--- /dev/null
+/*
+ * 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");
projects / profile / ivi / kernel-adaptation-intel-automotive.git / commitdiff