[linux.git] / drivers / spi / spi-sun4i.c

/*
 * Copyright (C) 2012 - 2014 Allwinner Tech
 * Pan Nan <[email protected]>
 *
 * Copyright (C) 2014 Maxime Ripard
 * Maxime Ripard <[email protected]>
 *
 * 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);

	/* We want to control the chip select manually */
	reg |= SUN4I_CTL_CS_MANUAL;

	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;

	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 * tfr->speed_hz)) {
		clk_set_rate(sspi->mclk, 2 * tfr->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 * tfr->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(tfr->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 <[email protected]>");
MODULE_AUTHOR("Maxime Ripard <[email protected]>");
MODULE_DESCRIPTION("Allwinner A1X/A20 SPI controller driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
b5f65179 MR	1	/*
	2	* Copyright (C) 2012 - 2014 Allwinner Tech
	3	* Pan Nan <[email protected]>
	4	*
	5	* Copyright (C) 2014 Maxime Ripard
	6	* Maxime Ripard <[email protected]>
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public License as
	10	* published by the Free Software Foundation; either version 2 of
	11	* the License, or (at your option) any later version.
	12	*/
	13
	14	#include <linux/clk.h>
	15	#include <linux/delay.h>
	16	#include <linux/device.h>
	17	#include <linux/interrupt.h>
	18	#include <linux/io.h>
	19	#include <linux/module.h>
	20	#include <linux/platform_device.h>
	21	#include <linux/pm_runtime.h>
b5f65179 MR	22
	23	#include <linux/spi/spi.h>
	24
	25	#define SUN4I_FIFO_DEPTH 64
	26
	27	#define SUN4I_RXDATA_REG 0x00
	28
	29	#define SUN4I_TXDATA_REG 0x04
	30
	31	#define SUN4I_CTL_REG 0x08
	32	#define SUN4I_CTL_ENABLE BIT(0)
	33	#define SUN4I_CTL_MASTER BIT(1)
	34	#define SUN4I_CTL_CPHA BIT(2)
	35	#define SUN4I_CTL_CPOL BIT(3)
	36	#define SUN4I_CTL_CS_ACTIVE_LOW BIT(4)
	37	#define SUN4I_CTL_LMTF BIT(6)
	38	#define SUN4I_CTL_TF_RST BIT(8)
	39	#define SUN4I_CTL_RF_RST BIT(9)
	40	#define SUN4I_CTL_XCH BIT(10)
	41	#define SUN4I_CTL_CS_MASK 0x3000
	42	#define SUN4I_CTL_CS(cs) (((cs) << 12) & SUN4I_CTL_CS_MASK)
	43	#define SUN4I_CTL_DHB BIT(15)
	44	#define SUN4I_CTL_CS_MANUAL BIT(16)
	45	#define SUN4I_CTL_CS_LEVEL BIT(17)
	46	#define SUN4I_CTL_TP BIT(18)
	47
	48	#define SUN4I_INT_CTL_REG 0x0c
	49	#define SUN4I_INT_CTL_TC BIT(16)
	50
	51	#define SUN4I_INT_STA_REG 0x10
	52
	53	#define SUN4I_DMA_CTL_REG 0x14
	54
	55	#define SUN4I_WAIT_REG 0x18
	56
	57	#define SUN4I_CLK_CTL_REG 0x1c
	58	#define SUN4I_CLK_CTL_CDR2_MASK 0xff
	59	#define SUN4I_CLK_CTL_CDR2(div) ((div) & SUN4I_CLK_CTL_CDR2_MASK)
	60	#define SUN4I_CLK_CTL_CDR1_MASK 0xf
	61	#define SUN4I_CLK_CTL_CDR1(div) (((div) & SUN4I_CLK_CTL_CDR1_MASK) << 8)
	62	#define SUN4I_CLK_CTL_DRS BIT(12)
	63
	64	#define SUN4I_BURST_CNT_REG 0x20
	65	#define SUN4I_BURST_CNT(cnt) ((cnt) & 0xffffff)
	66
	67	#define SUN4I_XMIT_CNT_REG 0x24
	68	#define SUN4I_XMIT_CNT(cnt) ((cnt) & 0xffffff)
	69
	70	#define SUN4I_FIFO_STA_REG 0x28
	71	#define SUN4I_FIFO_STA_RF_CNT_MASK 0x7f
	72	#define SUN4I_FIFO_STA_RF_CNT_BITS 0
	73	#define SUN4I_FIFO_STA_TF_CNT_MASK 0x7f
	74	#define SUN4I_FIFO_STA_TF_CNT_BITS 16
	75
	76	struct sun4i_spi {
	77	struct spi_master *master;
	78	void __iomem *base_addr;
	79	struct clk *hclk;
	80	struct clk *mclk;
	81
	82	struct completion done;
	83
	84	const u8 *tx_buf;
	85	u8 *rx_buf;
86	int len;
87	};
88
89	static inline u32 sun4i_spi_read(struct sun4i_spi *sspi, u32 reg)
90	{
91	return readl(sspi->base_addr + reg);
92	}
93
94	static inline void sun4i_spi_write(struct sun4i_spi *sspi, u32 reg, u32 value)
95	{
96	writel(value, sspi->base_addr + reg);
97	}
98
99	static inline void sun4i_spi_drain_fifo(struct sun4i_spi *sspi, int len)
100	{
101	u32 reg, cnt;
102	u8 byte;
103
104	/* See how much data is available */
105	reg = sun4i_spi_read(sspi, SUN4I_FIFO_STA_REG);
106	reg &= SUN4I_FIFO_STA_RF_CNT_MASK;
107	cnt = reg >> SUN4I_FIFO_STA_RF_CNT_BITS;
108
109	if (len > cnt)
110	len = cnt;
111
112	while (len--) {
113	byte = readb(sspi->base_addr + SUN4I_RXDATA_REG);
114	if (sspi->rx_buf)
115	*sspi->rx_buf++ = byte;
116	}
117	}
118
119	static inline void sun4i_spi_fill_fifo(struct sun4i_spi *sspi, int len)
120	{
121	u8 byte;
122
123	if (len > sspi->len)
124	len = sspi->len;
125
126	while (len--) {
127	byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
128	writeb(byte, sspi->base_addr + SUN4I_TXDATA_REG);
129	sspi->len--;
130	}
131	}
132
133	static void sun4i_spi_set_cs(struct spi_device *spi, bool enable)
134	{
135	struct sun4i_spi *sspi = spi_master_get_devdata(spi->master);
136	u32 reg;
137
138	reg = sun4i_spi_read(sspi, SUN4I_CTL_REG);
139
140	reg &= ~SUN4I_CTL_CS_MASK;
141	reg \|= SUN4I_CTL_CS(spi->chip_select);
142
218e0b57 MW	143	/* We want to control the chip select manually */
	144	reg \|= SUN4I_CTL_CS_MANUAL;
	145
b5f65179 MR	146	if (enable)
	147	reg \|= SUN4I_CTL_CS_LEVEL;
	148	else
	149	reg &= ~SUN4I_CTL_CS_LEVEL;
	150
	151	/*
	152	* Even though this looks irrelevant since we are supposed to
	153	* be controlling the chip select manually, this bit also
	154	* controls the levels of the chip select for inactive
	155	* devices.
	156	*
	157	* If we don't set it, the chip select level will go low by
	158	* default when the device is idle, which is not really
	159	* expected in the common case where the chip select is active
	160	* low.
	161	*/
	162	if (spi->mode & SPI_CS_HIGH)
	163	reg &= ~SUN4I_CTL_CS_ACTIVE_LOW;
	164	else
	165	reg \|= SUN4I_CTL_CS_ACTIVE_LOW;
	166
	167	sun4i_spi_write(sspi, SUN4I_CTL_REG, reg);
	168	}
	169
	170	static int sun4i_spi_transfer_one(struct spi_master *master,
	171	struct spi_device *spi,
	172	struct spi_transfer *tfr)
	173	{
	174	struct sun4i_spi *sspi = spi_master_get_devdata(master);
	175	unsigned int mclk_rate, div, timeout;
	176	unsigned int tx_len = 0;
	177	int ret = 0;
	178	u32 reg;
	179
	180	/* We don't support transfer larger than the FIFO */
	181	if (tfr->len > SUN4I_FIFO_DEPTH)
	182	return -EINVAL;
	183
	184	reinit_completion(&sspi->done);
	185	sspi->tx_buf = tfr->tx_buf;
	186	sspi->rx_buf = tfr->rx_buf;
	187	sspi->len = tfr->len;
	188
	189	/* Clear pending interrupts */
	190	sun4i_spi_write(sspi, SUN4I_INT_STA_REG, ~0);
	191
	192
	193	reg = sun4i_spi_read(sspi, SUN4I_CTL_REG);
	194
	195	/* Reset FIFOs */
	196	sun4i_spi_write(sspi, SUN4I_CTL_REG,
	197	reg \| SUN4I_CTL_RF_RST \| SUN4I_CTL_TF_RST);
	198
	199	/*
	200	* Setup the transfer control register: Chip Select,
	201	* polarities, etc.
	202	*/
	203	if (spi->mode & SPI_CPOL)
	204	reg \|= SUN4I_CTL_CPOL;
	205	else
	206	reg &= ~SUN4I_CTL_CPOL;
	207
	208	if (spi->mode & SPI_CPHA)
	209	reg \|= SUN4I_CTL_CPHA;
210	else
211	reg &= ~SUN4I_CTL_CPHA;
212
213	if (spi->mode & SPI_LSB_FIRST)
214	reg \|= SUN4I_CTL_LMTF;
215	else
216	reg &= ~SUN4I_CTL_LMTF;
217
218
219	/*
220	* If it's a TX only transfer, we don't want to fill the RX
221	* FIFO with bogus data
222	*/
223	if (sspi->rx_buf)
224	reg &= ~SUN4I_CTL_DHB;
225	else
226	reg \|= SUN4I_CTL_DHB;
227
b5f65179 MR	228	sun4i_spi_write(sspi, SUN4I_CTL_REG, reg);
	229
	230	/* Ensure that we have a parent clock fast enough */
	231	mclk_rate = clk_get_rate(sspi->mclk);
47284e3e MW	232	if (mclk_rate < (2 * tfr->speed_hz)) {
47284e3e MW	233	clk_set_rate(sspi->mclk, 2 * tfr->speed_hz);
b5f65179 MR	234	mclk_rate = clk_get_rate(sspi->mclk);
	235	}
	236
	237	/*
	238	* Setup clock divider.
	239	*
	240	* We have two choices there. Either we can use the clock
	241	* divide rate 1, which is calculated thanks to this formula:
	242	* SPI_CLK = MOD_CLK / (2 ^ (cdr + 1))
	243	* Or we can use CDR2, which is calculated with the formula:
	244	* SPI_CLK = MOD_CLK / (2 * (cdr + 1))
	245	* Wether we use the former or the latter is set through the
	246	* DRS bit.
	247	*
	248	* First try CDR2, and if we can't reach the expected
	249	* frequency, fall back to CDR1.
	250	*/
47284e3e	251	div = mclk_rate / (2 * tfr->speed_hz);
b5f65179 MR	252	if (div <= (SUN4I_CLK_CTL_CDR2_MASK + 1)) {
	253	if (div > 0)
	254	div--;
	255
	256	reg = SUN4I_CLK_CTL_CDR2(div) \| SUN4I_CLK_CTL_DRS;
	257	} else {
47284e3e	258	div = ilog2(mclk_rate) - ilog2(tfr->speed_hz);
b5f65179 MR	259	reg = SUN4I_CLK_CTL_CDR1(div);
	260	}
	261
	262	sun4i_spi_write(sspi, SUN4I_CLK_CTL_REG, reg);
	263
	264	/* Setup the transfer now... */
	265	if (sspi->tx_buf)
	266	tx_len = tfr->len;
	267
	268	/* Setup the counters */
	269	sun4i_spi_write(sspi, SUN4I_BURST_CNT_REG, SUN4I_BURST_CNT(tfr->len));
	270	sun4i_spi_write(sspi, SUN4I_XMIT_CNT_REG, SUN4I_XMIT_CNT(tx_len));
	271
	272	/* Fill the TX FIFO */
	273	sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH);
	274
	275	/* Enable the interrupts */
	276	sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, SUN4I_INT_CTL_TC);
	277
	278	/* Start the transfer */
	279	reg = sun4i_spi_read(sspi, SUN4I_CTL_REG);
	280	sun4i_spi_write(sspi, SUN4I_CTL_REG, reg \| SUN4I_CTL_XCH);
	281
	282	timeout = wait_for_completion_timeout(&sspi->done,
	283	msecs_to_jiffies(1000));
	284	if (!timeout) {
	285	ret = -ETIMEDOUT;
	286	goto out;
	287	}
	288
	289	sun4i_spi_drain_fifo(sspi, SUN4I_FIFO_DEPTH);
	290
	291	out:
	292	sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, 0);
	293
	294	return ret;
	295	}
	296
	297	static irqreturn_t sun4i_spi_handler(int irq, void *dev_id)
	298	{
	299	struct sun4i_spi *sspi = dev_id;
	300	u32 status = sun4i_spi_read(sspi, SUN4I_INT_STA_REG);
	301
	302	/* Transfer complete */
	303	if (status & SUN4I_INT_CTL_TC) {
	304	sun4i_spi_write(sspi, SUN4I_INT_STA_REG, SUN4I_INT_CTL_TC);
	305	complete(&sspi->done);
	306	return IRQ_HANDLED;
	307	}
	308
	309	return IRQ_NONE;
	310	}
	311
	312	static int sun4i_spi_runtime_resume(struct device *dev)
	313	{
	314	struct spi_master *master = dev_get_drvdata(dev);
	315	struct sun4i_spi *sspi = spi_master_get_devdata(master);
	316	int ret;
	317
	318	ret = clk_prepare_enable(sspi->hclk);
	319	if (ret) {
	320	dev_err(dev, "Couldn't enable AHB clock\n");
	321	goto out;
	322	}
323
324	ret = clk_prepare_enable(sspi->mclk);
325	if (ret) {
326	dev_err(dev, "Couldn't enable module clock\n");
327	goto err;
328	}
329
330	sun4i_spi_write(sspi, SUN4I_CTL_REG,
331	SUN4I_CTL_ENABLE \| SUN4I_CTL_MASTER \| SUN4I_CTL_TP);
332
333	return 0;
334
335	err:
336	clk_disable_unprepare(sspi->hclk);
337	out:
338	return ret;
339	}
340
341	static int sun4i_spi_runtime_suspend(struct device *dev)
342	{
343	struct spi_master *master = dev_get_drvdata(dev);
344	struct sun4i_spi *sspi = spi_master_get_devdata(master);
345
346	clk_disable_unprepare(sspi->mclk);
347	clk_disable_unprepare(sspi->hclk);
348
349	return 0;
350	}
351
352	static int sun4i_spi_probe(struct platform_device *pdev)
353	{
354	struct spi_master *master;
355	struct sun4i_spi *sspi;
356	struct resource *res;
357	int ret = 0, irq;
358
359	master = spi_alloc_master(&pdev->dev, sizeof(struct sun4i_spi));
360	if (!master) {
361	dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
362	return -ENOMEM;
363	}
364
365	platform_set_drvdata(pdev, master);
366	sspi = spi_master_get_devdata(master);
367
368	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
369	sspi->base_addr = devm_ioremap_resource(&pdev->dev, res);
370	if (IS_ERR(sspi->base_addr)) {
371	ret = PTR_ERR(sspi->base_addr);
372	goto err_free_master;
373	}
374
375	irq = platform_get_irq(pdev, 0);
376	if (irq < 0) {
377	dev_err(&pdev->dev, "No spi IRQ specified\n");
378	ret = -ENXIO;
379	goto err_free_master;
380	}
381
382	ret = devm_request_irq(&pdev->dev, irq, sun4i_spi_handler,
383	0, "sun4i-spi", sspi);
384	if (ret) {
385	dev_err(&pdev->dev, "Cannot request IRQ\n");
386	goto err_free_master;
387	}
388
389	sspi->master = master;
390	master->set_cs = sun4i_spi_set_cs;
391	master->transfer_one = sun4i_spi_transfer_one;
392	master->num_chipselect = 4;
393	master->mode_bits = SPI_CPOL \| SPI_CPHA \| SPI_CS_HIGH \| SPI_LSB_FIRST;
ba47644d	394	master->bits_per_word_mask = SPI_BPW_MASK(8);
b5f65179 MR	395	master->dev.of_node = pdev->dev.of_node;
	396	master->auto_runtime_pm = true;
	397
	398	sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
	399	if (IS_ERR(sspi->hclk)) {
	400	dev_err(&pdev->dev, "Unable to acquire AHB clock\n");
	401	ret = PTR_ERR(sspi->hclk);
	402	goto err_free_master;
	403	}
	404
	405	sspi->mclk = devm_clk_get(&pdev->dev, "mod");
	406	if (IS_ERR(sspi->mclk)) {
	407	dev_err(&pdev->dev, "Unable to acquire module clock\n");
	408	ret = PTR_ERR(sspi->mclk);
	409	goto err_free_master;
	410	}
	411
	412	init_completion(&sspi->done);
	413
	414	/*
	415	* This wake-up/shutdown pattern is to be able to have the
	416	* device woken up, even if runtime_pm is disabled
	417	*/
	418	ret = sun4i_spi_runtime_resume(&pdev->dev);
	419	if (ret) {
	420	dev_err(&pdev->dev, "Couldn't resume the device\n");
	421	goto err_free_master;
	422	}
	423
	424	pm_runtime_set_active(&pdev->dev);
	425	pm_runtime_enable(&pdev->dev);
	426	pm_runtime_idle(&pdev->dev);
	427
	428	ret = devm_spi_register_master(&pdev->dev, master);
	429	if (ret) {
	430	dev_err(&pdev->dev, "cannot register SPI master\n");
	431	goto err_pm_disable;
	432	}
	433
	434	return 0;
	435
	436	err_pm_disable:
	437	pm_runtime_disable(&pdev->dev);
	438	sun4i_spi_runtime_suspend(&pdev->dev);
	439	err_free_master:
	440	spi_master_put(master);
	441	return ret;
	442	}
	443
	444	static int sun4i_spi_remove(struct platform_device *pdev)
	445	{
	446	pm_runtime_disable(&pdev->dev);
	447
	448	return 0;
	449	}
	450
	451	static const struct of_device_id sun4i_spi_match[] = {
	452	{ .compatible = "allwinner,sun4i-a10-spi", },
	453	{}
	454	};
	455	MODULE_DEVICE_TABLE(of, sun4i_spi_match);
	456
	457	static const struct dev_pm_ops sun4i_spi_pm_ops = {
	458	.runtime_resume = sun4i_spi_runtime_resume,
459	.runtime_suspend = sun4i_spi_runtime_suspend,
460	};
461
462	static struct platform_driver sun4i_spi_driver = {
463	.probe = sun4i_spi_probe,
464	.remove = sun4i_spi_remove,
465	.driver = {
466	.name = "sun4i-spi",
b5f65179 MR	467	.of_match_table = sun4i_spi_match,
	468	.pm = &sun4i_spi_pm_ops,
	469	},
	470	};
	471	module_platform_driver(sun4i_spi_driver);
	472
	473	MODULE_AUTHOR("Pan Nan <[email protected]>");
	474	MODULE_AUTHOR("Maxime Ripard <[email protected]>");
	475	MODULE_DESCRIPTION("Allwinner A1X/A20 SPI controller driver");
	476	MODULE_LICENSE("GPL");