+++ /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/module.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_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;
- }
- }
-
- 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 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_get_platdata(dev);
- 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->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
- master->flags = SPI_MASTER_HALF_DUPLEX;
- 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 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 = ti_ssp_spi_remove,
- .driver = {
- .name = "ti-ssp-spi",
- .owner = THIS_MODULE,
- },
-};
-module_platform_driver(ti_ssp_spi_driver);
-
-MODULE_DESCRIPTION("SSP SPI Master");
-MODULE_AUTHOR("Cyril Chemparathy");
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:ti-ssp-spi");
projects / platform / kernel / linux-starfive.git / commitdiff