Hi Laurent,
On Thu, Oct 30, 2014 at 2:59 PM, Laurent Pinchart
wrote:
> I2C clients instantiated from OF get their IRQ mapped at device
> registration time. This leads to the IRQ being silently ignored if the
> related irqchip hasn't been proved yet.
>
> Fix this by moving IRQ mapping at probe time using of_get_irq(). The
> function operates as irq_of_parse_and_map() but additionally returns
> -EPROBE_DEFER if the irqchip isn't available, allowing us to defer I2C
> client probing.
>
> Signed-off-by: Laurent Pinchart
> ---
> drivers/i2c/i2c-core.c | 11 +--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 258765b29684..c6694f232240 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -631,6 +631,15 @@ static int i2c_device_probe(struct device *dev)
> if (!client)
> return 0;
>
> + if (!client->irq && dev->of_node) {
> + int irq = of_irq_get(dev->of_node, 0);
> +
> + if (irq < 0)
> + return irq;
This change broke all i2c slaves not having interrupts (e.g. da9210 and at24
on r8a7791/koelsch), which now fail to probe:
-DA9210: 1000 mV at 4600 mA
...
i2c /dev entries driver
-at24 2-0050: 256 byte 24c02 EEPROM, writable, 16 bytes/write
+at24: probe of 2-0050 failed with error -22
i2c-rcar e653.i2c: probed
...
+da9210: probe of 6-0068 failed with error -22
+i2c-sh_mobile e60b.i2c: I2C adapter 6, bus speed 10 Hz, DMA=y
i2c_device_probe() fails because of_irq_get() returns -EINVAL,
originating from of_irq_parse_one() not finding an "interrupts" property
(there is none).
Apparently you overlooked a difference between irq_of_parse_and_map()
and of_get_irq(): the former returns 0 if there's no "interrupts" property,
while the latter forwards the error code from of_irq_parse_one.
I see two ways to fix this:
1. Make of_get_irq() return 0 if no "interrupts" property was found, to
make it behave more similar to irq_of_parse_and_map().
Does any code rely on the error forwarding?
2. Make i2c_device_probe() only return if -EPROBE_DEFER, and ignore
all other error codes.
It seems irq_create_of_mapping() never returns an error code, but
0 in case of failures?
As platform_get_irq{,_byname}() do the latter, I'll cook a patch
to do that.
> + client->irq = irq;
> + }
> +
> driver = to_i2c_driver(dev->driver);
> if (!driver->probe || !driver->id_table)
> return -ENODEV;
> @@ -1412,7 +1421,6 @@ static void of_i2c_register_devices(struct i2c_adapter
> *adap)
> continue;
> }
>
> - info.irq = irq_of_parse_and_map(node, 0);
> info.of_node = of_node_get(node);
> info.archdata = &dev_ad;
>
> @@ -1426,7 +1434,6 @@ static void of_i2c_register_devices(struct i2c_adapter
> *adap)
> dev_err(&adap->dev, "of_i2c: Failure registering
> %s\n",
> node->full_name);
> of_node_put(node);
> - irq_dispose_mapping(info.irq);
> continue;
> }
> }
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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