mfd: stmpe: Pull IRQ GPIO number from DT during DT-based probe

In case of a DT-based probe of the stmpe MFD driver, the irq_gpio was zero, which resulted in the driver failing to probe.

Implement DT properties "irq-over-gpio" and "irq-gpios" which are already used in "arch/arm/boot/dts/spear320-hmi.dts" to circumvent these problems.

The new
behaviour is the expected one and copies the behavior of platform_data-based probe.

Signed-off-by Marek Vasut <[email protected]>

Cc Lee Jones <[email protected]>

Cc Linus Walleij <[email protected]>

Cc Samuel Ortiz <[email protected]>

Cc Vipul Kumar Samar <[email protected]>

Cc Viresh Kumar <[email protected]>

---
 drivers/mfd/stmpe.c |    5 +++++
 1 file changed, 5 insertions(+)

drivers/mfd/stmpe.c +0 -0

index 4b11202..fb9cd6f 100644

drivers/mfd/stmpe.c +4 -0

+	pdata->irq_gpio = of_get_named_gpio(np, "irq-gpios", 0);
+	if (!gpio_is_valid(pdata->irq_gpio))
+		pdata->irq_gpio = -1;
+
 	of_property_read_u32(np, "st,autosleep-timeout",
 			&pdata->autosleep_timeout);
 

Signature · 1 line

1.7.10.4

Quoted 6 lines

In case of a DT-based probe of the stmpe MFD driver, the irq_gpio was zero, which resulted in the driver failing to probe.

Implement DT properties "irq-over-gpio" and "irq-gpios" which are already used in "arch/arm/boot/dts/spear320-hmi.dts" to circumvent these problems.

This must have slipped through the gaps. It should be removed.

Quoted 3 lines

The new
behaviour is the expected one and copies the behavior of platform_data-based probe.

Blindly copying platform data behaviour to DT bindings is seldom a good idea.

Quoted 21 lines

Signed-off-by Marek Vasut <[email protected]>

Cc Lee Jones <[email protected]>

Cc Linus Walleij <[email protected]>

Cc Samuel Ortiz <[email protected]>

Cc Vipul Kumar Samar <[email protected]>

Cc Viresh Kumar <[email protected]>

---

 drivers/mfd/stmpe.c |    5 +++++
 1 file changed, 5 insertions(+)

drivers/mfd/stmpe.c +0 -0

index 4b11202..fb9cd6f 100644
@@ -1018,6 +1018,11 @@ void stmpe_of_probe(struct stmpe_platform_data
 *pdata, struct device_node *np)
 
 	pdata->id = -1;
 	pdata->irq_trigger = IRQF_TRIGGER_NONE;
 

drivers/mfd/stmpe.c void stmpe_of_probe(struct stmpe_platform_data *pdata, struct device_node *np) · line 1021

Quoted 1 line

drivers/mfd/stmpe.c +1 -0

+	pdata->irq_over_gpio = of_get_property(np, "irq-over-gpio", NULL);

This is a new DT binding and you haven't provided any documentation for it.

Also, there is no reason for the binding to exist.

Lots of drivers use GPIO pins as IRQs.

drivers/mfd/stmpe.c void stmpe_of_probe(struct stmpe_platform_data *pdata, struct device_node *np)

Quoted 8 lines

drivers/mfd/stmpe.c +4 -0

+	pdata->irq_gpio = of_get_named_gpio(np, "irq-gpios", 0);
+	if (!gpio_is_valid(pdata->irq_gpio))
+		pdata->irq_gpio = -1;
+
 

drivers/mfd/stmpe.c +0 -0

 	of_property_read_u32(np, "st,autosleep-timeout",
 
 			&pdata->autosleep_timeout);

Quoted 7 lines

drivers/mfd/stmpe.c void stmpe_of_probe(struct stmpe_platform_data *pdata, struct device_node *np) · line 1021

Quoted 1 line

drivers/mfd/stmpe.c +1 -0

+	pdata->irq_over_gpio = of_get_property(np, "irq-over-gpio", NULL);

This is a new DT binding and you haven't provided any documentation for it.

Also, there is no reason for the binding to exist.

Lots of drivers use GPIO pins as IRQs.

Right, this can be removed and only the 'irq-gpios' can be kept around. What do you say?

Quoted 6 lines

Quoted 3 lines

The new
behaviour is the expected one and copies the behavior of platform_data-based probe.

Blindly copying platform data behaviour to DT bindings is seldom a good idea.

Do you have suggestions how to pass these information? I suspect the irq-over- gpio property can be killed, since if irq-gpios prop is there, it implies irq- over-gpio anyway.

Quoted 10 lines · Marek Vasut

Quoted 6 lines

Quoted 3 lines

The new
behaviour is the expected one and copies the behavior of platform_data-based probe.

Blindly copying platform data behaviour to DT bindings is seldom a good idea.

Do you have suggestions how to pass these information? I suspect the irq-over- gpio property can be killed, since if irq-gpios prop is there, it implies irq- over-gpio anyway.

Both can be killed. gpios as interrupt lines can be requested as:

  interrupt-parent =<&gpio-controller>;
  interrupts =<25 0x1>;

and probably the stmpe driver doesn't have to bother at all if interrupt was over gpio
or not.
.

Quoted 7 lines

Both can be killed. gpios as interrupt lines can be requested as:

interrupt-parent =<&gpio-controller>;
interrupts =<25 0x1>;

and probably the stmpe driver doesn't have to bother at all if interrupt was over gpio or not.

Yes, both can be killed and similarly we did for spear1340 machine but some how we missed it on spear320-hmi.

Quoted 9 lines

Quoted 6 lines

Both can be killed. gpios as interrupt lines can be requested as:
interrupt-parent =<&gpio-controller>;
interrupts =<25 0x1>;

and probably the stmpe driver doesn't have to bother at all if interrupt was over gpio or not.

Yes, both can be killed and similarly we did for spear1340 machine but some how we missed it on spear320-hmi.

Bingo!

Quoted 7 lines

Quoted 7 lines

Quoted 6 lines

Both can be killed. gpios as interrupt lines can be requested as:
interrupt-parent =<&gpio-controller>;
interrupts =<25 0x1>;

and probably the stmpe driver doesn't have to bother at all if interrupt was over gpio or not.

Quoted 4 lines

Quoted 2 lines

Yes, both can be killed and similarly we did for spear1340 machine but some how we missed it on spear320-hmi.

Bingo!

All right, all right ... got it ;-)

I'll rework it and repost then.

Maybe I was too quick about understanding the issue at hand. So allow me a stupid question -- who's gonna configure the GPIO as input for it to work as IRQ GPIO?

Quoted 3 lines · Marek Vasut

Maybe I was too quick about understanding the issue at hand. So allow me a stupid question -- who's gonna configure the GPIO as input for it to work as IRQ GPIO?

Hmm.. I tried a bit, but couldn't find any such call :(
Probably an assumption is taken here. GPIO pins which are going to be used as interrupt lines, wouldn't be getting set in output mode at all. So, once they are put
in input mode in beginning, nobody would change it ever.

Much of gpio controllers configure gpio pins in input mode in their probe().

Maybe, there is something else :)

Quoted 9 lines

Hmm.. I tried a bit, but couldn't find any such call :(
Probably an assumption is taken here. GPIO pins which are going to be used as interrupt lines, wouldn't be getting set in output mode at all. So, once they are put
in input mode in beginning, nobody would change it ever.

Much of gpio controllers configure gpio pins in input mode in their probe().

Maybe, there is something else :)

Pinctrl?

Quoted 8 lines · Lee Jones

Quoted 8 lines

Hmm.. I tried a bit, but couldn't find any such call :(
Probably an assumption is taken here. GPIO pins which are going to be used as interrupt lines, wouldn't be getting set in output mode at all. So, once they are put
in input mode in beginning, nobody would change it ever.

Much of gpio controllers configure gpio pins in input mode in their probe().

Quoted 2 lines

Quoted 1 line

Maybe, there is something else :)

Pinctrl?

I don't think pinctrl is playing with it. I searched for "direction_input" string and
pinctrl routine also had similar name. I couldn't fine use of direction_input anywhere
in kernel, for setting them as irqs for OF cases.

I think we can do it in the gpio chip driver inthe function xxx_gpio_irq_set_type().
When you register any irq and if this callback is available from gpio chip driver then this will get called. and so the setting the pi to input mode as well as putting the pin in GPIO mode can be done here. This is what we are doing it in gpio-tegra driver.

Quoted 10 lines · Lee Jones

Quoted 9 lines

Hmm.. I tried a bit, but couldn't find any such call :(
Probably an assumption is taken here. GPIO pins which are going to be used as interrupt lines, wouldn't be getting set in output mode at all. So, once they are put
in input mode in beginning, nobody would change it ever.

Much of gpio controllers configure gpio pins in input mode in their probe().

Maybe, there is something else :)

Quoted 1 line

Pinctrl?

I don't think pinctrl is playing with it. I searched for "direction_input" string and
pinctrl routine also had similar name. I couldn't fine use of direction_input anywhere
in kernel, for setting them as irqs for OF cases.

Quoted 11 lines · Viresh Kumar

Quoted 10 lines · Lee Jones

Quoted 9 lines

Hmm.. I tried a bit, but couldn't find any such call :(
Probably an assumption is taken here. GPIO pins which are going to be used as interrupt lines, wouldn't be getting set in output mode at all. So, once they are put
in input mode in beginning, nobody would change it ever.

Much of gpio controllers configure gpio pins in input mode in their probe().

Maybe, there is something else :)

Quoted 7 lines

Quoted 1 line

Pinctrl?

I don't think pinctrl is playing with it. I searched for "direction_input" string and
pinctrl routine also had similar name. I couldn't fine use of direction_input anywhere
in kernel, for setting them as irqs for OF cases.

pinctrl has pinctrl_gpio_direction_input() and pinctrl_gpio_direction_output() which are supposed to be called *only* by GPIOlib frontends using pinctrl as backend to control the pins.

But if it's a pinctrl driver using standard pinconfig from include/linux/pinctrl/pinconf-generic.h
I'm all for adding a PIN_CONFIG_INPUT_ENABLE
to these definintions so it can be set up as input at boot from the device tree using hogs or something, that make things easy when using GPIOs as IRQ providers only.

So the alternative is to just set up the IRQ using the gpiolib functions for this: of_get_gpio() if you need the number from DT, then gpio_request() and gpio_direction_input() as on any GPIO. This can be done in the device driver or board code depending on use case.

In the Nomadik I did this (maybe ugly) hack for a
similar case:

(quoted diff) +21 -0

+/*
+ * The SMSC911x IRQ is connected to a GPIO pin, but the driver expects
+ * to simply request an IRQ passed as a resource. So the GPIO pin needs
+ * to be requested by this hog and set as input.
+ */
+static int __init cpu8815_eth_init(void)
+{
+       struct device_node *eth;
+       int gpio, irq, err;
+
+       eth = of_find_node_by_path("/external-bus at 34000000/ethernet at 300");
+       if (!eth) {
+               pr_info("could not find any ethernet controller\n");
+               return 0;
+       }
+       gpio = of_get_gpio(eth, 0);
+       err = gpio_request(gpio, "eth_irq");
+       if (err) {
+               pr_info("failed to request ethernet GPIO\n");
+               return -ENODEV;
+       }

I haven't read review comments on that patch.

Maybe it's not such a good idea to add the GPIO to the device itself when it's being hogged by board code like this. It's a bit of a grey area so I'm a bit confused here.

Maybe the GPIO lib actually needs a "hog" mechanism that can request and set GPIO pins as input/output on boot and then forget about them.

Yours,
Linus Walleij

Quoted 11 lines · Viresh Kumar

Quoted 10 lines · Lee Jones

Quoted 9 lines

Hmm.. I tried a bit, but couldn't find any such call :(
Probably an assumption is taken here. GPIO pins which are going to be used as interrupt lines, wouldn't be getting set in output mode at all. So, once they are put
in input mode in beginning, nobody would change it ever.

Much of gpio controllers configure gpio pins in input mode in their probe().

Maybe, there is something else :)

Quoted 7 lines

Quoted 1 line

Pinctrl?

I don't think pinctrl is playing with it. I searched for "direction_input" string and
pinctrl routine also had similar name. I couldn't fine use of direction_input anywhere
in kernel, for setting them as irqs for OF cases.

pinctrl has pinctrl_gpio_direction_input() and pinctrl_gpio_direction_output() which are supposed to be called *only* by GPIOlib frontends using pinctrl as backend to control the pins.

But if it's a pinctrl driver using standard pinconfig from include/linux/pinctrl/pinconf-generic.h
I'm all for adding a PIN_CONFIG_INPUT_ENABLE
to these definintions so it can be set up as input at boot from the device tree using hogs or something, that make things easy when using GPIOs as IRQ providers only.

So the alternative is to just set up the IRQ using the gpiolib functions for this: of_get_gpio() if you need the number from DT, then gpio_request() and gpio_direction_input() as on any GPIO. This can be done in the device driver or board code depending on use case.

In the Nomadik I did this (maybe ugly) hack for a
similar case:

(quoted diff) +31 -0

+/*
+ * The SMSC911x IRQ is connected to a GPIO pin, but the driver expects
+ * to simply request an IRQ passed as a resource. So the GPIO pin needs
+ * to be requested by this hog and set as input.
+ */
+static int __init cpu8815_eth_init(void)
+{
+       struct device_node *eth;
+       int gpio, irq, err;
+
+       eth = of_find_node_by_path("/external-bus at 34000000/ethernet at 300");
+       if (!eth) {
+               pr_info("could not find any ethernet controller\n");
+               return 0;
+       }
+       gpio = of_get_gpio(eth, 0);
+       err = gpio_request(gpio, "eth_irq");
+       if (err) {
+               pr_info("failed to request ethernet GPIO\n");
+               return -ENODEV;
+       }
+       err = gpio_direction_input(gpio);
+       if (err) {
+               pr_info("failed to set ehernet GPIO as input\n");
+               return -ENODEV;
+       }
+       irq = gpio_to_irq(gpio);
+       pr_info("enabled ethernet GPIO %d, IRQ %d\n", gpio, irq);
+       return 0;
+}
+device_initcall(cpu8815_eth_init);

I haven't read review comments on that patch.

Maybe it's not such a good idea to add the GPIO to the device itself when it's being hogged by board code like this. It's a bit of a grey area so I'm a bit confused here.

Maybe the GPIO lib actually needs a "hog" mechanism that can request and set GPIO pins as input/output on boot and then forget about them.

On Thu, 10 Jan 2013 12:42:53 +0100, Linus Walleij <[email protected]>

Quoted 1 line

On Tue, Jan 8, 2013 at 12:14 PM, Viresh Kumar <[email protected]>

Quoted 82 lines

Quoted 12 lines · Lee Jones

Quoted 11 lines

Quoted 10 lines

Hmm.. I tried a bit, but couldn't find any such call :( Probably an assumption is taken here. GPIO pins which are going to be used as interrupt lines, wouldn't be getting set in output mode at all. So, once they are put
in input mode in beginning, nobody would change it ever.

Much of gpio controllers configure gpio pins in input mode in their probe().

Maybe, there is something else :)

Quoted 7 lines

Quoted 1 line

Pinctrl?

I don't think pinctrl is playing with it. I searched for "direction_input" string and
pinctrl routine also had similar name. I couldn't fine use of direction_input anywhere
in kernel, for setting them as irqs for OF cases.

pinctrl has pinctrl_gpio_direction_input() and pinctrl_gpio_direction_output() which are supposed to be called *only* by GPIOlib frontends using pinctrl as backend to control the pins.

But if it's a pinctrl driver using standard pinconfig from include/linux/pinctrl/pinconf-generic.h
I'm all for adding a PIN_CONFIG_INPUT_ENABLE
to these definintions so it can be set up as input at boot from the device tree using hogs or something, that make things easy when using GPIOs as IRQ providers only.

So the alternative is to just set up the IRQ using the gpiolib functions for this: of_get_gpio() if you need the number from DT, then gpio_request() and gpio_direction_input() as on any GPIO. This can be done in the device driver or board code depending on use case.

In the Nomadik I did this (maybe ugly) hack for a
similar case:

(quoted diff) +11 -0

+/*
+ * The SMSC911x IRQ is connected to a GPIO pin, but the driver expects
+ * to simply request an IRQ passed as a resource. So the GPIO pin needs
+ * to be requested by this hog and set as input.
+ */
+static int __init cpu8815_eth_init(void)
+{
+       struct device_node *eth;
+       int gpio, irq, err;
+
+       eth =

of_find_node_by_path("/external-bus at 34000000/ethernet at 300"); + if
(!eth) {

(quoted diff) +19 -0

+               pr_info("could not find any ethernet controller\n");
+               return 0;
+       }
+       gpio = of_get_gpio(eth, 0);
+       err = gpio_request(gpio, "eth_irq");
+       if (err) {
+               pr_info("failed to request ethernet GPIO\n");
+               return -ENODEV;
+       }
+       err = gpio_direction_input(gpio);
+       if (err) {
+               pr_info("failed to set ehernet GPIO as input\n");
+               return -ENODEV;
+       }
+       irq = gpio_to_irq(gpio);
+       pr_info("enabled ethernet GPIO %d, IRQ %d\n", gpio, irq);
+       return 0;
+}
+device_initcall(cpu8815_eth_init);

I haven't read review comments on that patch.

Maybe it's not such a good idea to add the GPIO to the device itself when it's being hogged by board code like this. It's a bit of a grey area so I'm a bit confused here.

Quoted 3 lines

Maybe the GPIO lib actually needs a "hog" mechanism that can request and set GPIO pins as input/output on boot and then forget about them.

That would be reasonable. Probably as properties in the gpio controller node that specify how to set the inital state.