[PATCH 0/2] clk: sunxi: Fix APBS clock for Allwinner A80

Hi everyone,

When I did the A80 PRCM support, I failed to notice the A80's APBS clock
was not the same as the A23's APB0 clock. The former is a zero-based
divider, while the latter is a power-of-two divider. But the lowest 2
dividers are the same.

The hardware defaults to the lowest setting, or a /1 divider. Since the
child gates do not propagate clk_set_rate up, and no consumers here do
clk_set_rate, this actually works.

I realized my mistake while reviewing the A83T's PRCM patches. The A83T
shares the same PRCM clocks as the A80.


Regards
ChenYu


Chen-Yu Tsai (2):
  clk: sunxi: Add support for A80 APBS clock
  ARM: dts: sun9i: Fix apbs clock compatible

 Documentation/devicetree/bindings/clock/sunxi.txt |  1 +
 arch/arm/boot/dts/sun9i-a80.dtsi                  |  2 +-
 drivers/clk/sunxi/Makefile                        |  2 +-
 drivers/clk/sunxi/clk-sun9i-apbs.c                | 64 +++++++++++++++++++++++
 4 files changed, 67 insertions(+), 2 deletions(-)
 create mode 100644 drivers/clk/sunxi/clk-sun9i-apbs.c

-- 
2.7.0

The APBS clock on A80 is not compatible with A23's APB0 clock. The only
reason it works is becase the lowest and default divider is the same.

Signed-off-by: Chen-Yu Tsai <redacted>
---
 arch/arm/boot/dts/sun9i-a80.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/sun9i-a80.dtsi b/arch/arm/boot/dts/sun9i-a80.dtsi
index f68b3242b33a..2b4ce813b0ad 100644
--- a/arch/arm/boot/dts/sun9i-a80.dtsi
+++ b/arch/arm/boot/dts/sun9i-a80.dtsi

@@ -395,7 +395,7 @@
 		};
 
 		apbs: clk at 0800141c {
-			compatible = "allwinner,sun8i-a23-apb0-clk";
+			compatible = "allwinner,sun9i-a80-apbs-clk";
 			reg = <0x0800141c 0x4>;
 			#clock-cells = <0>;
 			clocks = <&ahbs>;

-- 
2.7.0

A80's APBS clock is not the same as the APB0 clock on A23. The A80's
is a zero-based divider, while the A23's is a power-of-two divider.

Signed-off-by: Chen-Yu Tsai <redacted>
---
 Documentation/devicetree/bindings/clock/sunxi.txt |  1 +
 drivers/clk/sunxi/Makefile                        |  2 +-
 drivers/clk/sunxi/clk-sun9i-apbs.c                | 64 +++++++++++++++++++++++
 3 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/sunxi/clk-sun9i-apbs.c

diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
index e59f57b24777..fad81157798c 100644
--- a/Documentation/devicetree/bindings/clock/sunxi.txt
+++ b/Documentation/devicetree/bindings/clock/sunxi.txt

@@ -58,6 +58,7 @@ Required properties:
 	"allwinner,sun6i-a31-apb2-gates-clk" - for the APB2 gates on A31
 	"allwinner,sun8i-a23-apb2-gates-clk" - for the APB2 gates on A23
 	"allwinner,sun8i-h3-bus-gates-clk" - for the bus gates on H3
+	"allwinner,sun9i-a80-apbs-clk" - for the APBS clock on A80
 	"allwinner,sun9i-a80-apbs-gates-clk" - for the APBS gates on A80
 	"allwinner,sun4i-a10-dram-gates-clk" - for the DRAM gates on A10
 	"allwinner,sun5i-a13-mbus-clk" - for the MBUS clock on A13

diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
index 3fd7901d48e4..df433b3f789d 100644
--- a/drivers/clk/sunxi/Makefile
+++ b/drivers/clk/sunxi/Makefile

@@ -17,7 +17,7 @@ obj-y += clk-sun9i-core.o
 obj-y += clk-sun9i-mmc.o
 obj-y += clk-usb.o
 
-obj-$(CONFIG_MACH_SUN9I) += clk-sun8i-apb0.o
+obj-$(CONFIG_MACH_SUN9I) += clk-sun9i-apbs.o
 obj-$(CONFIG_MACH_SUN9I) += clk-sun9i-cpus.o
 
 obj-$(CONFIG_MFD_SUN6I_PRCM) += \

diff --git a/drivers/clk/sunxi/clk-sun9i-apbs.c b/drivers/clk/sunxi/clk-sun9i-apbs.c
new file mode 100644
index 000000000000..aacb92873621
--- /dev/null
+++ b/drivers/clk/sunxi/clk-sun9i-apbs.c

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2016 Chen-Yu Tsai
+ * Author: Chen-Yu Tsai <wens@csie.org>
+ *
+ * Allwinner A80 APBS clock driver
+ *
+ * License Terms: GNU General Public License v2
+ *
+ * Based on clk-sun6i-apbs.c
+ * Allwinner A31 APB0 clock driver
+ *
+ * Copyright (C) 2014 Free Electrons
+ * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
+ *
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+
+static void sun9i_apbs_setup(struct device_node *node)
+{
+	const char *name = node->name;
+	const char *parent;
+	struct resource res;
+	struct clk *clk;
+	void __iomem *reg;
+	int ret;
+
+	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
+	if (IS_ERR(reg)) {
+		pr_err("Could not get registers for a80-apbs-clk\n");
+		return;
+	}
+
+	parent = of_clk_get_parent_name(node, 0);
+	if (!parent)
+		return;
+
+	of_property_read_string(node, "clock-output-names", &name);
+
+	/* The A80 APBS clock is a standard 2 bit wide divider clock */
+	clk = clk_register_divider(NULL, name, parent, 0, reg, 0, 2, 0, NULL);
+	if (IS_ERR(clk)) {
+		pr_err("failed to register a80-apbs-clk: %ld\n", PTR_ERR(clk));
+		goto err_unmap;
+	}
+
+	ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
+	if (ret)
+		goto err_unregister;
+
+	return;
+
+err_unregister:
+	clk_unregister_divider(clk);
+err_unmap:
+	iounmap(reg);
+	of_address_to_resource(node, 0, &res);
+	release_mem_region(res.start, resource_size(&res));
+}
+CLK_OF_DECLARE(sun9i_apbs, "allwinner,sun9i-a80-apbs-clk", sun9i_apbs_setup);

-- 
2.7.0

On Mon, Feb 01, 2016 at 10:42:48PM +0800, Chen-Yu Tsai wrote:

A80's APBS clock is not the same as the APB0 clock on A23. The A80's
is a zero-based divider, while the A23's is a power-of-two divider.

Signed-off-by: Chen-Yu Tsai <redacted>
---
 Documentation/devicetree/bindings/clock/sunxi.txt |  1 +

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

 drivers/clk/sunxi/Makefile                        |  2 +-
 drivers/clk/sunxi/clk-sun9i-apbs.c                | 64 +++++++++++++++++++++++
 3 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/sunxi/clk-sun9i-apbs.c

Hi Chen-Yu

On Mon, Feb 01, 2016 at 10:42:48PM +0800, Chen-Yu Tsai wrote:

So it's just a different set of flags? Maybe we can simply reuse the
same driver.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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On Tue, Feb 2, 2016 at 7:15 PM, Maxime Ripard
[off-list ref] wrote:

Hi Chen-Yu

On Mon, Feb 01, 2016 at 10:42:48PM +0800, Chen-Yu Tsai wrote:

quoted

A80's APBS clock is not the same as the APB0 clock on A23. The A80's
is a zero-based divider, while the A23's is a power-of-two divider.

Signed-off-by: Chen-Yu Tsai <redacted>
---
 Documentation/devicetree/bindings/clock/sunxi.txt |  1 +
 drivers/clk/sunxi/Makefile                        |  2 +-
 drivers/clk/sunxi/clk-sun9i-apbs.c                | 64 +++++++++++++++++++++++
 3 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/sunxi/clk-sun9i-apbs.c

diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
index e59f57b24777..fad81157798c 100644
--- a/Documentation/devicetree/bindings/clock/sunxi.txt
+++ b/Documentation/devicetree/bindings/clock/sunxi.txt

@@ -58,6 +58,7 @@ Required properties:
      "allwinner,sun6i-a31-apb2-gates-clk" - for the APB2 gates on A31
      "allwinner,sun8i-a23-apb2-gates-clk" - for the APB2 gates on A23
      "allwinner,sun8i-h3-bus-gates-clk" - for the bus gates on H3
+     "allwinner,sun9i-a80-apbs-clk" - for the APBS clock on A80
      "allwinner,sun9i-a80-apbs-gates-clk" - for the APBS gates on A80
      "allwinner,sun4i-a10-dram-gates-clk" - for the DRAM gates on A10
      "allwinner,sun5i-a13-mbus-clk" - for the MBUS clock on A13

diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
index 3fd7901d48e4..df433b3f789d 100644
--- a/drivers/clk/sunxi/Makefile
+++ b/drivers/clk/sunxi/Makefile

@@ -17,7 +17,7 @@ obj-y += clk-sun9i-core.o
 obj-y += clk-sun9i-mmc.o
 obj-y += clk-usb.o

-obj-$(CONFIG_MACH_SUN9I) += clk-sun8i-apb0.o
+obj-$(CONFIG_MACH_SUN9I) += clk-sun9i-apbs.o
 obj-$(CONFIG_MACH_SUN9I) += clk-sun9i-cpus.o

 obj-$(CONFIG_MFD_SUN6I_PRCM) += \

diff --git a/drivers/clk/sunxi/clk-sun9i-apbs.c b/drivers/clk/sunxi/clk-sun9i-apbs.c
new file mode 100644
index 000000000000..aacb92873621
--- /dev/null
+++ b/drivers/clk/sunxi/clk-sun9i-apbs.c

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2016 Chen-Yu Tsai
+ * Author: Chen-Yu Tsai <wens@csie.org>
+ *
+ * Allwinner A80 APBS clock driver
+ *
+ * License Terms: GNU General Public License v2
+ *
+ * Based on clk-sun6i-apbs.c
+ * Allwinner A31 APB0 clock driver
+ *
+ * Copyright (C) 2014 Free Electrons
+ * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
+ *
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+
+static void sun9i_apbs_setup(struct device_node *node)
+{
+     const char *name = node->name;
+     const char *parent;
+     struct resource res;
+     struct clk *clk;
+     void __iomem *reg;
+     int ret;
+
+     reg = of_io_request_and_map(node, 0, of_node_full_name(node));
+     if (IS_ERR(reg)) {
+             pr_err("Could not get registers for a80-apbs-clk\n");
+             return;
+     }
+
+     parent = of_clk_get_parent_name(node, 0);
+     if (!parent)
+             return;
+
+     of_property_read_string(node, "clock-output-names", &name);
+
+     /* The A80 APBS clock is a standard 2 bit wide divider clock */
+     clk = clk_register_divider(NULL, name, parent, 0, reg, 0, 2, 0, NULL);
+     if (IS_ERR(clk)) {
+             pr_err("failed to register a80-apbs-clk: %ld\n", PTR_ERR(clk));
+             goto err_unmap;
+     }
+
+     ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
+     if (ret)
+             goto err_unregister;
+
+     return;
+
+err_unregister:
+     clk_unregister_divider(clk);
+err_unmap:
+     iounmap(reg);
+     of_address_to_resource(node, 0, &res);
+     release_mem_region(res.start, resource_size(&res));
+}
+CLK_OF_DECLARE(sun9i_apbs, "allwinner,sun9i-a80-apbs-clk", sun9i_apbs_setup);

So it's just a different set of flags? Maybe we can simply reuse the
same driver.

We could. I'll look into it.

ChenYu