[linux-block.git] / drivers / spi / spi-oc-tiny.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * OpenCores tiny SPI master driver
 *
 * https://opencores.org/project,tiny_spi
 *
 * Copyright (C) 2011 Thomas Chou <thomas@wytron.com.tw>
 *
 * Based on spi_s3c24xx.c, which is:
 * Copyright (c) 2006 Ben Dooks
 * Copyright (c) 2006 Simtec Electronics
 *	Ben Dooks <ben@simtec.co.uk>
 */

#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/spi/spi_oc_tiny.h>
#include <linux/io.h>
#include <linux/of.h>

#define DRV_NAME "spi_oc_tiny"

#define TINY_SPI_RXDATA 0
#define TINY_SPI_TXDATA 4
#define TINY_SPI_STATUS 8
#define TINY_SPI_CONTROL 12
#define TINY_SPI_BAUD 16

#define TINY_SPI_STATUS_TXE 0x1
#define TINY_SPI_STATUS_TXR 0x2

struct tiny_spi {
	/* bitbang has to be first */
	struct spi_bitbang bitbang;
	struct completion done;

	void __iomem *base;
	int irq;
	unsigned int freq;
	unsigned int baudwidth;
	unsigned int baud;
	unsigned int speed_hz;
	unsigned int mode;
	unsigned int len;
	unsigned int txc, rxc;
	const u8 *txp;
	u8 *rxp;
};

static inline struct tiny_spi *tiny_spi_to_hw(struct spi_device *sdev)
{
	return spi_master_get_devdata(sdev->master);
}

static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz)
{
	struct tiny_spi *hw = tiny_spi_to_hw(spi);

	return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1;
}

static int tiny_spi_setup_transfer(struct spi_device *spi,
				   struct spi_transfer *t)
{
	struct tiny_spi *hw = tiny_spi_to_hw(spi);
	unsigned int baud = hw->baud;

	if (t) {
		if (t->speed_hz && t->speed_hz != hw->speed_hz)
			baud = tiny_spi_baud(spi, t->speed_hz);
	}
	writel(baud, hw->base + TINY_SPI_BAUD);
	writel(hw->mode, hw->base + TINY_SPI_CONTROL);
	return 0;
}

static int tiny_spi_setup(struct spi_device *spi)
{
	struct tiny_spi *hw = tiny_spi_to_hw(spi);

	if (spi->max_speed_hz != hw->speed_hz) {
		hw->speed_hz = spi->max_speed_hz;
		hw->baud = tiny_spi_baud(spi, hw->speed_hz);
	}
	hw->mode = spi->mode & SPI_MODE_X_MASK;
	return 0;
}

static inline void tiny_spi_wait_txr(struct tiny_spi *hw)
{
	while (!(readb(hw->base + TINY_SPI_STATUS) &
		 TINY_SPI_STATUS_TXR))
		cpu_relax();
}

static inline void tiny_spi_wait_txe(struct tiny_spi *hw)
{
	while (!(readb(hw->base + TINY_SPI_STATUS) &
		 TINY_SPI_STATUS_TXE))
		cpu_relax();
}

static int tiny_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
{
	struct tiny_spi *hw = tiny_spi_to_hw(spi);
	const u8 *txp = t->tx_buf;
	u8 *rxp = t->rx_buf;
	unsigned int i;

	if (hw->irq >= 0) {
		/* use interrupt driven data transfer */
		hw->len = t->len;
		hw->txp = t->tx_buf;
		hw->rxp = t->rx_buf;
		hw->txc = 0;
		hw->rxc = 0;

		/* send the first byte */
		if (t->len > 1) {
			writeb(hw->txp ? *hw->txp++ : 0,
			       hw->base + TINY_SPI_TXDATA);
			hw->txc++;
			writeb(hw->txp ? *hw->txp++ : 0,
			       hw->base + TINY_SPI_TXDATA);
			hw->txc++;
			writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS);
		} else {
			writeb(hw->txp ? *hw->txp++ : 0,
			       hw->base + TINY_SPI_TXDATA);
			hw->txc++;
			writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS);
		}

		wait_for_completion(&hw->done);
	} else {
		/* we need to tighten the transfer loop */
		writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
		for (i = 1; i < t->len; i++) {
			writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);

			if (rxp || (i != t->len - 1))
				tiny_spi_wait_txr(hw);
			if (rxp)
				*rxp++ = readb(hw->base + TINY_SPI_TXDATA);
		}
		tiny_spi_wait_txe(hw);
		if (rxp)
			*rxp++ = readb(hw->base + TINY_SPI_RXDATA);
	}

	return t->len;
}

static irqreturn_t tiny_spi_irq(int irq, void *dev)
{
	struct tiny_spi *hw = dev;

	writeb(0, hw->base + TINY_SPI_STATUS);
	if (hw->rxc + 1 == hw->len) {
		if (hw->rxp)
			*hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA);
		hw->rxc++;
		complete(&hw->done);
	} else {
		if (hw->rxp)
			*hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA);
		hw->rxc++;
		if (hw->txc < hw->len) {
			writeb(hw->txp ? *hw->txp++ : 0,
			       hw->base + TINY_SPI_TXDATA);
			hw->txc++;
			writeb(TINY_SPI_STATUS_TXR,
			       hw->base + TINY_SPI_STATUS);
		} else {
			writeb(TINY_SPI_STATUS_TXE,
			       hw->base + TINY_SPI_STATUS);
		}
	}
	return IRQ_HANDLED;
}

#ifdef CONFIG_OF
#include <linux/of_gpio.h>

static int tiny_spi_of_probe(struct platform_device *pdev)
{
	struct tiny_spi *hw = platform_get_drvdata(pdev);
	struct device_node *np = pdev->dev.of_node;
	u32 val;

	if (!np)
		return 0;
	hw->bitbang.master->dev.of_node = pdev->dev.of_node;
	if (!of_property_read_u32(np, "clock-frequency", &val))
		hw->freq = val;
	if (!of_property_read_u32(np, "baud-width", &val))
		hw->baudwidth = val;
	return 0;
}
#else /* !CONFIG_OF */
static int tiny_spi_of_probe(struct platform_device *pdev)
{
	return 0;
}
#endif /* CONFIG_OF */

static int tiny_spi_probe(struct platform_device *pdev)
{
	struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev);
	struct tiny_spi *hw;
	struct spi_master *master;
	int err = -ENODEV;

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

	/* setup the master state. */
	master->bus_num = pdev->id;
	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
	master->setup = tiny_spi_setup;
	master->use_gpio_descriptors = true;

	hw = spi_master_get_devdata(master);
	platform_set_drvdata(pdev, hw);

	/* setup the state for the bitbang driver */
	hw->bitbang.master = master;
	hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
	hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;

	/* find and map our resources */
	hw->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(hw->base)) {
		err = PTR_ERR(hw->base);
		goto exit;
	}
	/* irq is optional */
	hw->irq = platform_get_irq(pdev, 0);
	if (hw->irq >= 0) {
		init_completion(&hw->done);
		err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0,
				       pdev->name, hw);
		if (err)
			goto exit;
	}
	/* find platform data */
	if (platp) {
		hw->freq = platp->freq;
		hw->baudwidth = platp->baudwidth;
	} else {
		err = tiny_spi_of_probe(pdev);
		if (err)
			goto exit;
	}

	/* register our spi controller */
	err = spi_bitbang_start(&hw->bitbang);
	if (err)
		goto exit;
	dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);

	return 0;

exit:
	spi_master_put(master);
	return err;
}

static void tiny_spi_remove(struct platform_device *pdev)
{
	struct tiny_spi *hw = platform_get_drvdata(pdev);
	struct spi_master *master = hw->bitbang.master;

	spi_bitbang_stop(&hw->bitbang);
	spi_master_put(master);
}

#ifdef CONFIG_OF
static const struct of_device_id tiny_spi_match[] = {
	{ .compatible = "opencores,tiny-spi-rtlsvn2", },
	{},
};
MODULE_DEVICE_TABLE(of, tiny_spi_match);
#endif /* CONFIG_OF */

static struct platform_driver tiny_spi_driver = {
	.probe = tiny_spi_probe,
	.remove_new = tiny_spi_remove,
	.driver = {
		.name = DRV_NAME,
		.pm = NULL,
		.of_match_table = of_match_ptr(tiny_spi_match),
	},
};
module_platform_driver(tiny_spi_driver);

MODULE_DESCRIPTION("OpenCores tiny SPI driver");
MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
ce792580 TC	2	/*
	3	* OpenCores tiny SPI master driver
	4	*
3ea4eac3	5	* https://opencores.org/project,tiny_spi
ce792580 TC	6	*
	7	* Copyright (C) 2011 Thomas Chou <thomas@wytron.com.tw>
	8	*
	9	* Based on spi_s3c24xx.c, which is:
	10	* Copyright (c) 2006 Ben Dooks
	11	* Copyright (c) 2006 Simtec Electronics
	12	* Ben Dooks <ben@simtec.co.uk>
ce792580 TC	13	*/
ce792580 TC	14
ce792580 TC	15	#include <linux/interrupt.h>
ce792580 TC	16	#include <linux/errno.h>
d7614de4	17	#include <linux/module.h>
ce792580 TC	18	#include <linux/platform_device.h>
	19	#include <linux/spi/spi.h>
	20	#include <linux/spi/spi_bitbang.h>
	21	#include <linux/spi/spi_oc_tiny.h>
	22	#include <linux/io.h>
ce792580 TC	23	#include <linux/of.h>
	24
	25	#define DRV_NAME "spi_oc_tiny"
	26
	27	#define TINY_SPI_RXDATA 0
	28	#define TINY_SPI_TXDATA 4
	29	#define TINY_SPI_STATUS 8
	30	#define TINY_SPI_CONTROL 12
	31	#define TINY_SPI_BAUD 16
	32
	33	#define TINY_SPI_STATUS_TXE 0x1
	34	#define TINY_SPI_STATUS_TXR 0x2
	35
	36	struct tiny_spi {
	37	/* bitbang has to be first */
	38	struct spi_bitbang bitbang;
	39	struct completion done;
	40
	41	void __iomem *base;
	42	int irq;
	43	unsigned int freq;
	44	unsigned int baudwidth;
	45	unsigned int baud;
	46	unsigned int speed_hz;
	47	unsigned int mode;
	48	unsigned int len;
	49	unsigned int txc, rxc;
	50	const u8 *txp;
	51	u8 *rxp;
ce792580 TC	52	};
	53
	54	static inline struct tiny_spi tiny_spi_to_hw(struct spi_device sdev)
	55	{
	56	return spi_master_get_devdata(sdev->master);
	57	}
	58
	59	static unsigned int tiny_spi_baud(struct spi_device *spi, unsigned int hz)
	60	{
	61	struct tiny_spi *hw = tiny_spi_to_hw(spi);
	62
	63	return min(DIV_ROUND_UP(hw->freq, hz * 2), (1U << hw->baudwidth)) - 1;
	64	}
	65
ce792580 TC	66	static int tiny_spi_setup_transfer(struct spi_device *spi,
	67	struct spi_transfer *t)
	68	{
	69	struct tiny_spi *hw = tiny_spi_to_hw(spi);
	70	unsigned int baud = hw->baud;
	71
	72	if (t) {
	73	if (t->speed_hz && t->speed_hz != hw->speed_hz)
	74	baud = tiny_spi_baud(spi, t->speed_hz);
	75	}
	76	writel(baud, hw->base + TINY_SPI_BAUD);
	77	writel(hw->mode, hw->base + TINY_SPI_CONTROL);
	78	return 0;
	79	}
	80
	81	static int tiny_spi_setup(struct spi_device *spi)
	82	{
	83	struct tiny_spi *hw = tiny_spi_to_hw(spi);
	84
	85	if (spi->max_speed_hz != hw->speed_hz) {
	86	hw->speed_hz = spi->max_speed_hz;
	87	hw->baud = tiny_spi_baud(spi, hw->speed_hz);
	88	}
a2f2db6b	89	hw->mode = spi->mode & SPI_MODE_X_MASK;
ce792580 TC	90	return 0;
	91	}
	92
	93	static inline void tiny_spi_wait_txr(struct tiny_spi *hw)
	94	{
	95	while (!(readb(hw->base + TINY_SPI_STATUS) &
	96	TINY_SPI_STATUS_TXR))
	97	cpu_relax();
	98	}
	99
	100	static inline void tiny_spi_wait_txe(struct tiny_spi *hw)
	101	{
	102	while (!(readb(hw->base + TINY_SPI_STATUS) &
	103	TINY_SPI_STATUS_TXE))
	104	cpu_relax();
	105	}
	106
	107	static int tiny_spi_txrx_bufs(struct spi_device spi, struct spi_transfer t)
	108	{
	109	struct tiny_spi *hw = tiny_spi_to_hw(spi);
	110	const u8 *txp = t->tx_buf;
	111	u8 *rxp = t->rx_buf;
	112	unsigned int i;
	113
	114	if (hw->irq >= 0) {
886db6ac	115	/* use interrupt driven data transfer */
ce792580 TC	116	hw->len = t->len;
	117	hw->txp = t->tx_buf;
	118	hw->rxp = t->rx_buf;
	119	hw->txc = 0;
	120	hw->rxc = 0;
	121
	122	/* send the first byte */
	123	if (t->len > 1) {
	124	writeb(hw->txp ? *hw->txp++ : 0,
	125	hw->base + TINY_SPI_TXDATA);
	126	hw->txc++;
	127	writeb(hw->txp ? *hw->txp++ : 0,
	128	hw->base + TINY_SPI_TXDATA);
	129	hw->txc++;
	130	writeb(TINY_SPI_STATUS_TXR, hw->base + TINY_SPI_STATUS);
	131	} else {
	132	writeb(hw->txp ? *hw->txp++ : 0,
	133	hw->base + TINY_SPI_TXDATA);
	134	hw->txc++;
	135	writeb(TINY_SPI_STATUS_TXE, hw->base + TINY_SPI_STATUS);
	136	}
	137
	138	wait_for_completion(&hw->done);
ce792580	139	} else {
e826a7ff AL	140	/* we need to tighten the transfer loop */
	141	writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
	142	for (i = 1; i < t->len; i++) {
	143	writeb(txp ? *txp++ : 0, hw->base + TINY_SPI_TXDATA);
	144
	145	if (rxp \|\| (i != t->len - 1))
ce792580	146	tiny_spi_wait_txr(hw);
e826a7ff AL	147	if (rxp)
e826a7ff AL	148	*rxp++ = readb(hw->base + TINY_SPI_TXDATA);
ce792580 TC	149	}
ce792580 TC	150	tiny_spi_wait_txe(hw);
e826a7ff AL	151	if (rxp)
e826a7ff AL	152	*rxp++ = readb(hw->base + TINY_SPI_RXDATA);
ce792580	153	}
e826a7ff	154
ce792580 TC	155	return t->len;
	156	}
	157
	158	static irqreturn_t tiny_spi_irq(int irq, void *dev)
	159	{
	160	struct tiny_spi *hw = dev;
	161
	162	writeb(0, hw->base + TINY_SPI_STATUS);
	163	if (hw->rxc + 1 == hw->len) {
	164	if (hw->rxp)
	165	*hw->rxp++ = readb(hw->base + TINY_SPI_RXDATA);
	166	hw->rxc++;
	167	complete(&hw->done);
	168	} else {
	169	if (hw->rxp)
	170	*hw->rxp++ = readb(hw->base + TINY_SPI_TXDATA);
	171	hw->rxc++;
	172	if (hw->txc < hw->len) {
	173	writeb(hw->txp ? *hw->txp++ : 0,
	174	hw->base + TINY_SPI_TXDATA);
	175	hw->txc++;
	176	writeb(TINY_SPI_STATUS_TXR,
	177	hw->base + TINY_SPI_STATUS);
	178	} else {
	179	writeb(TINY_SPI_STATUS_TXE,
	180	hw->base + TINY_SPI_STATUS);
	181	}
	182	}
	183	return IRQ_HANDLED;
	184	}
	185
	186	#ifdef CONFIG_OF
	187	#include <linux/of_gpio.h>
	188
fd4a319b	189	static int tiny_spi_of_probe(struct platform_device *pdev)
ce792580 TC	190	{
	191	struct tiny_spi *hw = platform_get_drvdata(pdev);
	192	struct device_node *np = pdev->dev.of_node;
45a3e771	193	u32 val;
ce792580 TC	194
	195	if (!np)
	196	return 0;
ce792580	197	hw->bitbang.master->dev.of_node = pdev->dev.of_node;
45a3e771 TK	198	if (!of_property_read_u32(np, "clock-frequency", &val))
	199	hw->freq = val;
	200	if (!of_property_read_u32(np, "baud-width", &val))
	201	hw->baudwidth = val;
ce792580 TC	202	return 0;
	203	}
	204	#else /* !CONFIG_OF */
fd4a319b	205	static int tiny_spi_of_probe(struct platform_device *pdev)
ce792580 TC	206	{
	207	return 0;
	208	}
	209	#endif /* CONFIG_OF */
	210
fd4a319b	211	static int tiny_spi_probe(struct platform_device *pdev)
ce792580	212	{
8074cf06	213	struct tiny_spi_platform_data *platp = dev_get_platdata(&pdev->dev);
ce792580 TC	214	struct tiny_spi *hw;
ce792580 TC	215	struct spi_master *master;
ce792580 TC	216	int err = -ENODEV;
	217
	218	master = spi_alloc_master(&pdev->dev, sizeof(struct tiny_spi));
	219	if (!master)
	220	return err;
	221
	222	/* setup the master state. */
	223	master->bus_num = pdev->id;
ce792580 TC	224	master->mode_bits = SPI_CPOL \| SPI_CPHA \| SPI_CS_HIGH;
ce792580 TC	225	master->setup = tiny_spi_setup;
f03ee204	226	master->use_gpio_descriptors = true;
ce792580 TC	227
	228	hw = spi_master_get_devdata(master);
	229	platform_set_drvdata(pdev, hw);
	230
	231	/* setup the state for the bitbang driver */
94c69f76	232	hw->bitbang.master = master;
ce792580	233	hw->bitbang.setup_transfer = tiny_spi_setup_transfer;
ce792580 TC	234	hw->bitbang.txrx_bufs = tiny_spi_txrx_bufs;
	235
	236	/* find and map our resources */
f601a654	237	hw->base = devm_platform_ioremap_resource(pdev, 0);
b3136f8f JL	238	if (IS_ERR(hw->base)) {
	239	err = PTR_ERR(hw->base);
	240	goto exit;
	241	}
ce792580 TC	242	/* irq is optional */
	243	hw->irq = platform_get_irq(pdev, 0);
	244	if (hw->irq >= 0) {
	245	init_completion(&hw->done);
	246	err = devm_request_irq(&pdev->dev, hw->irq, tiny_spi_irq, 0,
	247	pdev->name, hw);
	248	if (err)
	249	goto exit;
	250	}
	251	/* find platform data */
	252	if (platp) {
ce792580 TC	253	hw->freq = platp->freq;
	254	hw->baudwidth = platp->baudwidth;
	255	} else {
	256	err = tiny_spi_of_probe(pdev);
	257	if (err)
	258	goto exit;
	259	}
ce792580 TC	260
	261	/* register our spi controller */
	262	err = spi_bitbang_start(&hw->bitbang);
	263	if (err)
	264	goto exit;
	265	dev_info(&pdev->dev, "base %p, irq %d\n", hw->base, hw->irq);
	266
	267	return 0;
	268
ce792580	269	exit:
ce792580 TC	270	spi_master_put(master);
	271	return err;
	272	}
	273
bdffa602	274	static void tiny_spi_remove(struct platform_device *pdev)
ce792580 TC	275	{
	276	struct tiny_spi *hw = platform_get_drvdata(pdev);
	277	struct spi_master *master = hw->bitbang.master;
ce792580 TC	278
ce792580 TC	279	spi_bitbang_stop(&hw->bitbang);
ce792580	280	spi_master_put(master);
ce792580 TC	281	}
	282
	283	#ifdef CONFIG_OF
	284	static const struct of_device_id tiny_spi_match[] = {
	285	{ .compatible = "opencores,tiny-spi-rtlsvn2", },
	286	{},
	287	};
	288	MODULE_DEVICE_TABLE(of, tiny_spi_match);
ce792580 TC	289	#endif /* CONFIG_OF */
	290
	291	static struct platform_driver tiny_spi_driver = {
	292	.probe = tiny_spi_probe,
bdffa602	293	.remove_new = tiny_spi_remove,
ce792580 TC	294	.driver = {
ce792580 TC	295	.name = DRV_NAME,
ce792580	296	.pm = NULL,
9547acce	297	.of_match_table = of_match_ptr(tiny_spi_match),
ce792580 TC	298	},
ce792580 TC	299	};
940ab889	300	module_platform_driver(tiny_spi_driver);
ce792580 TC	301
	302	MODULE_DESCRIPTION("OpenCores tiny SPI driver");
	303	MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
	304	MODULE_LICENSE("GPL");
	305	MODULE_ALIAS("platform:" DRV_NAME);