Add OMAP spi100k driver

This change adds the OMAP SPI 100k driver created by
Fabrice Crohas <fcrohas@gmail.com>.  This SPI bus is found on
OMAP7xx-series smartphones, and for many, the touchscreen is
attached to this bus.

The lion's share of the work was done by Fabrice on this driver --
I am merely porting it from the Linwizard project on his behalf.

Signed-off-by: Cory Maccarrone <darkstar6262@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

3 files changed, 642 insertions, 0 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index b9908e9a9954..07e5453f7b18 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -172,6 +172,12 @@ config SPI_OMAP24XX
           SPI master controller for OMAP24xx/OMAP34xx Multichannel SPI
           (McSPI) modules.
 
+config SPI_OMAP_100K
+        tristate "OMAP SPI 100K"
+        depends on SPI_MASTER && (ARCH_OMAP850 || ARCH_OMAP730)
+        help
+          OMAP SPI 100K master controller for omap7xx boards.
+
 config SPI_ORION
         tristate "Orion SPI master (EXPERIMENTAL)"
         depends on PLAT_ORION && EXPERIMENTAL
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index be6e8a50468e..ed8c1675b52f 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_SPI_LM70_LLP)		+= spi_lm70llp.o
 obj-$(CONFIG_SPI_PXA2XX)                += pxa2xx_spi.o
 obj-$(CONFIG_SPI_OMAP_UWIRE)            += omap_uwire.o
 obj-$(CONFIG_SPI_OMAP24XX)              += omap2_mcspi.o
+obj-$(CONFIG_SPI_OMAP_100K)             += omap_spi_100k.o
 obj-$(CONFIG_SPI_ORION)                 += orion_spi.o
 obj-$(CONFIG_SPI_PL022)                 += amba-pl022.o
 obj-$(CONFIG_SPI_MPC52xx_PSC)           += mpc52xx_psc_spi.o
diff --git a/drivers/spi/omap_spi_100k.c b/drivers/spi/omap_spi_100k.c
new file mode 100644
index 000000000000..5355d90d1bee
--- /dev/null
+++ b/drivers/spi/omap_spi_100k.c
@@ -0,0 +1,635 @@
+/*
+ * OMAP7xx SPI 100k controller driver
+ * Author: Fabrice Crohas <fcrohas@gmail.com>
+ * from original omap1_mcspi driver
+ *
+ * Copyright (C) 2005, 2006 Nokia Corporation
+ * Author:      Samuel Ortiz <samuel.ortiz@nokia.com> and
+ *              Juha Yrj�l� <juha.yrjola@nokia.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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/gpio.h>
+
+#include <linux/spi/spi.h>
+
+#include <plat/clock.h>
+
+#define OMAP1_SPI100K_MAX_FREQ          48000000
+
+#define ICR_SPITAS      (OMAP7XX_ICR_BASE + 0x12)
+
+#define SPI_SETUP1      0x00
+#define SPI_SETUP2      0x02
+#define SPI_CTRL        0x04
+#define SPI_STATUS      0x06
+#define SPI_TX_LSB      0x08
+#define SPI_TX_MSB      0x0a
+#define SPI_RX_LSB      0x0c
+#define SPI_RX_MSB      0x0e
+
+#define SPI_SETUP1_INT_READ_ENABLE      (1UL << 5)
+#define SPI_SETUP1_INT_WRITE_ENABLE     (1UL << 4)
+#define SPI_SETUP1_CLOCK_DIVISOR(x)     ((x) << 1)
+#define SPI_SETUP1_CLOCK_ENABLE         (1UL << 0)
+
+#define SPI_SETUP2_ACTIVE_EDGE_FALLING  (0UL << 0)
+#define SPI_SETUP2_ACTIVE_EDGE_RISING   (1UL << 0)
+#define SPI_SETUP2_NEGATIVE_LEVEL       (0UL << 5)
+#define SPI_SETUP2_POSITIVE_LEVEL       (1UL << 5)
+#define SPI_SETUP2_LEVEL_TRIGGER        (0UL << 10)
+#define SPI_SETUP2_EDGE_TRIGGER         (1UL << 10)
+
+#define SPI_CTRL_SEN(x)                 ((x) << 7)
+#define SPI_CTRL_WORD_SIZE(x)           (((x) - 1) << 2)
+#define SPI_CTRL_WR                     (1UL << 1)
+#define SPI_CTRL_RD                     (1UL << 0)
+
+#define SPI_STATUS_WE                   (1UL << 1)
+#define SPI_STATUS_RD                   (1UL << 0)
+
+#define WRITE 0
+#define READ  1
+
+
+/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
+ * cache operations; better heuristics consider wordsize and bitrate.
+ */
+#define DMA_MIN_BYTES                   8
+
+#define SPI_RUNNING     0
+#define SPI_SHUTDOWN    1
+
+struct omap1_spi100k {
+        struct work_struct      work;
+
+        /* lock protects queue and registers */
+        spinlock_t              lock;
+        struct list_head        msg_queue;
+        struct spi_master       *master;
+        struct clk              *ick;
+        struct clk              *fck;
+
+        /* Virtual base address of the controller */
+        void __iomem            *base;
+
+        /* State of the SPI */
+        unsigned int            state;
+};
+
+struct omap1_spi100k_cs {
+        void __iomem            *base;
+        int                     word_len;
+};
+
+static struct workqueue_struct *omap1_spi100k_wq;
+
+#define MOD_REG_BIT(val, mask, set) do { \
+        if (set) \
+                val |= mask; \
+        else \
+                val &= ~mask; \
+} while (0)
+
+static void spi100k_enable_clock(struct spi_master *master)
+{
+        unsigned int val;
+        struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
+
+        /* enable SPI */
+        val = readw(spi100k->base + SPI_SETUP1);
+        val |= SPI_SETUP1_CLOCK_ENABLE;
+        writew(val, spi100k->base + SPI_SETUP1);
+}
+
+static void spi100k_disable_clock(struct spi_master *master)
+{
+        unsigned int val;
+        struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
+
+        /* disable SPI */
+        val = readw(spi100k->base + SPI_SETUP1);
+        val &= ~SPI_SETUP1_CLOCK_ENABLE;
+        writew(val, spi100k->base + SPI_SETUP1);
+}
+
+static void spi100k_write_data(struct spi_master *master, int len, int data)
+{
+        struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
+
+        /* write 16-bit word */
+        spi100k_enable_clock(master);
+        writew( data , spi100k->base + SPI_TX_MSB);
+
+        writew(SPI_CTRL_SEN(0) |
+               SPI_CTRL_WORD_SIZE(len) |
+               SPI_CTRL_WR,
+               spi100k->base + SPI_CTRL);
+
+        /* Wait for bit ack send change */
+        while((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE);
+        udelay(1000);
+
+        spi100k_disable_clock(master);
+}
+
+static int spi100k_read_data(struct spi_master *master, int len)
+{
+        int dataH,dataL;
+        struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
+
+        spi100k_enable_clock(master);
+        writew(SPI_CTRL_SEN(0) |
+               SPI_CTRL_WORD_SIZE(len) |
+               SPI_CTRL_RD,
+               spi100k->base + SPI_CTRL);
+
+        while((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD);
+        udelay(1000);
+
+        dataL = readw(spi100k->base + SPI_RX_LSB);
+        dataH = readw(spi100k->base + SPI_RX_MSB);
+        spi100k_disable_clock(master);
+
+        return dataL;
+}
+
+static void spi100k_open(struct spi_master *master)
+{
+        /* get control of SPI */
+        struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
+
+        writew(SPI_SETUP1_INT_READ_ENABLE |
+               SPI_SETUP1_INT_WRITE_ENABLE |
+               SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);
+
+        /* configure clock and interrupts */
+        writew(SPI_SETUP2_ACTIVE_EDGE_FALLING |
+               SPI_SETUP2_NEGATIVE_LEVEL |
+               SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
+}
+
+static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
+{
+        if (enable)
+                writew(0x05fc, spi100k->base + SPI_CTRL);
+        else
+                writew(0x05fd, spi100k->base + SPI_CTRL);
+}
+
+static unsigned
+omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
+{
+        struct omap1_spi100k    *spi100k;
+        struct omap1_spi100k_cs *cs = spi->controller_state;
+        unsigned int            count, c;
+        int                     word_len;
+
+        spi100k = spi_master_get_devdata(spi->master);
+        count = xfer->len;
+        c = count;
+        word_len = cs->word_len;
+
+        /* RX_ONLY mode needs dummy data in TX reg */
+        if (xfer->tx_buf == NULL)
+                spi100k_write_data(spi->master,word_len, 0);
+
+        if (word_len <= 8) {
+                u8              *rx;
+                const u8        *tx;
+
+                rx = xfer->rx_buf;
+                tx = xfer->tx_buf;
+                do {
+                        c-=1;
+                        if (xfer->tx_buf != NULL)
+                                spi100k_write_data(spi->master,word_len, *tx);
+                        if (xfer->rx_buf != NULL)
+                                *rx = spi100k_read_data(spi->master,word_len);
+                } while(c);
+        } else if (word_len <= 16) {
+                u16             *rx;
+                const u16       *tx;
+
+                rx = xfer->rx_buf;
+                tx = xfer->tx_buf;
+                do {
+                        c-=2;
+                        if (xfer->tx_buf != NULL)
+                                spi100k_write_data(spi->master,word_len, *tx++);
+                        if (xfer->rx_buf != NULL)
+                                *rx++ = spi100k_read_data(spi->master,word_len);
+                } while(c);
+        } else if (word_len <= 32) {
+                u32             *rx;
+                const u32       *tx;
+
+                rx = xfer->rx_buf;
+                tx = xfer->tx_buf;
+                do {
+                        c-=4;
+                        if (xfer->tx_buf != NULL)
+                                spi100k_write_data(spi->master,word_len, *tx);
+                        if (xfer->rx_buf != NULL)
+                                *rx = spi100k_read_data(spi->master,word_len);
+                } while(c);
+        }
+        return count - c;
+}
+
+/* called only when no transfer is active to this device */
+static int omap1_spi100k_setup_transfer(struct spi_device *spi,
+                struct spi_transfer *t)
+{
+        struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
+        struct omap1_spi100k_cs *cs = spi->controller_state;
+        u8 word_len = spi->bits_per_word;
+
+        if (t != NULL && t->bits_per_word)
+                word_len = t->bits_per_word;
+        if (!word_len)
+                word_len = 8;
+
+        if (spi->bits_per_word > 32)
+                return -EINVAL;
+        cs->word_len = word_len;
+
+        /* SPI init before transfer */
+        writew(0x3e , spi100k->base + SPI_SETUP1);
+        writew(0x00 , spi100k->base + SPI_STATUS);
+        writew(0x3e , spi100k->base + SPI_CTRL);
+
+        return 0;
+}
+
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
+
+static int omap1_spi100k_setup(struct spi_device *spi)
+{
+        int                     ret;
+        struct omap1_spi100k    *spi100k;
+        struct omap1_spi100k_cs *cs = spi->controller_state;
+
+        if (spi->bits_per_word < 4 || spi->bits_per_word > 32) {
+                 dev_dbg(&spi->dev, "setup: unsupported %d bit words\n",
+                        spi->bits_per_word);
+                 return -EINVAL;
+        }
+
+        spi100k = spi_master_get_devdata(spi->master);
+
+        if (!cs) {
+                cs = kzalloc(sizeof *cs, GFP_KERNEL);
+                if (!cs)
+                        return -ENOMEM;
+                cs->base = spi100k->base + spi->chip_select * 0x14;
+                spi->controller_state = cs;
+        }
+
+        spi100k_open(spi->master);
+
+        clk_enable(spi100k->ick);
+        clk_enable(spi100k->fck);
+
+        ret = omap1_spi100k_setup_transfer(spi, NULL);
+
+        clk_disable(spi100k->ick);
+        clk_disable(spi100k->fck);
+
+        return ret;
+}
+
+static void omap1_spi100k_work(struct work_struct *work)
+{
+        struct omap1_spi100k    *spi100k;
+        int status = 0;
+
+        spi100k = container_of(work, struct omap1_spi100k, work);
+        spin_lock_irq(&spi100k->lock);
+
+        clk_enable(spi100k->ick);
+        clk_enable(spi100k->fck);
+
+        /* We only enable one channel at a time -- the one whose message is
+         * at the head of the queue -- although this controller would gladly
+         * arbitrate among multiple channels.  This corresponds to "single
+         * channel" master mode.  As a side effect, we need to manage the
+         * chipselect with the FORCE bit ... CS != channel enable.
+         */
+         while (!list_empty(&spi100k->msg_queue)) {
+                struct spi_message              *m;
+                struct spi_device               *spi;
+                struct spi_transfer             *t = NULL;
+                int                             cs_active = 0;
+                struct omap1_spi100k_cs         *cs;
+                int                             par_override = 0;
+
+                m = container_of(spi100k->msg_queue.next, struct spi_message,
+                                 queue);
+
+                list_del_init(&m->queue);
+                spin_unlock_irq(&spi100k->lock);
+
+                spi = m->spi;
+                cs = spi->controller_state;
+
+                list_for_each_entry(t, &m->transfers, transfer_list) {
+                        if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
+                                status = -EINVAL;
+                                break;
+                        }
+                        if (par_override || t->speed_hz || t->bits_per_word) {
+                                par_override = 1;
+                                status = omap1_spi100k_setup_transfer(spi, t);
+                                if (status < 0)
+                                        break;
+                                if (!t->speed_hz && !t->bits_per_word)
+                                        par_override = 0;
+                        }
+
+                        if (!cs_active) {
+                                omap1_spi100k_force_cs(spi100k, 1);
+                                cs_active = 1;
+                        }
+
+                        if (t->len) {
+                                unsigned count;
+
+                                /* RX_ONLY mode needs dummy data in TX reg */
+                                if (t->tx_buf == NULL)
+                                        spi100k_write_data(spi->master, 8, 0);
+
+                                count = omap1_spi100k_txrx_pio(spi, t);
+                                m->actual_length += count;
+
+                                if (count != t->len) {
+                                        status = -EIO;
+                                        break;
+                                }
+                        }
+
+                        if (t->delay_usecs)
+                                udelay(t->delay_usecs);
+
+                        /* ignore the "leave it on after last xfer" hint */
+
+                        if (t->cs_change) {
+                                omap1_spi100k_force_cs(spi100k, 0);
+                                cs_active = 0;
+                        }
+                }
+
+                /* Restore defaults if they were overriden */
+                if (par_override) {
+                        par_override = 0;
+                        status = omap1_spi100k_setup_transfer(spi, NULL);
+                }
+
+                if (cs_active)
+                        omap1_spi100k_force_cs(spi100k, 0);
+
+                m->status = status;
+                m->complete(m->context);
+
+                spin_lock_irq(&spi100k->lock);
+        }
+
+        clk_disable(spi100k->ick);
+        clk_disable(spi100k->fck);
+        spin_unlock_irq(&spi100k->lock);
+
+        if (status < 0)
+                printk(KERN_WARNING "spi transfer failed with %d\n", status);
+}
+
+static int omap1_spi100k_transfer(struct spi_device *spi, struct spi_message *m)
+{
+        struct omap1_spi100k    *spi100k;
+        unsigned long           flags;
+        struct spi_transfer     *t;
+
+        m->actual_length = 0;
+        m->status = -EINPROGRESS;
+
+        spi100k = spi_master_get_devdata(spi->master);
+
+        /* Don't accept new work if we're shutting down */
+        if (spi100k->state == SPI_SHUTDOWN)
+                return -ESHUTDOWN;
+
+        /* reject invalid messages and transfers */
+        if (list_empty(&m->transfers) || !m->complete)
+                return -EINVAL;
+
+        list_for_each_entry(t, &m->transfers, transfer_list) {
+                const void      *tx_buf = t->tx_buf;
+                void            *rx_buf = t->rx_buf;
+                unsigned        len = t->len;
+
+                if (t->speed_hz > OMAP1_SPI100K_MAX_FREQ
+                                || (len && !(rx_buf || tx_buf))
+                                || (t->bits_per_word &&
+                                        (  t->bits_per_word < 4
+                                        || t->bits_per_word > 32))) {
+                        dev_dbg(&spi->dev, "transfer: %d Hz, %d %s%s, %d bpw\n",
+                                        t->speed_hz,
+                                        len,
+                                        tx_buf ? "tx" : "",
+                                        rx_buf ? "rx" : "",
+                                        t->bits_per_word);
+                        return -EINVAL;
+                }
+
+                if (t->speed_hz && t->speed_hz < OMAP1_SPI100K_MAX_FREQ/(1<<16)) {
+                        dev_dbg(&spi->dev, "%d Hz max exceeds %d\n",
+                                        t->speed_hz,
+                                        OMAP1_SPI100K_MAX_FREQ/(1<<16));
+                        return -EINVAL;
+                }
+
+        }
+
+        spin_lock_irqsave(&spi100k->lock, flags);
+        list_add_tail(&m->queue, &spi100k->msg_queue);
+        queue_work(omap1_spi100k_wq, &spi100k->work);
+        spin_unlock_irqrestore(&spi100k->lock, flags);
+
+        return 0;
+}
+
+static int __init omap1_spi100k_reset(struct omap1_spi100k *spi100k)
+{
+        return 0;
+}
+
+static int __devinit omap1_spi100k_probe(struct platform_device *pdev)
+{
+        struct spi_master       *master;
+        struct omap1_spi100k    *spi100k;
+        int                     status = 0;
+
+        if (!pdev->id)
+                return -EINVAL;
+
+        master = spi_alloc_master(&pdev->dev, sizeof *spi100k);
+        if (master == NULL) {
+                dev_dbg(&pdev->dev, "master allocation failed\n");
+                return -ENOMEM;
+        }
+
+        if (pdev->id != -1)
+               master->bus_num = pdev->id;
+
+        master->setup = omap1_spi100k_setup;
+        master->transfer = omap1_spi100k_transfer;
+        master->cleanup = NULL;
+        master->num_chipselect = 2;
+        master->mode_bits = MODEBITS;
+
+        dev_set_drvdata(&pdev->dev, master);
+
+        spi100k = spi_master_get_devdata(master);
+        spi100k->master = master;
+
+        /*
+         * The memory region base address is taken as the platform_data.
+         * You should allocate this with ioremap() before initializing
+         * the SPI.
+         */
+        spi100k->base = (void __iomem *) pdev->dev.platform_data;
+
+        INIT_WORK(&spi100k->work, omap1_spi100k_work);
+
+        spin_lock_init(&spi100k->lock);
+        INIT_LIST_HEAD(&spi100k->msg_queue);
+        spi100k->ick = clk_get(&pdev->dev, "ick");
+        if (IS_ERR(spi100k->ick)) {
+                dev_dbg(&pdev->dev, "can't get spi100k_ick\n");
+                status = PTR_ERR(spi100k->ick);
+                goto err1;
+        }
+
+        spi100k->fck = clk_get(&pdev->dev, "fck");
+        if (IS_ERR(spi100k->fck)) {
+                dev_dbg(&pdev->dev, "can't get spi100k_fck\n");
+                status = PTR_ERR(spi100k->fck);
+                goto err2;
+        }
+
+        if (omap1_spi100k_reset(spi100k) < 0)
+                goto err3;
+
+        status = spi_register_master(master);
+        if (status < 0)
+                goto err3;
+
+        spi100k->state = SPI_RUNNING;
+
+        return status;
+
+err3:
+        clk_put(spi100k->fck);
+err2:
+        clk_put(spi100k->ick);
+err1:
+        spi_master_put(master);
+        return status;
+}
+
+static int __exit omap1_spi100k_remove(struct platform_device *pdev)
+{
+        struct spi_master       *master;
+        struct omap1_spi100k    *spi100k;
+        struct resource         *r;
+        unsigned                limit = 500;
+        unsigned long           flags;
+        int                     status = 0;
+
+        master = dev_get_drvdata(&pdev->dev);
+        spi100k = spi_master_get_devdata(master);
+
+        spin_lock_irqsave(&spi100k->lock, flags);
+
+        spi100k->state = SPI_SHUTDOWN;
+        while (!list_empty(&spi100k->msg_queue) && limit--) {
+                spin_unlock_irqrestore(&spi100k->lock, flags);
+                msleep(10);
+                spin_lock_irqsave(&spi100k->lock, flags);
+        }
+
+        if (!list_empty(&spi100k->msg_queue))
+                status = -EBUSY;
+
+        spin_unlock_irqrestore(&spi100k->lock, flags);
+
+        if (status != 0)
+                return status;
+
+        clk_put(spi100k->fck);
+        clk_put(spi100k->ick);
+
+        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+        spi_unregister_master(master);
+
+        return 0;
+}
+
+static struct platform_driver omap1_spi100k_driver = {
+        .driver = {
+                .name           = "omap1_spi100k",
+                .owner          = THIS_MODULE,
+        },
+        .remove         = __exit_p(omap1_spi100k_remove),
+};
+
+
+static int __init omap1_spi100k_init(void)
+{
+        omap1_spi100k_wq = create_singlethread_workqueue(
+                        omap1_spi100k_driver.driver.name);
+
+        if (omap1_spi100k_wq == NULL)
+                return -1;
+
+        return platform_driver_probe(&omap1_spi100k_driver, omap1_spi100k_probe);
+}
+
+static void __exit omap1_spi100k_exit(void)
+{
+        platform_driver_unregister(&omap1_spi100k_driver);
+
+        destroy_workqueue(omap1_spi100k_wq);
+}
+
+module_init(omap1_spi100k_init);
+module_exit(omap1_spi100k_exit);
+
+MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver");
+MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>");
+MODULE_LICENSE("GPL");
+