1 files changed, 317 insertions, 0 deletions
diff --git a/drivers/spi/spi-ath79.c b/drivers/spi/spi-ath79.c
new file mode 100644
index 000000000..b02eb4ac0
--- /dev/null
+++ b/drivers/spi/spi-ath79.c
@@ -0,0 +1,317 @@
+/*
+ * SPI controller driver for the Atheros AR71XX/AR724X/AR913X SoCs
+ *
+ * Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
+ *
+ * This driver has been based on the spi-gpio.c:
+ *	Copyright (C) 2006,2008 David Brownell
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/bitops.h>
+#include <linux/gpio.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include <asm/mach-ath79/ath79_spi_platform.h>
+
+#define DRV_NAME	"ath79-spi"
+
+#define ATH79_SPI_RRW_DELAY_FACTOR	12000
+#define MHZ				(1000 * 1000)
+
+struct ath79_spi {
+	struct spi_bitbang	bitbang;
+	u32			ioc_base;
+	u32			reg_ctrl;
+	void __iomem		*base;
+	struct clk		*clk;
+	unsigned		rrw_delay;
+};
+
+static inline u32 ath79_spi_rr(struct ath79_spi *sp, unsigned reg)
+{
+	return ioread32(sp->base + reg);
+}
+
+static inline void ath79_spi_wr(struct ath79_spi *sp, unsigned reg, u32 val)
+{
+	iowrite32(val, sp->base + reg);
+}
+
+static inline struct ath79_spi *ath79_spidev_to_sp(struct spi_device *spi)
+{
+	return spi_master_get_devdata(spi->master);
+}
+
+static inline void ath79_spi_delay(struct ath79_spi *sp, unsigned nsecs)
+{
+	if (nsecs > sp->rrw_delay)
+		ndelay(nsecs - sp->rrw_delay);
+}
+
+static void ath79_spi_chipselect(struct spi_device *spi, int is_active)
+{
+	struct ath79_spi *sp = ath79_spidev_to_sp(spi);
+	int cs_high = (spi->mode & SPI_CS_HIGH) ? is_active : !is_active;
+
+	if (is_active) {
+		/* set initial clock polarity */
+		if (spi->mode & SPI_CPOL)
+			sp->ioc_base |= AR71XX_SPI_IOC_CLK;
+		else
+			sp->ioc_base &= ~AR71XX_SPI_IOC_CLK;
+
+		ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);
+	}
+
+	if (spi->chip_select) {
+		struct ath79_spi_controller_data *cdata = spi->controller_data;
+
+		/* SPI is normally active-low */
+		gpio_set_value(cdata->gpio, cs_high);
+	} else {
+		if (cs_high)
+			sp->ioc_base |= AR71XX_SPI_IOC_CS0;
+		else
+			sp->ioc_base &= ~AR71XX_SPI_IOC_CS0;
+
+		ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);
+	}
+
+}
+
+static void ath79_spi_enable(struct ath79_spi *sp)
+{
+	/* enable GPIO mode */
+	ath79_spi_wr(sp, AR71XX_SPI_REG_FS, AR71XX_SPI_FS_GPIO);
+
+	/* save CTRL register */
+	sp->reg_ctrl = ath79_spi_rr(sp, AR71XX_SPI_REG_CTRL);
+	sp->ioc_base = ath79_spi_rr(sp, AR71XX_SPI_REG_IOC);
+
+	/* TODO: setup speed? */
+	ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, 0x43);
+}
+
+static void ath79_spi_disable(struct ath79_spi *sp)
+{
+	/* restore CTRL register */
+	ath79_spi_wr(sp, AR71XX_SPI_REG_CTRL, sp->reg_ctrl);
+	/* disable GPIO mode */
+	ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0);
+}
+
+static int ath79_spi_setup_cs(struct spi_device *spi)
+{
+	struct ath79_spi_controller_data *cdata;
+	int status;
+
+	cdata = spi->controller_data;
+	if (spi->chip_select && !cdata)
+		return -EINVAL;
+
+	status = 0;
+	if (spi->chip_select) {
+		unsigned long flags;
+
+		flags = GPIOF_DIR_OUT;
+		if (spi->mode & SPI_CS_HIGH)
+			flags |= GPIOF_INIT_LOW;
+		else
+			flags |= GPIOF_INIT_HIGH;
+
+		status = gpio_request_one(cdata->gpio, flags,
+					  dev_name(&spi->dev));
+	}
+
+	return status;
+}
+
+static void ath79_spi_cleanup_cs(struct spi_device *spi)
+{
+	if (spi->chip_select) {
+		struct ath79_spi_controller_data *cdata = spi->controller_data;
+		gpio_free(cdata->gpio);
+	}
+}
+
+static int ath79_spi_setup(struct spi_device *spi)
+{
+	int status = 0;
+
+	if (!spi->controller_state) {
+		status = ath79_spi_setup_cs(spi);
+		if (status)
+			return status;
+	}
+
+	status = spi_bitbang_setup(spi);
+	if (status && !spi->controller_state)
+		ath79_spi_cleanup_cs(spi);
+
+	return status;
+}
+
+static void ath79_spi_cleanup(struct spi_device *spi)
+{
+	ath79_spi_cleanup_cs(spi);
+	spi_bitbang_cleanup(spi);
+}
+
+static u32 ath79_spi_txrx_mode0(struct spi_device *spi, unsigned nsecs,
+			       u32 word, u8 bits)
+{
+	struct ath79_spi *sp = ath79_spidev_to_sp(spi);
+	u32 ioc = sp->ioc_base;
+
+	/* clock starts at inactive polarity */
+	for (word <<= (32 - bits); likely(bits); bits--) {
+		u32 out;
+
+		if (word & (1 << 31))
+			out = ioc | AR71XX_SPI_IOC_DO;
+		else
+			out = ioc & ~AR71XX_SPI_IOC_DO;
+
+		/* setup MSB (to slave) on trailing edge */
+		ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out);
+		ath79_spi_delay(sp, nsecs);
+		ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out | AR71XX_SPI_IOC_CLK);
+		ath79_spi_delay(sp, nsecs);
+		if (bits == 1)
+			ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, out);
+
+		word <<= 1;
+	}
+
+	return ath79_spi_rr(sp, AR71XX_SPI_REG_RDS);
+}
+
+static int ath79_spi_probe(struct platform_device *pdev)
+{
+	struct spi_master *master;
+	struct ath79_spi *sp;
+	struct ath79_spi_platform_data *pdata;
+	struct resource	*r;
+	unsigned long rate;
+	int ret;
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*sp));
+	if (master == NULL) {
+		dev_err(&pdev->dev, "failed to allocate spi master\n");
+		return -ENOMEM;
+	}
+
+	sp = spi_master_get_devdata(master);
+	platform_set_drvdata(pdev, sp);
+
+	pdata = dev_get_platdata(&pdev->dev);
+
+	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
+	master->setup = ath79_spi_setup;
+	master->cleanup = ath79_spi_cleanup;
+	if (pdata) {
+		master->bus_num = pdata->bus_num;
+		master->num_chipselect = pdata->num_chipselect;
+	}
+
+	sp->bitbang.master = master;
+	sp->bitbang.chipselect = ath79_spi_chipselect;
+	sp->bitbang.txrx_word[SPI_MODE_0] = ath79_spi_txrx_mode0;
+	sp->bitbang.setup_transfer = spi_bitbang_setup_transfer;
+	sp->bitbang.flags = SPI_CS_HIGH;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (r == NULL) {
+		ret = -ENOENT;
+		goto err_put_master;
+	}
+
+	sp->base = devm_ioremap(&pdev->dev, r->start, resource_size(r));
+	if (!sp->base) {
+		ret = -ENXIO;
+		goto err_put_master;
+	}
+
+	sp->clk = devm_clk_get(&pdev->dev, "ahb");
+	if (IS_ERR(sp->clk)) {
+		ret = PTR_ERR(sp->clk);
+		goto err_put_master;
+	}
+
+	ret = clk_enable(sp->clk);
+	if (ret)
+		goto err_put_master;
+
+	rate = DIV_ROUND_UP(clk_get_rate(sp->clk), MHZ);
+	if (!rate) {
+		ret = -EINVAL;
+		goto err_clk_disable;
+	}
+
+	sp->rrw_delay = ATH79_SPI_RRW_DELAY_FACTOR / rate;
+	dev_dbg(&pdev->dev, "register read/write delay is %u nsecs\n",
+		sp->rrw_delay);
+
+	ath79_spi_enable(sp);
+	ret = spi_bitbang_start(&sp->bitbang);
+	if (ret)
+		goto err_disable;
+
+	return 0;
+
+err_disable:
+	ath79_spi_disable(sp);
+err_clk_disable:
+	clk_disable(sp->clk);
+err_put_master:
+	spi_master_put(sp->bitbang.master);
+
+	return ret;
+}
+
+static int ath79_spi_remove(struct platform_device *pdev)
+{
+	struct ath79_spi *sp = platform_get_drvdata(pdev);
+
+	spi_bitbang_stop(&sp->bitbang);
+	ath79_spi_disable(sp);
+	clk_disable(sp->clk);
+	spi_master_put(sp->bitbang.master);
+
+	return 0;
+}
+
+static void ath79_spi_shutdown(struct platform_device *pdev)
+{
+	ath79_spi_remove(pdev);
+}
+
+static struct platform_driver ath79_spi_driver = {
+	.probe		= ath79_spi_probe,
+	.remove		= ath79_spi_remove,
+	.shutdown	= ath79_spi_shutdown,
+	.driver		= {
+		.name	= DRV_NAME,
+	},
+};
+module_platform_driver(ath79_spi_driver);
+
+MODULE_DESCRIPTION("SPI controller driver for Atheros AR71XX/AR724X/AR913X");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRV_NAME);