Commit 60cadec9 authored by Shadi Ammouri's avatar Shadi Ammouri Committed by Linus Torvalds
Browse files

spi: new orion_spi driver 



This adds an SPI driver for the SPI controller found in various Marvell
Orion ARM SoCs.  It currently supports only one slave, which must use SPI
mode 0.

[dbrownell@users.sourceforge.net: cleanups, meet specs, pass "sparse"]
Signed-off-by: default avatarShadi Ammouri <shadi@marvell.com>
Signed-off-by: default avatarSaeed Bishara <saeed@marvell.com>
Signed-off-by: default avatarLennert Buytenhek <buytenh@marvell.com>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 756fcab2

drivers/spi/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -149,6 +149,12 @@ config SPI_OMAP24XX 
	  SPI master controller for OMAP24xx/OMAP34xx Multichannel SPI

	  (McSPI) modules.



config SPI_ORION

	tristate "Orion SPI master (EXPERIMENTAL)"

	depends on PLAT_ORION && EXPERIMENTAL

	help

	  This enables using the SPI master controller on the Orion chips.



config SPI_PXA2XX

	tristate "PXA2xx SSP SPI master"

	depends on ARCH_PXA && EXPERIMENTAL

drivers/spi/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o 
obj-$(CONFIG_SPI_PXA2XX)		+= pxa2xx_spi.o

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_MPC83xx)		+= spi_mpc83xx.o

obj-$(CONFIG_SPI_S3C24XX_GPIO)		+= spi_s3c24xx_gpio.o

drivers/spi/orion_spi.c

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+574 −0
Original line number Diff line number Diff line 
/*

 * 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");

include/linux/spi/orion_spi.h

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+17 −0
Original line number Diff line number Diff line 
/*

 * orion_spi.h

 *

 * This file is licensed under the terms of the GNU General Public

 * License version 2. This program is licensed "as is" without any

 * warranty of any kind, whether express or implied.

 */



#ifndef __LINUX_SPI_ORION_SPI_H

#define __LINUX_SPI_ORION_SPI_H



struct orion_spi_info {

	u32	tclk;		/* no <linux/clk.h> support yet */

};





#endif