[PATCH 0/2 v2] changed irq handling for at86rf230

[PATCH 0/2 v2] changed irq handling for at86rf230

[Sascha Herrmann]

Hi,

Based on the feedback to the previous patch set, this patch set
makes the irq handling configurable. The first patch add the
option to configure the irq type of the plattform and the device.
The second patch changes the irq handling when edge type interrupts
are configured.

Without irq configuration of the irq type, the driver will remain
backward compatible.

Thanks,

Sascha Herrmann (2):
  at86rf230: add irq type configuration option
  at86rf230: change irq handling to prevent lockups with edge type irq

 drivers/net/ieee802154/at86rf230.c |   95 +++++++++++++++++++++++++-----------
 include/linux/spi/at86rf230.h      |   14 ++++++
 2 files changed, 81 insertions(+), 28 deletions(-)

-- 
1.7.10.4

[PATCH 1/2 v2] at86rf230: add irq type configuration option

[Sascha Herrmann]

Add option to at86rf230 platform data to configure the type of the
interrupt used by the driver. The irq polarity of the device will
be configured accordingly.

Signed-off-by: Sascha Herrmann <sascha-2k69yqSu1NaELgA04lAiVw@public.gmane.org>
---
 drivers/net/ieee802154/at86rf230.c |   44 ++++++++++++++++++++++++------------
 include/linux/spi/at86rf230.h      |   14 ++++++++++++
 2 files changed, 44 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ieee802154/at86rf230.c b/drivers/net/ieee802154/at86rf230.c
index fc315dd..c69acb2 100644
--- a/drivers/net/ieee802154/at86rf230.c
+++ b/drivers/net/ieee802154/at86rf230.c
@@ -219,6 +219,9 @@ struct at86rf230_local {
 #define IRQ_PLL_UNL	(1 << 1)
 #define IRQ_PLL_LOCK	(1 << 0)
 
+#define IRQ_ACTIVE_HIGH	0
+#define IRQ_ACTIVE_LOW	1
+
 #define STATE_P_ON		0x00	/* BUSY */
 #define STATE_BUSY_RX		0x01
 #define STATE_BUSY_TX		0x02
@@ -726,11 +729,16 @@ static irqreturn_t at86rf230_isr(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static int at86rf230_irq_polarity(struct at86rf230_local *lp, int pol)
+{
+	return at86rf230_write_subreg(lp, SR_IRQ_POLARITY, pol);
+}
 
 static int at86rf230_hw_init(struct at86rf230_local *lp)
 {
 	u8 status;
-	int rc;
+	int rc, irq_pol;
+	struct at86rf230_platform_data *pdata = lp->spi->dev.platform_data;
 
 	rc = at86rf230_read_subreg(lp, SR_TRX_STATUS, &status);
 	if (rc)
@@ -748,6 +756,16 @@ static int at86rf230_hw_init(struct at86rf230_local *lp)
 		dev_info(&lp->spi->dev, "Status: %02x\n", status);
 	}
 
+	/* configure irq polarity, defaults to high active */
+	if (pdata->irq_type & (IRQF_TRIGGER_FALLING | IRQF_TRIGGER_LOW))
+		irq_pol = IRQ_ACTIVE_LOW;
+	else
+		irq_pol = IRQ_ACTIVE_HIGH;
+
+	rc = at86rf230_irq_polarity(lp, irq_pol);
+	if (rc)
+		return rc;
+
 	rc = at86rf230_write_subreg(lp, SR_IRQ_MASK, 0xff); /* IRQ_TRX_UR |
 							     * IRQ_CCA_ED |
 							     * IRQ_TRX_END |
@@ -798,27 +816,21 @@ static int at86rf230_hw_init(struct at86rf230_local *lp)
 	return 0;
 }
 
-static int at86rf230_fill_data(struct spi_device *spi)
+static void at86rf230_fill_data(struct spi_device *spi)
 {
 	struct at86rf230_local *lp = spi_get_drvdata(spi);
 	struct at86rf230_platform_data *pdata = spi->dev.platform_data;
 
-	if (!pdata) {
-		dev_err(&spi->dev, "no platform_data\n");
-		return -EINVAL;
-	}
-
 	lp->rstn = pdata->rstn;
 	lp->slp_tr = pdata->slp_tr;
 	lp->dig2 = pdata->dig2;
-
-	return 0;
 }
 
 static int at86rf230_probe(struct spi_device *spi)
 {
 	struct ieee802154_dev *dev;
 	struct at86rf230_local *lp;
+	struct at86rf230_platform_data *pdata;
 	u8 man_id_0, man_id_1;
 	int rc;
 	const char *chip;
@@ -829,6 +841,12 @@ static int at86rf230_probe(struct spi_device *spi)
 		return -EINVAL;
 	}
 
+	pdata = spi->dev.platform_data;
+	if (!pdata) {
+		dev_err(&spi->dev, "no platform_data\n");
+		return -EINVAL;
+	}
+
 	dev = ieee802154_alloc_device(sizeof(*lp), &at86rf230_ops);
 	if (!dev)
 		return -ENOMEM;
@@ -851,9 +869,7 @@ static int at86rf230_probe(struct spi_device *spi)
 
 	spi_set_drvdata(spi, lp);
 
-	rc = at86rf230_fill_data(spi);
-	if (rc)
-		goto err_fill;
+	at86rf230_fill_data(spi);
 
 	rc = gpio_request(lp->rstn, "rstn");
 	if (rc)
@@ -928,7 +944,8 @@ static int at86rf230_probe(struct spi_device *spi)
 	if (rc)
 		goto err_gpio_dir;
 
-	rc = request_irq(spi->irq, at86rf230_isr, IRQF_SHARED,
+	rc = request_irq(spi->irq, at86rf230_isr,
+			 IRQF_SHARED | pdata->irq_type,
 			 dev_name(&spi->dev), lp);
 	if (rc)
 		goto err_gpio_dir;
@@ -948,7 +965,6 @@ err_gpio_dir:
 err_slp_tr:
 	gpio_free(lp->rstn);
 err_rstn:
-err_fill:
 	spi_set_drvdata(spi, NULL);
 	mutex_destroy(&lp->bmux);
 	ieee802154_free_device(lp->dev);
diff --git a/include/linux/spi/at86rf230.h b/include/linux/spi/at86rf230.h
index b2b1afb..aa327a8 100644
--- a/include/linux/spi/at86rf230.h
+++ b/include/linux/spi/at86rf230.h
@@ -26,6 +26,20 @@ struct at86rf230_platform_data {
 	int rstn;
 	int slp_tr;
 	int dig2;
+
+	/* Setting the irq_type will configure the driver to request
+	 * the platform irq trigger type according to the given value
+	 * and configure the interrupt polarity of the device to the
+	 * corresponding polarity.
+	 *
+	 * Allowed values are: IRQF_TRIGGER_RISING, IRQF_TRIGGER_FALLING,
+	 *                     IRQF_TRIGGER_HIGH and IRQF_TRIGGER_LOW
+	 *
+	 * Setting it to 0, the driver does not touch the trigger type
+	 * configuration of the interrupt and sets the interrupt polarity
+	 * of the device to high active (the default value).
+	 */
+	int irq_type;
 };
 
 #endif
-- 
1.7.10.4


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[PATCH 2/2 v2] at86rf230: change irq handling to prevent lockups with edge type irq

[Sascha Herrmann]

Implemented separate irq handling for edge and level type interrupt
configuration. For edge type interrupts calls to disable_irq_nosync()
and enable_irq() are removed. The at86rf230 resets the irq line only
after the irq status register is read. Disabling the irq can lock the
driver in situations where a irq is set by the radio while the driver
is still reading the frame buffer.

With irq_type configuration set to 0 the original behavior is
preserverd.

Additional the irq filter register is set to filter out all unused
interrupts and the irq status register is read in the probe
function to clear the irq line.

Signed-off-by: Sascha Herrmann <sascha@ps.nvbi.de>
---
 drivers/net/ieee802154/at86rf230.c |   53 ++++++++++++++++++++++++++----------
 1 file changed, 38 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ieee802154/at86rf230.c b/drivers/net/ieee802154/at86rf230.c
index c69acb2..c6d0a03 100644
--- a/drivers/net/ieee802154/at86rf230.c
+++ b/drivers/net/ieee802154/at86rf230.c
@@ -51,7 +51,7 @@ struct at86rf230_local {
 	struct ieee802154_dev *dev;
 
 	spinlock_t lock;
-	bool irq_disabled;
+	bool irq_busy;
 	bool is_tx;
 };
 
@@ -547,7 +547,7 @@ at86rf230_xmit(struct ieee802154_dev *dev, struct sk_buff *skb)
 	unsigned long flags;
 
 	spin_lock(&lp->lock);
-	if  (lp->irq_disabled) {
+	if  (lp->irq_busy) {
 		spin_unlock(&lp->lock);
 		return -EBUSY;
 	}
@@ -708,8 +708,16 @@ static void at86rf230_irqwork(struct work_struct *work)
 	}
 
 	spin_lock_irqsave(&lp->lock, flags);
-	lp->irq_disabled = 0;
+	lp->irq_busy = 0;
 	spin_unlock_irqrestore(&lp->lock, flags);
+}
+
+static void at86rf230_irqwork_level(struct work_struct *work)
+{
+	struct at86rf230_local *lp =
+		container_of(work, struct at86rf230_local, irqwork);
+
+	at86rf230_irqwork(work);
 
 	enable_irq(lp->spi->irq);
 }
@@ -718,10 +726,8 @@ static irqreturn_t at86rf230_isr(int irq, void *data)
 {
 	struct at86rf230_local *lp = data;
 
-	disable_irq_nosync(irq);
-
 	spin_lock(&lp->lock);
-	lp->irq_disabled = 1;
+	lp->irq_busy = 1;
 	spin_unlock(&lp->lock);
 
 	schedule_work(&lp->irqwork);
@@ -729,6 +735,13 @@ static irqreturn_t at86rf230_isr(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t at86rf230_isr_level(int irq, void *data)
+{
+	disable_irq_nosync(irq);
+
+	return at86rf230_isr(irq, data);
+}
+
 static int at86rf230_irq_polarity(struct at86rf230_local *lp, int pol)
 {
 	return at86rf230_write_subreg(lp, SR_IRQ_POLARITY, pol);
@@ -766,12 +779,7 @@ static int at86rf230_hw_init(struct at86rf230_local *lp)
 	if (rc)
 		return rc;
 
-	rc = at86rf230_write_subreg(lp, SR_IRQ_MASK, 0xff); /* IRQ_TRX_UR |
-							     * IRQ_CCA_ED |
-							     * IRQ_TRX_END |
-							     * IRQ_PLL_UNL |
-							     * IRQ_PLL_LOCK
-							     */
+	rc = at86rf230_write_subreg(lp, SR_IRQ_MASK, IRQ_TRX_END);
 	if (rc)
 		return rc;
 
@@ -831,10 +839,12 @@ static int at86rf230_probe(struct spi_device *spi)
 	struct ieee802154_dev *dev;
 	struct at86rf230_local *lp;
 	struct at86rf230_platform_data *pdata;
-	u8 man_id_0, man_id_1;
+	u8 man_id_0, man_id_1, status;
 	int rc;
 	const char *chip;
 	int supported = 0;
+	work_func_t irq_worker;
+	irq_handler_t irq_handler;
 
 	if (!spi->irq) {
 		dev_err(&spi->dev, "no IRQ specified\n");
@@ -862,8 +872,16 @@ static int at86rf230_probe(struct spi_device *spi)
 	dev->phy->channels_supported[0] = 0x7FFF800;
 	dev->flags = IEEE802154_HW_OMIT_CKSUM;
 
+	if (pdata->irq_type & (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)) {
+		irq_worker = at86rf230_irqwork;
+		irq_handler = at86rf230_isr;
+	} else {
+		irq_worker = at86rf230_irqwork_level;
+		irq_handler = at86rf230_isr_level;
+	}
+
 	mutex_init(&lp->bmux);
-	INIT_WORK(&lp->irqwork, at86rf230_irqwork);
+	INIT_WORK(&lp->irqwork, irq_worker);
 	spin_lock_init(&lp->lock);
 	init_completion(&lp->tx_complete);
 
@@ -944,12 +962,17 @@ static int at86rf230_probe(struct spi_device *spi)
 	if (rc)
 		goto err_gpio_dir;
 
-	rc = request_irq(spi->irq, at86rf230_isr,
+	rc = request_irq(spi->irq, irq_handler,
 			 IRQF_SHARED | pdata->irq_type,
 			 dev_name(&spi->dev), lp);
 	if (rc)
 		goto err_gpio_dir;
 
+	/* Read irq status register to reset irq line */
+	rc = at86rf230_read_subreg(lp, RG_IRQ_STATUS, 0xff, 0, &status);
+	if (rc)
+		goto err_irq;
+
 	rc = ieee802154_register_device(lp->dev);
 	if (rc)
 		goto err_irq;
-- 
1.7.10.4

Re: [PATCH 1/2 v2] at86rf230: add irq type configuration option

[David Miller]

From: Sascha Herrmann <sascha@ps.nvbi.de>
Date: Fri, 12 Apr 2013 00:16:13 +0200

>  static int at86rf230_hw_init(struct at86rf230_local *lp)
>  {
>  	u8 status;
> -	int rc;
> +	int rc, irq_pol;
> +	struct at86rf230_platform_data *pdata = lp->spi->dev.platform_data;

Please order local variable declarations from longest line to
shortest line, not the other way around.

Thanks.