[PATCH v6] spi: New driver for Altera SPI

Grant Likely grant.likely at secretlab.ca
Fri Feb 4 04:34:30 EST 2011


On Thu, Feb 03, 2011 at 06:02:06PM +0800, Thomas Chou wrote:
> This patch adds a new SPI driver to support the Altera SOPC Builder
> SPI component. It uses the bitbanging library.
> 
> Signed-off-by: Thomas Chou <thomas at wytron.com.tw>
> ---
> v2 add devicetree support
> v3 remove platform header, as Grant suggested.
>    no irq resource means polling.
> v4 minor cleanup, as Grant suggested.
> v5 add compat version.
> v6 change compatible vendor to uppercase, ALTR.
>    add dts binding doc.

Hi Thomas, comments below, but looking pretty close.

> 
>  .../devicetree/bindings/spi/spi_altera.txt         |    4 +
>  drivers/spi/Kconfig                                |    6 +
>  drivers/spi/Makefile                               |    1 +
>  drivers/spi/spi_altera.c                           |  360 ++++++++++++++++++++
>  4 files changed, 371 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/spi/spi_altera.txt
>  create mode 100644 drivers/spi/spi_altera.c
> 
> diff --git a/Documentation/devicetree/bindings/spi/spi_altera.txt b/Documentation/devicetree/bindings/spi/spi_altera.txt
> new file mode 100644
> index 0000000..dda3759
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/spi/spi_altera.txt
> @@ -0,0 +1,4 @@
> +Altera SPI
> +
> +Required properties:
> +- compatible : should be "ALTR,spi-1.0".
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index bb233a9..e791579 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -53,6 +53,12 @@ if SPI_MASTER
>  
>  comment "SPI Master Controller Drivers"
>  
> +config SPI_ALTERA
> +	tristate "Altera SPI Controller"
> +	select SPI_BITBANG

Will this compile on all architectures?  Will it break allyesconfig
on anything other than nios?

> +	help
> +	  This is the driver for the Altera SPI Controller.
> +
>  config SPI_ATH79
>  	tristate "Atheros AR71XX/AR724X/AR913X SPI controller driver"
>  	depends on ATH79 && GENERIC_GPIO
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index 86d1b5f..4d2e35a 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -9,6 +9,7 @@ ccflags-$(CONFIG_SPI_DEBUG) := -DDEBUG
>  obj-$(CONFIG_SPI_MASTER)		+= spi.o
>  
>  # SPI master controller drivers (bus)
> +obj-$(CONFIG_SPI_ALTERA)		+= spi_altera.o
>  obj-$(CONFIG_SPI_ATMEL)			+= atmel_spi.o
>  obj-$(CONFIG_SPI_ATH79)			+= ath79_spi.o
>  obj-$(CONFIG_SPI_BFIN)			+= spi_bfin5xx.o
> diff --git a/drivers/spi/spi_altera.c b/drivers/spi/spi_altera.c
> new file mode 100644
> index 0000000..1056ded
> --- /dev/null
> +++ b/drivers/spi/spi_altera.c
> @@ -0,0 +1,360 @@
> +/*
> + * Altera SPI driver
> + *
> + * Copyright (C) 2008 Thomas Chou <thomas at wytron.com.tw>
> + *
> + * Based on spi_s3c24xx.c, which is:
> + * Copyright (c) 2006 Ben Dooks
> + * Copyright (c) 2006 Simtec Electronics
> + *	Ben Dooks <ben at simtec.co.uk>
> + *
> + * 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/spinlock.h>
> +#include <linux/workqueue.h>
> +#include <linux/interrupt.h>
> +#include <linux/delay.h>
> +#include <linux/errno.h>
> +#include <linux/err.h>
> +#include <linux/clk.h>
> +#include <linux/platform_device.h>
> +#include <linux/spi/spi.h>
> +#include <linux/spi/spi_bitbang.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +
> +#define DRV_NAME "spi_altera"
> +
> +#define ALTERA_SPI_RXDATA	0
> +#define ALTERA_SPI_TXDATA	4
> +#define ALTERA_SPI_STATUS	8
> +#define ALTERA_SPI_CONTROL	12
> +#define ALTERA_SPI_SLAVE_SEL	20
> +
> +#define ALTERA_SPI_STATUS_ROE_MSK	0x8
> +#define ALTERA_SPI_STATUS_TOE_MSK	0x10
> +#define ALTERA_SPI_STATUS_TMT_MSK	0x20
> +#define ALTERA_SPI_STATUS_TRDY_MSK	0x40
> +#define ALTERA_SPI_STATUS_RRDY_MSK	0x80
> +#define ALTERA_SPI_STATUS_E_MSK		0x100
> +
> +#define ALTERA_SPI_CONTROL_IROE_MSK	0x8
> +#define ALTERA_SPI_CONTROL_ITOE_MSK	0x10
> +#define ALTERA_SPI_CONTROL_ITRDY_MSK	0x40
> +#define ALTERA_SPI_CONTROL_IRRDY_MSK	0x80
> +#define ALTERA_SPI_CONTROL_IE_MSK	0x100
> +#define ALTERA_SPI_CONTROL_SSO_MSK	0x400
> +
> +struct altera_spi {
> +	/* bitbang has to be first */
> +	struct spi_bitbang bitbang;
> +	struct completion done;
> +
> +	void __iomem *base;
> +	int irq;
> +	int len;
> +	int count;
> +	int bytes_per_word;
> +	unsigned long imr;
> +
> +	/* data buffers */
> +	const unsigned char *tx;
> +	unsigned char *rx;
> +};
> +
> +static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
> +{
> +	return spi_master_get_devdata(sdev->master);
> +}
> +
> +static void altera_spi_chipsel(struct spi_device *spi, int value)
> +{
> +	struct altera_spi *hw = altera_spi_to_hw(spi);
> +
> +	if (spi->mode & SPI_CS_HIGH) {
> +		switch (value) {
> +		case BITBANG_CS_INACTIVE:
> +			writel(1 << spi->chip_select,
> +			       hw->base + ALTERA_SPI_SLAVE_SEL);
> +			hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
> +			writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> +			break;
> +
> +		case BITBANG_CS_ACTIVE:
> +			hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
> +			writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> +			writel(0, hw->base + ALTERA_SPI_SLAVE_SEL);
> +			break;
> +		}
> +	} else {
> +		switch (value) {
> +		case BITBANG_CS_INACTIVE:
> +			hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
> +			writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> +			break;
> +
> +		case BITBANG_CS_ACTIVE:
> +			writel(1 << spi->chip_select,
> +			       hw->base + ALTERA_SPI_SLAVE_SEL);
> +			hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
> +			writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> +			break;
> +		}
> +	}
> +}
> +
> +static int altera_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
> +{
> +	return 0;
> +}
> +
> +static int altera_spi_setup(struct spi_device *spi)
> +{
> +	return 0;
> +}
> +
> +static inline unsigned int hw_txbyte(struct altera_spi *hw, int count)
> +{
> +	if (hw->tx) {
> +		switch (hw->bytes_per_word) {
> +		case 1:
> +			return hw->tx[count];
> +		case 2:
> +			return (hw->tx[count * 2]
> +				| (hw->tx[count * 2 + 1] << 8));
> +		}
> +	}
> +	return 0;
> +}
> +
> +static int altera_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
> +{
> +	struct altera_spi *hw = altera_spi_to_hw(spi);
> +
> +	hw->tx = t->tx_buf;
> +	hw->rx = t->rx_buf;
> +	hw->count = 0;
> +	hw->bytes_per_word = (t->bits_per_word ? : spi->bits_per_word) / 8;
> +	hw->len = t->len / hw->bytes_per_word;
> +
> +	if (hw->irq >= 0) {
> +		/* enable receive interrupt */
> +		hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
> +		writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> +
> +		/* send the first byte */
> +		writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
> +
> +		wait_for_completion(&hw->done);
> +		/* disable receive interrupt */
> +		hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
> +		writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> +	} else {
> +		/* send the first byte */
> +		writel(hw_txbyte(hw, 0), hw->base + ALTERA_SPI_TXDATA);
> +
> +		while (1) {
> +			unsigned int rxd;
> +
> +			while (!(readl(hw->base + ALTERA_SPI_STATUS) &
> +				 ALTERA_SPI_STATUS_RRDY_MSK))
> +				cpu_relax();
> +
> +			rxd = readl(hw->base + ALTERA_SPI_RXDATA);
> +			if (hw->rx) {
> +				switch (hw->bytes_per_word) {
> +				case 1:
> +					hw->rx[hw->count] = rxd;
> +					break;
> +				case 2:
> +					hw->rx[hw->count * 2] = rxd;
> +					hw->rx[hw->count * 2 + 1] = rxd >> 8;
> +					break;
> +				}
> +			}
> +
> +			hw->count++;
> +
> +			if (hw->count < hw->len)
> +				writel(hw_txbyte(hw, hw->count),
> +				       hw->base + ALTERA_SPI_TXDATA);
> +			else
> +				break;
> +		}
> +
> +	}
> +
> +	return hw->count * hw->bytes_per_word;
> +}
> +
> +static irqreturn_t altera_spi_irq(int irq, void *dev)
> +{
> +	struct altera_spi *hw = dev;
> +	unsigned int rxd;
> +
> +	rxd = readl(hw->base + ALTERA_SPI_RXDATA);
> +	if (hw->rx) {
> +		switch (hw->bytes_per_word) {
> +		case 1:
> +			hw->rx[hw->count] = rxd;
> +			break;
> +		case 2:
> +			hw->rx[hw->count * 2] = rxd;
> +			hw->rx[hw->count * 2 + 1] = rxd >> 8;
> +			break;
> +		}
> +	}
> +
> +	hw->count++;
> +
> +	if (hw->count < hw->len)
> +		writel(hw_txbyte(hw, hw->count), hw->base + ALTERA_SPI_TXDATA);
> +	else
> +		complete(&hw->done);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int __devinit altera_spi_probe(struct platform_device *pdev)
> +{
> +	struct altera_spi_platform_data *platp = pdev->dev.platform_data;
> +	struct altera_spi *hw;
> +	struct spi_master *master;
> +	struct resource *res;
> +	int err = 0;
> +
> +	master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
> +	if (master == NULL) {
> +		dev_err(&pdev->dev, "No memory for spi_master\n");
> +		err = -ENOMEM;
> +		goto err_no_mem;
> +	}
> +
> +	/* setup the master state. */
> +	master->bus_num = pdev->id;
> +	master->num_chipselect = 16;
> +	master->mode_bits = SPI_CS_HIGH;
> +	master->setup = altera_spi_setup;
> +
> +	hw = spi_master_get_devdata(master);
> +	platform_set_drvdata(pdev, hw);
> +
> +	/* setup the state for the bitbang driver */
> +	hw->bitbang.master = spi_master_get(master);
> +	if (hw->bitbang.master == NULL) {
> +		dev_err(&pdev->dev, "Cannot get device\n");
> +		err = -ENODEV;
> +		goto err_no_dev;
> +	}
> +	hw->bitbang.setup_transfer = altera_spi_setupxfer;
> +	hw->bitbang.chipselect = altera_spi_chipsel;
> +	hw->bitbang.txrx_bufs = altera_spi_txrx;
> +
> +	/* find and map our resources */
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (res == NULL) {
> +		dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
> +		err = -ENOENT;
> +		goto err_no_iores;
> +	}
> +	hw->base = ioremap(res->start, (res->end - res->start) + 1);
> +	if (hw->base == 0) {
> +		dev_err(&pdev->dev, "Cannot map IO\n");
> +		err = -ENXIO;
> +		goto err_no_iomap;
> +	}
> +	/* program defaults into the registers */
> +	hw->imr = 0;		/* disable spi interrupts */
> +	writel(hw->imr, hw->base + ALTERA_SPI_CONTROL);
> +	writel(0, hw->base + ALTERA_SPI_STATUS);	/* clear status reg */
> +	if (readl(hw->base + ALTERA_SPI_STATUS) & ALTERA_SPI_STATUS_RRDY_MSK)
> +		readl(hw->base + ALTERA_SPI_RXDATA);	/* flush rxdata */
> +	/* irq is optional */
> +	hw->irq = platform_get_irq(pdev, 0);
> +	if (hw->irq >= 0) {
> +		init_completion(&hw->done);
> +		err = request_irq(hw->irq, altera_spi_irq, 0, pdev->name, hw);
> +		if (err) {
> +			dev_err(&pdev->dev, "Cannot claim IRQ\n");
> +			goto err_no_irq;
> +		}
> +	}
> +	/* find platform data */
> +	if (!platp)
> +		hw->bitbang.master->dev.of_node = pdev->dev.of_node;
> +
> +	/* register our spi controller */
> +	err = spi_bitbang_start(&hw->bitbang);
> +	if (err) {
> +		dev_err(&pdev->dev, "Failed to register SPI master\n");
> +		goto err_register;
> +	}
> +	dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
> +
> +	return 0;
> +
> +err_register:
> +	if (hw->irq >= 0)
> +		free_irq(hw->irq, hw);
> +err_no_irq:
> +	iounmap(hw->base);
> +err_no_iomap:
> +err_no_iores:
> +err_no_dev:
> +	spi_master_put(master);
> +err_no_mem:
> +	return err;
> +}
> +
> +static int __devexit altera_spi_remove(struct platform_device *dev)
> +{
> +	struct altera_spi *hw = platform_get_drvdata(dev);
> +	struct spi_master *master = hw->bitbang.master;
> +
> +	spi_bitbang_stop(&hw->bitbang);
> +
> +	if (hw->irq >= 0)
> +		free_irq(hw->irq, hw);
> +	iounmap(hw->base);
> +
> +	platform_set_drvdata(dev, NULL);
> +	spi_master_put(master);
> +	return 0;
> +}
> +
> +static const struct of_device_id altera_spi_match[] = {
> +	{ .compatible = "ALTR,spi-1.0", },
> +	{},
> +}
> +MODULE_DEVICE_TABLE(of, altera_spi_match);
> +
> +static struct platform_driver altera_spidrv = {
> +	.remove = __devexit_p(altera_spi_remove),
> +	.driver = {
> +		.name = DRV_NAME,
> +		.owner = THIS_MODULE,
> +		.pm = NULL,
> +		.of_match_table = altera_spi_match,
> +	},
> +};
> +
> +static int __init altera_spi_init(void)
> +{
> +	return platform_driver_probe(&altera_spidrv, altera_spi_probe);

platform_driver_register() please, and put the altera_spi_probe()
routine into the driver structure.

> +}
> +module_init(altera_spi_init);
> +
> +static void __exit altera_spi_exit(void)
> +{
> +	platform_driver_unregister(&altera_spidrv);
> +}
> +module_exit(altera_spi_exit);
> +
> +MODULE_DESCRIPTION("Altera SPI driver");
> +MODULE_AUTHOR("Thomas Chou <thomas at wytron.com.tw>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:" DRV_NAME);
> -- 
> 1.7.3.5
> 


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