Initial import

1 files changed, 476 insertions, 0 deletions

diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c
new file mode 100644
index 000000000..fbb0a4d74
--- /dev/null
+++ b/drivers/spi/spi-sun4i.c
@@ -0,0 +1,476 @@
+/*
+ * Copyright (C) 2012 - 2014 Allwinner Tech
+ * Pan Nan <pannan@allwinnertech.com>
+ *
+ * Copyright (C) 2014 Maxime Ripard
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * 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/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#include <linux/spi/spi.h>
+
+#define SUN4I_FIFO_DEPTH		64
+
+#define SUN4I_RXDATA_REG		0x00
+
+#define SUN4I_TXDATA_REG		0x04
+
+#define SUN4I_CTL_REG			0x08
+#define SUN4I_CTL_ENABLE			BIT(0)
+#define SUN4I_CTL_MASTER			BIT(1)
+#define SUN4I_CTL_CPHA				BIT(2)
+#define SUN4I_CTL_CPOL				BIT(3)
+#define SUN4I_CTL_CS_ACTIVE_LOW			BIT(4)
+#define SUN4I_CTL_LMTF				BIT(6)
+#define SUN4I_CTL_TF_RST			BIT(8)
+#define SUN4I_CTL_RF_RST			BIT(9)
+#define SUN4I_CTL_XCH				BIT(10)
+#define SUN4I_CTL_CS_MASK			0x3000
+#define SUN4I_CTL_CS(cs)			(((cs) << 12) & SUN4I_CTL_CS_MASK)
+#define SUN4I_CTL_DHB				BIT(15)
+#define SUN4I_CTL_CS_MANUAL			BIT(16)
+#define SUN4I_CTL_CS_LEVEL			BIT(17)
+#define SUN4I_CTL_TP				BIT(18)
+
+#define SUN4I_INT_CTL_REG		0x0c
+#define SUN4I_INT_CTL_TC			BIT(16)
+
+#define SUN4I_INT_STA_REG		0x10
+
+#define SUN4I_DMA_CTL_REG		0x14
+
+#define SUN4I_WAIT_REG			0x18
+
+#define SUN4I_CLK_CTL_REG		0x1c
+#define SUN4I_CLK_CTL_CDR2_MASK			0xff
+#define SUN4I_CLK_CTL_CDR2(div)			((div) & SUN4I_CLK_CTL_CDR2_MASK)
+#define SUN4I_CLK_CTL_CDR1_MASK			0xf
+#define SUN4I_CLK_CTL_CDR1(div)			(((div) & SUN4I_CLK_CTL_CDR1_MASK) << 8)
+#define SUN4I_CLK_CTL_DRS			BIT(12)
+
+#define SUN4I_BURST_CNT_REG		0x20
+#define SUN4I_BURST_CNT(cnt)			((cnt) & 0xffffff)
+
+#define SUN4I_XMIT_CNT_REG		0x24
+#define SUN4I_XMIT_CNT(cnt)			((cnt) & 0xffffff)
+
+#define SUN4I_FIFO_STA_REG		0x28
+#define SUN4I_FIFO_STA_RF_CNT_MASK		0x7f
+#define SUN4I_FIFO_STA_RF_CNT_BITS		0
+#define SUN4I_FIFO_STA_TF_CNT_MASK		0x7f
+#define SUN4I_FIFO_STA_TF_CNT_BITS		16
+
+struct sun4i_spi {
+	struct spi_master	*master;
+	void __iomem		*base_addr;
+	struct clk		*hclk;
+	struct clk		*mclk;
+
+	struct completion	done;
+
+	const u8		*tx_buf;
+	u8			*rx_buf;
+	int			len;
+};
+
+static inline u32 sun4i_spi_read(struct sun4i_spi *sspi, u32 reg)
+{
+	return readl(sspi->base_addr + reg);
+}
+
+static inline void sun4i_spi_write(struct sun4i_spi *sspi, u32 reg, u32 value)
+{
+	writel(value, sspi->base_addr + reg);
+}
+
+static inline void sun4i_spi_drain_fifo(struct sun4i_spi *sspi, int len)
+{
+	u32 reg, cnt;
+	u8 byte;
+
+	/* See how much data is available */
+	reg = sun4i_spi_read(sspi, SUN4I_FIFO_STA_REG);
+	reg &= SUN4I_FIFO_STA_RF_CNT_MASK;
+	cnt = reg >> SUN4I_FIFO_STA_RF_CNT_BITS;
+
+	if (len > cnt)
+		len = cnt;
+
+	while (len--) {
+		byte = readb(sspi->base_addr + SUN4I_RXDATA_REG);
+		if (sspi->rx_buf)
+			*sspi->rx_buf++ = byte;
+	}
+}
+
+static inline void sun4i_spi_fill_fifo(struct sun4i_spi *sspi, int len)
+{
+	u8 byte;
+
+	if (len > sspi->len)
+		len = sspi->len;
+
+	while (len--) {
+		byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
+		writeb(byte, sspi->base_addr + SUN4I_TXDATA_REG);
+		sspi->len--;
+	}
+}
+
+static void sun4i_spi_set_cs(struct spi_device *spi, bool enable)
+{
+	struct sun4i_spi *sspi = spi_master_get_devdata(spi->master);
+	u32 reg;
+
+	reg = sun4i_spi_read(sspi, SUN4I_CTL_REG);
+
+	reg &= ~SUN4I_CTL_CS_MASK;
+	reg |= SUN4I_CTL_CS(spi->chip_select);
+
+	if (enable)
+		reg |= SUN4I_CTL_CS_LEVEL;
+	else
+		reg &= ~SUN4I_CTL_CS_LEVEL;
+
+	/*
+	 * Even though this looks irrelevant since we are supposed to
+	 * be controlling the chip select manually, this bit also
+	 * controls the levels of the chip select for inactive
+	 * devices.
+	 *
+	 * If we don't set it, the chip select level will go low by
+	 * default when the device is idle, which is not really
+	 * expected in the common case where the chip select is active
+	 * low.
+	 */
+	if (spi->mode & SPI_CS_HIGH)
+		reg &= ~SUN4I_CTL_CS_ACTIVE_LOW;
+	else
+		reg |= SUN4I_CTL_CS_ACTIVE_LOW;
+
+	sun4i_spi_write(sspi, SUN4I_CTL_REG, reg);
+}
+
+static int sun4i_spi_transfer_one(struct spi_master *master,
+				  struct spi_device *spi,
+				  struct spi_transfer *tfr)
+{
+	struct sun4i_spi *sspi = spi_master_get_devdata(master);
+	unsigned int mclk_rate, div, timeout;
+	unsigned int tx_len = 0;
+	int ret = 0;
+	u32 reg;
+
+	/* We don't support transfer larger than the FIFO */
+	if (tfr->len > SUN4I_FIFO_DEPTH)
+		return -EINVAL;
+
+	reinit_completion(&sspi->done);
+	sspi->tx_buf = tfr->tx_buf;
+	sspi->rx_buf = tfr->rx_buf;
+	sspi->len = tfr->len;
+
+	/* Clear pending interrupts */
+	sun4i_spi_write(sspi, SUN4I_INT_STA_REG, ~0);
+
+
+	reg = sun4i_spi_read(sspi, SUN4I_CTL_REG);
+
+	/* Reset FIFOs */
+	sun4i_spi_write(sspi, SUN4I_CTL_REG,
+			reg | SUN4I_CTL_RF_RST | SUN4I_CTL_TF_RST);
+
+	/*
+	 * Setup the transfer control register: Chip Select,
+	 * polarities, etc.
+	 */
+	if (spi->mode & SPI_CPOL)
+		reg |= SUN4I_CTL_CPOL;
+	else
+		reg &= ~SUN4I_CTL_CPOL;
+
+	if (spi->mode & SPI_CPHA)
+		reg |= SUN4I_CTL_CPHA;
+	else
+		reg &= ~SUN4I_CTL_CPHA;
+
+	if (spi->mode & SPI_LSB_FIRST)
+		reg |= SUN4I_CTL_LMTF;
+	else
+		reg &= ~SUN4I_CTL_LMTF;
+
+
+	/*
+	 * If it's a TX only transfer, we don't want to fill the RX
+	 * FIFO with bogus data
+	 */
+	if (sspi->rx_buf)
+		reg &= ~SUN4I_CTL_DHB;
+	else
+		reg |= SUN4I_CTL_DHB;
+
+	/* We want to control the chip select manually */
+	reg |= SUN4I_CTL_CS_MANUAL;
+
+	sun4i_spi_write(sspi, SUN4I_CTL_REG, reg);
+
+	/* Ensure that we have a parent clock fast enough */
+	mclk_rate = clk_get_rate(sspi->mclk);
+	if (mclk_rate < (2 * spi->max_speed_hz)) {
+		clk_set_rate(sspi->mclk, 2 * spi->max_speed_hz);
+		mclk_rate = clk_get_rate(sspi->mclk);
+	}
+
+	/*
+	 * Setup clock divider.
+	 *
+	 * We have two choices there. Either we can use the clock
+	 * divide rate 1, which is calculated thanks to this formula:
+	 * SPI_CLK = MOD_CLK / (2 ^ (cdr + 1))
+	 * Or we can use CDR2, which is calculated with the formula:
+	 * SPI_CLK = MOD_CLK / (2 * (cdr + 1))
+	 * Wether we use the former or the latter is set through the
+	 * DRS bit.
+	 *
+	 * First try CDR2, and if we can't reach the expected
+	 * frequency, fall back to CDR1.
+	 */
+	div = mclk_rate / (2 * spi->max_speed_hz);
+	if (div <= (SUN4I_CLK_CTL_CDR2_MASK + 1)) {
+		if (div > 0)
+			div--;
+
+		reg = SUN4I_CLK_CTL_CDR2(div) | SUN4I_CLK_CTL_DRS;
+	} else {
+		div = ilog2(mclk_rate) - ilog2(spi->max_speed_hz);
+		reg = SUN4I_CLK_CTL_CDR1(div);
+	}
+
+	sun4i_spi_write(sspi, SUN4I_CLK_CTL_REG, reg);
+
+	/* Setup the transfer now... */
+	if (sspi->tx_buf)
+		tx_len = tfr->len;
+
+	/* Setup the counters */
+	sun4i_spi_write(sspi, SUN4I_BURST_CNT_REG, SUN4I_BURST_CNT(tfr->len));
+	sun4i_spi_write(sspi, SUN4I_XMIT_CNT_REG, SUN4I_XMIT_CNT(tx_len));
+
+	/* Fill the TX FIFO */
+	sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH);
+
+	/* Enable the interrupts */
+	sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, SUN4I_INT_CTL_TC);
+
+	/* Start the transfer */
+	reg = sun4i_spi_read(sspi, SUN4I_CTL_REG);
+	sun4i_spi_write(sspi, SUN4I_CTL_REG, reg | SUN4I_CTL_XCH);
+
+	timeout = wait_for_completion_timeout(&sspi->done,
+					      msecs_to_jiffies(1000));
+	if (!timeout) {
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	sun4i_spi_drain_fifo(sspi, SUN4I_FIFO_DEPTH);
+
+out:
+	sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, 0);
+
+	return ret;
+}
+
+static irqreturn_t sun4i_spi_handler(int irq, void *dev_id)
+{
+	struct sun4i_spi *sspi = dev_id;
+	u32 status = sun4i_spi_read(sspi, SUN4I_INT_STA_REG);
+
+	/* Transfer complete */
+	if (status & SUN4I_INT_CTL_TC) {
+		sun4i_spi_write(sspi, SUN4I_INT_STA_REG, SUN4I_INT_CTL_TC);
+		complete(&sspi->done);
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static int sun4i_spi_runtime_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct sun4i_spi *sspi = spi_master_get_devdata(master);
+	int ret;
+
+	ret = clk_prepare_enable(sspi->hclk);
+	if (ret) {
+		dev_err(dev, "Couldn't enable AHB clock\n");
+		goto out;
+	}
+
+	ret = clk_prepare_enable(sspi->mclk);
+	if (ret) {
+		dev_err(dev, "Couldn't enable module clock\n");
+		goto err;
+	}
+
+	sun4i_spi_write(sspi, SUN4I_CTL_REG,
+			SUN4I_CTL_ENABLE | SUN4I_CTL_MASTER | SUN4I_CTL_TP);
+
+	return 0;
+
+err:
+	clk_disable_unprepare(sspi->hclk);
+out:
+	return ret;
+}
+
+static int sun4i_spi_runtime_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct sun4i_spi *sspi = spi_master_get_devdata(master);
+
+	clk_disable_unprepare(sspi->mclk);
+	clk_disable_unprepare(sspi->hclk);
+
+	return 0;
+}
+
+static int sun4i_spi_probe(struct platform_device *pdev)
+{
+	struct spi_master *master;
+	struct sun4i_spi *sspi;
+	struct resource	*res;
+	int ret = 0, irq;
+
+	master = spi_alloc_master(&pdev->dev, sizeof(struct sun4i_spi));
+	if (!master) {
+		dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(pdev, master);
+	sspi = spi_master_get_devdata(master);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sspi->base_addr = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sspi->base_addr)) {
+		ret = PTR_ERR(sspi->base_addr);
+		goto err_free_master;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "No spi IRQ specified\n");
+		ret = -ENXIO;
+		goto err_free_master;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq, sun4i_spi_handler,
+			       0, "sun4i-spi", sspi);
+	if (ret) {
+		dev_err(&pdev->dev, "Cannot request IRQ\n");
+		goto err_free_master;
+	}
+
+	sspi->master = master;
+	master->set_cs = sun4i_spi_set_cs;
+	master->transfer_one = sun4i_spi_transfer_one;
+	master->num_chipselect = 4;
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
+	master->bits_per_word_mask = SPI_BPW_MASK(8);
+	master->dev.of_node = pdev->dev.of_node;
+	master->auto_runtime_pm = true;
+
+	sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
+	if (IS_ERR(sspi->hclk)) {
+		dev_err(&pdev->dev, "Unable to acquire AHB clock\n");
+		ret = PTR_ERR(sspi->hclk);
+		goto err_free_master;
+	}
+
+	sspi->mclk = devm_clk_get(&pdev->dev, "mod");
+	if (IS_ERR(sspi->mclk)) {
+		dev_err(&pdev->dev, "Unable to acquire module clock\n");
+		ret = PTR_ERR(sspi->mclk);
+		goto err_free_master;
+	}
+
+	init_completion(&sspi->done);
+
+	/*
+	 * This wake-up/shutdown pattern is to be able to have the
+	 * device woken up, even if runtime_pm is disabled
+	 */
+	ret = sun4i_spi_runtime_resume(&pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't resume the device\n");
+		goto err_free_master;
+	}
+
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_idle(&pdev->dev);
+
+	ret = devm_spi_register_master(&pdev->dev, master);
+	if (ret) {
+		dev_err(&pdev->dev, "cannot register SPI master\n");
+		goto err_pm_disable;
+	}
+
+	return 0;
+
+err_pm_disable:
+	pm_runtime_disable(&pdev->dev);
+	sun4i_spi_runtime_suspend(&pdev->dev);
+err_free_master:
+	spi_master_put(master);
+	return ret;
+}
+
+static int sun4i_spi_remove(struct platform_device *pdev)
+{
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+static const struct of_device_id sun4i_spi_match[] = {
+	{ .compatible = "allwinner,sun4i-a10-spi", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, sun4i_spi_match);
+
+static const struct dev_pm_ops sun4i_spi_pm_ops = {
+	.runtime_resume		= sun4i_spi_runtime_resume,
+	.runtime_suspend	= sun4i_spi_runtime_suspend,
+};
+
+static struct platform_driver sun4i_spi_driver = {
+	.probe	= sun4i_spi_probe,
+	.remove	= sun4i_spi_remove,
+	.driver	= {
+		.name		= "sun4i-spi",
+		.of_match_table	= sun4i_spi_match,
+		.pm		= &sun4i_spi_pm_ops,
+	},
+};
+module_platform_driver(sun4i_spi_driver);
+
+MODULE_AUTHOR("Pan Nan <pannan@allwinnertech.com>");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_DESCRIPTION("Allwinner A1X/A20 SPI controller driver");
+MODULE_LICENSE("GPL");