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Message-Id: <1448902496-21218-2-git-send-email-lars@metafoo.de>
Date: Mon, 30 Nov 2015 17:54:56 +0100
From: Lars-Peter Clausen <lars@...afoo.de>
To: Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...eaurora.org>
Cc: linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
Lars-Peter Clausen <lars@...afoo.de>
Subject: [PATCH 2/2] clk: axi-clkgen: Add multi-parent support
The clock generator has two clock inputs that can be used as the reference
clock. Add support for switching between them at runtime.
Signed-off-by: Lars-Peter Clausen <lars@...afoo.de>
---
.../devicetree/bindings/clock/axi-clkgen.txt | 5 ++-
drivers/clk/clk-axi-clkgen.c | 40 ++++++++++++++++++----
2 files changed, 38 insertions(+), 7 deletions(-)
diff --git a/Documentation/devicetree/bindings/clock/axi-clkgen.txt b/Documentation/devicetree/bindings/clock/axi-clkgen.txt
index 20e1704..fb40da3 100644
--- a/Documentation/devicetree/bindings/clock/axi-clkgen.txt
+++ b/Documentation/devicetree/bindings/clock/axi-clkgen.txt
@@ -8,7 +8,10 @@ Required properties:
- compatible : shall be "adi,axi-clkgen-1.00.a" or "adi,axi-clkgen-2.00.a".
- #clock-cells : from common clock binding; Should always be set to 0.
- reg : Address and length of the axi-clkgen register set.
-- clocks : Phandle and clock specifier for the parent clock.
+- clocks : Phandle and clock specifier for the parent clock(s). This must
+ either reference one clock if only the first clock input is connected or two
+ if both clock inputs are connected. For the later case the clock connected
+ to the first input must be specified first.
Optional properties:
- clock-output-names : From common clock binding.
diff --git a/drivers/clk/clk-axi-clkgen.c b/drivers/clk/clk-axi-clkgen.c
index 8dedc60..9a0744c 100644
--- a/drivers/clk/clk-axi-clkgen.c
+++ b/drivers/clk/clk-axi-clkgen.c
@@ -17,6 +17,7 @@
#include <linux/err.h>
#define AXI_CLKGEN_V2_REG_RESET 0x40
+#define AXI_CLKGEN_V2_REG_CLKSEL 0x44
#define AXI_CLKGEN_V2_REG_DRP_CNTRL 0x70
#define AXI_CLKGEN_V2_REG_DRP_STATUS 0x74
@@ -349,12 +350,33 @@ static void axi_clkgen_disable(struct clk_hw *clk_hw)
axi_clkgen_mmcm_enable(axi_clkgen, false);
}
+static int axi_clkgen_set_parent(struct clk_hw *clk_hw, u8 index)
+{
+ struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
+
+ axi_clkgen_write(axi_clkgen, AXI_CLKGEN_V2_REG_CLKSEL, index);
+
+ return 0;
+}
+
+static u8 axi_clkgen_get_parent(struct clk_hw *clk_hw)
+{
+ struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
+ unsigned int parent;
+
+ axi_clkgen_read(axi_clkgen, AXI_CLKGEN_V2_REG_CLKSEL, &parent);
+
+ return parent;
+}
+
static const struct clk_ops axi_clkgen_ops = {
.recalc_rate = axi_clkgen_recalc_rate,
.round_rate = axi_clkgen_round_rate,
.set_rate = axi_clkgen_set_rate,
.enable = axi_clkgen_enable,
.disable = axi_clkgen_disable,
+ .set_parent = axi_clkgen_set_parent,
+ .get_parent = axi_clkgen_get_parent,
};
static const struct of_device_id axi_clkgen_ids[] = {
@@ -370,10 +392,11 @@ static int axi_clkgen_probe(struct platform_device *pdev)
const struct of_device_id *id;
struct axi_clkgen *axi_clkgen;
struct clk_init_data init;
- const char *parent_name;
+ const char *parent_names[2];
const char *clk_name;
struct resource *mem;
struct clk *clk;
+ unsigned int i;
if (!pdev->dev.of_node)
return -ENODEV;
@@ -391,19 +414,24 @@ static int axi_clkgen_probe(struct platform_device *pdev)
if (IS_ERR(axi_clkgen->base))
return PTR_ERR(axi_clkgen->base);
- parent_name = of_clk_get_parent_name(pdev->dev.of_node, 0);
- if (!parent_name)
+ init.num_parents = of_clk_get_parent_count(pdev->dev.of_node);
+ if (init.num_parents < 1 || init.num_parents > 2)
return -EINVAL;
+ for (i = 0; i < init.num_parents; i++) {
+ parent_names[i] = of_clk_get_parent_name(pdev->dev.of_node, i);
+ if (!parent_names[i])
+ return -EINVAL;
+ }
+
clk_name = pdev->dev.of_node->name;
of_property_read_string(pdev->dev.of_node, "clock-output-names",
&clk_name);
init.name = clk_name;
init.ops = &axi_clkgen_ops;
- init.flags = CLK_SET_RATE_GATE;
- init.parent_names = &parent_name;
- init.num_parents = 1;
+ init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
+ init.parent_names = parent_names;
axi_clkgen_mmcm_enable(axi_clkgen, false);
--
2.1.4
--
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