[PATCH 4/8] mfd: stm32-timers: add support for interrupts

[Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>]

There are two types of STM32 timers that may have:
- a global interrupt line
- 4 dedicated interrupt lines.
Those interrupts are optional as defined in the dt-bindings. Enforce checks
on either one, four or no interrupts are provided with their names.
Optionally get them here, to be used by child devices.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
---
 drivers/mfd/stm32-timers.c       | 46 ++++++++++++++++++++++++++++++++
 include/linux/mfd/stm32-timers.h | 11 ++++++++
 2 files changed, 57 insertions(+)

diff --git a/drivers/mfd/stm32-timers.c b/drivers/mfd/stm32-timers.c
index 44ed2fce0319..51fb97bdab9c 100644
--- a/drivers/mfd/stm32-timers.c
+++ b/drivers/mfd/stm32-timers.c
@@ -214,6 +214,48 @@ static void stm32_timers_dma_remove(struct device *dev,
 			dma_release_channel(ddata->dma.chans[i]);
 }
 
+static const char * const stm32_timers_irq_name[STM32_TIMERS_MAX_IRQS] = {
+	"brk", "up", "trg-com", "cc"
+};
+
+static int stm32_timers_irq_probe(struct platform_device *pdev,
+				  struct stm32_timers *ddata)
+{
+	int i, ret;
+
+	/*
+	 * STM32 Timer may have either:
+	 * - a unique global interrupt line
+	 * - four dedicated interrupt lines that may be handled separately.
+	 * Optionally get them here, to be used by child devices.
+	 */
+	ret = platform_get_irq_byname_optional(pdev, "global");
+	if (ret < 0 && ret != -ENXIO) {
+		return ret;
+	} else if (ret != -ENXIO) {
+		ddata->irq[STM32_TIMERS_IRQ_GLOBAL_BRK] = ret;
+		ddata->nr_irqs = 1;
+		return 0;
+	}
+
+	for (i = 0; i < STM32_TIMERS_MAX_IRQS; i++) {
+		ret = platform_get_irq_byname_optional(pdev, stm32_timers_irq_name[i]);
+		if (ret < 0 && ret != -ENXIO) {
+			return ret;
+		} else if (ret != -ENXIO) {
+			ddata->irq[i] = ret;
+			ddata->nr_irqs++;
+		}
+	}
+
+	if (ddata->nr_irqs && ddata->nr_irqs != STM32_TIMERS_MAX_IRQS) {
+		dev_err(&pdev->dev, "Invalid number of IRQs %d\n", ddata->nr_irqs);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int stm32_timers_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -245,6 +287,10 @@ static int stm32_timers_probe(struct platform_device *pdev)
 
 	stm32_timers_get_arr_size(ddata);
 
+	ret = stm32_timers_irq_probe(pdev, ddata);
+	if (ret)
+		return ret;
+
 	ret = stm32_timers_dma_probe(dev, ddata);
 	if (ret) {
 		stm32_timers_dma_remove(dev, ddata);
diff --git a/include/linux/mfd/stm32-timers.h b/include/linux/mfd/stm32-timers.h
index 1b94325febb3..ca35af30745f 100644
--- a/include/linux/mfd/stm32-timers.h
+++ b/include/linux/mfd/stm32-timers.h
@@ -102,6 +102,15 @@ enum stm32_timers_dmas {
 	STM32_TIMERS_MAX_DMAS,
 };
 
+/* STM32 Timer may have either a unique global interrupt or 4 interrupt lines */
+enum stm32_timers_irqs {
+	STM32_TIMERS_IRQ_GLOBAL_BRK, /* global or brk IRQ */
+	STM32_TIMERS_IRQ_UP,
+	STM32_TIMERS_IRQ_TRG_COM,
+	STM32_TIMERS_IRQ_CC,
+	STM32_TIMERS_MAX_IRQS,
+};
+
 /**
  * struct stm32_timers_dma - STM32 timer DMA handling.
  * @completion:		end of DMA transfer completion
@@ -123,6 +132,8 @@ struct stm32_timers {
 	struct regmap *regmap;
 	u32 max_arr;
 	struct stm32_timers_dma dma; /* Only to be used by the parent */
+	unsigned int nr_irqs;
+	int irq[STM32_TIMERS_MAX_IRQS];
 };
 
 #if IS_REACHABLE(CONFIG_MFD_STM32_TIMERS)
-- 
2.25.1