linux-imx

/*

 * Driver for Broadcom BCM2835 SPI Controllers

 *

 * Copyright (C) 2012 Chris Boot

 * Copyright (C) 2013 Stephen Warren

 * Copyright (C) 2015 Martin Sperl

 *

 * This driver is inspired by:

 * spi-ath79.c, Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>

 * spi-atmel.c, Copyright (C) 2006 Atmel Corporation

 *

 * 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.

 */

​

#include <linux/clk.h>

#include <linux/completion.h>

#include <linux/delay.h>

#include <linux/dma-mapping.h>

#include <linux/dmaengine.h>

#include <linux/err.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/of_device.h>

#include <linux/of_gpio.h>

#include <linux/of_irq.h>

#include <linux/spi/spi.h>

​

/* SPI register offsets */

#define BCM2835_SPI_CS          0x00

#define BCM2835_SPI_FIFO        0x04

#define BCM2835_SPI_CLK         0x08

#define BCM2835_SPI_DLEN        0x0c

#define BCM2835_SPI_LTOH        0x10

#define BCM2835_SPI_DC          0x14

​

/* Bitfields in CS */

#define BCM2835_SPI_CS_LEN_LONG     0x02000000

#define BCM2835_SPI_CS_DMA_LEN      0x01000000

#define BCM2835_SPI_CS_CSPOL2       0x00800000

#define BCM2835_SPI_CS_CSPOL1       0x00400000

#define BCM2835_SPI_CS_CSPOL0       0x00200000

#define BCM2835_SPI_CS_RXF      0x00100000

#define BCM2835_SPI_CS_RXR      0x00080000

#define BCM2835_SPI_CS_TXD      0x00040000

#define BCM2835_SPI_CS_RXD      0x00020000

#define BCM2835_SPI_CS_DONE     0x00010000

#define BCM2835_SPI_CS_LEN      0x00002000

#define BCM2835_SPI_CS_REN      0x00001000

#define BCM2835_SPI_CS_ADCS     0x00000800

#define BCM2835_SPI_CS_INTR     0x00000400

#define BCM2835_SPI_CS_INTD     0x00000200

#define BCM2835_SPI_CS_DMAEN        0x00000100

#define BCM2835_SPI_CS_TA       0x00000080

#define BCM2835_SPI_CS_CSPOL        0x00000040

#define BCM2835_SPI_CS_CLEAR_RX     0x00000020

#define BCM2835_SPI_CS_CLEAR_TX     0x00000010

#define BCM2835_SPI_CS_CPOL     0x00000008

#define BCM2835_SPI_CS_CPHA     0x00000004

#define BCM2835_SPI_CS_CS_10        0x00000002

#define BCM2835_SPI_CS_CS_01        0x00000001

​

#define BCM2835_SPI_FIFO_SIZE       64

#define BCM2835_SPI_FIFO_SIZE_3_4   48

#define BCM2835_SPI_POLLING_LIMIT_US    30

#define BCM2835_SPI_POLLING_JIFFIES 2

#define BCM2835_SPI_DMA_MIN_LENGTH  96

#define BCM2835_SPI_MODE_BITS   (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \

                | SPI_NO_CS | SPI_3WIRE)

​

#define DRV_NAME    "spi-bcm2835"

​

/**

 * struct bcm2835_spi - BCM2835 SPI controller

 * @regs: base address of register map

 * @clk: core clock, divided to calculate serial clock

 * @irq: interrupt, signals TX FIFO empty or RX FIFO ¾ full

 * @tfr: SPI transfer currently processed

 * @tx_buf: pointer whence next transmitted byte is read

 * @rx_buf: pointer where next received byte is written

 * @tx_len: remaining bytes to transmit