spi: add Broadcom BCM63xx SPI controller driver

This patch adds support for the SPI controller found on the Broadcom BCM63xx
SoCs.

Signed-off-by: Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 486 insertions, 0 deletions

diff --git a/drivers/spi/spi-bcm63xx.c b/drivers/spi/spi-bcm63xx.c
new file mode 100644
index 000000000000..f01b2648452e
--- /dev/null
+++ b/drivers/spi/spi-bcm63xx.c
@@ -0,0 +1,486 @@
+/*
+ * Broadcom BCM63xx SPI controller support
+ *
+ * Copyright (C) 2009-2011 Florian Fainelli <florian@openwrt.org>
+ * Copyright (C) 2010 Tanguy Bouzeloc <tanguy.bouzeloc@efixo.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.
+ *
+ * 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., 51 Franklin Street, Fifth Floor,
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/spi/spi.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+
+#include <bcm63xx_dev_spi.h>
+
+#define PFX             KBUILD_MODNAME
+#define DRV_VER         "0.1.2"
+
+struct bcm63xx_spi {
+        spinlock_t              lock;
+        int                     stopping;
+        struct completion       done;
+
+        void __iomem            *regs;
+        int                     irq;
+
+        /* Platform data */
+        u32                     speed_hz;
+        unsigned                fifo_size;
+
+        /* Data buffers */
+        const unsigned char     *tx_ptr;
+        unsigned char           *rx_ptr;
+
+        /* data iomem */
+        u8 __iomem              *tx_io;
+        const u8 __iomem        *rx_io;
+
+        int                     remaining_bytes;
+
+        struct clk              *clk;
+        struct platform_device  *pdev;
+};
+
+static inline u8 bcm_spi_readb(struct bcm63xx_spi *bs,
+                                unsigned int offset)
+{
+        return bcm_readb(bs->regs + bcm63xx_spireg(offset));
+}
+
+static inline u16 bcm_spi_readw(struct bcm63xx_spi *bs,
+                                unsigned int offset)
+{
+        return bcm_readw(bs->regs + bcm63xx_spireg(offset));
+}
+
+static inline void bcm_spi_writeb(struct bcm63xx_spi *bs,
+                                  u8 value, unsigned int offset)
+{
+        bcm_writeb(value, bs->regs + bcm63xx_spireg(offset));
+}
+
+static inline void bcm_spi_writew(struct bcm63xx_spi *bs,
+                                  u16 value, unsigned int offset)
+{
+        bcm_writew(value, bs->regs + bcm63xx_spireg(offset));
+}
+
+static const unsigned bcm63xx_spi_freq_table[SPI_CLK_MASK][2] = {
+        { 20000000, SPI_CLK_20MHZ },
+        { 12500000, SPI_CLK_12_50MHZ },
+        {  6250000, SPI_CLK_6_250MHZ },
+        {  3125000, SPI_CLK_3_125MHZ },
+        {  1563000, SPI_CLK_1_563MHZ },
+        {   781000, SPI_CLK_0_781MHZ },
+        {   391000, SPI_CLK_0_391MHZ }
+};
+
+static int bcm63xx_spi_setup_transfer(struct spi_device *spi,
+                                      struct spi_transfer *t)
+{
+        struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
+        u8 bits_per_word;
+        u8 clk_cfg, reg;
+        u32 hz;
+        int i;
+
+        bits_per_word = (t) ? t->bits_per_word : spi->bits_per_word;
+        hz = (t) ? t->speed_hz : spi->max_speed_hz;
+        if (bits_per_word != 8) {
+                dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
+                        __func__, bits_per_word);
+                return -EINVAL;
+        }
+
+        if (spi->chip_select > spi->master->num_chipselect) {
+                dev_err(&spi->dev, "%s, unsupported slave %d\n",
+                        __func__, spi->chip_select);
+                return -EINVAL;
+        }
+
+        /* Find the closest clock configuration */
+        for (i = 0; i < SPI_CLK_MASK; i++) {
+                if (hz <= bcm63xx_spi_freq_table[i][0]) {
+                        clk_cfg = bcm63xx_spi_freq_table[i][1];
+                        break;
+                }
+        }
+
+        /* No matching configuration found, default to lowest */
+        if (i == SPI_CLK_MASK)
+                clk_cfg = SPI_CLK_0_391MHZ;
+
+        /* clear existing clock configuration bits of the register */
+        reg = bcm_spi_readb(bs, SPI_CLK_CFG);
+        reg &= ~SPI_CLK_MASK;
+        reg |= clk_cfg;
+
+        bcm_spi_writeb(bs, reg, SPI_CLK_CFG);
+        dev_dbg(&spi->dev, "Setting clock register to %02x (hz %d)\n",
+                clk_cfg, hz);
+
+        return 0;
+}
+
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA)
+
+static int bcm63xx_spi_setup(struct spi_device *spi)
+{
+        struct bcm63xx_spi *bs;
+        int ret;
+
+        bs = spi_master_get_devdata(spi->master);
+
+        if (bs->stopping)
+                return -ESHUTDOWN;
+
+        if (!spi->bits_per_word)
+                spi->bits_per_word = 8;
+
+        if (spi->mode & ~MODEBITS) {
+                dev_err(&spi->dev, "%s, unsupported mode bits %x\n",
+                        __func__, spi->mode & ~MODEBITS);
+                return -EINVAL;
+        }
+
+        ret = bcm63xx_spi_setup_transfer(spi, NULL);
+        if (ret < 0) {
+                dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
+                        spi->mode & ~MODEBITS);
+                return ret;
+        }
+
+        dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n",
+                __func__, spi->mode & MODEBITS, spi->bits_per_word, 0);
+
+        return 0;
+}
+
+/* Fill the TX FIFO with as many bytes as possible */
+static void bcm63xx_spi_fill_tx_fifo(struct bcm63xx_spi *bs)
+{
+        u8 size;
+
+        /* Fill the Tx FIFO with as many bytes as possible */
+        size = bs->remaining_bytes < bs->fifo_size ? bs->remaining_bytes :
+                bs->fifo_size;
+        memcpy_toio(bs->tx_io, bs->tx_ptr, size);
+        bs->remaining_bytes -= size;
+}
+
+static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
+{
+        struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
+        u16 msg_ctl;
+        u16 cmd;
+
+        dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
+                t->tx_buf, t->rx_buf, t->len);
+
+        /* Transmitter is inhibited */
+        bs->tx_ptr = t->tx_buf;
+        bs->rx_ptr = t->rx_buf;
+        init_completion(&bs->done);
+
+        if (t->tx_buf) {
+                bs->remaining_bytes = t->len;
+                bcm63xx_spi_fill_tx_fifo(bs);
+        }
+
+        /* Enable the command done interrupt which
+         * we use to determine completion of a command */
+        bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK);
+
+        /* Fill in the Message control register */
+        msg_ctl = (t->len << SPI_BYTE_CNT_SHIFT);
+
+        if (t->rx_buf && t->tx_buf)
+                msg_ctl |= (SPI_FD_RW << SPI_MSG_TYPE_SHIFT);
+        else if (t->rx_buf)
+                msg_ctl |= (SPI_HD_R << SPI_MSG_TYPE_SHIFT);
+        else if (t->tx_buf)
+                msg_ctl |= (SPI_HD_W << SPI_MSG_TYPE_SHIFT);
+
+        bcm_spi_writew(bs, msg_ctl, SPI_MSG_CTL);
+
+        /* Issue the transfer */
+        cmd = SPI_CMD_START_IMMEDIATE;
+        cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
+        cmd |= (spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT);
+        bcm_spi_writew(bs, cmd, SPI_CMD);
+        wait_for_completion(&bs->done);
+
+        /* Disable the CMD_DONE interrupt */
+        bcm_spi_writeb(bs, 0, SPI_INT_MASK);
+
+        return t->len - bs->remaining_bytes;
+}
+
+static int bcm63xx_transfer(struct spi_device *spi, struct spi_message *m)
+{
+        struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
+        struct spi_transfer *t;
+        int ret = 0;
+
+        if (unlikely(list_empty(&m->transfers)))
+                return -EINVAL;
+
+        if (bs->stopping)
+                return -ESHUTDOWN;
+
+        list_for_each_entry(t, &m->transfers, transfer_list) {
+                ret += bcm63xx_txrx_bufs(spi, t);
+        }
+
+        m->complete(m->context);
+
+        return ret;
+}
+
+/* This driver supports single master mode only. Hence
+ * CMD_DONE is the only interrupt we care about
+ */
+static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id)
+{
+        struct spi_master *master = (struct spi_master *)dev_id;
+        struct bcm63xx_spi *bs = spi_master_get_devdata(master);
+        u8 intr;
+        u16 cmd;
+
+        /* Read interupts and clear them immediately */
+        intr = bcm_spi_readb(bs, SPI_INT_STATUS);
+        bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
+        bcm_spi_writeb(bs, 0, SPI_INT_MASK);
+
+        /* A tansfer completed */
+        if (intr & SPI_INTR_CMD_DONE) {
+                u8 rx_tail;
+
+                rx_tail = bcm_spi_readb(bs, SPI_RX_TAIL);
+
+                /* Read out all the data */
+                if (rx_tail)
+                        memcpy_fromio(bs->rx_ptr, bs->rx_io, rx_tail);
+
+                /* See if there is more data to send */
+                if (bs->remaining_bytes > 0) {
+                        bcm63xx_spi_fill_tx_fifo(bs);
+
+                        /* Start the transfer */
+                        bcm_spi_writew(bs, SPI_HD_W << SPI_MSG_TYPE_SHIFT,
+                                       SPI_MSG_CTL);
+                        cmd = bcm_spi_readw(bs, SPI_CMD);
+                        cmd |= SPI_CMD_START_IMMEDIATE;
+                        cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
+                        bcm_spi_writeb(bs, SPI_INTR_CMD_DONE, SPI_INT_MASK);
+                        bcm_spi_writew(bs, cmd, SPI_CMD);
+                } else {
+                        complete(&bs->done);
+                }
+        }
+
+        return IRQ_HANDLED;
+}
+
+
+static int __devinit bcm63xx_spi_probe(struct platform_device *pdev)
+{
+        struct resource *r;
+        struct device *dev = &pdev->dev;
+        struct bcm63xx_spi_pdata *pdata = pdev->dev.platform_data;
+        int irq;
+        struct spi_master *master;
+        struct clk *clk;
+        struct bcm63xx_spi *bs;
+        int ret;
+
+        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!r) {
+                dev_err(dev, "no iomem\n");
+                ret = -ENXIO;
+                goto out;
+        }
+
+        irq = platform_get_irq(pdev, 0);
+        if (irq < 0) {
+                dev_err(dev, "no irq\n");
+                ret = -ENXIO;
+                goto out;
+        }
+
+        clk = clk_get(dev, "spi");
+        if (IS_ERR(clk)) {
+                dev_err(dev, "no clock for device\n");
+                ret = PTR_ERR(clk);
+                goto out;
+        }
+
+        master = spi_alloc_master(dev, sizeof(*bs));
+        if (!master) {
+                dev_err(dev, "out of memory\n");
+                ret = -ENOMEM;
+                goto out_clk;
+        }
+
+        bs = spi_master_get_devdata(master);
+        init_completion(&bs->done);
+
+        platform_set_drvdata(pdev, master);
+        bs->pdev = pdev;
+
+        if (!devm_request_mem_region(&pdev->dev, r->start,
+                                        resource_size(r), PFX)) {
+                dev_err(dev, "iomem request failed\n");
+                ret = -ENXIO;
+                goto out_err;
+        }
+
+        bs->regs = devm_ioremap_nocache(&pdev->dev, r->start,
+                                                        resource_size(r));
+        if (!bs->regs) {
+                dev_err(dev, "unable to ioremap regs\n");
+                ret = -ENOMEM;
+                goto out_err;
+        }
+
+        bs->irq = irq;
+        bs->clk = clk;
+        bs->fifo_size = pdata->fifo_size;
+
+        ret = devm_request_irq(&pdev->dev, irq, bcm63xx_spi_interrupt, 0,
+                                                        pdev->name, master);
+        if (ret) {
+                dev_err(dev, "unable to request irq\n");
+                goto out_err;
+        }
+
+        master->bus_num = pdata->bus_num;
+        master->num_chipselect = pdata->num_chipselect;
+        master->setup = bcm63xx_spi_setup;
+        master->transfer = bcm63xx_transfer;
+        bs->speed_hz = pdata->speed_hz;
+        bs->stopping = 0;
+        bs->tx_io = (u8 *)(bs->regs + bcm63xx_spireg(SPI_MSG_DATA));
+        bs->rx_io = (const u8 *)(bs->regs + bcm63xx_spireg(SPI_RX_DATA));
+        spin_lock_init(&bs->lock);
+
+        /* Initialize hardware */
+        clk_enable(bs->clk);
+        bcm_spi_writeb(bs, SPI_INTR_CLEAR_ALL, SPI_INT_STATUS);
+
+        /* register and we are done */
+        ret = spi_register_master(master);
+        if (ret) {
+                dev_err(dev, "spi register failed\n");
+                goto out_clk_disable;
+        }
+
+        dev_info(dev, "at 0x%08x (irq %d, FIFOs size %d) v%s\n",
+                 r->start, irq, bs->fifo_size, DRV_VER);
+
+        return 0;
+
+out_clk_disable:
+        clk_disable(clk);
+out_err:
+        platform_set_drvdata(pdev, NULL);
+        spi_master_put(master);
+out_clk:
+        clk_put(clk);
+out:
+        return ret;
+}
+
+static int __devexit bcm63xx_spi_remove(struct platform_device *pdev)
+{
+        struct spi_master *master = platform_get_drvdata(pdev);
+        struct bcm63xx_spi *bs = spi_master_get_devdata(master);
+
+        /* reset spi block */
+        bcm_spi_writeb(bs, 0, SPI_INT_MASK);
+        spin_lock(&bs->lock);
+        bs->stopping = 1;
+
+        /* HW shutdown */
+        clk_disable(bs->clk);
+        clk_put(bs->clk);
+
+        spin_unlock(&bs->lock);
+        platform_set_drvdata(pdev, 0);
+        spi_unregister_master(master);
+
+        return 0;
+}
+
+#ifdef CONFIG_PM
+static int bcm63xx_spi_suspend(struct device *dev)
+{
+        struct spi_master *master =
+                        platform_get_drvdata(to_platform_device(dev));
+        struct bcm63xx_spi *bs = spi_master_get_devdata(master);
+
+        clk_disable(bs->clk);
+
+        return 0;
+}
+
+static int bcm63xx_spi_resume(struct device *dev)
+{
+        struct spi_master *master =
+                        platform_get_drvdata(to_platform_device(dev));
+        struct bcm63xx_spi *bs = spi_master_get_devdata(master);
+
+        clk_enable(bs->clk);
+
+        return 0;
+}
+
+static const struct dev_pm_ops bcm63xx_spi_pm_ops = {
+        .suspend        = bcm63xx_spi_suspend,
+        .resume         = bcm63xx_spi_resume,
+};
+
+#define BCM63XX_SPI_PM_OPS      (&bcm63xx_spi_pm_ops)
+#else
+#define BCM63XX_SPI_PM_OPS      NULL
+#endif
+
+static struct platform_driver bcm63xx_spi_driver = {
+        .driver = {
+                .name   = "bcm63xx-spi",
+                .owner  = THIS_MODULE,
+                .pm     = BCM63XX_SPI_PM_OPS,
+        },
+        .probe          = bcm63xx_spi_probe,
+        .remove         = __devexit_p(bcm63xx_spi_remove),
+};
+
+module_platform_driver(bcm63xx_spi_driver);
+
+MODULE_ALIAS("platform:bcm63xx_spi");
+MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
+MODULE_AUTHOR("Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>");
+MODULE_DESCRIPTION("Broadcom BCM63xx SPI Controller driver");
+MODULE_LICENSE("GPL");