moxtet: mark moxtet_bus_type as const

Now that the driver core can properly handle constant struct bus_type,
move the moxtet_bus_type to be a constant structure as well, placing it
into read-only memory which can not be modified at runtime.

Cc: Marek Behún <kabel@kernel.org>
Link: https://lore.kernel.org/r/2023121939-written-guru-db83@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

bus: moxtet: Add spi device table

The moxtet module fails to auto-load on. Add a SPI id table to
allow it to do so.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

bus: moxtet: Mark the irq as shared

The Turris Mox shares the moxtet IRQ with various devices on the board,
so mark the IRQ as shared in the driver as well.

Without this loading the module will fail with:
genirq: Flags mismatch irq 40. 00002002 (moxtet) vs. 00002080 (mcp7940x)

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
Cc: <stable@vger.kernel.org> # v6.2+
Reviewed-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

spi: make remove callback a void function

The value returned by an spi driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

treewide: change my e-mail address, fix my name

Change my e-mail address to kabel@kernel.org, and fix my name in
non-code parts (add diacritical mark).

Link: https://lkml.kernel.org/r/20210325171123.28093-2-kabel@kernel.org
Signed-off-by: Marek Behún <kabel@kernel.org>
Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jassi Brar <jassisinghbrar@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

bus: moxtet: fix potential stack buffer overflow

The input_read function declares the size of the hex array relative to
sizeof(buf), but buf is a pointer argument of the function. The hex
array is meant to contain hexadecimal representation of the bin array.

Link: https://lore.kernel.org/r/20200215142130.22743-1-marek.behun@nic.cz
Fixes: 5bc7f990cd98 ("bus: Add support for Moxtet bus")
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reported-by: sohu0106 <sohu0106@126.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

bus: moxtet: declare moxtet_bus_type as static

This symbol is not meant to be used from elsewhere.

Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

bus: moxtet: fix unsigned comparison to less than zero

Currently the size_t variable res is being checked for
an error failure however the unsigned variable is never
less than zero so this test is always false. Fix this by
making variable res ssize_t

Link: https://lore.kernel.org/r/20190822010351.15660-2-marek.behun@nic.cz
Addresses-Coverity: ("Unsigned compared against 0")
Fixes: 5bc7f990cd98 ("bus: Add support for Moxtet bus")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

bus: moxtet: remove set but not used variable 'dummy'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/bus/moxtet.c: In function moxtet_remove:
drivers/bus/moxtet.c:822:6: warning: variable dummy set but not used
[-Wunused-but-set-variable]

Link: https://lore.kernel.org/r/20190822010351.15660-3-marek.behun@nic.cz
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

bus: Add support for Moxtet bus

On the Turris Mox router different modules can be connected to the main
CPU board: currently a module with a SFP cage, a module with MiniPCIe
connector, a PCIe pass-through MiniPCIe connector module, a 4-port
switch module, an 8-port switch module, and a 4-port USB3 module.

For example:
[CPU]-[PCIe-pass-through]-[PCIe]-[8-port switch]-[8-port switch]-[SFP]

Each of this modules has an input and output shift register, and these
are connected via SPI to the CPU board.

Via SPI we are able to discover which modules are connected, in which
order, and we can also read some information about the modules (eg.
their interrupt status), and configure them.
From each module 8 bits can be read (of which low 4 bits identify the
module) and 8 bits can be written.

For example from the module with a SFP cage we can read the LOS,
TX-FAULT and MOD-DEF0 signals, while we can write TX-DISABLE and
RATE-SELECT signals.

This driver creates a new bus type, called "moxtet". For each Mox module
it finds via SPI, it creates a new device on the moxtet bus so that
drivers can be written for them.

It also implements a virtual interrupt controller for the modules which
send their interrupt status over the SPI shift register. These modules
do this in addition to sending their interrupt status via the shared
interrupt line. When the shared interrupt is triggered, we read from the
shift register and handle IRQs for all devices which are in interrupt.

The topology of how Mox modules are connected can then be read by
listing /sys/bus/moxtet/devices.

Link: https://lore.kernel.org/r/20190812161118.21476-2-marek.behun@nic.cz
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>