[PATCH v4] powerpc/5200: Add mpc5200-spi (non-PSC) device driver

Grant Likely
2009-06-18T02:55:18Z

From: Grant Likely <grant.likely@secretlab.ca>

Adds support for the dedicated SPI device on the Freescale MPC5200(b)
SoC.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---

Hi David,

It's been a while since I've posted this, but I believe I've addressed
all the outstanding comments against v3, and people are asking me for it.
The pre-message stuff is all gone and the error handling should be
better now.

BTW, the premessage stuff was to handle a platform I had where some of
the CS lines were controlled with a separate SPI transaction to the
same SPI controller. It almost looks like an SPI bridge. It requires
more thought before I try again.

Being a new driver, it would be nice to get it into 2.6.31, but
definitely not critical.

g.

drivers/spi/Kconfig | 8 +
drivers/spi/Makefile | 1
drivers/spi/mpc52xx_spi.c | 520 +++++++++++++++++++++++++++++++++++++++
include/linux/spi/mpc52xx_spi.h | 10 +
4 files changed, 539 insertions(+), 0 deletions(-)
create mode 100644 drivers/spi/mpc52xx_spi.c
create mode 100644 include/linux/spi/mpc52xx_spi.h

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 83a185d..1994bcd 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -132,6 +132,14 @@ config SPI_LM70_LLP
which interfaces to an LM70 temperature sensor using
a parallel port.

+config SPI_MPC52xx
+ tristate "Freescale MPC52xx SPI (non-PSC) controller support"
+ depends on PPC_MPC52xx && SPI
+ select SPI_MASTER_OF
+ help
+ This drivers supports the MPC52xx SPI controller in master SPI
+ mode.
+
config SPI_MPC52xx_PSC
tristate "Freescale MPC52xx PSC SPI controller"
depends on PPC_MPC52xx && EXPERIMENTAL
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 5d04519..8de32c7 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_SPI_OMAP_UWIRE) += omap_uwire.o
obj-$(CONFIG_SPI_OMAP24XX) += omap2_mcspi.o
obj-$(CONFIG_SPI_ORION) += orion_spi.o
obj-$(CONFIG_SPI_MPC52xx_PSC) += mpc52xx_psc_spi.o
+obj-$(CONFIG_SPI_MPC52xx) += mpc52xx_spi.o
obj-$(CONFIG_SPI_MPC83xx) += spi_mpc83xx.o
obj-$(CONFIG_SPI_S3C24XX_GPIO) += spi_s3c24xx_gpio.o
obj-$(CONFIG_SPI_S3C24XX) += spi_s3c24xx.o
diff --git a/drivers/spi/mpc52xx_spi.c b/drivers/spi/mpc52xx_spi.c
new file mode 100644
index 0000000..ef8379b
--- /dev/null
+++ b/drivers/spi/mpc52xx_spi.c
@@ -0,0 +1,520 @@
+/*
+ * MPC52xx SPI bus driver.
+ *
+ * Copyright (C) 2008 Secret Lab Technologies Ltd.
+ *
+ * This file is released under the GPLv2
+ *
+ * This is the driver for the MPC5200's dedicated SPI controller.
+ *
+ * Note: this driver does not support the MPC5200 PSC in SPI mode. For
+ * that driver see drivers/spi/mpc52xx_psc_spi.c
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/of_platform.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/mpc52xx_spi.h>
+#include <linux/of_spi.h>
+#include <linux/io.h>
+#include <asm/time.h>
+#include <asm/mpc52xx.h>
+
+MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
+MODULE_DESCRIPTION("MPC52xx SPI (non-PSC) Driver");
+MODULE_LICENSE("GPL");
+
+/* Register offsets */
+#define SPI_CTRL1 0x00
+#define SPI_CTRL1_SPIE (1 << 7)
+#define SPI_CTRL1_SPE (1 << 6)
+#define SPI_CTRL1_MSTR (1 << 4)
+#define SPI_CTRL1_CPOL (1 << 3)
+#define SPI_CTRL1_CPHA (1 << 2)
+#define SPI_CTRL1_SSOE (1 << 1)
+#define SPI_CTRL1_LSBFE (1 << 0)
+
+#define SPI_CTRL2 0x01
+#define SPI_BRR 0x04
+
+#define SPI_STATUS 0x05
+#define SPI_STATUS_SPIF (1 << 7)
+#define SPI_STATUS_WCOL (1 << 6)
+#define SPI_STATUS_MODF (1 << 4)
+
+#define SPI_DATA 0x09
+#define SPI_PORTDATA 0x0d
+#define SPI_DATADIR 0x10
+
+/* FSM state return values */
+#define FSM_STOP 0 /* Nothing more for the state machine to */
+ /* do. If something interesting happens */
+ /* then and IRQ will be received */
+#define FSM_POLL 1 /* need to poll for completion, an IRQ is */
+ /* not expected */
+#define FSM_CONTINUE 2 /* Keep iterating the state machine */
+
+/* Driver internal data */
+struct mpc52xx_spi {
+ struct spi_master *master;
+ u32 sysclk;
+ void __iomem *regs;
+ int irq0; /* MODF irq */
+ int irq1; /* SPIF irq */
+ int ipb_freq;
+
+ /* Statistics */
+ int msg_count;
+ int wcol_count;
+ int wcol_ticks;
+ u32 wcol_tx_timestamp;
+ int modf_count;
+ int byte_count;
+
+ struct list_head queue; /* queue of pending messages */
+ spinlock_t lock;
+ struct work_struct work;
+
+
+ /* Details of current transfer (length, and buffer pointers) */
+ struct spi_message *message; /* current message */
+ struct spi_transfer *transfer; /* current transfer */
+ int (*state)(int irq, struct mpc52xx_spi *ms, u8 status, u8 data);
+ int len;
+ int timestamp;
+ u8 *rx_buf;
+ const u8 *tx_buf;
+ int cs_change;
+};
+
+/*
+ * CS control function
+ */
+static void mpc52xx_spi_chipsel(struct mpc52xx_spi *ms, int value)
+{
+ out_8(ms->regs + SPI_PORTDATA, value ? 0 : 0x08);
+}
+
+/*
+ * Start a new transfer. This is called both by the idle state
+ * for the first transfer in a message, and by the wait state when the
+ * previous transfer in a message is complete.
+ */
+static void mpc52xx_spi_start_transfer(struct mpc52xx_spi *ms)
+{
+ ms->rx_buf = ms->transfer->rx_buf;
+ ms->tx_buf = ms->transfer->tx_buf;
+ ms->len = ms->transfer->len;
+
+ /* Activate the chip select */
+ if (ms->cs_change)
+ mpc52xx_spi_chipsel(ms, 1);
+ ms->cs_change = ms->transfer->cs_change;
+
+ /* Write out the first byte */
+ ms->wcol_tx_timestamp = get_tbl();
+ if (ms->tx_buf)
+ out_8(ms->regs + SPI_DATA, *ms->tx_buf++);
+ else
+ out_8(ms->regs + SPI_DATA, 0);
+}
+
+/* Forward declaration of state handlers */
+static int mpc52xx_spi_fsmstate_transfer(int irq, struct mpc52xx_spi *ms,
+ u8 status, u8 data);
+static int mpc52xx_spi_fsmstate_wait(int irq, struct mpc52xx_spi *ms,
+ u8 status, u8 data);
+
+/*
+ * IDLE state
+ *
+ * No transfers are in progress; if another transfer is pending then retrieve
+ * it and kick it off. Otherwise, stop processing the state machine
+ */
+static int
+mpc52xx_spi_fsmstate_idle(int irq, struct mpc52xx_spi *ms, u8 status, u8 data)
+{
+ struct spi_device *spi;
+ int spr, sppr;
+ u8 ctrl1;
+
+ if (status && (irq != NO_IRQ))
+ dev_err(&ms->master->dev, "spurious irq, status=0x%.2x\n",
+ status);
+
+ /* Check if there is another transfer waiting. */
+ if (list_empty(&ms->queue))
+ return FSM_STOP;
+
+ /* get the head of the queue */
+ ms->message = list_first_entry(&ms->queue, struct spi_message, queue);
+ list_del_init(&ms->message->queue);
+
+ /* Setup the controller parameters */
+ ctrl1 = SPI_CTRL1_SPIE | SPI_CTRL1_SPE | SPI_CTRL1_MSTR;
+ spi = ms->message->spi;
+ if (spi->mode & SPI_CPHA)
+ ctrl1 |= SPI_CTRL1_CPHA;
+ if (spi->mode & SPI_CPOL)
+ ctrl1 |= SPI_CTRL1_CPOL;
+ if (spi->mode & SPI_LSB_FIRST)
+ ctrl1 |= SPI_CTRL1_LSBFE;
+ out_8(ms->regs + SPI_CTRL1, ctrl1);
+
+ /* Setup the controller speed */
+ /* minimum divider is '2'. Also, add '1' to force rounding the
+ * divider up. */
+ sppr = ((ms->ipb_freq / ms->message->spi->max_speed_hz) + 1) >> 1;
+ spr = 0;
+ if (sppr < 1)
+ sppr = 1;
+ while (((sppr - 1) & ~0x7) != 0) {
+ sppr = (sppr + 1) >> 1; /* add '1' to force rounding up */
+ spr++;
+ }
+ sppr--; /* sppr quantity in register is offset by 1 */
+ if (spr > 7) {
+ /* Don't overrun limits of SPI baudrate register */
+ spr = 7;
+ sppr = 7;
+ }
+ out_8(ms->regs + SPI_BRR, sppr << 4 | spr); /* Set speed */
+
+ ms->cs_change = 1;
+ ms->transfer = container_of(ms->message->transfers.next,
+ struct spi_transfer, transfer_list);
+
+ mpc52xx_spi_start_transfer(ms);
+ ms->state = mpc52xx_spi_fsmstate_transfer;
+
+ return FSM_CONTINUE;
+}
+
+/*
+ * TRANSFER state
+ *
+ * In the middle of a transfer. If the SPI core has completed processing
+ * a byte, then read out the received data and write out the next byte
+ * (unless this transfer is finished; in which case go on to the wait
+ * state)
+ */
+static int mpc52xx_spi_fsmstate_transfer(int irq, struct mpc52xx_spi *ms,
+ u8 status, u8 data)
+{
+ if (!status)
+ return ms->irq0 ? FSM_STOP : FSM_POLL;
+
+ if (status & SPI_STATUS_WCOL) {
+ /* The SPI controller is stoopid. At slower speeds, it may
+ * raise the SPIF flag before the state machine is actually
+ * finished, which causes a collision (internal to the state
+ * machine only). The manual recommends inserting a delay
+ * between receiving the interrupt and sending the next byte,
+ * but it can also be worked around simply by retrying the
+ * transfer which is what we do here. */
+ ms->wcol_count++;
+ ms->wcol_ticks += get_tbl() - ms->wcol_tx_timestamp;
+ ms->wcol_tx_timestamp = get_tbl();
+ data = 0;
+ if (ms->tx_buf)
+ data = *(ms->tx_buf-1);
+ out_8(ms->regs + SPI_DATA, data); /* try again */
+ return FSM_CONTINUE;
+ } else if (status & SPI_STATUS_MODF) {
+ ms->modf_count++;
+ dev_err(&ms->master->dev, "mode fault\n");
+ mpc52xx_spi_chipsel(ms, 0);
+ ms->message->status = -EIO;
+ ms->message->complete(ms->message->context);
+ ms->state = mpc52xx_spi_fsmstate_idle;
+ return FSM_CONTINUE;
+ }
+
+ /* Read data out of the spi device */
+ ms->byte_count++;
+ if (ms->rx_buf)
+ *ms->rx_buf++ = data;
+
+ /* Is the transfer complete? */
+ ms->len--;
+ if (ms->len == 0) {
+ ms->timestamp = get_tbl();
+ ms->timestamp += ms->transfer->delay_usecs * tb_ticks_per_usec;
+ ms->state = mpc52xx_spi_fsmstate_wait;
+ return FSM_CONTINUE;
+ }
+
+ /* Write out the next byte */
+ ms->wcol_tx_timestamp = get_tbl();
+ if (ms->tx_buf)
+ out_8(ms->regs + SPI_DATA, *ms->tx_buf++);
+ else
+ out_8(ms->regs + SPI_DATA, 0);
+
+ return FSM_CONTINUE;
+}
+
+/*
+ * WAIT state
+ *
+ * A transfer has completed; need to wait for the delay period to complete
+ * before starting the next transfer
+ */
+static int
+mpc52xx_spi_fsmstate_wait(int irq, struct mpc52xx_spi *ms, u8 status, u8 data)
+{
+ if (status && irq)
+ dev_err(&ms->master->dev, "spurious irq, status=0x%.2x\n",
+ status);
+
+ if (((int)get_tbl()) - ms->timestamp < 0)
+ return FSM_POLL;
+
+ ms->message->actual_length += ms->transfer->len;
+
+ /* Check if there is another transfer in this message. If there
+ * aren't then deactivate CS, notify sender, and drop back to idle
+ * to start the next message. */
+ if (ms->transfer->transfer_list.next == &ms->message->transfers) {
+ ms->msg_count++;
+ mpc52xx_spi_chipsel(ms, 0);
+ ms->message->status = 0;
+ ms->message->complete(ms->message->context);
+ ms->state = mpc52xx_spi_fsmstate_idle;
+ return FSM_CONTINUE;
+ }
+
+ /* There is another transfer; kick it off */
+
+ if (ms->cs_change)
+ mpc52xx_spi_chipsel(ms, 0);
+
+ ms->transfer = container_of(ms->transfer->transfer_list.next,
+ struct spi_transfer, transfer_list);
+ mpc52xx_spi_start_transfer(ms);
+ ms->state = mpc52xx_spi_fsmstate_transfer;
+ return FSM_CONTINUE;
+}
+
+/**
+ * mpc52xx_spi_fsm_process - Finite State Machine iteration function
+ * @irq: irq number that triggered the FSM or 0 for polling
+ * @ms: pointer to mpc52xx_spi driver data
+ */
+static void mpc52xx_spi_fsm_process(int irq, struct mpc52xx_spi *ms)
+{
+ int rc = FSM_CONTINUE;
+ u8 status, data;
+
+ while (rc == FSM_CONTINUE) {
+ /* Interrupt cleared by read of STATUS followed by
+ * read of DATA registers */
+ status = in_8(ms->regs + SPI_STATUS);
+ data = in_8(ms->regs + SPI_DATA);
+ rc = ms->state(irq, ms, status, data);
+ }
+
+ if (rc == FSM_POLL)
+ schedule_work(&ms->work);
+}
+
+/**
+ * mpc52xx_spi_irq - IRQ handler
+ */
+static irqreturn_t mpc52xx_spi_irq(int irq, void *_ms)
+{
+ struct mpc52xx_spi *ms = _ms;
+ spin_lock(&ms->lock);
+ mpc52xx_spi_fsm_process(irq, ms);
+ spin_unlock(&ms->lock);
+ return IRQ_HANDLED;
+}
+
+/**
+ * mpc52xx_spi_wq - Workqueue function for polling the state machine
+ */
+static void mpc52xx_spi_wq(struct work_struct *work)
+{
+ struct mpc52xx_spi *ms = container_of(work, struct mpc52xx_spi, work);
+ unsigned long flags;
+
+ spin_lock_irqsave(&ms->lock, flags);
+ mpc52xx_spi_fsm_process(0, ms);
+ spin_unlock_irqrestore(&ms->lock, flags);
+}
+
+/*
+ * spi_master ops
+ */
+
+static int mpc52xx_spi_setup(struct spi_device *spi)
+{
+ if (spi->bits_per_word % 8)
+ return -EINVAL;
+
+ if (spi->mode & ~(SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST))
+ return -EINVAL;
+
+ if (spi->chip_select >= spi->master->num_chipselect)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int mpc52xx_spi_transfer(struct spi_device *spi, struct spi_message *m)
+{
+ struct mpc52xx_spi *ms = spi_master_get_devdata(spi->master);
+ unsigned long flags;
+
+ m->actual_length = 0;
+ m->status = -EINPROGRESS;
+
+ spin_lock_irqsave(&ms->lock, flags);
+ list_add_tail(&m->queue, &ms->queue);
+ spin_unlock_irqrestore(&ms->lock, flags);
+ schedule_work(&ms->work);
+
+ return 0;
+}
+
+/*
+ * OF Platform Bus Binding
+ */
+static int __devinit mpc52xx_spi_probe(struct of_device *op,
+ const struct of_device_id *match)
+{
+ struct spi_master *master;
+ struct mpc52xx_spi *ms;
+ void __iomem *regs;
+ int rc;
+
+ /* MMIO registers */
+ dev_dbg(&op->dev, "probing mpc5200 SPI device\n");
+ regs = of_iomap(op->node, 0);
+ if (!regs)
+ return -ENODEV;
+
+ /* initialize the device */
+ out_8(regs+SPI_CTRL1, SPI_CTRL1_SPIE | SPI_CTRL1_SPE | SPI_CTRL1_MSTR);
+ out_8(regs + SPI_CTRL2, 0x0);
+ out_8(regs + SPI_DATADIR, 0xe); /* Set output pins */
+ out_8(regs + SPI_PORTDATA, 0x8); /* Deassert /SS signal */
+
+ /* Clear the status register and re-read it to check for a MODF
+ * failure. This driver cannot currently handle multiple masters
+ * on the SPI bus. This fault will also occur if the SPI signals
+ * are not connected to any pins (port_config setting) */
+ in_8(regs + SPI_STATUS);
+ in_8(regs + SPI_DATA);
+ if (in_8(regs + SPI_STATUS) & SPI_STATUS_MODF) {
+ dev_err(&op->dev, "mode fault; is port_config correct?\n");
+ rc = -EIO;
+ goto err_init;
+ }
+
+ dev_dbg(&op->dev, "allocating spi_master struct\n");
+ master = spi_alloc_master(&op->dev, sizeof *ms);
+ if (!master) {
+ rc = -ENOMEM;
+ goto err_alloc;
+ }
+ master->bus_num = -1;
+ master->num_chipselect = 1;
+ master->setup = mpc52xx_spi_setup;
+ master->transfer = mpc52xx_spi_transfer;
+ dev_set_drvdata(&op->dev, master);
+
+ ms = spi_master_get_devdata(master);
+ ms->master = master;
+ ms->regs = regs;
+ ms->irq0 = irq_of_parse_and_map(op->node, 0);
+ ms->irq1 = irq_of_parse_and_map(op->node, 1);
+ ms->state = mpc52xx_spi_fsmstate_idle;
+ ms->ipb_freq = mpc5xxx_get_bus_frequency(op->node);
+ spin_lock_init(&ms->lock);
+ INIT_LIST_HEAD(&ms->queue);
+ INIT_WORK(&ms->work, mpc52xx_spi_wq);
+
+ /* Decide if interrupts can be used */
+ if (ms->irq0 && ms->irq1) {
+ rc = request_irq(ms->irq0, mpc52xx_spi_irq, IRQF_SAMPLE_RANDOM,
+ "mpc5200-spi-modf", ms);
+ rc |= request_irq(ms->irq1, mpc52xx_spi_irq, IRQF_SAMPLE_RANDOM,
+ "mpc5200-spi-spiF", ms);
+ if (rc) {
+ free_irq(ms->irq0, ms);
+ free_irq(ms->irq1, ms);
+ ms->irq0 = ms->irq1 = 0;
+ }
+ } else {
+ /* operate in polled mode */
+ ms->irq0 = ms->irq1 = 0;
+ }
+
+ if (!ms->irq0)
+ dev_info(&op->dev, "using polled mode\n");
+
+ dev_dbg(&op->dev, "registering spi_master struct\n");
+ rc = spi_register_master(master);
+ if (rc)
+ goto err_register;
+
+ of_register_spi_devices(master, op->node);
+ dev_info(&ms->master->dev, "registered MPC5200 SPI bus\n");
+
+ return rc;
+
+ err_register:
+ dev_err(&ms->master->dev, "initialization failed\n");
+ spi_master_put(master);
+ err_alloc:
+ err_init:
+ iounmap(regs);
+ return rc;
+}
+
+static int __devexit mpc52xx_spi_remove(struct of_device *op)
+{
+ struct spi_master *master = dev_get_drvdata(&op->dev);
+ struct mpc52xx_spi *ms = spi_master_get_devdata(master);
+
+ free_irq(ms->irq0, ms);
+ free_irq(ms->irq1, ms);
+
+ spi_unregister_master(master);
+ spi_master_put(master);
+ iounmap(ms->regs);
+
+ return 0;
+}
+
+static struct of_device_id mpc52xx_spi_match[] __devinitdata = {
+ { .compatible = "fsl,mpc5200-spi", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, mpc52xx_spi_match);
+
+static struct of_platform_driver mpc52xx_spi_of_driver = {
+ .owner = THIS_MODULE,
+ .name = "mpc52xx-spi",
+ .match_table = mpc52xx_spi_match,
+ .probe = mpc52xx_spi_probe,
+ .remove = __exit_p(mpc52xx_spi_remove),
+};
+
+static int __init mpc52xx_spi_init(void)
+{
+ return of_register_platform_driver(&mpc52xx_spi_of_driver);
+}
+module_init(mpc52xx_spi_init);
+
+static void __exit mpc52xx_spi_exit(void)
+{
+ of_unregister_platform_driver(&mpc52xx_spi_of_driver);
+}
+module_exit(mpc52xx_spi_exit);
+
diff --git a/include/linux/spi/mpc52xx_spi.h b/include/linux/spi/mpc52xx_spi.h
new file mode 100644
index 0000000..d1004cf
--- /dev/null
+++ b/include/linux/spi/mpc52xx_spi.h
@@ -0,0 +1,10 @@
+
+#ifndef INCLUDE_MPC5200_SPI_H
+#define INCLUDE_MPC5200_SPI_H
+
+extern void mpc52xx_spi_set_premessage_hook(struct spi_master *master,
+ void (*hook)(struct spi_message *m,
+ void *context),
+ void *hook_context);
+
+#endif