Initial import

1 files changed, 572 insertions, 0 deletions

diff --git a/drivers/spi/spi-orion.c b/drivers/spi/spi-orion.c
new file mode 100644
index 000000000..ff97cabda
--- /dev/null
+++ b/drivers/spi/spi-orion.c
@@ -0,0 +1,572 @@
+/*
+ * 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/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/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/clk.h>
+#include <linux/sizes.h>
+#include <asm/unaligned.h>
+
+#define DRIVER_NAME			"orion_spi"
+
+/* Runtime PM autosuspend timeout: PM is fairly light on this driver */
+#define SPI_AUTOSUSPEND_TIMEOUT		200
+
+/* Some SoCs using this driver support up to 8 chip selects.
+ * It is up to the implementer to only use the chip selects
+ * that are available.
+ */
+#define ORION_NUM_CHIPSELECTS		8
+
+#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_MODE_CPOL		(1 << 11)
+#define ORION_SPI_MODE_CPHA		(1 << 12)
+#define ORION_SPI_IF_8_16_BIT_MODE	(1 << 5)
+#define ORION_SPI_CLK_PRESCALE_MASK	0x1F
+#define ARMADA_SPI_CLK_PRESCALE_MASK	0xDF
+#define ORION_SPI_MODE_MASK		(ORION_SPI_MODE_CPOL | \
+					 ORION_SPI_MODE_CPHA)
+#define ORION_SPI_CS_MASK	0x1C
+#define ORION_SPI_CS_SHIFT	2
+#define ORION_SPI_CS(cs)	((cs << ORION_SPI_CS_SHIFT) & \
+					ORION_SPI_CS_MASK)
+
+enum orion_spi_type {
+	ORION_SPI,
+	ARMADA_SPI,
+};
+
+struct orion_spi_dev {
+	enum orion_spi_type	typ;
+	/*
+	 * min_divisor and max_hz should be exclusive, the only we can
+	 * have both is for managing the armada-370-spi case with old
+	 * device tree
+	 */
+	unsigned long		max_hz;
+	unsigned int		min_divisor;
+	unsigned int		max_divisor;
+	u32			prescale_mask;
+};
+
+struct orion_spi {
+	struct spi_master	*master;
+	void __iomem		*base;
+	struct clk              *clk;
+	const struct orion_spi_dev *devdata;
+};
+
+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_baudrate_set(struct spi_device *spi, unsigned int speed)
+{
+	u32 tclk_hz;
+	u32 rate;
+	u32 prescale;
+	u32 reg;
+	struct orion_spi *orion_spi;
+	const struct orion_spi_dev *devdata;
+
+	orion_spi = spi_master_get_devdata(spi->master);
+	devdata = orion_spi->devdata;
+
+	tclk_hz = clk_get_rate(orion_spi->clk);
+
+	if (devdata->typ == ARMADA_SPI) {
+		unsigned int clk, spr, sppr, sppr2, err;
+		unsigned int best_spr, best_sppr, best_err;
+
+		best_err = speed;
+		best_spr = 0;
+		best_sppr = 0;
+
+		/* Iterate over the valid range looking for best fit */
+		for (sppr = 0; sppr < 8; sppr++) {
+			sppr2 = 0x1 << sppr;
+
+			spr = tclk_hz / sppr2;
+			spr = DIV_ROUND_UP(spr, speed);
+			if ((spr == 0) || (spr > 15))
+				continue;
+
+			clk = tclk_hz / (spr * sppr2);
+			err = speed - clk;
+
+			if (err < best_err) {
+				best_spr = spr;
+				best_sppr = sppr;
+				best_err = err;
+			}
+		}
+
+		if ((best_sppr == 0) && (best_spr == 0))
+			return -EINVAL;
+
+		prescale = ((best_sppr & 0x6) << 5) |
+			((best_sppr & 0x1) << 4) | best_spr;
+	} else {
+		/*
+		 * 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 & ~devdata->prescale_mask) | prescale);
+	writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
+
+	return 0;
+}
+
+static void
+orion_spi_mode_set(struct spi_device *spi)
+{
+	u32 reg;
+	struct orion_spi *orion_spi;
+
+	orion_spi = spi_master_get_devdata(spi->master);
+
+	reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
+	reg &= ~ORION_SPI_MODE_MASK;
+	if (spi->mode & SPI_CPOL)
+		reg |= ORION_SPI_MODE_CPOL;
+	if (spi->mode & SPI_CPHA)
+		reg |= ORION_SPI_MODE_CPHA;
+	writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
+}
+
+/*
+ * 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;
+
+	orion_spi_mode_set(spi);
+
+	rc = orion_spi_baudrate_set(spi, speed);
+	if (rc)
+		return rc;
+
+	if (bits_per_word == 16)
+		orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
+				  ORION_SPI_IF_8_16_BIT_MODE);
+	else
+		orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
+				  ORION_SPI_IF_8_16_BIT_MODE);
+
+	return 0;
+}
+
+static void orion_spi_set_cs(struct spi_device *spi, bool enable)
+{
+	struct orion_spi *orion_spi;
+
+	orion_spi = spi_master_get_devdata(spi->master);
+
+	orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, ORION_SPI_CS_MASK);
+	orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG,
+				ORION_SPI_CS(spi->chip_select));
+
+	/* Chip select logic is inverted from spi_set_cs */
+	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;
+
+		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)
+{
+	unsigned int count;
+	int word_len;
+
+	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 int orion_spi_transfer_one(struct spi_master *master,
+					struct spi_device *spi,
+					struct spi_transfer *t)
+{
+	int status = 0;
+
+	status = orion_spi_setup_transfer(spi, t);
+	if (status < 0)
+		return status;
+
+	if (t->len)
+		orion_spi_write_read(spi, t);
+
+	return status;
+}
+
+static int orion_spi_setup(struct spi_device *spi)
+{
+	return orion_spi_setup_transfer(spi, NULL);
+}
+
+static int orion_spi_reset(struct orion_spi *orion_spi)
+{
+	/* Verify that the CS is deasserted */
+	orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
+	return 0;
+}
+
+static const struct orion_spi_dev orion_spi_dev_data = {
+	.typ = ORION_SPI,
+	.min_divisor = 4,
+	.max_divisor = 30,
+	.prescale_mask = ORION_SPI_CLK_PRESCALE_MASK,
+};
+
+static const struct orion_spi_dev armada_spi_dev_data = {
+	.typ = ARMADA_SPI,
+	.min_divisor = 4,
+	.max_divisor = 1920,
+	.max_hz = 50000000,
+	.prescale_mask = ARMADA_SPI_CLK_PRESCALE_MASK,
+};
+
+static const struct of_device_id orion_spi_of_match_table[] = {
+	{ .compatible = "marvell,orion-spi", .data = &orion_spi_dev_data, },
+	{ .compatible = "marvell,armada-370-spi", .data = &armada_spi_dev_data, },
+	{}
+};
+MODULE_DEVICE_TABLE(of, orion_spi_of_match_table);
+
+static int orion_spi_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *of_id;
+	const struct orion_spi_dev *devdata;
+	struct spi_master *master;
+	struct orion_spi *spi;
+	struct resource *r;
+	unsigned long tclk_hz;
+	int status = 0;
+
+	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;
+	if (pdev->dev.of_node) {
+		u32 cell_index;
+
+		if (!of_property_read_u32(pdev->dev.of_node, "cell-index",
+					  &cell_index))
+			master->bus_num = cell_index;
+	}
+
+	/* we support only mode 0, and no options */
+	master->mode_bits = SPI_CPHA | SPI_CPOL;
+	master->set_cs = orion_spi_set_cs;
+	master->transfer_one = orion_spi_transfer_one;
+	master->num_chipselect = ORION_NUM_CHIPSELECTS;
+	master->setup = orion_spi_setup;
+	master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16);
+	master->auto_runtime_pm = true;
+
+	platform_set_drvdata(pdev, master);
+
+	spi = spi_master_get_devdata(master);
+	spi->master = master;
+
+	of_id = of_match_device(orion_spi_of_match_table, &pdev->dev);
+	devdata = (of_id) ? of_id->data : &orion_spi_dev_data;
+	spi->devdata = devdata;
+
+	spi->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(spi->clk)) {
+		status = PTR_ERR(spi->clk);
+		goto out;
+	}
+
+	status = clk_prepare_enable(spi->clk);
+	if (status)
+		goto out;
+
+	tclk_hz = clk_get_rate(spi->clk);
+
+	/*
+	 * With old device tree, armada-370-spi could be used with
+	 * Armada XP, however for this SoC the maximum frequency is
+	 * 50MHz instead of tclk/4. On Armada 370, tclk cannot be
+	 * higher than 200MHz. So, in order to be able to handle both
+	 * SoCs, we can take the minimum of 50MHz and tclk/4.
+	 */
+	if (of_device_is_compatible(pdev->dev.of_node,
+					"marvell,armada-370-spi"))
+		master->max_speed_hz = min(devdata->max_hz,
+				DIV_ROUND_UP(tclk_hz, devdata->min_divisor));
+	else
+		master->max_speed_hz =
+			DIV_ROUND_UP(tclk_hz, devdata->min_divisor);
+	master->min_speed_hz = DIV_ROUND_UP(tclk_hz, devdata->max_divisor);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	spi->base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(spi->base)) {
+		status = PTR_ERR(spi->base);
+		goto out_rel_clk;
+	}
+
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
+	pm_runtime_enable(&pdev->dev);
+
+	status = orion_spi_reset(spi);
+	if (status < 0)
+		goto out_rel_pm;
+
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
+
+	master->dev.of_node = pdev->dev.of_node;
+	status = spi_register_master(master);
+	if (status < 0)
+		goto out_rel_pm;
+
+	return status;
+
+out_rel_pm:
+	pm_runtime_disable(&pdev->dev);
+out_rel_clk:
+	clk_disable_unprepare(spi->clk);
+out:
+	spi_master_put(master);
+	return status;
+}
+
+
+static int orion_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = platform_get_drvdata(pdev);
+	struct orion_spi *spi = spi_master_get_devdata(master);
+
+	pm_runtime_get_sync(&pdev->dev);
+	clk_disable_unprepare(spi->clk);
+
+	spi_unregister_master(master);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+MODULE_ALIAS("platform:" DRIVER_NAME);
+
+#ifdef CONFIG_PM
+static int orion_spi_runtime_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct orion_spi *spi = spi_master_get_devdata(master);
+
+	clk_disable_unprepare(spi->clk);
+	return 0;
+}
+
+static int orion_spi_runtime_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct orion_spi *spi = spi_master_get_devdata(master);
+
+	return clk_prepare_enable(spi->clk);
+}
+#endif
+
+static const struct dev_pm_ops orion_spi_pm_ops = {
+	SET_RUNTIME_PM_OPS(orion_spi_runtime_suspend,
+			   orion_spi_runtime_resume,
+			   NULL)
+};
+
+static struct platform_driver orion_spi_driver = {
+	.driver = {
+		.name	= DRIVER_NAME,
+		.pm	= &orion_spi_pm_ops,
+		.of_match_table = of_match_ptr(orion_spi_of_match_table),
+	},
+	.probe		= orion_spi_probe,
+	.remove		= orion_spi_remove,
+};
+
+module_platform_driver(orion_spi_driver);
+
+MODULE_DESCRIPTION("Orion SPI driver");
+MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
+MODULE_LICENSE("GPL");