/*
 * 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 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;

        /* Make sure its a bit width we support [4..16, 32] */
        if ((bits_per_word < 4)
            || ((bits_per_word > 16) && (bits_per_word != 32))
            || (bits_per_word > mpc8xxx_spi->max_bits_per_word))
                return -EINVAL;

        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;

        INIT_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;
        unsigned int cs_change;
        const int nsecs = 50;
        int status;

        cs_change = 1;
        status = 0;
        list_for_each_entry(t, &m->transfers, transfer_list) {
                if (t->bits_per_word || t->speed_hz) {
                        /* Don't allow changes if CS is active */
                        status = -EINVAL;

                        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;
        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 = kzalloc(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->platform_data;
        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->platform_data;
        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);

        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 mpc8xxx_spi_probe_info *pinfo = to_of_pinfo(dev->platform_data);
        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->platform_data;
        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->platform_data;
        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 (!pdev->dev.platform_data)
                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_RET(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");