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From: Robin van der Gracht <robin@protonic.nl>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Rob Herring <robh+dt@kernel.org>, Miguel Ojeda <ojeda@kernel.org>,
	Paul Burton <paulburton@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	"open list:BROADCOM NVRAM DRIVER" <linux-mips@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 16/17] auxdisplay: ht16k33: Add support for segment displays
Date: Mon, 29 Mar 2021 09:30:08 +0200	[thread overview]
Message-ID: <8376c4a183971aef9631c1bc64f9222c@protonic.nl> (raw)
In-Reply-To: <CAMuHMdXJV3duE=uhCD3XSVn35Y5=iafOOUu5_57-1TtW062ZJg@mail.gmail.com>

On 2021-03-29 09:15, Geert Uytterhoeven wrote:
> Hoi Robin,
> 
> On Mon, Mar 29, 2021 at 9:09 AM Robin van der Gracht 
> <robin@protonic.nl> wrote:
>> On 2021-03-22 15:48, Geert Uytterhoeven wrote:
>> > The Holtek HT16K33 LED controller is not only used for driving
>> > dot-matrix displays, but also for driving segment displays.
>> >
>> > Add support for 4-digit 7-segment and quad 14-segment alphanumeric
>> > displays, like the Adafruit 7-segment and 14-segment display backpack
>> > and FeatherWing expansion boards.  Use the character line display core
>> > support to display a message, which will be scrolled if it doesn't fit.
>> >
>> > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
>> > ---
>> > The 7-segment support is based on schematics, and untested on actual
>> > hardware.
>> > ---
>> >  drivers/auxdisplay/ht16k33.c | 198 +++++++++++++++++++++++++++++++++--
>> >  1 file changed, 191 insertions(+), 7 deletions(-)
>> >
>> ...
>> >
>> > +static int ht16k33_seg_probe(struct i2c_client *client,
>> > +                          struct ht16k33_priv *priv, uint32_t brightness)
>> > +{
>> > +     struct ht16k33_seg *seg = &priv->seg;
>> > +     struct device *dev = &client->dev;
>> > +     int err;
>> > +
>> > +     err = ht16k33_brightness_set(priv, MAX_BRIGHTNESS);
>> > +     if (err)
>> > +             return err;
>> > +
>> > +     switch (priv->type) {
>> > +     case DISP_MATRIX:
>> > +             /* not handled here */
>> > +             break;
>> 
>> This 'case' shouldn't happen. Having said that, the break here will
>> still
>> cause the linedisp_register() function to be called for the 
>> DISP_MATRIX
>> type.
>> If you'd like to handle this case, a return (or setting 'err') should
>> prevent this.
> 
> This function is never called if priv->type == DISP_MATRIX, so this
> cannot happen.  However, gcc complains if not all enum values are
> handled in a switch() statement, hence the dummy case.

I see. But if it's there it should work right? :P

> Is there a better way to handle this?

How about adding the default case:

default:
     /* not handled */
     err = -EINVAL;

Groetjes/Kind regards,
Robin van der Gracht

-- 
Protonic Holland
Factorij 36
1689AL Zwaag
+31 (0)229 212928
https://www.protonic.nl

  reply	other threads:[~2021-03-29  7:30 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-22 14:48 [PATCH 00/17] auxdisplay: ht16k33: Add character display support Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 01/17] uapi: Add <linux/map_to_14segment.h> Geert Uytterhoeven
2021-03-22 17:05   ` Miguel Ojeda
2021-03-22 17:51     ` Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 02/17] dt-bindings: auxdisplay: ht16k33: Document Adafruit segment displays Geert Uytterhoeven
2021-03-22 17:38   ` Rob Herring
2021-03-23  9:12   ` robin
2021-05-18 14:35     ` Geert Uytterhoeven
2021-05-19 10:37       ` Robin van der Gracht
2021-05-19 11:02         ` Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 03/17] auxdisplay: img-ascii-lcd: Fix lock-up when displaying empty string Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 04/17] auxdisplay: img-ascii-lcd: Add helper variable dev Geert Uytterhoeven
2021-03-22 16:59   ` Miguel Ojeda
2021-03-22 17:53     ` Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 05/17] auxdisplay: img-ascii-lcd: Convert device attribute to sysfs_emit() Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 06/17] auxdisplay: Extract character line display core support Geert Uytterhoeven
2021-03-23  8:18   ` robin
2021-03-23  8:52     ` Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 07/17] auxdisplay: linedisp: Use kmemdup_nul() helper Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 08/17] auxdisplay: linedisp: Add support for changing scroll rate Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 09/17] auxdisplay: ht16k33: Use HT16K33_FB_SIZE in ht16k33_initialize() Geert Uytterhoeven
2021-03-23  7:59   ` robin
2021-03-22 14:48 ` [PATCH 10/17] auxdisplay: ht16k33: Remove unneeded error check in keypad probe() Geert Uytterhoeven
2021-03-23  8:08   ` robin
2021-03-22 14:48 ` [PATCH 11/17] auxdisplay: ht16k33: Convert to simple i2c probe function Geert Uytterhoeven
2021-03-23  8:31   ` robin
2021-03-22 14:48 ` [PATCH 12/17] auxdisplay: ht16k33: Add helper variable dev Geert Uytterhoeven
2021-03-23  8:57   ` robin
2021-03-22 14:48 ` [PATCH 13/17] auxdisplay: ht16k33: Move delayed work Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 14/17] auxdisplay: ht16k33: Extract ht16k33_brightness_set() Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 15/17] auxdisplay: ht16k33: Extract frame buffer probing Geert Uytterhoeven
2021-03-22 14:48 ` [PATCH 16/17] auxdisplay: ht16k33: Add support for segment displays Geert Uytterhoeven
2021-03-29  7:08   ` Robin van der Gracht
2021-03-29  7:15     ` Geert Uytterhoeven
2021-03-29  7:30       ` Robin van der Gracht [this message]
2021-03-22 14:48 ` [PATCH 17/17] auxdisplay: ht16k33: Add segment display LED support Geert Uytterhoeven
2021-03-23 10:08   ` Robin van der Gracht
2021-03-23 12:32     ` Geert Uytterhoeven
2021-03-23 20:40       ` Pavel Machek
2021-03-24  8:31         ` Geert Uytterhoeven
2021-03-27 22:19           ` Pavel Machek
2021-06-25 12:39           ` Geert Uytterhoeven
2021-03-22 17:03 ` [PATCH 00/17] auxdisplay: ht16k33: Add character display support Miguel Ojeda

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