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Subject[PATCH 05/15] staging: wfx: repair external IRQ for SDIO
Date
From: Jérôme Pouiller <jerome.pouiller@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.pouiller@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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