spi: at91-usart: Remove some dead code

dma_request_chan() does not return NULL. It returns a valid pointer or an
error pointer.

So, some dead code can be removed.

The IS_ERR_OR_NULL() in the error handling path are still needed, because
the error handling path is common to the whole function and the
ctlr->dma_xx are NULL when at91_usart_spi_configure_dma() is called.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/84eb08daf85d203b34af9d8d08abf86804211413.1694961365.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: at91-usart: Use PTR_ERR_OR_ZERO() to simplify code

Return PTR_ERR_OR_ZERO() instead of return 0 or PTR_ERR() to
simplify code.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Link: https://lore.kernel.org/r/20230822124643.987079-1-ruanjinjie@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230714174955.4064174-1-robh@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: Get rid of old SPI_MASTER_MUST_TX & SPI_MASTER_MUST_RX

Convert the users from SPI_MASTER_MUST_TX and/or SPI_MASTER_MUST_RX
to SPI_CONTROLLER_MUST_TX and/or SPI_CONTROLLER_MUST_RX respectively
and kill the not used anymore definitions.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230710154932.68377-13-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

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

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 <amit.kumar-mahapatra@amd.com>
Acked-by: Heiko Stuebner <heiko@sntech.de> # Rockchip drivers
Reviewed-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org> # Aspeed driver
Reviewed-by: Dhruva Gole <d-gole@ti.com> # SPI Cadence QSPI
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com> # spi-stm32-qspi
Acked-by: William Zhang <william.zhang@broadcom.com> # bcm63xx-hsspi driver
Reviewed-by: Serge Semin <fancer.lancer@gmail.com> # DW SSI part
Link: https://lore.kernel.org/r/167847070432.26.15076794204368669839@mailman-core.alsa-project.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: at91-usart: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230303172041.2103336-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: at91-usart: switch to use modern name

Change legacy name master to modern name host or controller.

No functional changed.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20230110131805.2827248-3-yangyingliang@huawei.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: at91-usart: replacing legacy gpio interface for gpiod

Removing dependency of linux/of_gpio.h and replacing it for
linux/gpio/consumer.h

Signed-off-by: Maíra Canal <maira.canal@usp.br>
Link: https://lore.kernel.org/r/YW8I5Emdc3t0cqhz@fedora
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: spi-at91-usart: Remove unused OF table 'struct of_device_id'

The only way this driver can be probed by MFD via its parent device.

No other reference to 'microchip,at91sam9g45-usart-spi' exists in the kernel.

Fixes the following W=1 kernel build warning(s):

drivers/spi/spi-at91-usart.c:684:34: warning: ‘at91_usart_spi_dt_ids’ defined but not used [-Wunused-const-variable=]
684 | static const struct of_device_id at91_usart_spi_dt_ids[] = {
| ^~~~~~~~~~~~~~~~~~~~~

Suggested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Radu Pirea <radu_nicolae.pirea@upb.ro>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Link: https://lore.kernel.org/r/20200717135424.2442271-13-lee.jones@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: at91-usart: Use dma_request_chan() directly for channel request

dma_request_slave_channel_reason() is:
#define dma_request_slave_channel_reason(dev, name) \
dma_request_chan(dev, name)

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20191113094256.1108-2-peter.ujfalusi@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: at91-usart: add DMA support

This patch adds support for DMA. Transfers are done with dma only if
they are longer than 16 bytes in order to achieve a better performance.
DMA setup introduces a little overhead and for transfers shorter than 16
bytes there is no performance improvement.

Signed-off-by: Radu Pirea <radu_nicolae.pirea@upb.ro>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: at91-usart: Remove duplicated checking for spi->bits_per_word

This checking is already done in __spi_validate_bits_per_word().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: fix spi-at91-usart.c build errors when PINCTRL is not set

Fix build errors when CONFIG_PINCTRL is not enabled.
The header file <linux/pinctrl/consumer.h> handles both CONFIG_PINCTRL
enabled and disabled cases.

CC [M] drivers/spi/spi-at91-usart.o
../drivers/spi/spi-at91-usart.c: In function 'at91_usart_spi_runtime_suspend':
../drivers/spi/spi-at91-usart.c:409:2: error: implicit declaration of function 'pinctrl_pm_select_sleep_state' [-Werror=implicit-function-declaration]
pinctrl_pm_select_sleep_state(dev);
../drivers/spi/spi-at91-usart.c: In function 'at91_usart_spi_runtime_resume':
../drivers/spi/spi-at91-usart.c:419:2: error: implicit declaration of function 'pinctrl_pm_select_default_state' [-Werror=implicit-function-declaration]
pinctrl_pm_select_default_state(dev);

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Radu Pirea <radu.pirea@microchip.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: at91-usart: add power management support

This patch implements power management callback function for USART as
SPI driver.

Signed-off-by: Radu Pirea <radu_nicolae.pirea@upb.ro>
Signed-off-by: Mark Brown <broonie@kernel.org>

spi: at91-usart: Make local functions static

Suggested-by: Radu Nicolae Pirea <pirea.radu@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

spi: at91-usart: Add driver for at91-usart as SPI

This is the driver for at91-usart in spi mode. The USART IP can be configured
to work in many modes and one of them is SPI.

The driver was tested on sama5d3-xplained and sama5d4-xplained boards with
enc28j60 ethernet controller as slave.

Signed-off-by: Radu Pirea <radu.pirea@microchip.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviwed-by: Mark Brown <broonie@kernel.org>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>