linux/drivers/spi/spi-fsl-spi.c

/*
 * Freescale SPI controller driver.
 *
 * Maintainer: Kumar Gala
 *
 * Copyright (C) 2006 Polycom, Inc.
 * Copyright 2010 Freescale Semiconductor, Inc.
 *
 * CPM SPI and QE buffer descriptors mode support:
 * Copyright (c) 2009  MontaVista Software, Inc.
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * GRLIB support:
 * Copyright (c) 2012 Aeroflex Gaisler AB.
 * Author: Andreas Larsson <andreas@gaisler.com>
 *
 * 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.
 */
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/platform_device.h>
#include <linux/fsl_devices.h>
#include <linux/dma-mapping.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>

#include "spi-fsl-lib.h"
#include "spi-fsl-cpm.h"
#include "spi-fsl-spi.h"

#define TYPE_FSL	0
#define TYPE_GRLIB	1

struct fsl_spi_match_data {
	int type;
};

static struct fsl_spi_match_data of_fsl_spi_fsl_config = {
	.type = TYPE_FSL,
};

static struct fsl_spi_match_data of_fsl_spi_grlib_config = {
	.type = TYPE_GRLIB,
};

static const struct of_device_id of_fsl_spi_match[] = {
	{
		.compatible = "fsl,spi",
		.data = &of_fsl_spi_fsl_config,
	},
	{
		.compatible = "aeroflexgaisler,spictrl",
		.data = &of_fsl_spi_grlib_config,
	},
	{}
};
MODULE_DEVICE_TABLE(of, of_fsl_spi_match);

static int fsl_spi_get_type(struct device *dev)
{
	const struct of_device_id *match;

	if (dev->of_node) {
		match = of_match_node(of_fsl_spi_match, dev->of_node);
		if (match && match->data)
			return ((struct fsl_spi_match_data *)match->data)->type;
	}
	return TYPE_FSL;
}

static void fsl_spi_change_mode(struct spi_device *spi)
{
	struct mpc8xxx_spi *mspi = spi_master_get_devdata(spi->master);
	struct spi_mpc8xxx_cs *cs = spi->controller_state;
	struct fsl_spi_reg *reg_base = mspi->reg_base;
	__be32 __iomem *mode = &reg_base->mode;
	unsigned long flags;

	if (cs->hw_mode == mpc8xxx_spi_read_reg(mode))
		return;

	/* Turn off IRQs locally to minimize time that SPI is disabled. */
	local_irq_save(flags);

	/* Turn off SPI unit prior changing mode */
	mpc8xxx_spi_write_reg(mode, cs->hw_mode & ~SPMODE_ENABLE);

	/* When in CPM mode, we need to reinit tx and rx. */
	if (mspi->flags & SPI_CPM_MODE) {
		fsl_spi_cpm_reinit_txrx(mspi);
	}
	mpc8xxx_spi_write_reg(mode, cs->hw_mode);
	local_irq_restore(flags);
}

static void fsl_spi_chipselect(struct spi_device *spi, int value)
{
	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
	struct fsl_spi_platform_data *pdata;
	bool pol = spi->mode & SPI_CS_HIGH;
	struct spi_mpc8xxx_cs	*cs = spi->controller_state;

	pdata = spi->dev.parent->parent->platform_data;

	if (value == BITBANG_CS_INACTIVE) {
		if (pdata->cs_control)
			pdata->cs_control(spi, !pol);
	}

	if (value == BITBANG_CS_ACTIVE) {
		mpc8xxx_spi->rx_shift = cs->rx_shift;
		mpc8xxx_spi->tx_shift = cs->tx_shift;
		mpc8xxx_spi->get_rx = cs->get_rx;
		mpc8xxx_spi->get_tx = cs->get_tx;

		fsl_spi_change_mode(spi);

		if (pdata->cs_control)
			pdata->cs_control(spi, pol);
	}
}

static void fsl_spi_qe_cpu_set_shifts(u32 *rx_shift, u32 *tx_shift,
				      int bits_per_word, int msb_first)
{
	*rx_shift = 0;
	*tx_shift = 0;
	if (msb_first) {
		if (bits_per_word <= 8) {
			*rx_shift = 16;
			*tx_shift = 24;
		} else if (bits_per_word <= 16) {
			*rx_shift = 16;
			*tx_shift = 16;
		}
	} else {
		if (bits_per_word <= 8)
			*rx_shift = 8;
	}
}

static void fsl_spi_grlib_set_shifts(u32 *rx_shift, u32 *tx_shift,
				     int bits_per_word, int msb_first)
{
	*rx_shift = 0;
	*tx_shift = 0;
	if (bits_per_word <= 16) {
		if (msb_first) {
			*rx_shift = 16; /* LSB in bit 16 */
			*tx_shift = 32 - bits_per_word; /* MSB in bit 31 */
		} else {
			*rx_shift = 16 - bits_per_word; /* MSB in bit 15 */
		}
	}
}

static int mspi_apply_cpu_mode_quirks(struct spi_mpc8xxx_cs *cs,
				struct spi_device *spi,
				struct mpc8xxx_spi *mpc8xxx_spi,
				int bits_per_word)
{
	cs->rx_shift = 0;
	cs->tx_shift = 0;
	if (bits_per_word <= 8) {
		cs->get_rx = mpc8xxx_spi_rx_buf_u8;
		cs->get_tx = mpc8xxx_spi_tx_buf_u8;
	} else if (bits_per_word <= 16) {
		cs->get_rx = mpc8xxx_spi_rx_buf_u16;
		cs->get_tx = mpc8xxx_spi_tx_buf_u16;
	} else if (bits_per_word <= 32) {
		cs->get_rx = mpc8xxx_spi_rx_buf_u32;
		cs->get_tx = mpc8xxx_spi_tx_buf_u32;
	} else
		return -EINVAL;

	if (mpc8xxx_spi->set_shifts)
		mpc8xxx_spi->set_shifts(&cs->rx_shift, &cs->tx_shift,
					bits_per_word,
					!(spi->mode & SPI_LSB_FIRST));

	mpc8xxx_spi->rx_shift = cs->rx_shift;
	mpc8xxx_spi->tx_shift = cs->tx_shift;
	mpc8xxx_spi->get_rx = cs->get_rx;
	mpc8xxx_spi->get_tx = cs->get_tx;

	return bits_per_word;
}

static int mspi_apply_qe_mode_quirks(struct spi_mpc8xxx_cs *cs,
				struct spi_device *spi,
				int bits_per_word)
{
	/* QE uses Little Endian for words > 8
	 * so transform all words > 8 into 8 bits
	 * Unfortnatly that doesn't work for LSB so
	 * reject these for now */
	/* Note: 32 bits word, LSB works iff
	 * tfcr/rfcr is set to CPMFCR_GBL */
	if (spi->mode & SPI_LSB_FIRST &&
	    bits_per_word > 8)
		return -EINVAL;
	if (bits_per_word > 8)
		return 8; /* pretend its 8 bits */
	return bits_per_word;
}

static int fsl_spi_setup_transfer(struct spi_device *spi,
					struct spi_transfer *t)
{
	struct mpc8xxx_spi *mpc8xxx_spi;
	int bits_per_word = 0;
	u8 pm;
	u32 hz = 0;
	struct spi_mpc8xxx_cs	*cs = spi->controller_state;

	mpc8xxx_spi = spi_master_get_devdata(spi->master);

	if (t) {
		bits_per_word = t->bits_per_word;
		hz = t->speed_hz;
	}

	/* spi_transfer level calls that work per-word */
	if (!bits_per_word)
		bits_per_word = spi->bits_per_word;

	if (!hz)
		hz = spi->max_speed_hz;

	if (!(mpc8xxx_spi->flags & SPI_CPM_MODE))
		bits_per_word = mspi_apply_cpu_mode_quirks(cs, spi,
							   mpc8xxx_spi,
							   bits_per_word);
	else if (mpc8xxx_spi->flags & SPI_QE)
		bits_per_word = mspi_apply_qe_mode_quirks(cs, spi,
							  bits_per_word);

	if (bits_per_word < 0)
		return bits_per_word;

	if (bits_per_word == 32)
		bits_per_word = 0;
	else
		bits_per_word = bits_per_word - 1;

	/* mask out bits we are going to set */
	cs->hw_mode &= ~(SPMODE_LEN(0xF) | SPMODE_DIV16
				  | SPMODE_PM(0xF));

	cs->hw_mode |= SPMODE_LEN(bits_per_word);

	if ((mpc8xxx_spi->spibrg / hz) > 64) {
		cs->hw_mode |= SPMODE_DIV16;
		pm = (mpc8xxx_spi->spibrg - 1) / (hz * 64) + 1;

		WARN_ONCE(pm > 16, "%s: Requested speed is too low: %d Hz. "
			  "Will use %d Hz instead.\n", dev_name(&spi->dev),
			  hz, mpc8xxx_spi->spibrg / 1024);
		if (pm > 16)
			pm = 16;
	} else {
		pm = (mpc8xxx_spi->spibrg - 1) / (hz * 4) + 1;
	}
	if (pm)
		pm--;

	cs->hw_mode |= SPMODE_PM(pm);

	fsl_spi_change_mode(spi);
	return 0;
}

static int fsl_spi_cpu_bufs(struct mpc8xxx_spi *mspi,
				struct spi_transfer *t, unsigned int len)
{
	u32 word;
	struct fsl_spi_reg *reg_base = mspi->reg_base;

	mspi->count = len;

	/* enable rx ints */
	mpc8xxx_spi_write_reg(&reg_base->mask, SPIM_NE);

	/* transmit word */
	word = mspi->get_tx(mspi);
	mpc8xxx_spi_write_reg(&reg_base->transmit, word);

	return 0;
}

static int fsl_spi_bufs(struct spi_device *spi, struct spi_transfer *t,
			    bool is_dma_mapped)
{
	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
	struct fsl_spi_reg *reg_base;
	unsigned int len = t->len;
	u8 bits_per_word;
	int ret;

	reg_base = mpc8xxx_spi->reg_base;
	bits_per_word = spi->bits_per_word;
	if (t->bits_per_word)
		bits_per_word = t->bits_per_word;

	if (bits_per_word > 8) {
		/* invalid length? */
		if (len & 1)
			return -EINVAL;
		len /= 2;
	}
	if (bits_per_word > 16) {
		/* invalid length? */
		if (len & 1)
			return -EINVAL;
		len /= 2;
	}

	mpc8xxx_spi->tx = t->tx_buf;
	mpc8xxx_spi->rx = t->rx_buf;

	reinit_completion(&mpc8xxx_spi->done);

	if (mpc8xxx_spi->flags & SPI_CPM_MODE)
		ret = fsl_spi_cpm_bufs(mpc8xxx_spi, t, is_dma_mapped);
	else
		ret = fsl_spi_cpu_bufs(mpc8xxx_spi, t, len);
	if (ret)
		return ret;

	wait_for_completion(&mpc8xxx_spi->done);

	/* disable rx ints */
	mpc8xxx_spi_write_reg(&reg_base->mask, 0);

	if (mpc8xxx_spi->flags & SPI_CPM_MODE)
		fsl_spi_cpm_bufs_complete(mpc8xxx_spi);

	return mpc8xxx_spi->count;
}

static void fsl_spi_do_one_msg(struct spi_message *m)
{
	struct spi_device *spi = m->spi;
	struct spi_transfer *t, *first;
	unsigned int cs_change;
	const int nsecs = 50;
	int status;

	/* Don't allow changes if CS is active */
	first = list_first_entry(&m->transfers, struct spi_transfer,
			transfer_list);
	list_for_each_entry(t, &m->transfers, transfer_list) {
		if ((first->bits_per_word != t->bits_per_word) ||
			(first->speed_hz != t->speed_hz)) {
			status = -EINVAL;
			dev_err(&spi->dev,
				"bits_per_word/speed_hz should be same for the same SPI transfer\n");
			return;
		}
	}

	cs_change = 1;
	status = -EINVAL;
	list_for_each_entry(t, &m->transfers, transfer_list) {
		if (t->bits_per_word || t->speed_hz) {
			if (cs_change)
				status = fsl_spi_setup_transfer(spi, t);
			if (status < 0)
				break;
		}

		if (cs_change) {
			fsl_spi_chipselect(spi, BITBANG_CS_ACTIVE);
			ndelay(nsecs);
		}
		cs_change = t->cs_change;
		if (t->len)
			status = fsl_spi_bufs(spi, t, m->is_dma_mapped);
		if (status) {
			status = -EMSGSIZE;
			break;
		}
		m->actual_length += t->len;

		if (t->delay_usecs)
			udelay(t->delay_usecs);

		if (cs_change) {
			ndelay(nsecs);
			fsl_spi_chipselect(spi, BITBANG_CS_INACTIVE);
			ndelay(nsecs);
		}
	}

	m->status = status;
	if (m->complete)
		m->complete(m->context);

	if (status || !cs_change) {
		ndelay(nsecs);
		fsl_spi_chipselect(spi, BITBANG_CS_INACTIVE);
	}

	fsl_spi_setup_transfer(spi, NULL);
}

static int fsl_spi_setup(struct spi_device *spi)
{
	struct mpc8xxx_spi *mpc8xxx_spi;
	struct fsl_spi_reg *reg_base;
	int retval;
	u32 hw_mode;
	struct spi_mpc8xxx_cs	*cs = spi->controller_state;

	if (!spi->max_speed_hz)
		return -EINVAL;

	if (!cs) {
		cs = devm_kzalloc(&spi->dev, sizeof(*cs), GFP_KERNEL);
		if (!cs)
			return -ENOMEM;
		spi->controller_state = cs;
	}
	mpc8xxx_spi = spi_master_get_devdata(spi->master);

	reg_base = mpc8xxx_spi->reg_base;

	hw_mode = cs->hw_mode; /* Save original settings */
	cs->hw_mode = mpc8xxx_spi_read_reg(&reg_base->mode);
	/* mask out bits we are going to set */
	cs->hw_mode &= ~(SPMODE_CP_BEGIN_EDGECLK | SPMODE_CI_INACTIVEHIGH
			 | SPMODE_REV | SPMODE_LOOP);

	if (spi->mode & SPI_CPHA)
		cs->hw_mode |= SPMODE_CP_BEGIN_EDGECLK;
	if (spi->mode & SPI_CPOL)
		cs->hw_mode |= SPMODE_CI_INACTIVEHIGH;
	if (!(spi->mode & SPI_LSB_FIRST))
		cs->hw_mode |= SPMODE_REV;
	if (spi->mode & SPI_LOOP)
		cs->hw_mode |= SPMODE_LOOP;

	retval = fsl_spi_setup_transfer(spi, NULL);
	if (retval < 0) {
		cs->hw_mode = hw_mode; /* Restore settings */
		return retval;
	}

	if (mpc8xxx_spi->type == TYPE_GRLIB) {
		if (gpio_is_valid(spi->cs_gpio)) {
			int desel;

			retval = gpio_request(spi->cs_gpio,
					      dev_name(&spi->dev));
			if (retval)
				return retval;

			desel = !(spi->mode & SPI_CS_HIGH);
			retval = gpio_direction_output(spi->cs_gpio, desel);
			if (retval) {
				gpio_free(spi->cs_gpio);
				return retval;
			}
		} else if (spi->cs_gpio != -ENOENT) {
			if (spi->cs_gpio < 0)
				return spi->cs_gpio;
			return -EINVAL;
		}
		/* When spi->cs_gpio == -ENOENT, a hole in the phandle list
		 * indicates to use native chipselect if present, or allow for
		 * an always selected chip
		 */
	}

	/* Initialize chipselect - might be active for SPI_CS_HIGH mode */
	fsl_spi_chipselect(spi, BITBANG_CS_INACTIVE);

	return 0;
}

static void fsl_spi_cleanup(struct spi_device *spi)
{
	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);

	if (mpc8xxx_spi->type == TYPE_GRLIB && gpio_is_valid(spi->cs_gpio))
		gpio_free(spi->cs_gpio);
}

static void fsl_spi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
{
	struct fsl_spi_reg *reg_base = mspi->reg_base;

	/* We need handle RX first */
	if (events & SPIE_NE) {
		u32 rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);

		if (mspi->rx)
			mspi->get_rx(rx_data, mspi);
	}

	if ((events & SPIE_NF) == 0)
		/* spin until TX is done */
		while (((events =
			mpc8xxx_spi_read_reg(&reg_base->event)) &
						SPIE_NF) == 0)
			cpu_relax();

	/* Clear the events */
	mpc8xxx_spi_write_reg(&reg_base->event, events);

	mspi->count -= 1;
	if (mspi->count) {
		u32 word = mspi->get_tx(mspi);

		mpc8xxx_spi_write_reg(&reg_base->transmit, word);
	} else {
		complete(&mspi->done);
	}
}

static irqreturn_t fsl_spi_irq(s32 irq, void *context_data)
{
	struct mpc8xxx_spi *mspi = context_data;
	irqreturn_t ret = IRQ_NONE;
	u32 events;
	struct fsl_spi_reg *reg_base = mspi->reg_base;

	/* Get interrupt events(tx/rx) */
	events = mpc8xxx_spi_read_reg(&reg_base->event);
	if (events)
		ret = IRQ_HANDLED;

	dev_dbg(mspi->dev, "%s: events %x\n", __func__, events);

	if (mspi->flags & SPI_CPM_MODE)
		fsl_spi_cpm_irq(mspi, events);
	else
		fsl_spi_cpu_irq(mspi, events);

	return ret;
}

static void fsl_spi_remove(struct mpc8xxx_spi *mspi)
{
	iounmap(mspi->reg_base);
	fsl_spi_cpm_free(mspi);
}

static void fsl_spi_grlib_cs_control(struct spi_device *spi, bool on)
{
	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master);
	struct fsl_spi_reg *reg_base = mpc8xxx_spi->reg_base;
	u32 slvsel;
	u16 cs = spi->chip_select;

	if (gpio_is_valid(spi->cs_gpio)) {
		gpio_set_value(spi->cs_gpio, on);
	} else if (cs < mpc8xxx_spi->native_chipselects) {
		slvsel = mpc8xxx_spi_read_reg(&reg_base->slvsel);
		slvsel = on ? (slvsel | (1 << cs)) : (slvsel & ~(1 << cs));
		mpc8xxx_spi_write_reg(&reg_base->slvsel, slvsel);
	}
}

static void fsl_spi_grlib_probe(struct device *dev)
{
	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
	struct spi_master *master = dev_get_drvdata(dev);
	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(master);
	struct fsl_spi_reg *reg_base = mpc8xxx_spi->reg_base;
	int mbits;
	u32 capabilities;

	capabilities = mpc8xxx_spi_read_reg(&reg_base->cap);

	mpc8xxx_spi->set_shifts = fsl_spi_grlib_set_shifts;
	mbits = SPCAP_MAXWLEN(capabilities);
	if (mbits)
		mpc8xxx_spi->max_bits_per_word = mbits + 1;

	mpc8xxx_spi->native_chipselects = 0;
	if (SPCAP_SSEN(capabilities)) {
		mpc8xxx_spi->native_chipselects = SPCAP_SSSZ(capabilities);
		mpc8xxx_spi_write_reg(&reg_base->slvsel, 0xffffffff);
	}
	master->num_chipselect = mpc8xxx_spi->native_chipselects;
	pdata->cs_control = fsl_spi_grlib_cs_control;
}

static struct spi_master * fsl_spi_probe(struct device *dev,
		struct resource *mem, unsigned int irq)
{
	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
	struct spi_master *master;
	struct mpc8xxx_spi *mpc8xxx_spi;
	struct fsl_spi_reg *reg_base;
	u32 regval;
	int ret = 0;

	master = spi_alloc_master(dev, sizeof(struct mpc8xxx_spi));
	if (master == NULL) {
		ret = -ENOMEM;
		goto err;
	}

	dev_set_drvdata(dev, master);

	ret = mpc8xxx_spi_probe(dev, mem, irq);
	if (ret)
		goto err_probe;

	master->setup = fsl_spi_setup;
	master->cleanup = fsl_spi_cleanup;

	mpc8xxx_spi = spi_master_get_devdata(master);
	mpc8xxx_spi->spi_do_one_msg = fsl_spi_do_one_msg;
	mpc8xxx_spi->spi_remove = fsl_spi_remove;
	mpc8xxx_spi->max_bits_per_word = 32;
	mpc8xxx_spi->type = fsl_spi_get_type(dev);

	ret = fsl_spi_cpm_init(mpc8xxx_spi);
	if (ret)
		goto err_cpm_init;

	mpc8xxx_spi->reg_base = ioremap(mem->start, resource_size(mem));
	if (mpc8xxx_spi->reg_base == NULL) {
		ret = -ENOMEM;
		goto err_ioremap;
	}

	if (mpc8xxx_spi->type == TYPE_GRLIB)
		fsl_spi_grlib_probe(dev);

	master->bits_per_word_mask =
		(SPI_BPW_RANGE_MASK(4, 16) | SPI_BPW_MASK(32)) &
		SPI_BPW_RANGE_MASK(1, mpc8xxx_spi->max_bits_per_word);

	if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE)
		mpc8xxx_spi->set_shifts = fsl_spi_qe_cpu_set_shifts;

	if (mpc8xxx_spi->set_shifts)
		/* 8 bits per word and MSB first */
		mpc8xxx_spi->set_shifts(&mpc8xxx_spi->rx_shift,
					&mpc8xxx_spi->tx_shift, 8, 1);

	/* Register for SPI Interrupt */
	ret = request_irq(mpc8xxx_spi->irq, fsl_spi_irq,
			  0, "fsl_spi", mpc8xxx_spi);

	if (ret != 0)
		goto free_irq;

	reg_base = mpc8xxx_spi->reg_base;

	/* SPI controller initializations */
	mpc8xxx_spi_write_reg(&reg_base->mode, 0);
	mpc8xxx_spi_write_reg(&reg_base->mask, 0);
	mpc8xxx_spi_write_reg(&reg_base->command, 0);
	mpc8xxx_spi_write_reg(&reg_base->event, 0xffffffff);

	/* Enable SPI interface */
	regval = pdata->initial_spmode | SPMODE_INIT_VAL | SPMODE_ENABLE;
	if (mpc8xxx_spi->max_bits_per_word < 8) {
		regval &= ~SPMODE_LEN(0xF);
		regval |= SPMODE_LEN(mpc8xxx_spi->max_bits_per_word - 1);
	}
	if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE)
		regval |= SPMODE_OP;

	mpc8xxx_spi_write_reg(&reg_base->mode, regval);

	ret = spi_register_master(master);
	if (ret < 0)
		goto unreg_master;

	dev_info(dev, "at 0x%p (irq = %d), %s mode\n", reg_base,
		 mpc8xxx_spi->irq, mpc8xxx_spi_strmode(mpc8xxx_spi->flags));

	return master;

unreg_master:
	free_irq(mpc8xxx_spi->irq, mpc8xxx_spi);
free_irq:
	iounmap(mpc8xxx_spi->reg_base);
err_ioremap:
	fsl_spi_cpm_free(mpc8xxx_spi);
err_cpm_init:
err_probe:
	spi_master_put(master);
err:
	return ERR_PTR(ret);
}

static void fsl_spi_cs_control(struct spi_device *spi, bool on)
{
	struct device *dev = spi->dev.parent->parent;
	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
	struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata);
	u16 cs = spi->chip_select;
	int gpio = pinfo->gpios[cs];
	bool alow = pinfo->alow_flags[cs];

	gpio_set_value(gpio, on ^ alow);
}

static int of_fsl_spi_get_chipselects(struct device *dev)
{
	struct device_node *np = dev->of_node;
	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
	struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata);
	int ngpios;
	int i = 0;
	int ret;

	ngpios = of_gpio_count(np);
	if (ngpios <= 0) {
		/*
		 * SPI w/o chip-select line. One SPI device is still permitted
		 * though.
		 */
		pdata->max_chipselect = 1;
		return 0;
	}

	pinfo->gpios = kmalloc(ngpios * sizeof(*pinfo->gpios), GFP_KERNEL);
	if (!pinfo->gpios)
		return -ENOMEM;
	memset(pinfo->gpios, -1, ngpios * sizeof(*pinfo->gpios));

	pinfo->alow_flags = kzalloc(ngpios * sizeof(*pinfo->alow_flags),
				    GFP_KERNEL);
	if (!pinfo->alow_flags) {
		ret = -ENOMEM;
		goto err_alloc_flags;
	}

	for (; i < ngpios; i++) {
		int gpio;
		enum of_gpio_flags flags;

		gpio = of_get_gpio_flags(np, i, &flags);
		if (!gpio_is_valid(gpio)) {
			dev_err(dev, "invalid gpio #%d: %d\n", i, gpio);
			ret = gpio;
			goto err_loop;
		}

		ret = gpio_request(gpio, dev_name(dev));
		if (ret) {
			dev_err(dev, "can't request gpio #%d: %d\n", i, ret);
			goto err_loop;
		}

		pinfo->gpios[i] = gpio;
		pinfo->alow_flags[i] = flags & OF_GPIO_ACTIVE_LOW;

		ret = gpio_direction_output(pinfo->gpios[i],
					    pinfo->alow_flags[i]);
		if (ret) {
			dev_err(dev, "can't set output direction for gpio "
				"#%d: %d\n", i, ret);
			goto err_loop;
		}
	}

	pdata->max_chipselect = ngpios;
	pdata->cs_control = fsl_spi_cs_control;

	return 0;

err_loop:
	while (i >= 0) {
		if (gpio_is_valid(pinfo->gpios[i]))
			gpio_free(pinfo->gpios[i]);
		i--;
	}

	kfree(pinfo->alow_flags);
	pinfo->alow_flags = NULL;
err_alloc_flags:
	kfree(pinfo->gpios);
	pinfo->gpios = NULL;
	return ret;
}

static int of_fsl_spi_free_chipselects(struct device *dev)
{
	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
	struct mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(pdata);
	int i;

	if (!pinfo->gpios)
		return 0;

	for (i = 0; i < pdata->max_chipselect; i++) {
		if (gpio_is_valid(pinfo->gpios[i]))
			gpio_free(pinfo->gpios[i]);
	}

	kfree(pinfo->gpios);
	kfree(pinfo->alow_flags);
	return 0;
}

static int of_fsl_spi_probe(struct platform_device *ofdev)
{
	struct device *dev = &ofdev->dev;
	struct device_node *np = ofdev->dev.of_node;
	struct spi_master *master;
	struct resource mem;
	int irq, type;
	int ret = -ENOMEM;

	ret = of_mpc8xxx_spi_probe(ofdev);
	if (ret)
		return ret;

	type = fsl_spi_get_type(&ofdev->dev);
	if (type == TYPE_FSL) {
		ret = of_fsl_spi_get_chipselects(dev);
		if (ret)
			goto err;
	}

	ret = of_address_to_resource(np, 0, &mem);
	if (ret)
		goto err;

	irq = irq_of_parse_and_map(np, 0);
	if (!irq) {
		ret = -EINVAL;
		goto err;
	}

	master = fsl_spi_probe(dev, &mem, irq);
	if (IS_ERR(master)) {
		ret = PTR_ERR(master);
		goto err;
	}

	return 0;

err:
	if (type == TYPE_FSL)
		of_fsl_spi_free_chipselects(dev);
	return ret;
}

static int of_fsl_spi_remove(struct platform_device *ofdev)
{
	struct spi_master *master = platform_get_drvdata(ofdev);
	struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(master);
	int ret;

	ret = mpc8xxx_spi_remove(&ofdev->dev);
	if (ret)
		return ret;
	if (mpc8xxx_spi->type == TYPE_FSL)
		of_fsl_spi_free_chipselects(&ofdev->dev);
	return 0;
}

static struct platform_driver of_fsl_spi_driver = {
	.driver = {
		.name = "fsl_spi",
		.owner = THIS_MODULE,
		.of_match_table = of_fsl_spi_match,
	},
	.probe		= of_fsl_spi_probe,
	.remove		= of_fsl_spi_remove,
};

#ifdef CONFIG_MPC832x_RDB
/*
 * XXX XXX XXX
 * This is "legacy" platform driver, was used by the MPC8323E-RDB boards
 * only. The driver should go away soon, since newer MPC8323E-RDB's device
 * tree can work with OpenFirmware driver. But for now we support old trees
 * as well.
 */
static int plat_mpc8xxx_spi_probe(struct platform_device *pdev)
{
	struct resource *mem;
	int irq;
	struct spi_master *master;

	if (!dev_get_platdata(&pdev->dev))
		return -EINVAL;

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem)
		return -EINVAL;

	irq = platform_get_irq(pdev, 0);
	if (irq <= 0)
		return -EINVAL;

	master = fsl_spi_probe(&pdev->dev, mem, irq);
	return PTR_ERR_OR_ZERO(master);
}

static int plat_mpc8xxx_spi_remove(struct platform_device *pdev)
{
	return mpc8xxx_spi_remove(&pdev->dev);
}

MODULE_ALIAS("platform:mpc8xxx_spi");
static struct platform_driver mpc8xxx_spi_driver = {
	.probe = plat_mpc8xxx_spi_probe,
	.remove = plat_mpc8xxx_spi_remove,
	.driver = {
		.name = "mpc8xxx_spi",
		.owner = THIS_MODULE,
	},
};

static bool legacy_driver_failed;

static void __init legacy_driver_register(void)
{
	legacy_driver_failed = platform_driver_register(&mpc8xxx_spi_driver);
}

static void __exit legacy_driver_unregister(void)
{
	if (legacy_driver_failed)
		return;
	platform_driver_unregister(&mpc8xxx_spi_driver);
}
#else
static void __init legacy_driver_register(void) {}
static void __exit legacy_driver_unregister(void) {}
#endif /* CONFIG_MPC832x_RDB */

static int __init fsl_spi_init(void)
{
	legacy_driver_register();
	return platform_driver_register(&of_fsl_spi_driver);
}
module_init(fsl_spi_init);

static void __exit fsl_spi_exit(void)
{
	platform_driver_unregister(&of_fsl_spi_driver);
	legacy_driver_unregister();
}
module_exit(fsl_spi_exit);

MODULE_AUTHOR("Kumar Gala");
MODULE_DESCRIPTION("Simple Freescale SPI Driver");
MODULE_LICENSE("GPL");