1 files changed, 402 insertions, 0 deletions

diff --git a/drivers/spi/ti-ssp-spi.c b/drivers/spi/ti-ssp-spi.c
new file mode 100644
index 000000000000..ee22795c7973
--- /dev/null
+++ b/drivers/spi/ti-ssp-spi.c
@@ -0,0 +1,402 @@
+/*
+ * Sequencer Serial Port (SSP) based SPI master driver
+ *
+ * Copyright (C) 2010 Texas Instruments Inc
+ *
+ * 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/err.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/mfd/ti_ssp.h>
+
+#define MODE_BITS       (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH)
+
+struct ti_ssp_spi {
+        struct spi_master               *master;
+        struct device                   *dev;
+        spinlock_t                      lock;
+        struct list_head                msg_queue;
+        struct completion               complete;
+        bool                            shutdown;
+        struct workqueue_struct         *workqueue;
+        struct work_struct              work;
+        u8                              mode, bpw;
+        int                             cs_active;
+        u32                             pc_en, pc_dis, pc_wr, pc_rd;
+        void                            (*select)(int cs);
+};
+
+static u32 ti_ssp_spi_rx(struct ti_ssp_spi *hw)
+{
+        u32 ret;
+
+        ti_ssp_run(hw->dev, hw->pc_rd, 0, &ret);
+        return ret;
+}
+
+static void ti_ssp_spi_tx(struct ti_ssp_spi *hw, u32 data)
+{
+        ti_ssp_run(hw->dev, hw->pc_wr, data << (32 - hw->bpw), NULL);
+}
+
+static int ti_ssp_spi_txrx(struct ti_ssp_spi *hw, struct spi_message *msg,
+                       struct spi_transfer *t)
+{
+        int count;
+
+        if (hw->bpw <= 8) {
+                u8              *rx = t->rx_buf;
+                const u8        *tx = t->tx_buf;
+
+                for (count = 0; count < t->len; count += 1) {
+                        if (t->tx_buf)
+                                ti_ssp_spi_tx(hw, *tx++);
+                        if (t->rx_buf)
+                                *rx++ = ti_ssp_spi_rx(hw);
+                }
+        } else if (hw->bpw <= 16) {
+                u16             *rx = t->rx_buf;
+                const u16       *tx = t->tx_buf;
+
+                for (count = 0; count < t->len; count += 2) {
+                        if (t->tx_buf)
+                                ti_ssp_spi_tx(hw, *tx++);
+                        if (t->rx_buf)
+                                *rx++ = ti_ssp_spi_rx(hw);
+                }
+        } else {
+                u32             *rx = t->rx_buf;
+                const u32       *tx = t->tx_buf;
+
+                for (count = 0; count < t->len; count += 4) {
+                        if (t->tx_buf)
+                                ti_ssp_spi_tx(hw, *tx++);
+                        if (t->rx_buf)
+                                *rx++ = ti_ssp_spi_rx(hw);
+                }
+        }
+
+        msg->actual_length += count; /* bytes transferred */
+
+        dev_dbg(&msg->spi->dev, "xfer %s%s, %d bytes, %d bpw, count %d%s\n",
+                t->tx_buf ? "tx" : "", t->rx_buf ? "rx" : "", t->len,
+                hw->bpw, count, (count < t->len) ? " (under)" : "");
+
+        return (count < t->len) ? -EIO : 0; /* left over data */
+}
+
+static void ti_ssp_spi_chip_select(struct ti_ssp_spi *hw, int cs_active)
+{
+        cs_active = !!cs_active;
+        if (cs_active == hw->cs_active)
+                return;
+        ti_ssp_run(hw->dev, cs_active ? hw->pc_en : hw->pc_dis, 0, NULL);
+        hw->cs_active = cs_active;
+}
+
+#define __SHIFT_OUT(bits)       (SSP_OPCODE_SHIFT | SSP_OUT_MODE | \
+                                 cs_en | clk | SSP_COUNT((bits) * 2 - 1))
+#define __SHIFT_IN(bits)        (SSP_OPCODE_SHIFT | SSP_IN_MODE  | \
+                                 cs_en | clk | SSP_COUNT((bits) * 2 - 1))
+
+static int ti_ssp_spi_setup_transfer(struct ti_ssp_spi *hw, u8 bpw, u8 mode)
+{
+        int error, idx = 0;
+        u32 seqram[16];
+        u32 cs_en, cs_dis, clk;
+        u32 topbits, botbits;
+
+        mode &= MODE_BITS;
+        if (mode == hw->mode && bpw == hw->bpw)
+                return 0;
+
+        cs_en  = (mode & SPI_CS_HIGH) ? SSP_CS_HIGH : SSP_CS_LOW;
+        cs_dis = (mode & SPI_CS_HIGH) ? SSP_CS_LOW  : SSP_CS_HIGH;
+        clk    = (mode & SPI_CPOL)    ? SSP_CLK_HIGH : SSP_CLK_LOW;
+
+        /* Construct instructions */
+
+        /* Disable Chip Select */
+        hw->pc_dis = idx;
+        seqram[idx++] = SSP_OPCODE_DIRECT | SSP_OUT_MODE | cs_dis | clk;
+        seqram[idx++] = SSP_OPCODE_STOP   | SSP_OUT_MODE | cs_dis | clk;
+
+        /* Enable Chip Select */
+        hw->pc_en = idx;
+        seqram[idx++] = SSP_OPCODE_DIRECT | SSP_OUT_MODE | cs_en | clk;
+        seqram[idx++] = SSP_OPCODE_STOP   | SSP_OUT_MODE | cs_en | clk;
+
+        /* Reads and writes need to be split for bpw > 16 */
+        topbits = (bpw > 16) ? 16 : bpw;
+        botbits = bpw - topbits;
+
+        /* Write */
+        hw->pc_wr = idx;
+        seqram[idx++] = __SHIFT_OUT(topbits) | SSP_ADDR_REG;
+        if (botbits)
+                seqram[idx++] = __SHIFT_OUT(botbits)  | SSP_DATA_REG;
+        seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_en | clk;
+
+        /* Read */
+        hw->pc_rd = idx;
+        if (botbits)
+                seqram[idx++] = __SHIFT_IN(botbits) | SSP_ADDR_REG;
+        seqram[idx++] = __SHIFT_IN(topbits) | SSP_DATA_REG;
+        seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_en | clk;
+
+        error = ti_ssp_load(hw->dev, 0, seqram, idx);
+        if (error < 0)
+                return error;
+
+        error = ti_ssp_set_mode(hw->dev, ((mode & SPI_CPHA) ?
+                                          0 : SSP_EARLY_DIN));
+        if (error < 0)
+                return error;
+
+        hw->bpw = bpw;
+        hw->mode = mode;
+
+        return error;
+}
+
+static void ti_ssp_spi_work(struct work_struct *work)
+{
+        struct ti_ssp_spi *hw = container_of(work, struct ti_ssp_spi, work);
+
+        spin_lock(&hw->lock);
+
+         while (!list_empty(&hw->msg_queue)) {
+                struct spi_message      *m;
+                struct spi_device       *spi;
+                struct spi_transfer     *t = NULL;
+                int                     status = 0;
+
+                m = container_of(hw->msg_queue.next, struct spi_message,
+                                 queue);
+
+                list_del_init(&m->queue);
+
+                spin_unlock(&hw->lock);
+
+                spi = m->spi;
+
+                if (hw->select)
+                        hw->select(spi->chip_select);
+
+                list_for_each_entry(t, &m->transfers, transfer_list) {
+                        int bpw = spi->bits_per_word;
+                        int xfer_status;
+
+                        if (t->bits_per_word)
+                                bpw = t->bits_per_word;
+
+                        if (ti_ssp_spi_setup_transfer(hw, bpw, spi->mode) < 0)
+                                break;
+
+                        ti_ssp_spi_chip_select(hw, 1);
+
+                        xfer_status = ti_ssp_spi_txrx(hw, m, t);
+                        if (xfer_status < 0)
+                                status = xfer_status;
+
+                        if (t->delay_usecs)
+                                udelay(t->delay_usecs);
+
+                        if (t->cs_change)
+                                ti_ssp_spi_chip_select(hw, 0);
+                }
+
+                ti_ssp_spi_chip_select(hw, 0);
+                m->status = status;
+                m->complete(m->context);
+
+                spin_lock(&hw->lock);
+        }
+
+        if (hw->shutdown)
+                complete(&hw->complete);
+
+        spin_unlock(&hw->lock);
+}
+
+static int ti_ssp_spi_setup(struct spi_device *spi)
+{
+        if (spi->bits_per_word > 32)
+                return -EINVAL;
+
+        return 0;
+}
+
+static int ti_ssp_spi_transfer(struct spi_device *spi, struct spi_message *m)
+{
+        struct ti_ssp_spi       *hw;
+        struct spi_transfer     *t;
+        int                     error = 0;
+
+        m->actual_length = 0;
+        m->status = -EINPROGRESS;
+
+        hw = spi_master_get_devdata(spi->master);
+
+        if (list_empty(&m->transfers) || !m->complete)
+                return -EINVAL;
+
+        list_for_each_entry(t, &m->transfers, transfer_list) {
+                if (t->len && !(t->rx_buf || t->tx_buf)) {
+                        dev_err(&spi->dev, "invalid xfer, no buffer\n");
+                        return -EINVAL;
+                }
+
+                if (t->len && t->rx_buf && t->tx_buf) {
+                        dev_err(&spi->dev, "invalid xfer, full duplex\n");
+                        return -EINVAL;
+                }
+
+                if (t->bits_per_word > 32) {
+                        dev_err(&spi->dev, "invalid xfer width %d\n",
+                                t->bits_per_word);
+                        return -EINVAL;
+                }
+        }
+
+        spin_lock(&hw->lock);
+        if (hw->shutdown) {
+                error = -ESHUTDOWN;
+                goto error_unlock;
+        }
+        list_add_tail(&m->queue, &hw->msg_queue);
+        queue_work(hw->workqueue, &hw->work);
+error_unlock:
+        spin_unlock(&hw->lock);
+        return error;
+}
+
+static int __devinit ti_ssp_spi_probe(struct platform_device *pdev)
+{
+        const struct ti_ssp_spi_data *pdata;
+        struct ti_ssp_spi *hw;
+        struct spi_master *master;
+        struct device *dev = &pdev->dev;
+        int error = 0;
+
+        pdata = dev->platform_data;
+        if (!pdata) {
+                dev_err(dev, "platform data not found\n");
+                return -EINVAL;
+        }
+
+        master = spi_alloc_master(dev, sizeof(struct ti_ssp_spi));
+        if (!master) {
+                dev_err(dev, "cannot allocate SPI master\n");
+                return -ENOMEM;
+        }
+
+        hw = spi_master_get_devdata(master);
+        platform_set_drvdata(pdev, hw);
+
+        hw->master = master;
+        hw->dev = dev;
+        hw->select = pdata->select;
+
+        spin_lock_init(&hw->lock);
+        init_completion(&hw->complete);
+        INIT_LIST_HEAD(&hw->msg_queue);
+        INIT_WORK(&hw->work, ti_ssp_spi_work);
+
+        hw->workqueue = create_singlethread_workqueue(dev_name(dev));
+        if (!hw->workqueue) {
+                error = -ENOMEM;
+                dev_err(dev, "work queue creation failed\n");
+                goto error_wq;
+        }
+
+        error = ti_ssp_set_iosel(hw->dev, pdata->iosel);
+        if (error < 0) {
+                dev_err(dev, "io setup failed\n");
+                goto error_iosel;
+        }
+
+        master->bus_num         = pdev->id;
+        master->num_chipselect  = pdata->num_cs;
+        master->mode_bits       = MODE_BITS;
+        master->flags           = SPI_MASTER_HALF_DUPLEX;
+        master->setup           = ti_ssp_spi_setup;
+        master->transfer        = ti_ssp_spi_transfer;
+
+        error = spi_register_master(master);
+        if (error) {
+                dev_err(dev, "master registration failed\n");
+                goto error_reg;
+        }
+
+        return 0;
+
+error_reg:
+error_iosel:
+        destroy_workqueue(hw->workqueue);
+error_wq:
+        spi_master_put(master);
+        return error;
+}
+
+static int __devexit ti_ssp_spi_remove(struct platform_device *pdev)
+{
+        struct ti_ssp_spi *hw = platform_get_drvdata(pdev);
+        int error;
+
+        hw->shutdown = 1;
+        while (!list_empty(&hw->msg_queue)) {
+                error = wait_for_completion_interruptible(&hw->complete);
+                if (error < 0) {
+                        hw->shutdown = 0;
+                        return error;
+                }
+        }
+        destroy_workqueue(hw->workqueue);
+        spi_unregister_master(hw->master);
+
+        return 0;
+}
+
+static struct platform_driver ti_ssp_spi_driver = {
+        .probe          = ti_ssp_spi_probe,
+        .remove         = __devexit_p(ti_ssp_spi_remove),
+        .driver         = {
+                .name   = "ti-ssp-spi",
+                .owner  = THIS_MODULE,
+        },
+};
+
+static int __init ti_ssp_spi_init(void)
+{
+        return platform_driver_register(&ti_ssp_spi_driver);
+}
+module_init(ti_ssp_spi_init);
+
+static void __exit ti_ssp_spi_exit(void)
+{
+        platform_driver_unregister(&ti_ssp_spi_driver);
+}
+module_exit(ti_ssp_spi_exit);
+
+MODULE_DESCRIPTION("SSP SPI Master");
+MODULE_AUTHOR("Cyril Chemparathy");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ti-ssp-spi");