[PATCH v2 0/5] mfd: tqmx86: new hardware and GPIO/I2C IRQ improvements/additions

[PATCH v2 0/5] mfd: tqmx86: new hardware and GPIO/I2C IRQ improvements/additions

[Matthias Schiffer]

Patch 1 adds support for 3 new TQMx86 COMs. GPIO support on SMARC
modules is currently limited (not all GPIOs can be controlled, pins use
incorrect default directions, IRQ configuration is handled incorrectly),
however this is a preexisting issue also effecting the TQMxE39S and
TQMxE40S, not only the new TQMxE41S. This will be addressed by a future
patch series involving both the TQMx86 MFD and GPIO drivers.

Patches 2-5 improve module parameter description and error handling of
GPIO IRQ configuration and add support for configuring an IRQ for the
TQMx86's OpenCores I2C controller in the same way.

Changelog:

v2: improve module parameter description (new patch 2, adjusted patch 5)

Gregor Herburger (1):
  mfd: tqmx86: add I2C IRQ support

Matthias Schiffer (4):
  mfd: tqmx86: add board definitions for TQMx120UC, TQMx130UC and
    TQMxE41S
  mfd: tqmx86: improve gpio_irq module parameter description
  mfd: tqmx86: refactor GPIO IRQ setup
  mfd: tqmx86: make IRQ setup errors non-fatal

 drivers/mfd/tqmx86.c | 111 +++++++++++++++++++++++++++++++------------
 1 file changed, 80 insertions(+), 31 deletions(-)

-- 
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
https://www.tq-group.com/

[PATCH v2 1/5] mfd: tqmx86: add board definitions for TQMx120UC, TQMx130UC and TQMxE41S

[Matthias Schiffer]

This adds support for 3 new TQMx86 COMs:

- TQMx120UC/TQMx130UC: COM Express Compact Type 6 modules with 12th and
  13th Generation Intel Core CPUs ([1, 2])
- TQMxE41S: SMARC 2.1 module with Intel Atom x7000E and compatible CPUs [3]

[1] https://www.tq-group.com/en/products/tq-embedded/x86-architecture/tqmx120uc/
[2] https://www.tq-group.com/en/products/tq-embedded/x86-architecture/tqmx130uc/
[3] https://www.tq-group.com/en/products/tq-embedded/x86-architecture/tqmxe41s/

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---

v2: no changes

 drivers/mfd/tqmx86.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
index fac02875fe7d9..e15b9be98c2db 100644
--- a/drivers/mfd/tqmx86.c
+++ b/drivers/mfd/tqmx86.c
@@ -35,11 +35,14 @@
 #define TQMX86_REG_BOARD_ID_E39C2	7
 #define TQMX86_REG_BOARD_ID_70EB	8
 #define TQMX86_REG_BOARD_ID_80UC	9
+#define TQMX86_REG_BOARD_ID_120UC	10
 #define TQMX86_REG_BOARD_ID_110EB	11
 #define TQMX86_REG_BOARD_ID_E40M	12
 #define TQMX86_REG_BOARD_ID_E40S	13
 #define TQMX86_REG_BOARD_ID_E40C1	14
 #define TQMX86_REG_BOARD_ID_E40C2	15
+#define TQMX86_REG_BOARD_ID_130UC	16
+#define TQMX86_REG_BOARD_ID_E41S	19
 #define TQMX86_REG_BOARD_REV	0x01
 #define TQMX86_REG_IO_EXT_INT	0x06
 #define TQMX86_REG_IO_EXT_INT_NONE		0
@@ -132,6 +135,8 @@ static const char *tqmx86_board_id_to_name(u8 board_id, u8 sauc)
 		return "TQMx70EB";
 	case TQMX86_REG_BOARD_ID_80UC:
 		return "TQMx80UC";
+	case TQMX86_REG_BOARD_ID_120UC:
+		return "TQMx120UC";
 	case TQMX86_REG_BOARD_ID_110EB:
 		return "TQMx110EB";
 	case TQMX86_REG_BOARD_ID_E40M:
@@ -142,6 +147,10 @@ static const char *tqmx86_board_id_to_name(u8 board_id, u8 sauc)
 		return "TQMxE40C1";
 	case TQMX86_REG_BOARD_ID_E40C2:
 		return "TQMxE40C2";
+	case TQMX86_REG_BOARD_ID_130UC:
+		return "TQMx130UC";
+	case TQMX86_REG_BOARD_ID_E41S:
+		return "TQMxE41S";
 	default:
 		return "Unknown";
 	}
@@ -154,11 +163,14 @@ static int tqmx86_board_id_to_clk_rate(struct device *dev, u8 board_id)
 	case TQMX86_REG_BOARD_ID_60EB:
 	case TQMX86_REG_BOARD_ID_70EB:
 	case TQMX86_REG_BOARD_ID_80UC:
+	case TQMX86_REG_BOARD_ID_120UC:
 	case TQMX86_REG_BOARD_ID_110EB:
 	case TQMX86_REG_BOARD_ID_E40M:
 	case TQMX86_REG_BOARD_ID_E40S:
 	case TQMX86_REG_BOARD_ID_E40C1:
 	case TQMX86_REG_BOARD_ID_E40C2:
+	case TQMX86_REG_BOARD_ID_130UC:
+	case TQMX86_REG_BOARD_ID_E41S:
 		return 24000;
 	case TQMX86_REG_BOARD_ID_E39MS:
 	case TQMX86_REG_BOARD_ID_E39C1:
-- 
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
https://www.tq-group.com/

[PATCH v2 2/5] mfd: tqmx86: improve gpio_irq module parameter description

[Matthias Schiffer]

Clarify that "7, 9, 12" refers to the valid arguments that can be
passed as gpio_irq.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---

v2: new patch

 drivers/mfd/tqmx86.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
index e15b9be98c2db..7b2f9490a9af5 100644
--- a/drivers/mfd/tqmx86.c
+++ b/drivers/mfd/tqmx86.c
@@ -58,7 +58,7 @@
 
 static uint gpio_irq;
 module_param(gpio_irq, uint, 0);
-MODULE_PARM_DESC(gpio_irq, "GPIO IRQ number (7, 9, 12)");
+MODULE_PARM_DESC(gpio_irq, "GPIO IRQ number (valid parameters: 7, 9, 12)");
 
 static const struct resource tqmx_i2c_soft_resources[] = {
 	DEFINE_RES_IO(TQMX86_IOBASE_I2C, TQMX86_IOSIZE_I2C),
-- 
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
https://www.tq-group.com/

[PATCH v2 3/5] mfd: tqmx86: refactor GPIO IRQ setup

[Matthias Schiffer]

Move IRQ setup into a helper function. The string "GPIO" for error
messages is replaced with a label argument to prepare for reusing the
function for the I2C IRQ.

No functional change intended.

Co-developed-by: Gregor Herburger <gregor.herburger@tq-group.com>
Signed-off-by: Gregor Herburger <gregor.herburger@tq-group.com>
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---

v2: no changes (was patch 2/4)

 drivers/mfd/tqmx86.c | 72 +++++++++++++++++++++++++++-----------------
 1 file changed, 45 insertions(+), 27 deletions(-)

diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
index 7b2f9490a9af5..5aa51ead00a28 100644
--- a/drivers/mfd/tqmx86.c
+++ b/drivers/mfd/tqmx86.c
@@ -186,32 +186,54 @@ static int tqmx86_board_id_to_clk_rate(struct device *dev, u8 board_id)
 	}
 }
 
-static int tqmx86_probe(struct platform_device *pdev)
+static int tqmx86_irq_to_irq_cfg(struct device *dev, const char *label, u8 irq)
 {
-	u8 board_id, sauc, rev, i2c_det, io_ext_int_val;
-	struct device *dev = &pdev->dev;
-	u8 gpio_irq_cfg, readback;
-	const char *board_name;
-	void __iomem *io_base;
-	int err;
-
-	switch (gpio_irq) {
+	switch (irq) {
 	case 0:
-		gpio_irq_cfg = TQMX86_REG_IO_EXT_INT_NONE;
-		break;
+		return TQMX86_REG_IO_EXT_INT_NONE;
 	case 7:
-		gpio_irq_cfg = TQMX86_REG_IO_EXT_INT_7;
-		break;
+		return TQMX86_REG_IO_EXT_INT_7;
 	case 9:
-		gpio_irq_cfg = TQMX86_REG_IO_EXT_INT_9;
-		break;
+		return TQMX86_REG_IO_EXT_INT_9;
 	case 12:
-		gpio_irq_cfg = TQMX86_REG_IO_EXT_INT_12;
-		break;
+		return TQMX86_REG_IO_EXT_INT_12;
 	default:
-		pr_err("tqmx86: Invalid GPIO IRQ (%d)\n", gpio_irq);
+		dev_err(dev, "invalid %s IRQ (%d)\n", label, irq);
 		return -EINVAL;
 	}
+}
+
+static int tqmx86_setup_irq(struct device *dev, const char *label, u8 irq,
+			    void __iomem *io_base, u8 reg_shift)
+{
+	u8 val, readback;
+	int irq_cfg;
+
+	irq_cfg = tqmx86_irq_to_irq_cfg(dev, label, irq);
+	if (irq_cfg < 0)
+		return irq_cfg;
+
+	val = ioread8(io_base + TQMX86_REG_IO_EXT_INT);
+	val &= ~(TQMX86_REG_IO_EXT_INT_MASK << reg_shift);
+	val |= (irq_cfg & TQMX86_REG_IO_EXT_INT_MASK) << reg_shift;
+
+	iowrite8(val, io_base + TQMX86_REG_IO_EXT_INT);
+	readback = ioread8(io_base + TQMX86_REG_IO_EXT_INT);
+	if (readback != val) {
+		dev_warn(dev, "%s interrupts not supported\n", label);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int tqmx86_probe(struct platform_device *pdev)
+{
+	u8 board_id, sauc, rev, i2c_det;
+	struct device *dev = &pdev->dev;
+	const char *board_name;
+	void __iomem *io_base;
+	int err;
 
 	io_base = devm_ioport_map(dev, TQMX86_IOBASE, TQMX86_IOSIZE);
 	if (!io_base)
@@ -233,15 +255,11 @@ static int tqmx86_probe(struct platform_device *pdev)
 	 */
 	i2c_det = inb(TQMX86_REG_I2C_DETECT);
 
-	if (gpio_irq_cfg) {
-		io_ext_int_val =
-			gpio_irq_cfg << TQMX86_REG_IO_EXT_INT_GPIO_SHIFT;
-		iowrite8(io_ext_int_val, io_base + TQMX86_REG_IO_EXT_INT);
-		readback = ioread8(io_base + TQMX86_REG_IO_EXT_INT);
-		if (readback != io_ext_int_val) {
-			dev_warn(dev, "GPIO interrupts not supported.\n");
-			return -EINVAL;
-		}
+	if (gpio_irq) {
+		err = tqmx86_setup_irq(dev, "GPIO", gpio_irq, io_base,
+				       TQMX86_REG_IO_EXT_INT_GPIO_SHIFT);
+		if (err)
+			return err;
 
 		/* Assumes the IRQ resource is first. */
 		tqmx_gpio_resources[0].start = gpio_irq;
-- 
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
https://www.tq-group.com/

[PATCH v2 4/5] mfd: tqmx86: make IRQ setup errors non-fatal

[Matthias Schiffer]

GPIO IRQ setup can fail either because an invalid IRQ was passed as a
parameter, or because the GPIO controller does not support interrupts.
Neither is severe enough to stop the whole probe; simply disable IRQ
support in the GPIO resource when setup fails.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---

v2: no changes (was patch 3/4)

 drivers/mfd/tqmx86.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
index 5aa51ead00a28..7f9ccd83278dd 100644
--- a/drivers/mfd/tqmx86.c
+++ b/drivers/mfd/tqmx86.c
@@ -259,13 +259,14 @@ static int tqmx86_probe(struct platform_device *pdev)
 		err = tqmx86_setup_irq(dev, "GPIO", gpio_irq, io_base,
 				       TQMX86_REG_IO_EXT_INT_GPIO_SHIFT);
 		if (err)
-			return err;
+			gpio_irq = 0;
+	}
 
+	if (gpio_irq)
 		/* Assumes the IRQ resource is first. */
 		tqmx_gpio_resources[0].start = gpio_irq;
-	} else {
+	else
 		tqmx_gpio_resources[0].flags = 0;
-	}
 
 	ocores_platform_data.clock_khz = tqmx86_board_id_to_clk_rate(dev, board_id);
 
-- 
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
https://www.tq-group.com/

[PATCH v2 5/5] mfd: tqmx86: add I2C IRQ support

[Matthias Schiffer]

From: Gregor Herburger <gregor.herburger@tq-group.com>

The i2c-ocores controller can run in interrupt mode on tqmx86 modules.
Add module parameter to allow configuring the IRQ number, similar to the
handling of the GPIO IRQ.

Signed-off-by: Gregor Herburger <gregor.herburger@tq-group.com>
Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---

v2: improve module parameter description (was patch 4/4)

 drivers/mfd/tqmx86.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
index 7f9ccd83278dd..dcd5fa3e18c50 100644
--- a/drivers/mfd/tqmx86.c
+++ b/drivers/mfd/tqmx86.c
@@ -50,6 +50,7 @@
 #define TQMX86_REG_IO_EXT_INT_9			2
 #define TQMX86_REG_IO_EXT_INT_12		3
 #define TQMX86_REG_IO_EXT_INT_MASK		0x3
+#define TQMX86_REG_IO_EXT_INT_I2C_SHIFT		0
 #define TQMX86_REG_IO_EXT_INT_GPIO_SHIFT	4
 #define TQMX86_REG_SAUC		0x17
 
@@ -60,7 +61,12 @@ static uint gpio_irq;
 module_param(gpio_irq, uint, 0);
 MODULE_PARM_DESC(gpio_irq, "GPIO IRQ number (valid parameters: 7, 9, 12)");
 
-static const struct resource tqmx_i2c_soft_resources[] = {
+static uint i2c_irq;
+module_param(i2c_irq, uint, 0);
+MODULE_PARM_DESC(i2c_irq, "I2C IRQ number (valid parameters: 7, 9, 12)");
+
+static struct resource tqmx_i2c_soft_resources[] = {
+	DEFINE_RES_IRQ(0),
 	DEFINE_RES_IO(TQMX86_IOBASE_I2C, TQMX86_IOSIZE_I2C),
 };
 
@@ -271,6 +277,18 @@ static int tqmx86_probe(struct platform_device *pdev)
 	ocores_platform_data.clock_khz = tqmx86_board_id_to_clk_rate(dev, board_id);
 
 	if (i2c_det == TQMX86_REG_I2C_DETECT_SOFT) {
+		if (i2c_irq) {
+			err = tqmx86_setup_irq(dev, "I2C", i2c_irq, io_base,
+					       TQMX86_REG_IO_EXT_INT_I2C_SHIFT);
+			if (err)
+				i2c_irq = 0;
+		}
+
+		if (i2c_irq)
+			tqmx_i2c_soft_resources[0].start = i2c_irq;
+		else
+			tqmx_i2c_soft_resources[0].flags = 0;
+
 		err = devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
 					   tqmx86_i2c_soft_dev,
 					   ARRAY_SIZE(tqmx86_i2c_soft_dev),
-- 
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
https://www.tq-group.com/

Re: [PATCH v2 4/5] mfd: tqmx86: make IRQ setup errors non-fatal

[Lee Jones]

On Mon, 17 Jun 2024, Matthias Schiffer wrote:

> GPIO IRQ setup can fail either because an invalid IRQ was passed as a
> parameter, or because the GPIO controller does not support interrupts.
> Neither is severe enough to stop the whole probe; simply disable IRQ
> support in the GPIO resource when setup fails.
> 
> Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> ---
> 
> v2: no changes (was patch 3/4)
> 
>  drivers/mfd/tqmx86.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
> index 5aa51ead00a28..7f9ccd83278dd 100644
> --- a/drivers/mfd/tqmx86.c
> +++ b/drivers/mfd/tqmx86.c
> @@ -259,13 +259,14 @@ static int tqmx86_probe(struct platform_device *pdev)
>  		err = tqmx86_setup_irq(dev, "GPIO", gpio_irq, io_base,
>  				       TQMX86_REG_IO_EXT_INT_GPIO_SHIFT);
>  		if (err)
> -			return err;
> +			gpio_irq = 0;
> +	}
>  
> +	if (gpio_irq)

Stacking identical if()s one after another doesn't sound very efficient.

Why not put the contents of this one inside the one above?

>  		/* Assumes the IRQ resource is first. */
>  		tqmx_gpio_resources[0].start = gpio_irq;
> -	} else {
> +	else
>  		tqmx_gpio_resources[0].flags = 0;
> -	}
>  
>  	ocores_platform_data.clock_khz = tqmx86_board_id_to_clk_rate(dev, board_id);
>  
> -- 
> TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
> Amtsgericht München, HRB 105018
> Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
> https://www.tq-group.com/
> 

-- 
Lee Jones [李琼斯]

Re: [PATCH v2 4/5] mfd: tqmx86: make IRQ setup errors non-fatal

[Matthias Schiffer]

On Thu, 2024-06-20 at 17:35 +0100, Lee Jones wrote:
> 
> On Mon, 17 Jun 2024, Matthias Schiffer wrote:
> 
> > GPIO IRQ setup can fail either because an invalid IRQ was passed as a
> > parameter, or because the GPIO controller does not support interrupts.
> > Neither is severe enough to stop the whole probe; simply disable IRQ
> > support in the GPIO resource when setup fails.
> > 
> > Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> > ---
> > 
> > v2: no changes (was patch 3/4)
> > 
> >  drivers/mfd/tqmx86.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
> > index 5aa51ead00a28..7f9ccd83278dd 100644
> > --- a/drivers/mfd/tqmx86.c
> > +++ b/drivers/mfd/tqmx86.c
> > @@ -259,13 +259,14 @@ static int tqmx86_probe(struct platform_device *pdev)
> >  		err = tqmx86_setup_irq(dev, "GPIO", gpio_irq, io_base,
> >  				       TQMX86_REG_IO_EXT_INT_GPIO_SHIFT);
> >  		if (err)
> > -			return err;
> > +			gpio_irq = 0;
> > +	}
> >  
> > +	if (gpio_irq)
> 
> Stacking identical if()s one after another doesn't sound very efficient.
> 
> Why not put the contents of this one inside the one above?

The intention was to have the "else" branch be executed both when gpio_irq was reset to 0 in the
above error path, and when gpio_irq was 0 in the first place (so the above section running
tqmx86_setup_irq() hasn't even been executed).

I got a better idea now however - by initializing flags to 0 and only setting it together with the
IRQ in the success path, no (!gpio_irq) branch is needed here at all. Will change in v3.

Best regards,
Matthias



> 
> >  		/* Assumes the IRQ resource is first. */
> >  		tqmx_gpio_resources[0].start = gpio_irq;
> > -	} else {
> > +	else
> >  		tqmx_gpio_resources[0].flags = 0;
> > -	}
> >  
> >  	ocores_platform_data.clock_khz = tqmx86_board_id_to_clk_rate(dev, board_id);
> >  
> > -- 
> > TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
> > Amtsgericht München, HRB 105018
> > Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
> > https://www.tq-group.com/
> > 
> 

-- 
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
https://www.tq-group.com/

Re: [PATCH v2 4/5] mfd: tqmx86: make IRQ setup errors non-fatal

[Lee Jones]

On Mon, 24 Jun 2024, Matthias Schiffer wrote:

> On Thu, 2024-06-20 at 17:35 +0100, Lee Jones wrote:
> > 
> > On Mon, 17 Jun 2024, Matthias Schiffer wrote:
> > 
> > > GPIO IRQ setup can fail either because an invalid IRQ was passed as a
> > > parameter, or because the GPIO controller does not support interrupts.
> > > Neither is severe enough to stop the whole probe; simply disable IRQ
> > > support in the GPIO resource when setup fails.
> > > 
> > > Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> > > ---
> > > 
> > > v2: no changes (was patch 3/4)
> > > 
> > >  drivers/mfd/tqmx86.c | 7 ++++---
> > >  1 file changed, 4 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
> > > index 5aa51ead00a28..7f9ccd83278dd 100644
> > > --- a/drivers/mfd/tqmx86.c
> > > +++ b/drivers/mfd/tqmx86.c
> > > @@ -259,13 +259,14 @@ static int tqmx86_probe(struct platform_device *pdev)
> > >  		err = tqmx86_setup_irq(dev, "GPIO", gpio_irq, io_base,
> > >  				       TQMX86_REG_IO_EXT_INT_GPIO_SHIFT);
> > >  		if (err)
> > > -			return err;
> > > +			gpio_irq = 0;
> > > +	}
> > >  
> > > +	if (gpio_irq)
> > 
> > Stacking identical if()s one after another doesn't sound very efficient.
> > 
> > Why not put the contents of this one inside the one above?
> 
> The intention was to have the "else" branch be executed both when gpio_irq was reset to 0 in the
> above error path, and when gpio_irq was 0 in the first place (so the above section running
> tqmx86_setup_irq() hasn't even been executed).
> 
> I got a better idea now however - by initializing flags to 0 and only setting it together with the
> IRQ in the success path, no (!gpio_irq) branch is needed here at all. Will change in v3.

That sounds like a better approach, thanks.

-- 
Lee Jones [李琼斯]