[PATCH 07/15] staging: wfx: introduce a way to poll IRQ

[Jerome Pouiller]

From: Jérôme Pouiller <jerome.pouil...@silabs.com>

It is possible to check if an IRQ is ending by polling the control
register. This function must used with care: if an IRQ fires while the
host reads control register, the IRQ can be lost. However, it could be
useful in some cases.

Signed-off-by: Jérôme Pouiller <jerome.pouil...@silabs.com>
---
 drivers/staging/wfx/bh.c | 28 ++++++++++++++++++++++++++++
 drivers/staging/wfx/bh.h |  1 +
 2 files changed, 29 insertions(+)

diff --git a/drivers/staging/wfx/bh.c b/drivers/staging/wfx/bh.c
index ba7fa0a7cd9a..d3e7eed89c38 100644
--- a/drivers/staging/wfx/bh.c
+++ b/drivers/staging/wfx/bh.c
@@ -307,6 +307,34 @@ void wfx_bh_request_tx(struct wfx_dev *wdev)
        queue_work(system_highpri_wq, &wdev->hif.bh);
 }
 
+/*
+ * If IRQ is not available, this function allow to manually poll the control
+ * register and simulate an IRQ ahen an event happened.
+ *
+ * Note that the device has a bug: If an IRQ raise while host read control
+ * register, the IRQ is lost. So, use this function carefully (only duing
+ * device initialisation).
+ */
+void wfx_bh_poll_irq(struct wfx_dev *wdev)
+{
+       ktime_t now, start;
+       u32 reg;
+
+       start = ktime_get();
+       for (;;) {
+               control_reg_read(wdev, &reg);
+               now = ktime_get();
+               if (reg & 0xFFF)
+                       break;
+               if (ktime_after(now, ktime_add_ms(start, 1000))) {
+                       dev_err(wdev->dev, "time out while polling control 
register\n");
+                       return;
+               }
+               udelay(200);
+       }
+       wfx_bh_request_rx(wdev);
+}
+
 void wfx_bh_register(struct wfx_dev *wdev)
 {
        INIT_WORK(&wdev->hif.bh, bh_work);
diff --git a/drivers/staging/wfx/bh.h b/drivers/staging/wfx/bh.h
index 93ca98424e0b..4b73437869e1 100644
--- a/drivers/staging/wfx/bh.h
+++ b/drivers/staging/wfx/bh.h
@@ -28,5 +28,6 @@ void wfx_bh_register(struct wfx_dev *wdev);
 void wfx_bh_unregister(struct wfx_dev *wdev);
 void wfx_bh_request_rx(struct wfx_dev *wdev);
 void wfx_bh_request_tx(struct wfx_dev *wdev);
+void wfx_bh_poll_irq(struct wfx_dev *wdev);
 
 #endif /* WFX_BH_H */
-- 
2.26.1

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