mpc52xx_psc_spi.c

linux 内核源代码

/*
 * MPC52xx SPC in SPI mode driver.
 *
 * Maintainer: Dragos Carp
 *
 * Copyright (C) 2006 TOPTICA Photonics AG.
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/interrupt.h>

#if defined(CONFIG_PPC_MERGE)
#include <asm/of_platform.h>
#else
#include <linux/platform_device.h>
#endif

#include <linux/workqueue.h>
#include <linux/completion.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/spi/spi.h>
#include <linux/fsl_devices.h>

#include <asm/mpc52xx.h>
#include <asm/mpc52xx_psc.h>

#define MCLK 20000000 /* PSC port MClk in hz */

struct mpc52xx_psc_spi {
	/* fsl_spi_platform data */
	void (*activate_cs)(u8, u8);
	void (*deactivate_cs)(u8, u8);
	u32 sysclk;

	/* driver internal data */
	struct mpc52xx_psc __iomem *psc;
	unsigned int irq;
	u8 bits_per_word;
	u8 busy;

	struct workqueue_struct *workqueue;
	struct work_struct work;

	struct list_head queue;
	spinlock_t lock;

	struct completion done;
};

/* controller state */
struct mpc52xx_psc_spi_cs {
	int bits_per_word;
	int speed_hz;
};

/* set clock freq, clock ramp, bits per work
 * if t is NULL then reset the values to the default values
 */
static int mpc52xx_psc_spi_transfer_setup(struct spi_device *spi,
		struct spi_transfer *t)
{
	struct mpc52xx_psc_spi_cs *cs = spi->controller_state;

	cs->speed_hz = (t && t->speed_hz)
			? t->speed_hz : spi->max_speed_hz;
	cs->bits_per_word = (t && t->bits_per_word)
			? t->bits_per_word : spi->bits_per_word;
	cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
	return 0;
}

static void mpc52xx_psc_spi_activate_cs(struct spi_device *spi)
{
	struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
	struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
	struct mpc52xx_psc __iomem *psc = mps->psc;
	u32 sicr;
	u16 ccr;

	sicr = in_be32(&psc->sicr);

	/* Set clock phase and polarity */
	if (spi->mode & SPI_CPHA)
		sicr |= 0x00001000;
	else
		sicr &= ~0x00001000;
	if (spi->mode & SPI_CPOL)
		sicr |= 0x00002000;
	else
		sicr &= ~0x00002000;

	if (spi->mode & SPI_LSB_FIRST)
		sicr |= 0x10000000;
	else
		sicr &= ~0x10000000;
	out_be32(&psc->sicr, sicr);

	/* Set clock frequency and bits per word
	 * Because psc->ccr is defined as 16bit register instead of 32bit
	 * just set the lower byte of BitClkDiv
	 */
	ccr = in_be16(&psc->ccr);
	ccr &= 0xFF00;
	if (cs->speed_hz)
		ccr |= (MCLK / cs->speed_hz - 1) & 0xFF;
	else /* by default SPI Clk 1MHz */
		ccr |= (MCLK / 1000000 - 1) & 0xFF;
	out_be16(&psc->ccr, ccr);
	mps->bits_per_word = cs->bits_per_word;

	if (mps->activate_cs)
		mps->activate_cs(spi->chip_select,
				(spi->mode & SPI_CS_HIGH) ? 1 : 0);
}

static void mpc52xx_psc_spi_deactivate_cs(struct spi_device *spi)
{
	struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);

	if (mps->deactivate_cs)
		mps->deactivate_cs(spi->chip_select,
				(spi->mode & SPI_CS_HIGH) ? 1 : 0);
}

#define MPC52xx_PSC_BUFSIZE (MPC52xx_PSC_RFNUM_MASK + 1)
/* wake up when 80% fifo full */
#define MPC52xx_PSC_RFALARM (MPC52xx_PSC_BUFSIZE * 20 / 100)

static int mpc52xx_psc_spi_transfer_rxtx(struct spi_device *spi,
						struct spi_transfer *t)
{
	struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
	struct mpc52xx_psc __iomem *psc = mps->psc;
	unsigned rb = 0;	/* number of bytes receieved */
	unsigned sb = 0;	/* number of bytes sent */
	unsigned char *rx_buf = (unsigned char *)t->rx_buf;
	unsigned char *tx_buf = (unsigned char *)t->tx_buf;
	unsigned rfalarm;
	unsigned send_at_once = MPC52xx_PSC_BUFSIZE;
	unsigned recv_at_once;
	unsigned bpw = mps->bits_per_word / 8;

	if (!t->tx_buf && !t->rx_buf && t->len)
		return -EINVAL;

	/* enable transmiter/receiver */
	out_8(&psc->command, MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
	while (rb < t->len) {
		if (t->len - rb > MPC52xx_PSC_BUFSIZE) {
			rfalarm = MPC52xx_PSC_RFALARM;
		} else {
			send_at_once = t->len - sb;
			rfalarm = MPC52xx_PSC_BUFSIZE - (t->len - rb);
		}

		dev_dbg(&spi->dev, "send %d bytes...\n", send_at_once);
		if (tx_buf) {
			for (; send_at_once; sb++, send_at_once--) {
				/* set EOF flag */
				if (mps->bits_per_word
						&& (sb + 1) % bpw == 0)
					out_8(&psc->ircr2, 0x01);
				out_8(&psc->mpc52xx_psc_buffer_8, tx_buf[sb]);
			}
		} else {
			for (; send_at_once; sb++, send_at_once--) {
				/* set EOF flag */
				if (mps->bits_per_word
						&& ((sb + 1) % bpw) == 0)
					out_8(&psc->ircr2, 0x01);
				out_8(&psc->mpc52xx_psc_buffer_8, 0);
			}
		}


		/* enable interrupts and wait for wake up
		 * if just one byte is expected the Rx FIFO genererates no
		 * FFULL interrupt, so activate the RxRDY interrupt
		 */
		out_8(&psc->command, MPC52xx_PSC_SEL_MODE_REG_1);
		if (t->len - rb == 1) {
			out_8(&psc->mode, 0);
		} else {
			out_8(&psc->mode, MPC52xx_PSC_MODE_FFULL);
			out_be16(&psc->rfalarm, rfalarm);
		}
		out_be16(&psc->mpc52xx_psc_imr, MPC52xx_PSC_IMR_RXRDY);
		wait_for_completion(&mps->done);
		recv_at_once = in_be16(&psc->rfnum);
		dev_dbg(&spi->dev, "%d bytes received\n", recv_at_once);

		send_at_once = recv_at_once;
		if (rx_buf) {
			for (; recv_at_once; rb++, recv_at_once--)
				rx_buf[rb] = in_8(&psc->mpc52xx_psc_buffer_8);
		} else {
			for (; recv_at_once; rb++, recv_at_once--)
				in_8(&psc->mpc52xx_psc_buffer_8);
		}
	}
	/* disable transmiter/receiver */
	out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);

	return 0;
}

static void mpc52xx_psc_spi_work(struct work_struct *work)
{
	struct mpc52xx_psc_spi *mps =
		container_of(work, struct mpc52xx_psc_spi, work);

	spin_lock_irq(&mps->lock);
	mps->busy = 1;
	while (!list_empty(&mps->queue)) {
		struct spi_message *m;
		struct spi_device *spi;
		struct spi_transfer *t = NULL;
		unsigned cs_change;
		int status;

		m = container_of(mps->queue.next, struct spi_message, queue);
		list_del_init(&m->queue);
		spin_unlock_irq(&mps->lock);

		spi = m->spi;
		cs_change = 1;
		status = 0;
		list_for_each_entry (t, &m->transfers, transfer_list) {
			if (t->bits_per_word || t->speed_hz) {
				status = mpc52xx_psc_spi_transfer_setup(spi, t);
				if (status < 0)
					break;
			}

			if (cs_change)
				mpc52xx_psc_spi_activate_cs(spi);
			cs_change = t->cs_change;

			status = mpc52xx_psc_spi_transfer_rxtx(spi, t);
			if (status)
				break;
			m->actual_length += t->len;

			if (t->delay_usecs)
				udelay(t->delay_usecs);

			if (cs_change)
				mpc52xx_psc_spi_deactivate_cs(spi);
		}

		m->status = status;
		m->complete(m->context);

		if (status || !cs_change)
			mpc52xx_psc_spi_deactivate_cs(spi);

		mpc52xx_psc_spi_transfer_setup(spi, NULL);

		spin_lock_irq(&mps->lock);
	}
	mps->busy = 0;
	spin_unlock_irq(&mps->lock);
}

/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST)

static int mpc52xx_psc_spi_setup(struct spi_device *spi)
{
	struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
	struct mpc52xx_psc_spi_cs *cs = spi->controller_state;
	unsigned long flags;

	if (spi->bits_per_word%8)
		return -EINVAL;

	if (spi->mode & ~MODEBITS) {
		dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
			spi->mode & ~MODEBITS);
		return -EINVAL;
	}

	if (!cs) {
		cs = kzalloc(sizeof *cs, GFP_KERNEL);
		if (!cs)
			return -ENOMEM;
		spi->controller_state = cs;
	}

	cs->bits_per_word = spi->bits_per_word;
	cs->speed_hz = spi->max_speed_hz;

	spin_lock_irqsave(&mps->lock, flags);
	if (!mps->busy)
		mpc52xx_psc_spi_deactivate_cs(spi);
	spin_unlock_irqrestore(&mps->lock, flags);

	return 0;
}

static int mpc52xx_psc_spi_transfer(struct spi_device *spi,
		struct spi_message *m)
{
	struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
	unsigned long flags;

	m->actual_length = 0;
	m->status = -EINPROGRESS;

	spin_lock_irqsave(&mps->lock, flags);
	list_add_tail(&m->queue, &mps->queue);
	queue_work(mps->workqueue, &mps->work);
	spin_unlock_irqrestore(&mps->lock, flags);

	return 0;
}

static void mpc52xx_psc_spi_cleanup(struct spi_device *spi)
{
	kfree(spi->controller_state);
}

static int mpc52xx_psc_spi_port_config(int psc_id, struct mpc52xx_psc_spi *mps)