Linux 4.19-rc7

[linux-2.6/btrfs-unstable.git] / drivers / spi / spi-orion.c

/*
 * Marvell Orion SPI controller driver
 *
 * Author: Shadi Ammouri <shadi@marvell.com>
 * Copyright (C) 2007-2008 Marvell Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/clk.h>
#include <linux/sizes.h>
#include <linux/gpio.h>
#include <asm/unaligned.h>

#define DRIVER_NAME                     "orion_spi"

/* Runtime PM autosuspend timeout: PM is fairly light on this driver */
#define SPI_AUTOSUSPEND_TIMEOUT         200

/* Some SoCs using this driver support up to 8 chip selects.
 * It is up to the implementer to only use the chip selects
 * that are available.
 */
#define ORION_NUM_CHIPSELECTS           8

#define ORION_SPI_WAIT_RDY_MAX_LOOP     2000 /* in usec */

#define ORION_SPI_IF_CTRL_REG           0x00
#define ORION_SPI_IF_CONFIG_REG         0x04
#define ORION_SPI_IF_RXLSBF             BIT(14)
#define ORION_SPI_IF_TXLSBF             BIT(13)
#define ORION_SPI_DATA_OUT_REG          0x08
#define ORION_SPI_DATA_IN_REG           0x0c
#define ORION_SPI_INT_CAUSE_REG         0x10
#define ORION_SPI_TIMING_PARAMS_REG     0x18

/* Register for the "Direct Mode" */
#define SPI_DIRECT_WRITE_CONFIG_REG     0x20

#define ORION_SPI_TMISO_SAMPLE_MASK     (0x3 << 6)
#define ORION_SPI_TMISO_SAMPLE_1        (1 << 6)
#define ORION_SPI_TMISO_SAMPLE_2        (2 << 6)

#define ORION_SPI_MODE_CPOL             (1 << 11)
#define ORION_SPI_MODE_CPHA             (1 << 12)
#define ORION_SPI_IF_8_16_BIT_MODE      (1 << 5)
#define ORION_SPI_CLK_PRESCALE_MASK     0x1F
#define ARMADA_SPI_CLK_PRESCALE_MASK    0xDF
#define ORION_SPI_MODE_MASK             (ORION_SPI_MODE_CPOL | \
                                         ORION_SPI_MODE_CPHA)
#define ORION_SPI_CS_MASK       0x1C
#define ORION_SPI_CS_SHIFT      2
#define ORION_SPI_CS(cs)        ((cs << ORION_SPI_CS_SHIFT) & \
                                        ORION_SPI_CS_MASK)

enum orion_spi_type {
        ORION_SPI,
        ARMADA_SPI,
};

struct orion_spi_dev {
        enum orion_spi_type     typ;
        /*
         * min_divisor and max_hz should be exclusive, the only we can
         * have both is for managing the armada-370-spi case with old
         * device tree
         */
        unsigned long           max_hz;
        unsigned int            min_divisor;
        unsigned int            max_divisor;
        u32                     prescale_mask;
        bool                    is_errata_50mhz_ac;
};

struct orion_direct_acc {
        void __iomem            *vaddr;
        u32                     size;
};

struct orion_child_options {
        struct orion_direct_acc direct_access;
};

struct orion_spi {
        struct spi_master       *master;
        void __iomem            *base;
        struct clk              *clk;
        struct clk              *axi_clk;
        const struct orion_spi_dev *devdata;
        int                     unused_hw_gpio;

        struct orion_child_options      child[ORION_NUM_CHIPSELECTS];
};

static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
{
        return orion_spi->base + reg;
}

static inline void
orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
{
        void __iomem *reg_addr = spi_reg(orion_spi, reg);
        u32 val;

        val = readl(reg_addr);
        val |= mask;
        writel(val, reg_addr);
}

static inline void
orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
{
        void __iomem *reg_addr = spi_reg(orion_spi, reg);
        u32 val;

        val = readl(reg_addr);
        val &= ~mask;
        writel(val, reg_addr);
}

static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
{
        u32 tclk_hz;
        u32 rate;
        u32 prescale;
        u32 reg;
        struct orion_spi *orion_spi;
        const struct orion_spi_dev *devdata;

        orion_spi = spi_master_get_devdata(spi->master);
        devdata = orion_spi->devdata;

        tclk_hz = clk_get_rate(orion_spi->clk);

        if (devdata->typ == ARMADA_SPI) {
                /*
                 * Given the core_clk (tclk_hz) and the target rate (speed) we
                 * determine the best values for SPR (in [0 .. 15]) and SPPR (in
                 * [0..7]) such that
                 *
                 *      core_clk / (SPR * 2 ** SPPR)
                 *
                 * is as big as possible but not bigger than speed.
                 */

                /* best integer divider: */
                unsigned divider = DIV_ROUND_UP(tclk_hz, speed);
                unsigned spr, sppr;

                if (divider < 16) {
                        /* This is the easy case, divider is less than 16 */
                        spr = divider;
                        sppr = 0;

                } else {
                        unsigned two_pow_sppr;
                        /*
                         * Find the highest bit set in divider. This and the
                         * three next bits define SPR (apart from rounding).
                         * SPPR is then the number of zero bits that must be
                         * appended:
                         */
                        sppr = fls(divider) - 4;

                        /*
                         * As SPR only has 4 bits, we have to round divider up
                         * to the next multiple of 2 ** sppr.
                         */
                        two_pow_sppr = 1 << sppr;
                        divider = (divider + two_pow_sppr - 1) & -two_pow_sppr;

                        /*
                         * recalculate sppr as rounding up divider might have
                         * increased it enough to change the position of the
                         * highest set bit. In this case the bit that now
                         * doesn't make it into SPR is 0, so there is no need to
                         * round again.
                         */
                        sppr = fls(divider) - 4;
                        spr = divider >> sppr;

                        /*
                         * Now do range checking. SPR is constructed to have a
                         * width of 4 bits, so this is fine for sure. So we
                         * still need to check for sppr to fit into 3 bits:
                         */
                        if (sppr > 7)
                                return -EINVAL;
                }

                prescale = ((sppr & 0x6) << 5) | ((sppr & 0x1) << 4) | spr;
        } else {
                /*
                 * the supported rates are: 4,6,8...30
                 * round up as we look for equal or less speed
                 */
                rate = DIV_ROUND_UP(tclk_hz, speed);
                rate = roundup(rate, 2);

                /* check if requested speed is too small */
                if (rate > 30)
                        return -EINVAL;

                if (rate < 4)
                        rate = 4;

                /* Convert the rate to SPI clock divisor value. */
                prescale = 0x10 + rate/2;
        }

        reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
        reg = ((reg & ~devdata->prescale_mask) | prescale);
        writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));

        return 0;
}

static void
orion_spi_mode_set(struct spi_device *spi)
{
        u32 reg;
        struct orion_spi *orion_spi;

        orion_spi = spi_master_get_devdata(spi->master);

        reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
        reg &= ~ORION_SPI_MODE_MASK;
        if (spi->mode & SPI_CPOL)
                reg |= ORION_SPI_MODE_CPOL;
        if (spi->mode & SPI_CPHA)
                reg |= ORION_SPI_MODE_CPHA;
        if (spi->mode & SPI_LSB_FIRST)
                reg |= ORION_SPI_IF_RXLSBF | ORION_SPI_IF_TXLSBF;
        else
                reg &= ~(ORION_SPI_IF_RXLSBF | ORION_SPI_IF_TXLSBF);

        writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
}

static void
orion_spi_50mhz_ac_timing_erratum(struct spi_device *spi, unsigned int speed)
{
        u32 reg;
        struct orion_spi *orion_spi;

        orion_spi = spi_master_get_devdata(spi->master);

        /*
         * Erratum description: (Erratum NO. FE-9144572) The device
         * SPI interface supports frequencies of up to 50 MHz.
         * However, due to this erratum, when the device core clock is
         * 250 MHz and the SPI interfaces is configured for 50MHz SPI
         * clock and CPOL=CPHA=1 there might occur data corruption on
         * reads from the SPI device.
         * Erratum Workaround:
         * Work in one of the following configurations:
         * 1. Set CPOL=CPHA=0 in "SPI Interface Configuration
         * Register".
         * 2. Set TMISO_SAMPLE value to 0x2 in "SPI Timing Parameters 1
         * Register" before setting the interface.
         */
        reg = readl(spi_reg(orion_spi, ORION_SPI_TIMING_PARAMS_REG));
        reg &= ~ORION_SPI_TMISO_SAMPLE_MASK;

        if (clk_get_rate(orion_spi->clk) == 250000000 &&
                        speed == 50000000 && spi->mode & SPI_CPOL &&
                        spi->mode & SPI_CPHA)
                reg |= ORION_SPI_TMISO_SAMPLE_2;
        else
                reg |= ORION_SPI_TMISO_SAMPLE_1; /* This is the default value */

        writel(reg, spi_reg(orion_spi, ORION_SPI_TIMING_PARAMS_REG));
}

/*
 * called only when no transfer is active on the bus
 */
static int
orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
{
        struct orion_spi *orion_spi;
        unsigned int speed = spi->max_speed_hz;
        unsigned int bits_per_word = spi->bits_per_word;
        int     rc;

        orion_spi = spi_master_get_devdata(spi->master);

        if ((t != NULL) && t->speed_hz)
                speed = t->speed_hz;

        if ((t != NULL) && t->bits_per_word)
                bits_per_word = t->bits_per_word;

        orion_spi_mode_set(spi);

        if (orion_spi->devdata->is_errata_50mhz_ac)
                orion_spi_50mhz_ac_timing_erratum(spi, speed);

        rc = orion_spi_baudrate_set(spi, speed);
        if (rc)
                return rc;

        if (bits_per_word == 16)
                orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
                                  ORION_SPI_IF_8_16_BIT_MODE);
        else
                orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
                                  ORION_SPI_IF_8_16_BIT_MODE);

        return 0;
}

static void orion_spi_set_cs(struct spi_device *spi, bool enable)
{
        struct orion_spi *orion_spi;
        int cs;

        orion_spi = spi_master_get_devdata(spi->master);

        if (gpio_is_valid(spi->cs_gpio))
                cs = orion_spi->unused_hw_gpio;
        else
                cs = spi->chip_select;

        orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, ORION_SPI_CS_MASK);
        orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG,
                                ORION_SPI_CS(cs));

        /* Chip select logic is inverted from spi_set_cs */
        if (!enable)
                orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
        else
                orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
}

static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
{
        int i;

        for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
                if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
                        return 1;

                udelay(1);
        }

        return -1;
}

static inline int
orion_spi_write_read_8bit(struct spi_device *spi,
                          const u8 **tx_buf, u8 **rx_buf)
{
        void __iomem *tx_reg, *rx_reg, *int_reg;
        struct orion_spi *orion_spi;

        orion_spi = spi_master_get_devdata(spi->master);
        tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
        rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
        int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);

        /* clear the interrupt cause register */
        writel(0x0, int_reg);

        if (tx_buf && *tx_buf)
                writel(*(*tx_buf)++, tx_reg);
        else
                writel(0, tx_reg);

        if (orion_spi_wait_till_ready(orion_spi) < 0) {
                dev_err(&spi->dev, "TXS timed out\n");
                return -1;
        }

        if (rx_buf && *rx_buf)
                *(*rx_buf)++ = readl(rx_reg);

        return 1;
}

static inline int
orion_spi_write_read_16bit(struct spi_device *spi,
                           const u16 **tx_buf, u16 **rx_buf)
{
        void __iomem *tx_reg, *rx_reg, *int_reg;
        struct orion_spi *orion_spi;

        orion_spi = spi_master_get_devdata(spi->master);
        tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
        rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
        int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);

        /* clear the interrupt cause register */
        writel(0x0, int_reg);

        if (tx_buf && *tx_buf)
                writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
        else
                writel(0, tx_reg);

        if (orion_spi_wait_till_ready(orion_spi) < 0) {
                dev_err(&spi->dev, "TXS timed out\n");
                return -1;
        }

        if (rx_buf && *rx_buf)
                put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);

        return 1;
}

static unsigned int
orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
{
        unsigned int count;
        int word_len;
        struct orion_spi *orion_spi;
        int cs = spi->chip_select;

        word_len = spi->bits_per_word;
        count = xfer->len;

        orion_spi = spi_master_get_devdata(spi->master);

        /*
         * Use SPI direct write mode if base address is available. Otherwise
         * fall back to PIO mode for this transfer.
         */
        if ((orion_spi->child[cs].direct_access.vaddr) && (xfer->tx_buf) &&
            (word_len == 8)) {
                unsigned int cnt = count / 4;
                unsigned int rem = count % 4;

                /*
                 * Send the TX-data to the SPI device via the direct
                 * mapped address window
                 */
                iowrite32_rep(orion_spi->child[cs].direct_access.vaddr,
                              xfer->tx_buf, cnt);
                if (rem) {
                        u32 *buf = (u32 *)xfer->tx_buf;

                        iowrite8_rep(orion_spi->child[cs].direct_access.vaddr,
                                     &buf[cnt], rem);
                }

                return count;
        }

        if (word_len == 8) {
                const u8 *tx = xfer->tx_buf;
                u8 *rx = xfer->rx_buf;

                do {
                        if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
                                goto out;
                        count--;
                } while (count);
        } else if (word_len == 16) {
                const u16 *tx = xfer->tx_buf;
                u16 *rx = xfer->rx_buf;

                do {
                        if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
                                goto out;
                        count -= 2;
                } while (count);
        }

out:
        return xfer->len - count;
}

static int orion_spi_transfer_one(struct spi_master *master,
                                        struct spi_device *spi,
                                        struct spi_transfer *t)
{
        int status = 0;

        status = orion_spi_setup_transfer(spi, t);
        if (status < 0)
                return status;

        if (t->len)
                orion_spi_write_read(spi, t);

        return status;
}

static int orion_spi_setup(struct spi_device *spi)
{
        if (gpio_is_valid(spi->cs_gpio)) {
                gpio_direction_output(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));
        }
        return orion_spi_setup_transfer(spi, NULL);
}

static int orion_spi_reset(struct orion_spi *orion_spi)
{
        /* Verify that the CS is deasserted */
        orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);

        /* Don't deassert CS between the direct mapped SPI transfers */
        writel(0, spi_reg(orion_spi, SPI_DIRECT_WRITE_CONFIG_REG));

        return 0;
}

static const struct orion_spi_dev orion_spi_dev_data = {
        .typ = ORION_SPI,
        .min_divisor = 4,
        .max_divisor = 30,
        .prescale_mask = ORION_SPI_CLK_PRESCALE_MASK,
};

static const struct orion_spi_dev armada_370_spi_dev_data = {
        .typ = ARMADA_SPI,
        .min_divisor = 4,
        .max_divisor = 1920,
        .max_hz = 50000000,
        .prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
};

static const struct orion_spi_dev armada_xp_spi_dev_data = {
        .typ = ARMADA_SPI,
        .max_hz = 50000000,
        .max_divisor = 1920,
        .prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
};

static const struct orion_spi_dev armada_375_spi_dev_data = {
        .typ = ARMADA_SPI,
        .min_divisor = 15,
        .max_divisor = 1920,
        .prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
};

static const struct orion_spi_dev armada_380_spi_dev_data = {
        .typ = ARMADA_SPI,
        .max_hz = 50000000,
        .max_divisor = 1920,
        .prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
        .is_errata_50mhz_ac = true,
};

static const struct of_device_id orion_spi_of_match_table[] = {
        {
                .compatible = "marvell,orion-spi",
                .data = &orion_spi_dev_data,
        },
        {
                .compatible = "marvell,armada-370-spi",
                .data = &armada_370_spi_dev_data,
        },
        {
                .compatible = "marvell,armada-375-spi",
                .data = &armada_375_spi_dev_data,
        },
        {
                .compatible = "marvell,armada-380-spi",
                .data = &armada_380_spi_dev_data,
        },
        {
                .compatible = "marvell,armada-390-spi",
                .data = &armada_xp_spi_dev_data,
        },
        {
                .compatible = "marvell,armada-xp-spi",
                .data = &armada_xp_spi_dev_data,
        },

        {}
};
MODULE_DEVICE_TABLE(of, orion_spi_of_match_table);

static int orion_spi_probe(struct platform_device *pdev)
{
        const struct of_device_id *of_id;
        const struct orion_spi_dev *devdata;
        struct spi_master *master;
        struct orion_spi *spi;
        struct resource *r;
        unsigned long tclk_hz;
        int status = 0;
        struct device_node *np;

        master = spi_alloc_master(&pdev->dev, sizeof(*spi));
        if (master == NULL) {
                dev_dbg(&pdev->dev, "master allocation failed\n");
                return -ENOMEM;
        }

        if (pdev->id != -1)
                master->bus_num = pdev->id;
        if (pdev->dev.of_node) {
                u32 cell_index;

                if (!of_property_read_u32(pdev->dev.of_node, "cell-index",
                                          &cell_index))
                        master->bus_num = cell_index;
        }

        /* we support all 4 SPI modes and LSB first option */
        master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LSB_FIRST;
        master->set_cs = orion_spi_set_cs;
        master->transfer_one = orion_spi_transfer_one;
        master->num_chipselect = ORION_NUM_CHIPSELECTS;
        master->setup = orion_spi_setup;
        master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
        master->auto_runtime_pm = true;
        master->flags = SPI_MASTER_GPIO_SS;

        platform_set_drvdata(pdev, master);

        spi = spi_master_get_devdata(master);
        spi->master = master;
        spi->unused_hw_gpio = -1;

        of_id = of_match_device(orion_spi_of_match_table, &pdev->dev);
        devdata = (of_id) ? of_id->data : &orion_spi_dev_data;
        spi->devdata = devdata;

        spi->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(spi->clk)) {
                status = PTR_ERR(spi->clk);
                goto out;
        }

        status = clk_prepare_enable(spi->clk);
        if (status)
                goto out;

        /* The following clock is only used by some SoCs */
        spi->axi_clk = devm_clk_get(&pdev->dev, "axi");
        if (IS_ERR(spi->axi_clk) &&
            PTR_ERR(spi->axi_clk) == -EPROBE_DEFER) {
                status = -EPROBE_DEFER;
                goto out_rel_clk;
        }
        if (!IS_ERR(spi->axi_clk))
                clk_prepare_enable(spi->axi_clk);

        tclk_hz = clk_get_rate(spi->clk);

        /*
         * With old device tree, armada-370-spi could be used with
         * Armada XP, however for this SoC the maximum frequency is
         * 50MHz instead of tclk/4. On Armada 370, tclk cannot be
         * higher than 200MHz. So, in order to be able to handle both
         * SoCs, we can take the minimum of 50MHz and tclk/4.
         */
        if (of_device_is_compatible(pdev->dev.of_node,
                                        "marvell,armada-370-spi"))
                master->max_speed_hz = min(devdata->max_hz,
                                DIV_ROUND_UP(tclk_hz, devdata->min_divisor));
        else if (devdata->min_divisor)
                master->max_speed_hz =
                        DIV_ROUND_UP(tclk_hz, devdata->min_divisor);
        else
                master->max_speed_hz = devdata->max_hz;
        master->min_speed_hz = DIV_ROUND_UP(tclk_hz, devdata->max_divisor);

        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        spi->base = devm_ioremap_resource(&pdev->dev, r);
        if (IS_ERR(spi->base)) {
                status = PTR_ERR(spi->base);
                goto out_rel_axi_clk;
        }

        for_each_available_child_of_node(pdev->dev.of_node, np) {
                u32 cs;
                int cs_gpio;

                /* Get chip-select number from the "reg" property */
                status = of_property_read_u32(np, "reg", &cs);
                if (status) {
                        dev_err(&pdev->dev,
                                "%pOF has no valid 'reg' property (%d)\n",
                                np, status);
                        continue;
                }

                /*
                 * Initialize the CS GPIO:
                 * - properly request the actual GPIO signal
                 * - de-assert the logical signal so that all GPIO CS lines
                 *   are inactive when probing for slaves
                 * - find an unused physical CS which will be driven for any
                 *   slave which uses a CS GPIO
                 */
                cs_gpio = of_get_named_gpio(pdev->dev.of_node, "cs-gpios", cs);
                if (cs_gpio > 0) {
                        char *gpio_name;
                        int cs_flags;

                        if (spi->unused_hw_gpio == -1) {
                                dev_info(&pdev->dev,
                                        "Selected unused HW CS#%d for any GPIO CSes\n",
                                        cs);
                                spi->unused_hw_gpio = cs;
                        }

                        gpio_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
                                        "%s-CS%d", dev_name(&pdev->dev), cs);
                        if (!gpio_name) {
                                status = -ENOMEM;
                                goto out_rel_axi_clk;
                        }

                        cs_flags = of_property_read_bool(np, "spi-cs-high") ?
                                GPIOF_OUT_INIT_LOW : GPIOF_OUT_INIT_HIGH;
                        status = devm_gpio_request_one(&pdev->dev, cs_gpio,
                                        cs_flags, gpio_name);
                        if (status) {
                                dev_err(&pdev->dev,
                                        "Can't request GPIO for CS %d\n", cs);
                                goto out_rel_axi_clk;
                        }
                }

                /*
                 * Check if an address is configured for this SPI device. If
                 * not, the MBus mapping via the 'ranges' property in the 'soc'
                 * node is not configured and this device should not use the
                 * direct mode. In this case, just continue with the next
                 * device.
                 */
                status = of_address_to_resource(pdev->dev.of_node, cs + 1, r);
                if (status)
                        continue;

                /*
                 * Only map one page for direct access. This is enough for the
                 * simple TX transfer which only writes to the first word.
                 * This needs to get extended for the direct SPI-NOR / SPI-NAND
                 * support, once this gets implemented.
                 */
                spi->child[cs].direct_access.vaddr = devm_ioremap(&pdev->dev,
                                                            r->start,
                                                            PAGE_SIZE);
                if (!spi->child[cs].direct_access.vaddr) {
                        status = -ENOMEM;
                        goto out_rel_axi_clk;
                }
                spi->child[cs].direct_access.size = PAGE_SIZE;

                dev_info(&pdev->dev, "CS%d configured for direct access\n", cs);
        }

        pm_runtime_set_active(&pdev->dev);
        pm_runtime_use_autosuspend(&pdev->dev);
        pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
        pm_runtime_enable(&pdev->dev);

        status = orion_spi_reset(spi);
        if (status < 0)
                goto out_rel_pm;

        pm_runtime_mark_last_busy(&pdev->dev);
        pm_runtime_put_autosuspend(&pdev->dev);

        master->dev.of_node = pdev->dev.of_node;
        status = spi_register_master(master);
        if (status < 0)
                goto out_rel_pm;

        return status;

out_rel_pm:
        pm_runtime_disable(&pdev->dev);
out_rel_axi_clk:
        clk_disable_unprepare(spi->axi_clk);
out_rel_clk:
        clk_disable_unprepare(spi->clk);
out:
        spi_master_put(master);
        return status;
}


static int orion_spi_remove(struct platform_device *pdev)
{
        struct spi_master *master = platform_get_drvdata(pdev);
        struct orion_spi *spi = spi_master_get_devdata(master);

        pm_runtime_get_sync(&pdev->dev);
        clk_disable_unprepare(spi->axi_clk);
        clk_disable_unprepare(spi->clk);

        spi_unregister_master(master);
        pm_runtime_disable(&pdev->dev);

        return 0;
}

MODULE_ALIAS("platform:" DRIVER_NAME);

#ifdef CONFIG_PM
static int orion_spi_runtime_suspend(struct device *dev)
{
        struct spi_master *master = dev_get_drvdata(dev);
        struct orion_spi *spi = spi_master_get_devdata(master);

        clk_disable_unprepare(spi->axi_clk);
        clk_disable_unprepare(spi->clk);
        return 0;
}

static int orion_spi_runtime_resume(struct device *dev)
{
        struct spi_master *master = dev_get_drvdata(dev);
        struct orion_spi *spi = spi_master_get_devdata(master);

        if (!IS_ERR(spi->axi_clk))
                clk_prepare_enable(spi->axi_clk);
        return clk_prepare_enable(spi->clk);
}
#endif

static const struct dev_pm_ops orion_spi_pm_ops = {
        SET_RUNTIME_PM_OPS(orion_spi_runtime_suspend,
                           orion_spi_runtime_resume,
                           NULL)
};

static struct platform_driver orion_spi_driver = {
        .driver = {
                .name   = DRIVER_NAME,
                .pm     = &orion_spi_pm_ops,
                .of_match_table = of_match_ptr(orion_spi_of_match_table),
        },
        .probe          = orion_spi_probe,
        .remove         = orion_spi_remove,
};

module_platform_driver(orion_spi_driver);

MODULE_DESCRIPTION("Orion SPI driver");
MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
MODULE_LICENSE("GPL");