linux-toradex.git/drivers/spi/spi-gpio.c, branch v6.4

spi: Replace all spi->chip_select and spi->cs_gpiod references with function call

2023-03-11T12:34:01+00:00

Supporting multi-cs in spi drivers would require the chip_select & cs_gpiod
members of struct spi_device to be an array. But changing the type of these
members to array would break the spi driver functionality. To make the
transition smoother introduced four new APIs to get/set the
spi->chip_select & spi->cs_gpiod and replaced all spi->chip_select and
spi->cs_gpiod references with get or set API calls.
While adding multi-cs support in further patches the chip_select & cs_gpiod
members of the spi_device structure would be converted to arrays & the
"idx" parameter of the APIs would be used as array index i.e.,
spi->chip_select[idx] & spi->cs_gpiod[idx] respectively.

Signed-off-by: Amit Kumar Mahapatra 
Acked-by: Heiko Stuebner  # Rockchip drivers
Reviewed-by: Michal Simek 
Reviewed-by: Cédric Le Goater  # Aspeed driver
Reviewed-by: Dhruva Gole  # SPI Cadence QSPI
Reviewed-by: Patrice Chotard  # spi-stm32-qspi
Acked-by: William Zhang  # bcm63xx-hsspi driver
Reviewed-by: Serge Semin  # DW SSI part
Link: https://lore.kernel.org/r/167847070432.26.15076794204368669839@mailman-core.alsa-project.org
Signed-off-by: Mark Brown

spi: spi-gpio: Don't set MOSI as an input if not 3WIRE mode

2022-12-08T11:46:41+00:00

The addition of 3WIRE support would affect MOSI direction even
when still in standard (4 wire) mode. This can lead to MOSI being
at an invalid logic level when a device driver sets an SPI
message with a NULL tx_buf.

spi.h states that if tx_buf is NULL then "zeros will be shifted
out ... " If MOSI is tristated then the data shifted out is subject
to pull resistors, keepers, or in the absence of those, noise.

This issue came to light when using spi-gpio connected to an
ADS7843 touchscreen controller. MOSI pulled high when clocking
MISO data in caused the SPI device to interpret this as a command
which would put the device in an unexpected and non-functional
state.

Fixes: 4b859db2c606 ("spi: spi-gpio: add SPI_3WIRE support")
Fixes: 5132b3d28371 ("spi: gpio: Support 3WIRE high-impedance turn-around")
Signed-off-by: Kris Bahnsen 
Link: https://lore.kernel.org/r/20221207230853.6174-1-kris@embeddedTS.com
Signed-off-by: Mark Brown

spi: gpio: Implement LSB First bitbang support

2022-02-22T11:56:41+00:00

Add support for slave DT property spi-lsb-first, i.e., SPI_LSB_FIRST mode.
Duplicate the inline helpers bitbang_txrx_be_cpha{0,1} as LE versions.
Conditionally call them from all the spi-gpio txrx_word callbacks.

Some alternatives to this implementation approach were discussed back
then [0], but eventually it was considered reasonable.

[0] https://lore.kernel.org/linux-arm-kernel/20191212033952.5967-8-afaerber@suse.de/

Signed-off-by: Andreas Färber 
Signed-off-by: Heiner Kallweit 
Tested-by: Christian Hewitt 
Link: https://lore.kernel.org/r/feac3377-4ad1-77d8-9a18-3588d80fb909@gmail.com
Signed-off-by: Mark Brown

spi: gpio: Don't leak SPI master in probe error path

2020-12-07T14:18:54+00:00

If the call to devm_spi_register_master() fails on probe of the GPIO SPI
driver, the spi_master struct is erroneously not freed:

After allocating the spi_master, its reference count is 1.  The driver
unconditionally decrements the reference count on unbind using a devm
action.  Before calling devm_spi_register_master(), the driver
unconditionally increments the reference count because on success,
that function will decrement the reference count on unbind.  However on
failure, devm_spi_register_master() does *not* decrement the reference
count, so the spi_master is leaked.

The issue was introduced by commits 8b797490b4db ("spi: gpio: Make sure
spi_master_put() is called in every error path") and 79567c1a321e ("spi:
gpio: Use devm_spi_register_master()"), which sought to plug leaks
introduced by 9b00bc7b901f ("spi: spi-gpio: Rewrite to use GPIO
descriptors") but missed this remaining leak.

The situation was later aggravated by commit d3b0ffa1d75d ("spi: gpio:
prevent memory leak in spi_gpio_probe"), which introduced a
use-after-free because it releases a reference on the spi_master if
devm_add_action_or_reset() fails even though the function already
does that.

Fix by switching over to the new devm_spi_alloc_master() helper.

Fixes: 9b00bc7b901f ("spi: spi-gpio: Rewrite to use GPIO descriptors")
Signed-off-by: Lukas Wunner 
Reviewed-by: Linus Walleij 
Cc:  # v4.17+: 5e844cc37a5c: spi: Introduce device-managed SPI controller allocation
Cc:  # v5.1-: 8b797490b4db: spi: gpio: Make sure spi_master_put() is called in every error path
Cc:  # v5.1-: 45beec351998: spi: bitbang: Introduce spi_bitbang_init()
Cc:  # v5.1-: 79567c1a321e: spi: gpio: Use devm_spi_register_master()
Cc:  # v5.4-: d3b0ffa1d75d: spi: gpio: prevent memory leak in spi_gpio_probe
Cc:  # v4.17+
Cc: Navid Emamdoost 
Cc: Andrey Smirnov 
Link: https://lore.kernel.org/r/86eaed27431c3d709e3748eb76ceecbfc790dd37.1607286887.git.lukas@wunner.de
Signed-off-by: Mark Brown

Merge branch 'for-5.4' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi into spi-5.5

2019-10-08T18:12:28+00:00

spi: gpio: Look for a device node instead of match

2019-10-07T12:55:40+00:00

This driver doesn't do anything with the match for the device node. The
logic is the same as looking to see if a device node exists or not
because this driver wouldn't probe unless there is a device node match
when the device is created from DT. Just test for the presence of the
device node to simplify and avoid referencing a potentially undefined
match table when CONFIG_OF=n.

Cc: Arnd Bergmann 
Cc: Geert Uytterhoeven 
Cc: Mark Brown 
Cc: Rob Herring 
Cc: Frank Rowand 
Cc: 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20191004214334.149976-9-swboyd@chromium.org
Signed-off-by: Mark Brown

spi: gpio: prevent memory leak in spi_gpio_probe

2019-10-01T17:38:52+00:00

In spi_gpio_probe an SPI master is allocated via spi_alloc_master, but
this controller should be released if devm_add_action_or_reset fails,
otherwise memory leaks. In order to avoid leak spi_contriller_put must
be called in case of failure for devm_add_action_or_reset.

Fixes: 8b797490b4db ("spi: gpio: Make sure spi_master_put() is called in every error path")
Signed-off-by: Navid Emamdoost 
Link: https://lore.kernel.org/r/20190930205241.5483-1-navid.emamdoost@gmail.com
Signed-off-by: Mark Brown

spi-gpio: Use PTR_ERR_OR_ZERO() in spi_gpio_request()

2019-09-09T10:05:39+00:00

Simplify this function implementation by using a known function.

Generated by: scripts/coccinelle/api/ptr_ret.cocci

Signed-off-by: Markus Elfring 
Reviewed-by: Geert Uytterhoeven 
Link: https://lore.kernel.org/r/b2dd074a-1693-3aea-42b4-da1f5ec155c4@web.de
Signed-off-by: Mark Brown

spi: gpio: Add SPI_MASTER_GPIO_SS flag

2019-07-17T17:51:21+00:00

The GPIO SPI master has some code in its local CS
callback to set the initial sck GPIO value. This was
lost in the commit converting it to use SPI core
GPIO handling as this callback isn't called if the
internal GPIO handling is active.

Add the special SPI_MASTER_GPIO_SS to ascertain it
gets called anyway so we get the initial SCK setting
right. There is some platform provided GPIO handling
there as well but this will be skipped as the cs_gpios
will be NULL.

My test targets seem not to care about the initial
SCK value so I am uncertain if this is a regression,
but to preserve the previous semantic we better do
this.

Cc: Andrey Smirnov 
Fixes: 249e2632dcd0 ("spi: gpio: Don't request CS GPIO in DT use-case")
Signed-off-by: Linus Walleij 
Link: https://lore.kernel.org/r/20190716204651.7743-1-linus.walleij@linaro.org
Signed-off-by: Mark Brown

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

2019-05-30T18:26:37+00:00

Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Richard Fontana 
Reviewed-by: Kate Stewart 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman