[PATCH 05/15] staging: wfx: repair external IRQ for SDIO

[Jerome Pouiller]

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

When used over SDIO bus, device is able to use an external line to
signal IRQs (also called Out-Of-Band IRQ). The current code have several
problems:
  1. The ISR cannot directly acknowledge IRQ since access to the bus is
     not atomic. This patch use a threaded IRQ to solve that issue.
  2. On certain platforms, it is necessary to keep SDIO interruption
     enabled (with register SDIO_CCCR_IENx) (this part has inspired from
     the brcmfmac driver).

Signed-off-by: Jérôme Pouiller <jerome.pouil...@silabs.com>
---
 drivers/staging/wfx/bus_sdio.c | 38 ++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 13 deletions(-)

diff --git a/drivers/staging/wfx/bus_sdio.c b/drivers/staging/wfx/bus_sdio.c
index 9ac87178270f..2f782120e438 100644
--- a/drivers/staging/wfx/bus_sdio.c
+++ b/drivers/staging/wfx/bus_sdio.c
@@ -6,10 +6,12 @@
  * Copyright (c) 2010, ST-Ericsson
  */
 #include <linux/module.h>
+#include <linux/mmc/sdio.h>
 #include <linux/mmc/sdio_func.h>
 #include <linux/mmc/card.h>
 #include <linux/interrupt.h>
 #include <linux/of_irq.h>
+#include <linux/irq.h>
 
 #include "bus.h"
 #include "wfx.h"
@@ -106,31 +108,41 @@ static irqreturn_t wfx_sdio_irq_handler_ext(int irq, void 
*priv)
 
 static int wfx_sdio_irq_subscribe(struct wfx_sdio_priv *bus)
 {
+       u32 flags;
        int ret;
+       u8 cccr;
 
-       if (bus->of_irq) {
-               ret = request_irq(bus->of_irq, wfx_sdio_irq_handler_ext,
-                                 IRQF_TRIGGER_RISING, "wfx", bus);
-       } else {
+       if (!bus->of_irq) {
                sdio_claim_host(bus->func);
                ret = sdio_claim_irq(bus->func, wfx_sdio_irq_handler);
                sdio_release_host(bus->func);
+               return ret;
        }
-       return ret;
+
+       sdio_claim_host(bus->func);
+       cccr = sdio_f0_readb(bus->func, SDIO_CCCR_IENx, NULL);
+       cccr |= BIT(0);
+       cccr |= BIT(bus->func->num);
+       sdio_f0_writeb(bus->func, cccr, SDIO_CCCR_IENx, NULL);
+       sdio_release_host(bus->func);
+       flags = irq_get_trigger_type(bus->of_irq);
+       if (!flags)
+               flags = IRQF_TRIGGER_HIGH;
+       flags |= IRQF_ONESHOT;
+       return devm_request_threaded_irq(&bus->func->dev, bus->of_irq, NULL,
+                                        wfx_sdio_irq_handler_ext, flags,
+                                        "wfx", bus);
 }
 
 static int wfx_sdio_irq_unsubscribe(struct wfx_sdio_priv *bus)
 {
        int ret;
 
-       if (bus->of_irq) {
-               free_irq(bus->of_irq, bus);
-               ret = 0;
-       } else {
-               sdio_claim_host(bus->func);
-               ret = sdio_release_irq(bus->func);
-               sdio_release_host(bus->func);
-       }
+       if (bus->of_irq)
+               devm_free_irq(&bus->func->dev, bus->of_irq, bus);
+       sdio_claim_host(bus->func);
+       ret = sdio_release_irq(bus->func);
+       sdio_release_host(bus->func);
        return ret;
 }
 
-- 
2.26.1

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