[v1,09/10] spi: pxa2xx: Remove outdated documentation

diff --git a/Documentation/spi/pxa2xx.rst b/Documentation/spi/pxa2xx.rst
deleted file mode 100644
index 33d2ad95901e..000000000000
--- a/Documentation/spi/pxa2xx.rst
+++ /dev/null
@@ -1,208 +0,0 @@ 
-==============================
-PXA2xx SPI on SSP driver HOWTO
-==============================
-
-This a mini HOWTO on the pxa2xx_spi driver. The driver turns a PXA2xx
-synchronous serial port into an SPI host controller
-(see Documentation/spi/spi-summary.rst). The driver has the following features
-
-- Support for any PXA2xx and compatible SSP.
-- SSP PIO and SSP DMA data transfers.
-- External and Internal (SSPFRM) chip selects.
-- Per peripheral device (chip) configuration.
-- Full suspend, freeze, resume support.
-
-The driver is built around a &struct spi_message FIFO serviced by kernel
-thread. The kernel thread, spi_pump_messages(), drives message FIFO and
-is responsible for queuing SPI transactions and setting up and launching
-the DMA or interrupt driven transfers.
-
-Declaring PXA2xx host controllers
----------------------------------
-Typically, for a legacy platform, an SPI host controller is defined in the
-arch/.../mach-*/board-*.c as a "platform device". The host controller configuration
-is passed to the driver via a table found in include/linux/spi/pxa2xx_spi.h::
-
-  struct pxa2xx_spi_controller {
-	u8 num_chipselect;
-	u8 enable_dma;
-	...
-  };
-
-The "pxa2xx_spi_controller.num_chipselect" field is used to determine the number of
-peripheral devices (chips) attached to this SPI host controller.
-
-The "pxa2xx_spi_controller.enable_dma" field informs the driver that SSP DMA should
-be used. This caused the driver to acquire two DMA channels: Rx channel and
-Tx channel. The Rx channel has a higher DMA service priority than the Tx channel.
-See the "PXA2xx Developer Manual" section "DMA Controller".
-
-For the new platforms the description of the controller and peripheral devices
-comes from Device Tree or ACPI.
-
-NSSP HOST SAMPLE
-----------------
-Below is a sample configuration using the PXA255 NSSP for a legacy platform::
-
-  static struct resource pxa_spi_nssp_resources[] = {
-	[0] = {
-		.start	= __PREG(SSCR0_P(2)), /* Start address of NSSP */
-		.end	= __PREG(SSCR0_P(2)) + 0x2c, /* Range of registers */
-		.flags	= IORESOURCE_MEM,
-	},
-	[1] = {
-		.start	= IRQ_NSSP, /* NSSP IRQ */
-		.end	= IRQ_NSSP,
-		.flags	= IORESOURCE_IRQ,
-	},
-  };
-
-  static struct pxa2xx_spi_controller pxa_nssp_controller_info = {
-	.num_chipselect = 1, /* Matches the number of chips attached to NSSP */
-	.enable_dma = 1, /* Enables NSSP DMA */
-  };
-
-  static struct platform_device pxa_spi_nssp = {
-	.name = "pxa2xx-spi", /* MUST BE THIS VALUE, so device match driver */
-	.id = 2, /* Bus number, MUST MATCH SSP number 1..n */
-	.resource = pxa_spi_nssp_resources,
-	.num_resources = ARRAY_SIZE(pxa_spi_nssp_resources),
-	.dev = {
-		.platform_data = &pxa_nssp_controller_info, /* Passed to driver */
-	},
-  };
-
-  static struct platform_device *devices[] __initdata = {
-	&pxa_spi_nssp,
-  };
-
-  static void __init board_init(void)
-  {
-	(void)platform_add_device(devices, ARRAY_SIZE(devices));
-  }
-
-Declaring peripheral devices
-----------------------------
-Typically, for a legacy platform, each SPI peripheral device (chip) is defined in the
-arch/.../mach-*/board-*.c using the "spi_board_info" structure found in
-"linux/spi/spi.h". See "Documentation/spi/spi-summary.rst" for additional
-information.
-
-Each peripheral device (chip) attached to the PXA2xx must provide specific chip configuration
-information via the structure "pxa2xx_spi_chip" found in
-"include/linux/spi/pxa2xx_spi.h". The PXA2xx host controller driver will use
-the configuration whenever the driver communicates with the peripheral
-device. All fields are optional.
-
-::
-
-  struct pxa2xx_spi_chip {
-	u8 tx_threshold;
-	u8 rx_threshold;
-	u8 dma_burst_size;
-	u32 timeout;
-  };
-
-The "pxa2xx_spi_chip.tx_threshold" and "pxa2xx_spi_chip.rx_threshold" fields are
-used to configure the SSP hardware FIFO. These fields are critical to the
-performance of pxa2xx_spi driver and misconfiguration will result in rx
-FIFO overruns (especially in PIO mode transfers). Good default values are::
-
-	.tx_threshold = 8,
-	.rx_threshold = 8,
-
-The range is 1 to 16 where zero indicates "use default".
-
-The "pxa2xx_spi_chip.dma_burst_size" field is used to configure PXA2xx DMA
-engine and is related the "spi_device.bits_per_word" field.  Read and understand
-the PXA2xx "Developer Manual" sections on the DMA controller and SSP Controllers
-to determine the correct value. An SSP configured for byte-wide transfers would
-use a value of 8. The driver will determine a reasonable default if
-dma_burst_size == 0.
-
-The "pxa2xx_spi_chip.timeout" fields is used to efficiently handle
-trailing bytes in the SSP receiver FIFO. The correct value for this field is
-dependent on the SPI bus speed ("spi_board_info.max_speed_hz") and the specific
-peripheral device. Please note that the PXA2xx SSP 1 does not support trailing byte
-timeouts and must busy-wait any trailing bytes.
-
-NOTE: the SPI driver cannot control the chip select if SSPFRM is used, so the
-chipselect is dropped after each spi_transfer.  Most devices need chip select
-asserted around the complete message. Use SSPFRM as a GPIO (through a descriptor)
-to accommodate these chips.
-
-
-NSSP PERIPHERAL SAMPLE
-----------------------
-For a legacy platform or in some other cases, the pxa2xx_spi_chip structure
-is passed to the pxa2xx_spi driver in the "spi_board_info.controller_data"
-field. Below is a sample configuration using the PXA255 NSSP.
-
-::
-
-  static struct pxa2xx_spi_chip cs8415a_chip_info = {
-	.tx_threshold = 8, /* SSP hardware FIFO threshold */
-	.rx_threshold = 8, /* SSP hardware FIFO threshold */
-	.dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */
-	.timeout = 235, /* See Intel documentation */
-  };
-
-  static struct pxa2xx_spi_chip cs8405a_chip_info = {
-	.tx_threshold = 8, /* SSP hardware FIFO threshold */
-	.rx_threshold = 8, /* SSP hardware FIFO threshold */
-	.dma_burst_size = 8, /* Byte wide transfers used so 8 byte bursts */
-	.timeout = 235, /* See Intel documentation */
-  };
-
-  static struct spi_board_info streetracer_spi_board_info[] __initdata = {
-	{
-		.modalias = "cs8415a", /* Name of spi_driver for this device */
-		.max_speed_hz = 3686400, /* Run SSP as fast a possible */
-		.bus_num = 2, /* Framework bus number */
-		.chip_select = 0, /* Framework chip select */
-		.platform_data = NULL; /* No spi_driver specific config */
-		.controller_data = &cs8415a_chip_info, /* Host controller config */
-		.irq = STREETRACER_APCI_IRQ, /* Peripheral device interrupt */
-	},
-	{
-		.modalias = "cs8405a", /* Name of spi_driver for this device */
-		.max_speed_hz = 3686400, /* Run SSP as fast a possible */
-		.bus_num = 2, /* Framework bus number */
-		.chip_select = 1, /* Framework chip select */
-		.controller_data = &cs8405a_chip_info, /* Host controller config */
-		.irq = STREETRACER_APCI_IRQ, /* Peripheral device interrupt */
-	},
-  };
-
-  static void __init streetracer_init(void)
-  {
-	spi_register_board_info(streetracer_spi_board_info,
-				ARRAY_SIZE(streetracer_spi_board_info));
-  }
-
-
-DMA and PIO I/O Support
------------------------
-The pxa2xx_spi driver supports both DMA and interrupt driven PIO message
-transfers.  The driver defaults to PIO mode and DMA transfers must be enabled
-by setting the "enable_dma" flag in the "pxa2xx_spi_controller" structure.
-For the newer platforms, that are known to support DMA, the driver will enable
-it automatically and try it first with a possible fallback to PIO. The DMA
-mode supports both coherent and stream based DMA mappings.
-
-The following logic is used to determine the type of I/O to be used on
-a per "spi_transfer" basis::
-
-  if spi_message.len > 65536 then
-	print "rate limited" warning
-	use PIO transfers
-
-  if enable_dma and the size is in the range [DMA burst size..65536] then
-	use streaming DMA mode
-
-  otherwise
-	use PIO transfer
-
-THANKS TO
----------
-David Brownell and others for mentoring the development of this driver.