--- /dev/null
+/*
+ * orion_spi.c -- Marvell Orion SPI controller driver
+ *
+ * Author: Shadi Ammouri <shadi@marvell.com>
+ * Copyright (C) 2007-2008 Marvell Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/orion_spi.h>
+#include <asm/unaligned.h>
+
+#define DRIVER_NAME "orion_spi"
+
+#define ORION_NUM_CHIPSELECTS 1 /* only one slave is supported*/
+#define ORION_SPI_WAIT_RDY_MAX_LOOP 2000 /* in usec */
+
+#define ORION_SPI_IF_CTRL_REG 0x00
+#define ORION_SPI_IF_CONFIG_REG 0x04
+#define ORION_SPI_DATA_OUT_REG 0x08
+#define ORION_SPI_DATA_IN_REG 0x0c
+#define ORION_SPI_INT_CAUSE_REG 0x10
+
+#define ORION_SPI_IF_8_16_BIT_MODE (1 << 5)
+#define ORION_SPI_CLK_PRESCALE_MASK 0x1F
+
+struct orion_spi {
+ struct work_struct work;
+
+ /* Lock access to transfer list. */
+ spinlock_t lock;
+
+ struct list_head msg_queue;
+ struct spi_master *master;
+ void __iomem *base;
+ unsigned int max_speed;
+ unsigned int min_speed;
+ struct orion_spi_info *spi_info;
+};
+
+static struct workqueue_struct *orion_spi_wq;
+
+static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
+{
+ return orion_spi->base + reg;
+}
+
+static inline void
+orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
+{
+ void __iomem *reg_addr = spi_reg(orion_spi, reg);
+ u32 val;
+
+ val = readl(reg_addr);
+ val |= mask;
+ writel(val, reg_addr);
+}
+
+static inline void
+orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
+{
+ void __iomem *reg_addr = spi_reg(orion_spi, reg);
+ u32 val;
+
+ val = readl(reg_addr);
+ val &= ~mask;
+ writel(val, reg_addr);
+}
+
+static int orion_spi_set_transfer_size(struct orion_spi *orion_spi, int size)
+{
+ if (size == 16) {
+ orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
+ ORION_SPI_IF_8_16_BIT_MODE);
+ } else if (size == 8) {
+ orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
+ ORION_SPI_IF_8_16_BIT_MODE);
+ } else {
+ pr_debug("Bad bits per word value %d (only 8 or 16 are "
+ "allowed).\n", size);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
+{
+ u32 tclk_hz;
+ u32 rate;
+ u32 prescale;
+ u32 reg;
+ struct orion_spi *orion_spi;
+
+ orion_spi = spi_master_get_devdata(spi->master);
+
+ tclk_hz = orion_spi->spi_info->tclk;
+
+ /*
+ * the supported rates are: 4,6,8...30
+ * round up as we look for equal or less speed
+ */
+ rate = DIV_ROUND_UP(tclk_hz, speed);
+ rate = roundup(rate, 2);
+
+ /* check if requested speed is too small */
+ if (rate > 30)
+ return -EINVAL;
+
+ if (rate < 4)
+ rate = 4;
+
+ /* Convert the rate to SPI clock divisor value. */
+ prescale = 0x10 + rate/2;
+
+ reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
+ reg = ((reg & ~ORION_SPI_CLK_PRESCALE_MASK) | prescale);
+ writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
+
+ return 0;
+}
+
+/*
+ * called only when no transfer is active on the bus
+ */
+static int
+orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct orion_spi *orion_spi;
+ unsigned int speed = spi->max_speed_hz;
+ unsigned int bits_per_word = spi->bits_per_word;
+ int rc;
+
+ orion_spi = spi_master_get_devdata(spi->master);
+
+ if ((t != NULL) && t->speed_hz)
+ speed = t->speed_hz;
+
+ if ((t != NULL) && t->bits_per_word)
+ bits_per_word = t->bits_per_word;
+
+ rc = orion_spi_baudrate_set(spi, speed);
+ if (rc)
+ return rc;
+
+ return orion_spi_set_transfer_size(orion_spi, bits_per_word);
+}
+
+static void orion_spi_set_cs(struct orion_spi *orion_spi, int enable)
+{
+ if (enable)
+ orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
+ else
+ orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
+}
+
+static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
+{
+ int i;
+
+ for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
+ if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
+ return 1;
+ else
+ udelay(1);
+ }
+
+ return -1;
+}
+
+static inline int
+orion_spi_write_read_8bit(struct spi_device *spi,
+ const u8 **tx_buf, u8 **rx_buf)
+{
+ void __iomem *tx_reg, *rx_reg, *int_reg;
+ struct orion_spi *orion_spi;
+
+ orion_spi = spi_master_get_devdata(spi->master);
+ tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
+ rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
+ int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
+
+ /* clear the interrupt cause register */
+ writel(0x0, int_reg);
+
+ if (tx_buf && *tx_buf)
+ writel(*(*tx_buf)++, tx_reg);
+ else
+ writel(0, tx_reg);
+
+ if (orion_spi_wait_till_ready(orion_spi) < 0) {
+ dev_err(&spi->dev, "TXS timed out\n");
+ return -1;
+ }
+
+ if (rx_buf && *rx_buf)
+ *(*rx_buf)++ = readl(rx_reg);
+
+ return 1;
+}
+
+static inline int
+orion_spi_write_read_16bit(struct spi_device *spi,
+ const u16 **tx_buf, u16 **rx_buf)
+{
+ void __iomem *tx_reg, *rx_reg, *int_reg;
+ struct orion_spi *orion_spi;
+
+ orion_spi = spi_master_get_devdata(spi->master);
+ tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
+ rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
+ int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
+
+ /* clear the interrupt cause register */
+ writel(0x0, int_reg);
+
+ if (tx_buf && *tx_buf)
+ writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
+ else
+ writel(0, tx_reg);
+
+ if (orion_spi_wait_till_ready(orion_spi) < 0) {
+ dev_err(&spi->dev, "TXS timed out\n");
+ return -1;
+ }
+
+ if (rx_buf && *rx_buf)
+ put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);
+
+ return 1;
+}
+
+static unsigned int
+orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
+{
+ struct orion_spi *orion_spi;
+ unsigned int count;
+ int word_len;
+
+ orion_spi = spi_master_get_devdata(spi->master);
+ word_len = spi->bits_per_word;
+ count = xfer->len;
+
+ if (word_len == 8) {
+ const u8 *tx = xfer->tx_buf;
+ u8 *rx = xfer->rx_buf;
+
+ do {
+ if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
+ goto out;
+ count--;
+ } while (count);
+ } else if (word_len == 16) {
+ const u16 *tx = xfer->tx_buf;
+ u16 *rx = xfer->rx_buf;
+
+ do {
+ if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
+ goto out;
+ count -= 2;
+ } while (count);
+ }
+
+out:
+ return xfer->len - count;
+}
+
+
+static void orion_spi_work(struct work_struct *work)
+{
+ struct orion_spi *orion_spi =
+ container_of(work, struct orion_spi, work);
+
+ spin_lock_irq(&orion_spi->lock);
+ while (!list_empty(&orion_spi->msg_queue)) {
+ struct spi_message *m;
+ struct spi_device *spi;
+ struct spi_transfer *t = NULL;
+ int par_override = 0;
+ int status = 0;
+ int cs_active = 0;
+
+ m = container_of(orion_spi->msg_queue.next, struct spi_message,
+ queue);
+
+ list_del_init(&m->queue);
+ spin_unlock_irq(&orion_spi->lock);
+
+ spi = m->spi;
+
+ /* Load defaults */
+ status = orion_spi_setup_transfer(spi, NULL);
+
+ if (status < 0)
+ goto msg_done;
+
+ list_for_each_entry(t, &m->transfers, transfer_list) {
+ if (par_override || t->speed_hz || t->bits_per_word) {
+ par_override = 1;
+ status = orion_spi_setup_transfer(spi, t);
+ if (status < 0)
+ break;
+ if (!t->speed_hz && !t->bits_per_word)
+ par_override = 0;
+ }
+
+ if (!cs_active) {
+ orion_spi_set_cs(orion_spi, 1);
+ cs_active = 1;
+ }
+
+ if (t->len)
+ m->actual_length +=
+ orion_spi_write_read(spi, t);
+
+ if (t->delay_usecs)
+ udelay(t->delay_usecs);
+
+ if (t->cs_change) {
+ orion_spi_set_cs(orion_spi, 0);
+ cs_active = 0;
+ }
+ }
+
+msg_done:
+ if (cs_active)
+ orion_spi_set_cs(orion_spi, 0);
+
+ m->status = status;
+ m->complete(m->context);
+
+ spin_lock_irq(&orion_spi->lock);
+ }
+
+ spin_unlock_irq(&orion_spi->lock);
+}
+
+static int __init orion_spi_reset(struct orion_spi *orion_spi)
+{
+ /* Verify that the CS is deasserted */
+ orion_spi_set_cs(orion_spi, 0);
+
+ return 0;
+}
+
+static int orion_spi_setup(struct spi_device *spi)
+{
+ struct orion_spi *orion_spi;
+
+ orion_spi = spi_master_get_devdata(spi->master);
+
+ if (spi->mode) {
+ dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
+ spi->mode);
+ return -EINVAL;
+ }
+
+ if (spi->bits_per_word == 0)
+ spi->bits_per_word = 8;
+
+ if ((spi->max_speed_hz == 0)
+ || (spi->max_speed_hz > orion_spi->max_speed))
+ spi->max_speed_hz = orion_spi->max_speed;
+
+ if (spi->max_speed_hz < orion_spi->min_speed) {
+ dev_err(&spi->dev, "setup: requested speed too low %d Hz\n",
+ spi->max_speed_hz);
+ return -EINVAL;
+ }
+
+ /*
+ * baudrate & width will be set orion_spi_setup_transfer
+ */
+ return 0;
+}
+
+static int orion_spi_transfer(struct spi_device *spi, struct spi_message *m)
+{
+ struct orion_spi *orion_spi;
+ struct spi_transfer *t = NULL;
+ unsigned long flags;
+
+ m->actual_length = 0;
+ m->status = 0;
+
+ /* reject invalid messages and transfers */
+ if (list_empty(&m->transfers) || !m->complete)
+ return -EINVAL;
+
+ orion_spi = spi_master_get_devdata(spi->master);
+
+ list_for_each_entry(t, &m->transfers, transfer_list) {
+ unsigned int bits_per_word = spi->bits_per_word;
+
+ if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
+ dev_err(&spi->dev,
+ "message rejected : "
+ "invalid transfer data buffers\n");
+ goto msg_rejected;
+ }
+
+ if ((t != NULL) && t->bits_per_word)
+ bits_per_word = t->bits_per_word;
+
+ if ((bits_per_word != 8) && (bits_per_word != 16)) {
+ dev_err(&spi->dev,
+ "message rejected : "
+ "invalid transfer bits_per_word (%d bits)\n",
+ bits_per_word);
+ goto msg_rejected;
+ }
+ /*make sure buffer length is even when working in 16 bit mode*/
+ if ((t != NULL) && (t->bits_per_word == 16) && (t->len & 1)) {
+ dev_err(&spi->dev,
+ "message rejected : "
+ "odd data length (%d) while in 16 bit mode\n",
+ t->len);
+ goto msg_rejected;
+ }
+
+ if (t->speed_hz < orion_spi->min_speed) {
+ dev_err(&spi->dev,
+ "message rejected : "
+ "device min speed (%d Hz) exceeds "
+ "required transfer speed (%d Hz)\n",
+ orion_spi->min_speed, t->speed_hz);
+ goto msg_rejected;
+ }
+ }
+
+
+ spin_lock_irqsave(&orion_spi->lock, flags);
+ list_add_tail(&m->queue, &orion_spi->msg_queue);
+ queue_work(orion_spi_wq, &orion_spi->work);
+ spin_unlock_irqrestore(&orion_spi->lock, flags);
+
+ return 0;
+msg_rejected:
+ /* Message rejected and not queued */
+ m->status = -EINVAL;
+ if (m->complete)
+ m->complete(m->context);
+ return -EINVAL;
+}
+
+static int __init orion_spi_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct orion_spi *spi;
+ struct resource *r;
+ struct orion_spi_info *spi_info;
+ int status = 0;
+
+ spi_info = pdev->dev.platform_data;
+
+ master = spi_alloc_master(&pdev->dev, sizeof *spi);
+ if (master == NULL) {
+ dev_dbg(&pdev->dev, "master allocation failed\n");
+ return -ENOMEM;
+ }
+
+ if (pdev->id != -1)
+ master->bus_num = pdev->id;
+
+ master->setup = orion_spi_setup;
+ master->transfer = orion_spi_transfer;
+ master->num_chipselect = ORION_NUM_CHIPSELECTS;
+
+ dev_set_drvdata(&pdev->dev, master);
+
+ spi = spi_master_get_devdata(master);
+ spi->master = master;
+ spi->spi_info = spi_info;
+
+ spi->max_speed = DIV_ROUND_UP(spi_info->tclk, 4);
+ spi->min_speed = DIV_ROUND_UP(spi_info->tclk, 30);
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (r == NULL) {
+ status = -ENODEV;
+ goto out;
+ }
+
+ if (!request_mem_region(r->start, (r->end - r->start) + 1,
+ pdev->dev.bus_id)) {
+ status = -EBUSY;
+ goto out;
+ }
+ spi->base = ioremap(r->start, SZ_1K);
+
+ INIT_WORK(&spi->work, orion_spi_work);
+
+ spin_lock_init(&spi->lock);
+ INIT_LIST_HEAD(&spi->msg_queue);
+
+ if (orion_spi_reset(spi) < 0)
+ goto out_rel_mem;
+
+ status = spi_register_master(master);
+ if (status < 0)
+ goto out_rel_mem;
+
+ return status;
+
+out_rel_mem:
+ release_mem_region(r->start, (r->end - r->start) + 1);
+
+out:
+ spi_master_put(master);
+ return status;
+}
+
+
+static int __exit orion_spi_remove(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct orion_spi *spi;
+ struct resource *r;
+
+ master = dev_get_drvdata(&pdev->dev);
+ spi = spi_master_get_devdata(master);
+
+ cancel_work_sync(&spi->work);
+
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ release_mem_region(r->start, (r->end - r->start) + 1);
+
+ spi_unregister_master(master);
+
+ return 0;
+}
+
+MODULE_ALIAS("platform:" DRIVER_NAME);
+
+static struct platform_driver orion_spi_driver = {
+ .driver = {
+ .name = DRIVER_NAME,
+ .owner = THIS_MODULE,
+ },
+ .remove = __exit_p(orion_spi_remove),
+};
+
+static int __init orion_spi_init(void)
+{
+ orion_spi_wq = create_singlethread_workqueue(
+ orion_spi_driver.driver.name);
+ if (orion_spi_wq == NULL)
+ return -ENOMEM;
+
+ return platform_driver_probe(&orion_spi_driver, orion_spi_probe);
+}
+module_init(orion_spi_init);
+
+static void __exit orion_spi_exit(void)
+{
+ flush_workqueue(orion_spi_wq);
+ platform_driver_unregister(&orion_spi_driver);
+
+ destroy_workqueue(orion_spi_wq);
+}
+module_exit(orion_spi_exit);
+
+MODULE_DESCRIPTION("Orion SPI driver");
+MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
+MODULE_LICENSE("GPL");
projects / linux-2.6 / commitdiff