From: "Noralf Trønnes" <noralf@tronnes.org>
To: Mark Brown <broonie@kernel.org>
Cc: balbi@kernel.org, linux-usb@vger.kernel.org,
lee.jones@linaro.org, dri-devel@lists.freedesktop.org
Subject: Re: [RFC 1/9] regmap: Add USB support
Date: Mon, 17 Feb 2020 23:15:37 +0100 [thread overview]
Message-ID: <34adf00c-a465-6d6d-23bd-a2a00290c1fa@tronnes.org> (raw)
In-Reply-To: <20200217213911.GV9304@sirena.org.uk>
Den 17.02.2020 22.39, skrev Mark Brown:
> On Mon, Feb 17, 2020 at 10:33:58PM +0100, Noralf Trønnes wrote:
>> Den 17.02.2020 13.11, skrev Mark Brown:
>
>>> This looks like you just don't support a straight write operation, if
>>> you need to do this emulation push it up the stack.
>
>> After going through the stack I realise that I have a problem.
>> What I have failed to fully comprehend is this regmap requirement:
>
>> if (val_len % map->format.val_bytes)
>> return -EINVAL;
>
>> There will be a spi and i2c driver down the line which will transfer
>> buffers of any size, and having to use 8-bit register values will not be
>> great.
>
> Out of interest why are 8 bit registers going to be a problem?
>
I have written 3 drivers so far and they all have some registers that
need to deal with values larger than 255. If I would need to add a lot
of code because of dropping regmap, then I would have looked at ways to
work around this in order to keep regmap, hi/lo registers perhaps with
wrapping access functions. But it looks like the LOC won't change much,
I need a few lines to ensure values are little endian, but I can also
remove some lines that's not needed anymore.
Noralf.
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next prev parent reply other threads:[~2020-02-17 22:15 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-16 17:21 [RFC 0/9] Regmap over USB for Multifunction USB Device (gpio, display, ...) Noralf Trønnes
2020-02-16 17:21 ` [RFC 1/9] regmap: Add USB support Noralf Trønnes
2020-02-17 12:11 ` Mark Brown
2020-02-17 21:33 ` Noralf Trønnes
2020-02-17 21:39 ` Mark Brown
2020-02-17 22:15 ` Noralf Trønnes [this message]
2020-02-17 22:44 ` Mark Brown
2020-02-16 17:21 ` [RFC 2/9] mfd: Add driver for Multifunction USB Device Noralf Trønnes
2020-02-27 9:09 ` Lee Jones
2020-02-29 13:26 ` Noralf Trønnes
2020-02-29 16:02 ` Alan Stern
2020-02-16 17:21 ` [RFC 3/9] usb: gadget: function: Add Multifunction USB Device support Noralf Trønnes
2020-02-16 17:21 ` [RFC 4/9] pinctrl: Add Multifunction USB Device pinctrl driver Noralf Trønnes
2020-02-16 17:21 ` [RFC 5/9] usb: gadget: function: mud: Add gpio support Noralf Trønnes
2020-02-16 17:21 ` [RFC 6/9] regmap: Speed up _regmap_raw_write_impl() for large buffers Noralf Trønnes
2020-02-17 12:15 ` Mark Brown
2020-02-16 17:21 ` [RFC 7/9] drm: Add Multifunction USB Device display driver Noralf Trønnes
2020-02-16 17:21 ` [RFC 8/9] drm/client: Add drm_client_init_from_id() and drm_client_modeset_set() Noralf Trønnes
2020-02-17 9:38 ` Daniel Vetter
2020-02-23 17:43 ` Noralf Trønnes
2020-02-23 20:59 ` Daniel Vetter
2020-02-16 17:21 ` [RFC 9/9] usb: gadget: function: mud: Add display support Noralf Trønnes
2020-02-17 9:40 ` [RFC 0/9] Regmap over USB for Multifunction USB Device (gpio, display, ...) Daniel Vetter
2020-02-17 10:32 ` Neil Armstrong
2020-02-17 14:05 ` Noralf Trønnes
2020-02-18 20:57 ` Andy Shevchenko
2020-02-18 21:31 ` Noralf Trønnes
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