[PATCH v2 6/9] clk: clocking-wizard: add user clock monitor support

[Harry Austen <hpausten@xxxxxxxxxxxxxx>]

Xilinx clocking wizard IP core supports monitoring of up to four
optional user clock inputs, with a corresponding interrupt for
notification in change of clock state (stop, underrun, overrun or
glitch). Give access to this monitor logic through use of an auxiliary
device.

Use presence of the user monitor interrupt description in devicetree to
indicate whether or not the auxiliary device should be registered. Also,
this functionality is only supported from v6.0 onwards, so add
indication of support to the device match data, in order to be tied to
the utilised compatible string.

Signed-off-by: Harry Austen <hpausten@xxxxxxxxxxxxxx>
---
v1 -> v2:
- Remove direct UIO dependency by utilising auxiliary device
- Move some logic from probe into clk_wzrd_setup_monitor for tidiness

 drivers/clk/xilinx/Kconfig                 |  1 +
 drivers/clk/xilinx/clk-xlnx-clock-wizard.c | 60 ++++++++++++++++++++--
 2 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/xilinx/Kconfig b/drivers/clk/xilinx/Kconfig
index 051756953558b..87f507bd9b6f3 100644
--- a/drivers/clk/xilinx/Kconfig
+++ b/drivers/clk/xilinx/Kconfig
@@ -21,6 +21,7 @@ config COMMON_CLK_XLNX_CLKWZRD
 	tristate "Xilinx Clocking Wizard"
 	depends on OF
 	depends on HAS_IOMEM
+	select AUXILIARY_BUS
 	help
 	  Support for the Xilinx Clocking Wizard IP core clock generator.
 	  Adds support for clocking wizard and compatible.
diff --git a/drivers/clk/xilinx/clk-xlnx-clock-wizard.c b/drivers/clk/xilinx/clk-xlnx-clock-wizard.c
index 1f8023d24029f..557e11017faf9 100644
--- a/drivers/clk/xilinx/clk-xlnx-clock-wizard.c
+++ b/drivers/clk/xilinx/clk-xlnx-clock-wizard.c
@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/auxiliary_bus.h>
 #include <linux/bitfield.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>
@@ -129,6 +130,7 @@ enum clk_wzrd_int_clks {
  * @axi_clk:		Handle to input clock 's_axi_aclk'
  * @clks_internal:	Internal clocks
  * @speed_grade:	Speed grade of the device
+ * @adev:		User clock monitor auxiliary device
  * @suspended:		Flag indicating power state of the device
  */
 struct clk_wzrd {
@@ -139,6 +141,7 @@ struct clk_wzrd {
 	struct clk_hw *clks_internal[wzrd_clk_int_max];
 	unsigned int speed_grade;
 	bool suspended;
+	struct auxiliary_device adev;
 	struct clk_hw_onecell_data clk_data;
 };
 
@@ -171,8 +174,9 @@ struct clk_wzrd_divider {
 	spinlock_t *lock;  /* divider lock */
 };
 
-struct versal_clk_data {
+struct clk_wzrd_data {
 	bool is_versal;
+	bool supports_monitor;
 };
 
 #define to_clk_wzrd(_nb) container_of(_nb, struct clk_wzrd, nb)
@@ -958,16 +962,58 @@ static int __maybe_unused clk_wzrd_resume(struct device *dev)
 static SIMPLE_DEV_PM_OPS(clk_wzrd_dev_pm_ops, clk_wzrd_suspend,
 			 clk_wzrd_resume);
 
-static const struct versal_clk_data versal_data = {
-	.is_versal	= true,
+static const struct clk_wzrd_data version_6_0_data = {
+	.is_versal		= false,
+	.supports_monitor	= true,
 };
 
+static const struct clk_wzrd_data versal_data = {
+	.is_versal		= true,
+	.supports_monitor	= true,
+};
+
+static void clk_wzrd_unregister_adev(void *_adev)
+{
+	struct auxiliary_device *adev = _adev;
+
+	auxiliary_device_delete(adev);
+	auxiliary_device_uninit(adev);
+}
+
+static int clk_wzrd_setup_monitor(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct clk_wzrd_data *data = device_get_match_data(dev);
+	struct clk_wzrd *clk_wzrd = dev_get_drvdata(dev);
+	struct auxiliary_device *adev = &clk_wzrd->adev;
+	int ret;
+
+	if (!data || !data->supports_monitor)
+		return 0;
+
+	adev->name = "clk-mon";
+	adev->dev.parent = dev;
+	adev->dev.platform_data = (__force void *)clk_wzrd->base;
+
+	ret = auxiliary_device_init(adev);
+	if (ret)
+		return ret;
+
+	ret = auxiliary_device_add(adev);
+	if (ret) {
+		auxiliary_device_uninit(adev);
+		return ret;
+	}
+
+	return devm_add_action_or_reset(dev, clk_wzrd_unregister_adev, adev);
+}
+
 static int clk_wzrd_register_output_clocks(struct device *dev, int nr_outputs)
 {
 	const char *clkout_name, *clk_name, *clk_mul_name;
 	struct clk_wzrd *clk_wzrd = dev_get_drvdata(dev);
 	u32 regl, regh, edge, regld, reghd, edged, div;
-	const struct versal_clk_data *data;
+	const struct clk_wzrd_data *data;
 	unsigned long flags = 0;
 	bool is_versal = false;
 	void __iomem *ctrl_reg;
@@ -1170,6 +1216,10 @@ static int clk_wzrd_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	ret = clk_wzrd_setup_monitor(pdev);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "failed to setup monitor\n");
+
 	ret = clk_wzrd_register_output_clocks(&pdev->dev, nr_outputs);
 	if (ret)
 		return ret;
@@ -1204,7 +1254,7 @@ static const struct of_device_id clk_wzrd_ids[] = {
 	{ .compatible = "xlnx,versal-clk-wizard", .data = &versal_data },
 	{ .compatible = "xlnx,clocking-wizard"   },
 	{ .compatible = "xlnx,clocking-wizard-v5.2"   },
-	{ .compatible = "xlnx,clocking-wizard-v6.0"  },
+	{ .compatible = "xlnx,clocking-wizard-v6.0", .data = &version_6_0_data },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, clk_wzrd_ids);
-- 
2.46.0