Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Thu, 14 May 2020 13:59:35 +0200 | Subject | Re: [PATCH v9 2/4] media: i2c: Add MAX9286 driver |
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Hi Kieran,
On Thu, May 14, 2020 at 1:47 PM Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> wrote: > On 14/05/2020 11:13, Manivannan Sadhasivam wrote: > > On Thu, May 14, 2020 at 11:02:53AM +0100, Kieran Bingham wrote: > >> On 12/05/2020 19:17, Manivannan Sadhasivam wrote: > >>> On Tue, May 12, 2020 at 04:51:03PM +0100, Kieran Bingham wrote: > >>>> The MAX9286 is a 4-channel GMSL deserializer with coax or STP input and > >>>> CSI-2 output. The device supports multicamera streaming applications, > >>>> and features the ability to synchronise the attached cameras. > >>>> > >>>> CSI-2 output can be configured with 1 to 4 lanes, and a control channel > >>>> is supported over I2C, which implements an I2C mux to facilitate > >>>> communications with connected cameras across the reverse control > >>>> channel. > >>>> > >>>> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org> > >>>> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> > >>>> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> > >>>> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> >>>> --- /dev/null > >>>> +++ b/drivers/media/i2c/max9286.c
> >>>> +static int max9286_register_gpio(struct max9286_priv *priv) > >>>> +{ > >>>> + struct device *dev = &priv->client->dev; > >>>> + struct gpio_chip *gpio = &priv->gpio; > >>>> + int ret; > >>>> + > >>>> + static const char * const names[] = { > >>>> + "GPIO0OUT", > >>>> + "GPIO1OUT", > >>>> + }; > >>>> + > >>>> + /* Configure the GPIO */ > >>>> + gpio->label = dev_name(dev); > >>> > >>> So if you have more than one MAX9286 in a system, all gpiochips will appear > >>> with the same name. I'd recommend to append the index to distinguish properly. > >> > >> Ah yes, that's a good point, and I think I've even seen that. > >> > >> I'll fix it now. > > Oh, in fact actually this doesn't. > > gpiodetect prints: > > gpiochip10 [4-004c] (2 lines) > gpiochip11 [4-006c] (2 lines) > > and mostly references them as gpiochip10 and gpiochip11.
Indeed, dev_name() should be different for each instance.
> However, > > > [ 2.318533] gpio gpiochip11: Detected name collision for GPIO name 'GPIO0OUT' > > [ 2.325739] gpio gpiochip11: Detected name collision for GPIO name 'GPIO1OUT' > > That seems to be more of a problem for the gpio library, so I think I'll > just drop the const names. I don't think they add much value.
These are the line names. If they're not unique, a warning is printed, but they are still registered. So probably you want to use kasprintf("%s.%s", dev_name(dev), names[i]) to generate names.
See "[PATCH] gpiolib: Document that GPIO line names are not globally unique" (https://lore.kernel.org/linux-gpio/20200511101828.30046-1-geert+renesas@glider.be/) to clear up the details.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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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