[linux-block.git] / drivers / spi / spi-xtensa-xtfpga.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Xtensa xtfpga SPI controller driver
 *
 * Copyright (c) 2014 Cadence Design Systems Inc.
 */

#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>

#define XTFPGA_SPI_NAME "xtfpga_spi"

#define XTFPGA_SPI_START	0x0
#define XTFPGA_SPI_BUSY		0x4
#define XTFPGA_SPI_DATA		0x8

#define BUSY_WAIT_US		100

struct xtfpga_spi {
	struct spi_bitbang bitbang;
	void __iomem *regs;
	u32 data;
	unsigned data_sz;
};

static inline void xtfpga_spi_write32(const struct xtfpga_spi *spi,
				      unsigned addr, u32 val)
{
	__raw_writel(val, spi->regs + addr);
}

static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi *spi,
					     unsigned addr)
{
	return __raw_readl(spi->regs + addr);
}

static inline void xtfpga_spi_wait_busy(struct xtfpga_spi *xspi)
{
	unsigned i;

	for (i = 0; xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY) &&
	     i < BUSY_WAIT_US; ++i)
		udelay(1);
	WARN_ON_ONCE(i == BUSY_WAIT_US);
}

static u32 xtfpga_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
				u32 v, u8 bits, unsigned flags)
{
	struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);

	xspi->data = (xspi->data << bits) | (v & GENMASK(bits - 1, 0));
	xspi->data_sz += bits;
	if (xspi->data_sz >= 16) {
		xtfpga_spi_write32(xspi, XTFPGA_SPI_DATA,
				   xspi->data >> (xspi->data_sz - 16));
		xspi->data_sz -= 16;
		xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 1);
		xtfpga_spi_wait_busy(xspi);
		xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
	}

	return 0;
}

static void xtfpga_spi_chipselect(struct spi_device *spi, int is_on)
{
	struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);

	WARN_ON(xspi->data_sz != 0);
	xspi->data_sz = 0;
}

static int xtfpga_spi_probe(struct platform_device *pdev)
{
	struct xtfpga_spi *xspi;
	struct resource *mem;
	int ret;
	struct spi_master *master;

	master = spi_alloc_master(&pdev->dev, sizeof(struct xtfpga_spi));
	if (!master)
		return -ENOMEM;

	master->flags = SPI_MASTER_NO_RX;
	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
	master->bus_num = pdev->dev.id;
	master->dev.of_node = pdev->dev.of_node;

	xspi = spi_master_get_devdata(master);
	xspi->bitbang.master = master;
	xspi->bitbang.chipselect = xtfpga_spi_chipselect;
	xspi->bitbang.txrx_word[SPI_MODE_0] = xtfpga_spi_txrx_word;

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem) {
		dev_err(&pdev->dev, "No memory resource\n");
		ret = -ENODEV;
		goto err;
	}
	xspi->regs = devm_ioremap_resource(&pdev->dev, mem);
	if (IS_ERR(xspi->regs)) {
		ret = PTR_ERR(xspi->regs);
		goto err;
	}

	xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
	usleep_range(1000, 2000);
	if (xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY)) {
		dev_err(&pdev->dev, "Device stuck in busy state\n");
		ret = -EBUSY;
		goto err;
	}

	ret = spi_bitbang_start(&xspi->bitbang);
	if (ret < 0) {
		dev_err(&pdev->dev, "spi_bitbang_start failed\n");
		goto err;
	}

	platform_set_drvdata(pdev, master);
	return 0;
err:
	spi_master_put(master);
	return ret;
}

static int xtfpga_spi_remove(struct platform_device *pdev)
{
	struct spi_master *master = platform_get_drvdata(pdev);
	struct xtfpga_spi *xspi = spi_master_get_devdata(master);

	spi_bitbang_stop(&xspi->bitbang);
	spi_master_put(master);

	return 0;
}

MODULE_ALIAS("platform:" XTFPGA_SPI_NAME);

#ifdef CONFIG_OF
static const struct of_device_id xtfpga_spi_of_match[] = {
	{ .compatible = "cdns,xtfpga-spi", },
	{}
};
MODULE_DEVICE_TABLE(of, xtfpga_spi_of_match);
#endif

static struct platform_driver xtfpga_spi_driver = {
	.probe = xtfpga_spi_probe,
	.remove = xtfpga_spi_remove,
	.driver = {
		.name = XTFPGA_SPI_NAME,
		.of_match_table = of_match_ptr(xtfpga_spi_of_match),
	},
};
module_platform_driver(xtfpga_spi_driver);

MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");
MODULE_DESCRIPTION("xtensa xtfpga SPI driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
6840cc29 MF	2	/*
	3	* Xtensa xtfpga SPI controller driver
	4	*
	5	* Copyright (c) 2014 Cadence Design Systems Inc.
6840cc29 MF	6	*/
	7
	8	#include <linux/delay.h>
	9	#include <linux/io.h>
	10	#include <linux/module.h>
	11	#include <linux/of.h>
	12	#include <linux/platform_device.h>
	13	#include <linux/spi/spi.h>
	14	#include <linux/spi/spi_bitbang.h>
	15
	16	#define XTFPGA_SPI_NAME "xtfpga_spi"
	17
	18	#define XTFPGA_SPI_START 0x0
	19	#define XTFPGA_SPI_BUSY 0x4
	20	#define XTFPGA_SPI_DATA 0x8
	21
	22	#define BUSY_WAIT_US 100
	23
	24	struct xtfpga_spi {
	25	struct spi_bitbang bitbang;
	26	void __iomem *regs;
	27	u32 data;
	28	unsigned data_sz;
	29	};
	30
	31	static inline void xtfpga_spi_write32(const struct xtfpga_spi *spi,
	32	unsigned addr, u32 val)
	33	{
b0b48550	34	__raw_writel(val, spi->regs + addr);
6840cc29 MF	35	}
	36
	37	static inline unsigned int xtfpga_spi_read32(const struct xtfpga_spi *spi,
	38	unsigned addr)
	39	{
b0b48550	40	return __raw_readl(spi->regs + addr);
6840cc29 MF	41	}
	42
	43	static inline void xtfpga_spi_wait_busy(struct xtfpga_spi *xspi)
	44	{
	45	unsigned i;
cdc67fa9	46
6840cc29 MF	47	for (i = 0; xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY) &&
	48	i < BUSY_WAIT_US; ++i)
	49	udelay(1);
	50	WARN_ON_ONCE(i == BUSY_WAIT_US);
	51	}
	52
	53	static u32 xtfpga_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
304d3436	54	u32 v, u8 bits, unsigned flags)
6840cc29 MF	55	{
	56	struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);
	57
	58	xspi->data = (xspi->data << bits) \| (v & GENMASK(bits - 1, 0));
	59	xspi->data_sz += bits;
	60	if (xspi->data_sz >= 16) {
	61	xtfpga_spi_write32(xspi, XTFPGA_SPI_DATA,
	62	xspi->data >> (xspi->data_sz - 16));
	63	xspi->data_sz -= 16;
	64	xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 1);
	65	xtfpga_spi_wait_busy(xspi);
	66	xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
	67	}
	68
	69	return 0;
	70	}
	71
	72	static void xtfpga_spi_chipselect(struct spi_device *spi, int is_on)
	73	{
	74	struct xtfpga_spi *xspi = spi_master_get_devdata(spi->master);
	75
	76	WARN_ON(xspi->data_sz != 0);
	77	xspi->data_sz = 0;
	78	}
	79
	80	static int xtfpga_spi_probe(struct platform_device *pdev)
	81	{
	82	struct xtfpga_spi *xspi;
	83	struct resource *mem;
	84	int ret;
	85	struct spi_master *master;
	86
	87	master = spi_alloc_master(&pdev->dev, sizeof(struct xtfpga_spi));
	88	if (!master)
	89	return -ENOMEM;
	90
	91	master->flags = SPI_MASTER_NO_RX;
	92	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
	93	master->bus_num = pdev->dev.id;
	94	master->dev.of_node = pdev->dev.of_node;
	95
	96	xspi = spi_master_get_devdata(master);
	97	xspi->bitbang.master = master;
	98	xspi->bitbang.chipselect = xtfpga_spi_chipselect;
	99	xspi->bitbang.txrx_word[SPI_MODE_0] = xtfpga_spi_txrx_word;
	100
	101	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	102	if (!mem) {
	103	dev_err(&pdev->dev, "No memory resource\n");
	104	ret = -ENODEV;
	105	goto err;
	106	}
	107	xspi->regs = devm_ioremap_resource(&pdev->dev, mem);
	108	if (IS_ERR(xspi->regs)) {
	109	ret = PTR_ERR(xspi->regs);
	110	goto err;
	111	}
	112
	113	xtfpga_spi_write32(xspi, XTFPGA_SPI_START, 0);
	114	usleep_range(1000, 2000);
	115	if (xtfpga_spi_read32(xspi, XTFPGA_SPI_BUSY)) {
	116	dev_err(&pdev->dev, "Device stuck in busy state\n");
	117	ret = -EBUSY;
	118	goto err;
119	}
120
121	ret = spi_bitbang_start(&xspi->bitbang);
122	if (ret < 0) {
123	dev_err(&pdev->dev, "spi_bitbang_start failed\n");
124	goto err;
125	}
126
127	platform_set_drvdata(pdev, master);
128	return 0;
129	err:
130	spi_master_put(master);
131	return ret;
132	}
133
134	static int xtfpga_spi_remove(struct platform_device *pdev)
135	{
136	struct spi_master *master = platform_get_drvdata(pdev);
137	struct xtfpga_spi *xspi = spi_master_get_devdata(master);
138
139	spi_bitbang_stop(&xspi->bitbang);
140	spi_master_put(master);
141
142	return 0;
143	}
144
145	MODULE_ALIAS("platform:" XTFPGA_SPI_NAME);
146
147	#ifdef CONFIG_OF
148	static const struct of_device_id xtfpga_spi_of_match[] = {
149	{ .compatible = "cdns,xtfpga-spi", },
150	{}
151	};
152	MODULE_DEVICE_TABLE(of, xtfpga_spi_of_match);
153	#endif
154
155	static struct platform_driver xtfpga_spi_driver = {
156	.probe = xtfpga_spi_probe,
157	.remove = xtfpga_spi_remove,
158	.driver = {
159	.name = XTFPGA_SPI_NAME,
6840cc29 MF	160	.of_match_table = of_match_ptr(xtfpga_spi_of_match),
	161	},
	162	};
	163	module_platform_driver(xtfpga_spi_driver);
	164
	165	MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");
	166	MODULE_DESCRIPTION("xtensa xtfpga SPI driver");
	167	MODULE_LICENSE("GPL");