path: root/drivers/spi/spi-pxa2xx.c

/*
 * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
 * Copyright (C) 2013, Intel 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/spi/pxa2xx_spi.h>
#include <linux/spi/spi.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/acpi.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/delay.h>

#include "spi-pxa2xx.h"

MODULE_AUTHOR("Stephen Street");
MODULE_DESCRIPTION("PXA2xx SSP SPI Controller");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pxa2xx-spi");

#define MAX_BUSES 3

#define TIMOUT_DFLT		1000

/*
 * for testing SSCR1 changes that require SSP restart, basically
 * everything except the service and interrupt enables, the pxa270 developer
 * manual says only SSCR1_SCFR, SSCR1_SPH, SSCR1_SPO need to be in this
 * list, but the PXA255 dev man says all bits without really meaning the
 * service and interrupt enables
 */
#define SSCR1_CHANGE_MASK (SSCR1_TTELP | SSCR1_TTE | SSCR1_SCFR \
				| SSCR1_ECRA | SSCR1_ECRB | SSCR1_SCLKDIR \
				| SSCR1_SFRMDIR | SSCR1_RWOT | SSCR1_TRAIL \
				| SSCR1_IFS | SSCR1_STRF | SSCR1_EFWR \
				| SSCR1_RFT | SSCR1_TFT | SSCR1_MWDS \
				| SSCR1_SPH | SSCR1_SPO | SSCR1_LBM)

#define LPSS_RX_THRESH_DFLT	64
#define LPSS_TX_LOTHRESH_DFLT	160
#define LPSS_TX_HITHRESH_DFLT	224

/* Offset from drv_data->lpss_base */
#define GENERAL_REG		0x08
#define GENERAL_REG_RXTO_HOLDOFF_DISABLE BIT(24)
#define SSP_REG			0x0c
#define SPI_CS_CONTROL		0x18
#define SPI_CS_CONTROL_SW_MODE	BIT(0)
#define SPI_CS_CONTROL_CS_HIGH	BIT(1)

static bool is_lpss_ssp(const struct driver_data *drv_data)
{
	return drv_data->ssp_type == LPSS_SSP;
}

/*
 * Read and write LPSS SSP private registers. Caller must first check that
 * is_lpss_ssp() returns true before these can be called.
 */
static u32 __lpss_ssp_read_priv(struct driver_data *drv_data, unsigned offset)
{
	WARN_ON(!drv_data->lpss_base);
	return readl(drv_data->lpss_base + offset);
}

static void __lpss_ssp_write_priv(struct driver_data *drv_data,
				  unsigned offset, u32 value)
{
	WARN_ON(!drv_data->lpss_base);
	writel(value, drv_data->lpss_base + offset);
}

/*
 * lpss_ssp_setup - perform LPSS SSP specific setup
 * @drv_data: pointer to the driver private data
 *
 * Perform LPSS SSP specific setup. This function must be called first if
 * one is going to use LPSS SSP private registers.
 */
static void lpss_ssp_setup(struct driver_data *drv_data)
{
	unsigned offset = 0x400;
	u32 value, orig;

	if (</