger.kernel.org
---
v3:
  - Add Acked-by,
  - Rename "int_clk" to "brg_int".
---
 Documentation/devicetree/bindings/serial/renesas,sci-serial.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
index 31cc0631ef7ca22d..f4ad30ef1628f8da 100644
--- a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
+++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt
@@ -56,6 +56,12 @@ Required properties:
     On (H)SCI(F) and some SCIFA, an additional clock may be specified:
       - "hsck" for the optional external clock input (on HSCIF),
       - "sck" for the optional external clock input (on other variants).
+    On UARTs equipped with a Baud Rate Generator for External Clock (BRG)
+    (some SCIF and HSCIF), additional clocks may be specified:
+      - "brg_int" for the optional internal clock source for the frequency
+	divider (typically the (AXI or SHwy) bus clock),
+      - "scif_clk" for the optional external clock source for the frequency
+	divider (SCIF_CLK).
 
 Note: Each enabled SCIx UART should have an alias correctly numbered in the
 "aliases" node.
-- 
1.9.1

[PATCH v3 20/27] serial: sh-sci: Correct SCIF type on R-Car for BRG

[Geert Uytterhoeven]

The "renesas,scif" compatible value is currently used for the SCIF
variant in all Renesas SoCs of the R-Car family.  However, the variant
used in the R-Car family is not the common "SH-4(A)" variant, but a
derivative with added "Baud Rate Generator for External Clock" (BRG),
which is also present in sh7734.

Use the family-specific SCIF compatible values for R-Car Gen1, Gen2, and
Gen3 SoCs to differentiate.  The "renesas,scif" compatible value can
still be used as a common denominator for SCIF variants with the
"SH-4(A)" register layout (i.e. ignoring the "Serial Extension Mode
Register" (SCEMR) and the new BRG-specific registers).

Signed-off-by: Geert Uytterhoeven <geert+renesas-gXvu3+zWzMSzQB+pC5nmwQ@public.gmane.org>
Acked-by: Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
v3:
  - Add Acked-by,
  - Use family-specific instead of SoC-specific compatible values.
---
 drivers/tty/serial/sh-sci.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 5b8504bfd42e9906..a202e4e40b8adafb 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -2625,6 +2625,17 @@ static const struct of_device_id of_sci_match[] = {
 		.compatible = "renesas,scif-r7s72100",
 		.data = SCI_OF_DATA(PORT_SCIF, SCIx_SH2_SCIF_FIFODATA_REGTYPE),
 	},
+	/* Family-specific types */
+	{
+		.compatible = "renesas,rcar-gen1-scif",
+		.data = SCI_OF_DATA(PORT_SCIF, SCIx_SH4_SCIF_BRG_REGTYPE),
+	}, {
+		.compatible = "renesas,rcar-gen2-scif",
+		.data = SCI_OF_DATA(PORT_SCIF, SCIx_SH4_SCIF_BRG_REGTYPE),
+	}, {
+		.compatible = "renesas,rcar-gen3-scif",
+		.data = SCI_OF_DATA(PORT_SCIF, SCIx_SH4_SCIF_BRG_REGTYPE),
+	},
 	/* Generic types */
 	{
 		.compatible = "renesas,scif",
-- 
1.9.1

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Re: [PATCH v3 03/27] serial: sh-sci: Update DT binding documentation for external clock input

[Rob Herring]

On Mon, Dec 14, 2015 at 07:57:12PM +0100, Geert Uytterhoeven wrote:
> Amend the DT bindings to include the optional external clock on
> (H)SCI(F) and some SCIFA, where this pin can serve as a clock input,
> depending on board wiring.
> 
> Clarify the use of the divided functional clock as a source for the
> sampling clock.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: devicetree@vger.kernel.org
> ---
> v3:
>   - Add Acked-by,
>   - Clarify the use of the divided functional clock.
> ---
>  Documentation/devicetree/bindings/serial/renesas,sci-serial.txt | 5 +++++
>  1 file changed, 5 insertions(+)

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v3 02/27] serial: sh-sci: Add fallback compatibility strings

[Rob Herring]

On Mon, Dec 14, 2015 at 07:57:11PM +0100, Geert Uytterhoeven wrote:
> Add fallback compatibility strings for R-Car Gen1, Gen2, and Gen3.
> This is in keeping with the fallback scheme being adopted wherever
> appropriate for drivers for Renesas SoCs.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Cc: devicetree@vger.kernel.org
> ---
> v3:
>   - New.
> ---
>  .../devicetree/bindings/serial/renesas,sci-serial.txt   | 17 +++++++++++++----
>  1 file changed, 13 insertions(+), 4 deletions(-)

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH v3 04/27] serial: sh-sci: Update DT binding documentation for BRG support

[Rob Herring]

On Mon, Dec 14, 2015 at 07:57:13PM +0100, Geert Uytterhoeven wrote:
> Amend the DT bindings to include the optional clock sources for the Baud
> Rate Generator for External Clock (BRG), as found on some SCIF variants
> and on HSCIF.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: devicetree@vger.kernel.org
> ---
> v3:
>   - Add Acked-by,
>   - Rename "int_clk" to "brg_int".
> ---
>  Documentation/devicetree/bindings/serial/renesas,sci-serial.txt | 6 ++++++
>  1 file changed, 6 insertions(+)

Acked-by: Rob Herring <robh@kernel.org>