[mirror_ubuntu-artful-kernel.git] / drivers / spi / spi-fsl-lpspi.c

/*
 * Freescale i.MX7ULP LPSPI driver
 *
 * Copyright 2016 Freescale Semiconductor, Inc.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/types.h>

#define DRIVER_NAME "fsl_lpspi"

/* i.MX7ULP LPSPI registers */
#define IMX7ULP_VERID	0x0
#define IMX7ULP_PARAM	0x4
#define IMX7ULP_CR	0x10
#define IMX7ULP_SR	0x14
#define IMX7ULP_IER	0x18
#define IMX7ULP_DER	0x1c
#define IMX7ULP_CFGR0	0x20
#define IMX7ULP_CFGR1	0x24
#define IMX7ULP_DMR0	0x30
#define IMX7ULP_DMR1	0x34
#define IMX7ULP_CCR	0x40
#define IMX7ULP_FCR	0x58
#define IMX7ULP_FSR	0x5c
#define IMX7ULP_TCR	0x60
#define IMX7ULP_TDR	0x64
#define IMX7ULP_RSR	0x70
#define IMX7ULP_RDR	0x74

/* General control register field define */
#define CR_RRF		BIT(9)
#define CR_RTF		BIT(8)
#define CR_RST		BIT(1)
#define CR_MEN		BIT(0)
#define SR_TCF		BIT(10)
#define SR_RDF		BIT(1)
#define SR_TDF		BIT(0)
#define IER_TCIE	BIT(10)
#define IER_RDIE	BIT(1)
#define IER_TDIE	BIT(0)
#define CFGR1_PCSCFG	BIT(27)
#define CFGR1_PCSPOL	BIT(8)
#define CFGR1_NOSTALL	BIT(3)
#define CFGR1_MASTER	BIT(0)
#define RSR_RXEMPTY	BIT(1)
#define TCR_CPOL	BIT(31)
#define TCR_CPHA	BIT(30)
#define TCR_CONT	BIT(21)
#define TCR_CONTC	BIT(20)
#define TCR_RXMSK	BIT(19)
#define TCR_TXMSK	BIT(18)

static int clkdivs[] = {1, 2, 4, 8, 16, 32, 64, 128};

struct lpspi_config {
	u8 bpw;
	u8 chip_select;
	u8 prescale;
	u16 mode;
	u32 speed_hz;
};

struct fsl_lpspi_data {
	struct device *dev;
	void __iomem *base;
	struct clk *clk;

	void *rx_buf;
	const void *tx_buf;
	void (*tx)(struct fsl_lpspi_data *);
	void (*rx)(struct fsl_lpspi_data *);

	u32 remain;
	u8 txfifosize;
	u8 rxfifosize;

	struct lpspi_config config;
	struct completion xfer_done;
};

static const struct of_device_id fsl_lpspi_dt_ids[] = {
	{ .compatible = "fsl,imx7ulp-spi", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, fsl_lpspi_dt_ids);

#define LPSPI_BUF_RX(type)						\
static void fsl_lpspi_buf_rx_##type(struct fsl_lpspi_data *fsl_lpspi)	\
{									\
	unsigned int val = readl(fsl_lpspi->base + IMX7ULP_RDR);	\
									\
	if (fsl_lpspi->rx_buf) {					\
		*(type *)fsl_lpspi->rx_buf = val;			\
		fsl_lpspi->rx_buf += sizeof(type);                      \
	}								\
}

#define LPSPI_BUF_TX(type)						\
static void fsl_lpspi_buf_tx_##type(struct fsl_lpspi_data *fsl_lpspi)	\
{									\
	type val = 0;							\
									\
	if (fsl_lpspi->tx_buf) {					\
		val = *(type *)fsl_lpspi->tx_buf;			\
		fsl_lpspi->tx_buf += sizeof(type);			\
	}								\
									\
	fsl_lpspi->remain -= sizeof(type);				\
	writel(val, fsl_lpspi->base + IMX7ULP_TDR);			\
}

LPSPI_BUF_RX(u8)
LPSPI_BUF_TX(u8)
LPSPI_BUF_RX(u16)
LPSPI_BUF_TX(u16)
LPSPI_BUF_RX(u32)
LPSPI_BUF_TX(u32)

static void fsl_lpspi_intctrl(struct fsl_lpspi_data *fsl_lpspi,
			      unsigned int enable)
{
	writel(enable, fsl_lpspi->base + IMX7ULP_IER);
}

static int lpspi_prepare_xfer_hardware(struct spi_master *master)
{
	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);

	return clk_prepare_enable(fsl_lpspi->clk);
}

static int lpspi_unprepare_xfer_hardware(struct spi_master *master)
{
	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);

	clk_disable_unprepare(fsl_lpspi->clk);

	return 0;
}

static int fsl_lpspi_txfifo_empty(struct fsl_lpspi_data *fsl_lpspi)
{
	u32 txcnt;
	unsigned long orig_jiffies = jiffies;

	do {
		txcnt = readl(fsl_lpspi->base + IMX7ULP_FSR) & 0xff;

		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
			dev_dbg(fsl_lpspi->dev, "txfifo empty timeout\n");
			return -ETIMEDOUT;
		}
		schedule();

	} while (txcnt);

	return 0;
}

static void fsl_lpspi_write_tx_fifo(struct fsl_lpspi_data *fsl_lpspi)
{
	u8 txfifo_cnt;

	txfifo_cnt = readl(fsl_lpspi->base + IMX7ULP_FSR) & 0xff;

	while (txfifo_cnt < fsl_lpspi->txfifosize) {
		if (!fsl_lpspi->remain)
			break;
		fsl_lpspi->tx(fsl_lpspi);
		txfifo_cnt++;
	}

	if (!fsl_lpspi->remain && (txfifo_cnt < fsl_lpspi->txfifosize))
		writel(0, fsl_lpspi->base + IMX7ULP_TDR);
	else
		fsl_lpspi_intctrl(fsl_lpspi, IER_TDIE);
}

static void fsl_lpspi_read_rx_fifo(struct fsl_lpspi_data *fsl_lpspi)
{
	while (!(readl(fsl_lpspi->base + IMX7ULP_RSR) & RSR_RXEMPTY))
		fsl_lpspi->rx(fsl_lpspi);
}

static void fsl_lpspi_set_cmd(struct fsl_lpspi_data *fsl_lpspi,
			      bool is_first_xfer)
{
	u32 temp = 0;

	temp |= fsl_lpspi->config.bpw - 1;
	temp |= fsl_lpspi->config.prescale << 27;
	temp |= (fsl_lpspi->config.mode & 0x11) << 30;
	temp |= (fsl_lpspi->config.chip_select & 0x3) << 24;

	/*
	 * Set TCR_CONT will keep SS asserted after current transfer.
	 * For the first transfer, clear TCR_CONTC to assert SS.
	 * For subsequent transfer, set TCR_CONTC to keep SS asserted.
	 */
	temp |= TCR_CONT;
	if (is_first_xfer)
		temp &= ~TCR_CONTC;
	else
		temp |= TCR_CONTC;

	writel(temp, fsl_lpspi->base + IMX7ULP_TCR);

	dev_dbg(fsl_lpspi->dev, "TCR=0x%x\n", temp);
}

static void fsl_lpspi_set_watermark(struct fsl_lpspi_data *fsl_lpspi)
{
	u8 txwatermark, rxwatermark;
	u32 temp;

	temp = readl(fsl_lpspi->base + IMX7ULP_PARAM);
	fsl_lpspi->txfifosize = 1 << (temp & 0x0f);
	fsl_lpspi->rxfifosize = 1 << ((temp >> 8) & 0x0f);
	rxwatermark = fsl_lpspi->txfifosize >> 1;
	txwatermark = fsl_lpspi->rxfifosize >> 1;
	temp = txwatermark | rxwatermark << 16;

	writel(temp, fsl_lpspi->base + IMX7ULP_FCR);

	dev_dbg(fsl_lpspi->dev, "FCR=0x%x\n", temp);
}

static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi)
{
	struct lpspi_config config = fsl_lpspi->config;
	unsigned int perclk_rate, scldiv;
	u8 prescale;

	perclk_rate = clk_get_rate(fsl_lpspi->clk);
	for (prescale = 0; prescale < 8; prescale++) {
		scldiv = perclk_rate /
			 (clkdivs[prescale] * config.speed_hz) - 2;
		if (scldiv < 256) {
			fsl_lpspi->config.prescale = prescale;
			break;
		}
	}

	if (prescale == 8 && scldiv >= 256)
		return -EINVAL;

	writel(scldiv, fsl_lpspi->base + IMX7ULP_CCR);

	dev_dbg(fsl_lpspi->dev, "perclk=%d, speed=%d, prescale =%d, scldiv=%d\n",
		perclk_rate, config.speed_hz, prescale, scldiv);

	return 0;
}

static int fsl_lpspi_config(struct fsl_lpspi_data *fsl_lpspi)
{
	u32 temp;
	int ret;

	temp = CR_RST;
	writel(temp, fsl_lpspi->base + IMX7ULP_CR);
	writel(0, fsl_lpspi->base + IMX7ULP_CR);

	ret = fsl_lpspi_set_bitrate(fsl_lpspi);
	if (ret)
		return ret;

	fsl_lpspi_set_watermark(fsl_lpspi);

	temp = CFGR1_PCSCFG | CFGR1_MASTER | CFGR1_NOSTALL;
	if (fsl_lpspi->config.mode & SPI_CS_HIGH)
		temp |= CFGR1_PCSPOL;
	writel(temp, fsl_lpspi->base + IMX7ULP_CFGR1);

	temp = readl(fsl_lpspi->base + IMX7ULP_CR);
	temp |= CR_RRF | CR_RTF | CR_MEN;
	writel(temp, fsl_lpspi->base + IMX7ULP_CR);

	return 0;
}

static void fsl_lpspi_setup_transfer(struct spi_device *spi,
				     struct spi_transfer *t)
{
	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(spi->master);

	fsl_lpspi->config.mode = spi->mode;
	fsl_lpspi->config.bpw = t ? t->bits_per_word : spi->bits_per_word;
	fsl_lpspi->config.speed_hz = t ? t->speed_hz : spi->max_speed_hz;
	fsl_lpspi->config.chip_select = spi->chip_select;

	if (!fsl_lpspi->config.speed_hz)
		fsl_lpspi->config.speed_hz = spi->max_speed_hz;
	if (!fsl_lpspi->config.bpw)
		fsl_lpspi->config.bpw = spi->bits_per_word;

	/* Initialize the functions for transfer */
	if (fsl_lpspi->config.bpw <= 8) {
		fsl_lpspi->rx = fsl_lpspi_buf_rx_u8;
		fsl_lpspi->tx = fsl_lpspi_buf_tx_u8;
	} else if (fsl_lpspi->config.bpw <= 16) {
		fsl_lpspi->rx = fsl_lpspi_buf_rx_u16;
		fsl_lpspi->tx = fsl_lpspi_buf_tx_u16;
	} else {
		fsl_lpspi->rx = fsl_lpspi_buf_rx_u32;
		fsl_lpspi->tx = fsl_lpspi_buf_tx_u32;
	}

	fsl_lpspi_config(fsl_lpspi);
}

static int fsl_lpspi_transfer_one(struct spi_master *master,
				  struct spi_device *spi,
				  struct spi_transfer *t)
{
	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
	int ret;

	fsl_lpspi->tx_buf = t->tx_buf;
	fsl_lpspi->rx_buf = t->rx_buf;
	fsl_lpspi->remain = t->len;

	reinit_completion(&fsl_lpspi->xfer_done);
	fsl_lpspi_write_tx_fifo(fsl_lpspi);
	wait_for_completion(&fsl_lpspi->xfer_done);

	ret = fsl_lpspi_txfifo_empty(fsl_lpspi);
	fsl_lpspi_read_rx_fifo(fsl_lpspi);

	return ret;
}

static int fsl_lpspi_transfer_one_msg(struct spi_master *master,
				      struct spi_message *msg)
{
	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
	struct spi_device *spi = msg->spi;
	struct spi_transfer *xfer;
	bool is_first_xfer = true;
	u32 temp;
	int ret;

	msg->status = 0;
	msg->actual_length = 0;

	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
		fsl_lpspi_setup_transfer(spi, xfer);
		fsl_lpspi_set_cmd(fsl_lpspi, is_first_xfer);

		is_first_xfer = false;

		ret = fsl_lpspi_transfer_one(master, spi, xfer);
		if (ret < 0)
			goto complete;

		msg->actual_length += xfer->len;
	}

complete:
	/* de-assert SS, then finalize current message */
	temp = readl(fsl_lpspi->base + IMX7ULP_TCR);
	temp &= ~TCR_CONTC;
	writel(temp, fsl_lpspi->base + IMX7ULP_TCR);

	msg->status = ret;
	spi_finalize_current_message(master);

	return ret;
}

static irqreturn_t fsl_lpspi_isr(int irq, void *dev_id)
{
	struct fsl_lpspi_data *fsl_lpspi = dev_id;
	u32 temp;

	fsl_lpspi_intctrl(fsl_lpspi, 0);
	temp = readl(fsl_lpspi->base + IMX7ULP_SR);

	fsl_lpspi_read_rx_fifo(fsl_lpspi);

	if (temp & SR_TDF) {
		fsl_lpspi_write_tx_fifo(fsl_lpspi);

		if (!fsl_lpspi->remain)
			complete(&fsl_lpspi->xfer_done);

		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int fsl_lpspi_probe(struct platform_device *pdev)
{
	struct fsl_lpspi_data *fsl_lpspi;
	struct spi_master *master;
	struct resource *res;
	int ret, irq;

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

	platform_set_drvdata(pdev, master);

	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32);
	master->bus_num = pdev->id;

	fsl_lpspi = spi_master_get_devdata(master);
	fsl_lpspi->dev = &pdev->dev;

	master->transfer_one_message = fsl_lpspi_transfer_one_msg;
	master->prepare_transfer_hardware = lpspi_prepare_xfer_hardware;
	master->unprepare_transfer_hardware = lpspi_unprepare_xfer_hardware;
	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
	master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX;
	master->dev.of_node = pdev->dev.of_node;
	master->bus_num = pdev->id;

	init_completion(&fsl_lpspi->xfer_done);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	fsl_lpspi->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(fsl_lpspi->base)) {
		ret = PTR_ERR(fsl_lpspi->base);
		goto out_master_put;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		ret = irq;
		goto out_master_put;
	}

	ret = devm_request_irq(&pdev->dev, irq, fsl_lpspi_isr, 0,
			       dev_name(&pdev->dev), fsl_lpspi);
	if (ret) {
		dev_err(&pdev->dev, "can't get irq%d: %d\n", irq, ret);
		goto out_master_put;
	}

	fsl_lpspi->clk = devm_clk_get(&pdev->dev, "ipg");
	if (IS_ERR(fsl_lpspi->clk)) {
		ret = PTR_ERR(fsl_lpspi->clk);
		goto out_master_put;
	}

	ret = devm_spi_register_master(&pdev->dev, master);
	if (ret < 0) {
		dev_err(&pdev->dev, "spi_register_master error.\n");
		goto out_master_put;
	}

	return 0;

out_master_put:
	spi_master_put(master);

	return ret;
}

static int fsl_lpspi_remove(struct platform_device *pdev)
{
	struct spi_master *master = platform_get_drvdata(pdev);
	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);

	clk_disable_unprepare(fsl_lpspi->clk);

	return 0;
}

static struct platform_driver fsl_lpspi_driver = {
	.driver = {
		   .name = DRIVER_NAME,
		   .of_match_table = fsl_lpspi_dt_ids,
		   },
	.probe = fsl_lpspi_probe,
	.remove = fsl_lpspi_remove,
};
module_platform_driver(fsl_lpspi_driver);

MODULE_DESCRIPTION("LPSPI Master Controller driver");
MODULE_AUTHOR("Gao Pan <pandy.gao@nxp.com>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
5314987d GP	1	/*
	2	* Freescale i.MX7ULP LPSPI driver
	3	*
	4	* Copyright 2016 Freescale Semiconductor, Inc.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	*/
	17
	18	#include <linux/clk.h>
	19	#include <linux/completion.h>
	20	#include <linux/delay.h>
	21	#include <linux/err.h>
	22	#include <linux/interrupt.h>
	23	#include <linux/io.h>
	24	#include <linux/irq.h>
	25	#include <linux/kernel.h>
	26	#include <linux/module.h>
	27	#include <linux/of.h>
	28	#include <linux/of_device.h>
	29	#include <linux/platform_device.h>
	30	#include <linux/slab.h>
	31	#include <linux/spi/spi.h>
	32	#include <linux/spi/spi_bitbang.h>
	33	#include <linux/types.h>
	34
	35	#define DRIVER_NAME "fsl_lpspi"
	36
	37	/* i.MX7ULP LPSPI registers */
	38	#define IMX7ULP_VERID 0x0
	39	#define IMX7ULP_PARAM 0x4
	40	#define IMX7ULP_CR 0x10
	41	#define IMX7ULP_SR 0x14
	42	#define IMX7ULP_IER 0x18
	43	#define IMX7ULP_DER 0x1c
	44	#define IMX7ULP_CFGR0 0x20
	45	#define IMX7ULP_CFGR1 0x24
	46	#define IMX7ULP_DMR0 0x30
	47	#define IMX7ULP_DMR1 0x34
	48	#define IMX7ULP_CCR 0x40
	49	#define IMX7ULP_FCR 0x58
	50	#define IMX7ULP_FSR 0x5c
	51	#define IMX7ULP_TCR 0x60
	52	#define IMX7ULP_TDR 0x64
	53	#define IMX7ULP_RSR 0x70
	54	#define IMX7ULP_RDR 0x74
	55
	56	/* General control register field define */
	57	#define CR_RRF BIT(9)
	58	#define CR_RTF BIT(8)
	59	#define CR_RST BIT(1)
	60	#define CR_MEN BIT(0)
	61	#define SR_TCF BIT(10)
	62	#define SR_RDF BIT(1)
	63	#define SR_TDF BIT(0)
	64	#define IER_TCIE BIT(10)
65	#define IER_RDIE BIT(1)
66	#define IER_TDIE BIT(0)
67	#define CFGR1_PCSCFG BIT(27)
68	#define CFGR1_PCSPOL BIT(8)
69	#define CFGR1_NOSTALL BIT(3)
70	#define CFGR1_MASTER BIT(0)
71	#define RSR_RXEMPTY BIT(1)
72	#define TCR_CPOL BIT(31)
73	#define TCR_CPHA BIT(30)
74	#define TCR_CONT BIT(21)
75	#define TCR_CONTC BIT(20)
76	#define TCR_RXMSK BIT(19)
77	#define TCR_TXMSK BIT(18)
78
79	static int clkdivs[] = {1, 2, 4, 8, 16, 32, 64, 128};
80
81	struct lpspi_config {
82	u8 bpw;
83	u8 chip_select;
84	u8 prescale;
85	u16 mode;
86	u32 speed_hz;
87	};
88
89	struct fsl_lpspi_data {
90	struct device *dev;
91	void __iomem *base;
92	struct clk *clk;
93
94	void *rx_buf;
95	const void *tx_buf;
96	void (tx)(struct fsl_lpspi_data );
97	void (rx)(struct fsl_lpspi_data );
98
99	u32 remain;
100	u8 txfifosize;
101	u8 rxfifosize;
102
103	struct lpspi_config config;
104	struct completion xfer_done;
105	};
106
107	static const struct of_device_id fsl_lpspi_dt_ids[] = {
108	{ .compatible = "fsl,imx7ulp-spi", },
109	{ /* sentinel */ }
110	};
111	MODULE_DEVICE_TABLE(of, fsl_lpspi_dt_ids);
112
113	#define LPSPI_BUF_RX(type) \
114	static void fsl_lpspi_buf_rx_##type(struct fsl_lpspi_data *fsl_lpspi) \
115	{ \
116	unsigned int val = readl(fsl_lpspi->base + IMX7ULP_RDR); \
117	\
118	if (fsl_lpspi->rx_buf) { \
119	(type )fsl_lpspi->rx_buf = val; \
120	fsl_lpspi->rx_buf += sizeof(type); \
121	} \
122	}
123
124	#define LPSPI_BUF_TX(type) \
125	static void fsl_lpspi_buf_tx_##type(struct fsl_lpspi_data *fsl_lpspi) \
126	{ \
127	type val = 0; \
128	\
129	if (fsl_lpspi->tx_buf) { \
130	val = (type )fsl_lpspi->tx_buf; \
131	fsl_lpspi->tx_buf += sizeof(type); \
132	} \
133	\
134	fsl_lpspi->remain -= sizeof(type); \
135	writel(val, fsl_lpspi->base + IMX7ULP_TDR); \
136	}
137
138	LPSPI_BUF_RX(u8)
139	LPSPI_BUF_TX(u8)
140	LPSPI_BUF_RX(u16)
141	LPSPI_BUF_TX(u16)
142	LPSPI_BUF_RX(u32)
143	LPSPI_BUF_TX(u32)
144
145	static void fsl_lpspi_intctrl(struct fsl_lpspi_data *fsl_lpspi,
146	unsigned int enable)
147	{
148	writel(enable, fsl_lpspi->base + IMX7ULP_IER);
149	}
150
3ffa1a5d	151	static int lpspi_prepare_xfer_hardware(struct spi_master *master)
5314987d GP	152	{
	153	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
	154
	155	return clk_prepare_enable(fsl_lpspi->clk);
	156	}
	157
3ffa1a5d	158	static int lpspi_unprepare_xfer_hardware(struct spi_master *master)
5314987d GP	159	{
	160	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
	161
	162	clk_disable_unprepare(fsl_lpspi->clk);
	163
	164	return 0;
	165	}
	166
	167	static int fsl_lpspi_txfifo_empty(struct fsl_lpspi_data *fsl_lpspi)
	168	{
	169	u32 txcnt;
	170	unsigned long orig_jiffies = jiffies;
	171
	172	do {
	173	txcnt = readl(fsl_lpspi->base + IMX7ULP_FSR) & 0xff;
	174
	175	if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
	176	dev_dbg(fsl_lpspi->dev, "txfifo empty timeout\n");
	177	return -ETIMEDOUT;
	178	}
	179	schedule();
	180
	181	} while (txcnt);
	182
	183	return 0;
	184	}
	185
	186	static void fsl_lpspi_write_tx_fifo(struct fsl_lpspi_data *fsl_lpspi)
	187	{
	188	u8 txfifo_cnt;
	189
	190	txfifo_cnt = readl(fsl_lpspi->base + IMX7ULP_FSR) & 0xff;
	191
	192	while (txfifo_cnt < fsl_lpspi->txfifosize) {
	193	if (!fsl_lpspi->remain)
	194	break;
	195	fsl_lpspi->tx(fsl_lpspi);
	196	txfifo_cnt++;
	197	}
	198
	199	if (!fsl_lpspi->remain && (txfifo_cnt < fsl_lpspi->txfifosize))
	200	writel(0, fsl_lpspi->base + IMX7ULP_TDR);
	201	else
	202	fsl_lpspi_intctrl(fsl_lpspi, IER_TDIE);
	203	}
	204
	205	static void fsl_lpspi_read_rx_fifo(struct fsl_lpspi_data *fsl_lpspi)
	206	{
	207	while (!(readl(fsl_lpspi->base + IMX7ULP_RSR) & RSR_RXEMPTY))
	208	fsl_lpspi->rx(fsl_lpspi);
	209	}
	210
	211	static void fsl_lpspi_set_cmd(struct fsl_lpspi_data *fsl_lpspi,
	212	bool is_first_xfer)
	213	{
	214	u32 temp = 0;
	215
	216	temp \|= fsl_lpspi->config.bpw - 1;
	217	temp \|= fsl_lpspi->config.prescale << 27;
	218	temp \|= (fsl_lpspi->config.mode & 0x11) << 30;
	219	temp \|= (fsl_lpspi->config.chip_select & 0x3) << 24;
	220
	221	/*
	222	* Set TCR_CONT will keep SS asserted after current transfer.
223	* For the first transfer, clear TCR_CONTC to assert SS.
224	* For subsequent transfer, set TCR_CONTC to keep SS asserted.
225	*/
226	temp \|= TCR_CONT;
227	if (is_first_xfer)
228	temp &= ~TCR_CONTC;
229	else
230	temp \|= TCR_CONTC;
231
232	writel(temp, fsl_lpspi->base + IMX7ULP_TCR);
233
234	dev_dbg(fsl_lpspi->dev, "TCR=0x%x\n", temp);
235	}
236
237	static void fsl_lpspi_set_watermark(struct fsl_lpspi_data *fsl_lpspi)
238	{
239	u8 txwatermark, rxwatermark;
240	u32 temp;
241
242	temp = readl(fsl_lpspi->base + IMX7ULP_PARAM);
243	fsl_lpspi->txfifosize = 1 << (temp & 0x0f);
244	fsl_lpspi->rxfifosize = 1 << ((temp >> 8) & 0x0f);
245	rxwatermark = fsl_lpspi->txfifosize >> 1;
246	txwatermark = fsl_lpspi->rxfifosize >> 1;
247	temp = txwatermark \| rxwatermark << 16;
248
249	writel(temp, fsl_lpspi->base + IMX7ULP_FCR);
250
251	dev_dbg(fsl_lpspi->dev, "FCR=0x%x\n", temp);
252	}
253
254	static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi)
255	{
256	struct lpspi_config config = fsl_lpspi->config;
257	unsigned int perclk_rate, scldiv;
258	u8 prescale;
259
260	perclk_rate = clk_get_rate(fsl_lpspi->clk);
261	for (prescale = 0; prescale < 8; prescale++) {
262	scldiv = perclk_rate /
263	(clkdivs[prescale] * config.speed_hz) - 2;
264	if (scldiv < 256) {
265	fsl_lpspi->config.prescale = prescale;
266	break;
267	}
268	}
269
270	if (prescale == 8 && scldiv >= 256)
271	return -EINVAL;
272
273	writel(scldiv, fsl_lpspi->base + IMX7ULP_CCR);
274
275	dev_dbg(fsl_lpspi->dev, "perclk=%d, speed=%d, prescale =%d, scldiv=%d\n",
276	perclk_rate, config.speed_hz, prescale, scldiv);
277
278	return 0;
279	}
280
281	static int fsl_lpspi_config(struct fsl_lpspi_data *fsl_lpspi)
282	{
283	u32 temp;
284	int ret;
285
286	temp = CR_RST;
287	writel(temp, fsl_lpspi->base + IMX7ULP_CR);
288	writel(0, fsl_lpspi->base + IMX7ULP_CR);
289
290	ret = fsl_lpspi_set_bitrate(fsl_lpspi);
291	if (ret)
292	return ret;
293
294	fsl_lpspi_set_watermark(fsl_lpspi);
295
296	temp = CFGR1_PCSCFG \| CFGR1_MASTER \| CFGR1_NOSTALL;
297	if (fsl_lpspi->config.mode & SPI_CS_HIGH)
298	temp \|= CFGR1_PCSPOL;
299	writel(temp, fsl_lpspi->base + IMX7ULP_CFGR1);
300
301	temp = readl(fsl_lpspi->base + IMX7ULP_CR);
302	temp \|= CR_RRF \| CR_RTF \| CR_MEN;
303	writel(temp, fsl_lpspi->base + IMX7ULP_CR);
304
305	return 0;
306	}
307
308	static void fsl_lpspi_setup_transfer(struct spi_device *spi,
309	struct spi_transfer *t)
310	{
311	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(spi->master);
312
313	fsl_lpspi->config.mode = spi->mode;
314	fsl_lpspi->config.bpw = t ? t->bits_per_word : spi->bits_per_word;
315	fsl_lpspi->config.speed_hz = t ? t->speed_hz : spi->max_speed_hz;
316	fsl_lpspi->config.chip_select = spi->chip_select;
317
318	if (!fsl_lpspi->config.speed_hz)
319	fsl_lpspi->config.speed_hz = spi->max_speed_hz;
320	if (!fsl_lpspi->config.bpw)
321	fsl_lpspi->config.bpw = spi->bits_per_word;
322
323	/* Initialize the functions for transfer */
324	if (fsl_lpspi->config.bpw <= 8) {
325	fsl_lpspi->rx = fsl_lpspi_buf_rx_u8;
326	fsl_lpspi->tx = fsl_lpspi_buf_tx_u8;
327	} else if (fsl_lpspi->config.bpw <= 16) {
328	fsl_lpspi->rx = fsl_lpspi_buf_rx_u16;
329	fsl_lpspi->tx = fsl_lpspi_buf_tx_u16;
330	} else {
331	fsl_lpspi->rx = fsl_lpspi_buf_rx_u32;
332	fsl_lpspi->tx = fsl_lpspi_buf_tx_u32;
333	}
334
335	fsl_lpspi_config(fsl_lpspi);
336	}
337
338	static int fsl_lpspi_transfer_one(struct spi_master *master,
339	struct spi_device *spi,
340	struct spi_transfer *t)
341	{
342	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
343	int ret;
344
345	fsl_lpspi->tx_buf = t->tx_buf;
346	fsl_lpspi->rx_buf = t->rx_buf;
347	fsl_lpspi->remain = t->len;
348
349	reinit_completion(&fsl_lpspi->xfer_done);
350	fsl_lpspi_write_tx_fifo(fsl_lpspi);
351	wait_for_completion(&fsl_lpspi->xfer_done);
352
353	ret = fsl_lpspi_txfifo_empty(fsl_lpspi);
354	fsl_lpspi_read_rx_fifo(fsl_lpspi);
355
356	return ret;
357	}
358
359	static int fsl_lpspi_transfer_one_msg(struct spi_master *master,
360	struct spi_message *msg)
361	{
362	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
363	struct spi_device *spi = msg->spi;
364	struct spi_transfer *xfer;
365	bool is_first_xfer = true;
366	u32 temp;
367	int ret;
368
369	msg->status = 0;
370	msg->actual_length = 0;
371
372	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
373	fsl_lpspi_setup_transfer(spi, xfer);
374	fsl_lpspi_set_cmd(fsl_lpspi, is_first_xfer);
375
376	is_first_xfer = false;
377
378	ret = fsl_lpspi_transfer_one(master, spi, xfer);
379	if (ret < 0)
380	goto complete;
381
382	msg->actual_length += xfer->len;
383	}
384
385	complete:
386	/* de-assert SS, then finalize current message */
387	temp = readl(fsl_lpspi->base + IMX7ULP_TCR);
388	temp &= ~TCR_CONTC;
389	writel(temp, fsl_lpspi->base + IMX7ULP_TCR);
390
391	msg->status = ret;
392	spi_finalize_current_message(master);
393
394	return ret;
395	}
396
397	static irqreturn_t fsl_lpspi_isr(int irq, void *dev_id)
398	{
399	struct fsl_lpspi_data *fsl_lpspi = dev_id;
400	u32 temp;
401
402	fsl_lpspi_intctrl(fsl_lpspi, 0);
403	temp = readl(fsl_lpspi->base + IMX7ULP_SR);
404
405	fsl_lpspi_read_rx_fifo(fsl_lpspi);
406
407	if (temp & SR_TDF) {
408	fsl_lpspi_write_tx_fifo(fsl_lpspi);
409
410	if (!fsl_lpspi->remain)
411	complete(&fsl_lpspi->xfer_done);
412
413	return IRQ_HANDLED;
414	}
415
416	return IRQ_NONE;
417	}
418
419	static int fsl_lpspi_probe(struct platform_device *pdev)
420	{
421	struct fsl_lpspi_data *fsl_lpspi;
422	struct spi_master *master;
423	struct resource *res;
424	int ret, irq;
425
426	master = spi_alloc_master(&pdev->dev, sizeof(struct fsl_lpspi_data));
427	if (!master)
428	return -ENOMEM;
429
430	platform_set_drvdata(pdev, master);
431
432	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32);
433	master->bus_num = pdev->id;
434
435	fsl_lpspi = spi_master_get_devdata(master);
436	fsl_lpspi->dev = &pdev->dev;
437
438	master->transfer_one_message = fsl_lpspi_transfer_one_msg;
3ffa1a5d GP	439	master->prepare_transfer_hardware = lpspi_prepare_xfer_hardware;
3ffa1a5d GP	440	master->unprepare_transfer_hardware = lpspi_unprepare_xfer_hardware;
5314987d GP	441	master->mode_bits = SPI_CPOL \| SPI_CPHA \| SPI_CS_HIGH;
	442	master->flags = SPI_MASTER_MUST_RX \| SPI_MASTER_MUST_TX;
	443	master->dev.of_node = pdev->dev.of_node;
	444	master->bus_num = pdev->id;
	445
	446	init_completion(&fsl_lpspi->xfer_done);
	447
	448	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	449	fsl_lpspi->base = devm_ioremap_resource(&pdev->dev, res);
	450	if (IS_ERR(fsl_lpspi->base)) {
	451	ret = PTR_ERR(fsl_lpspi->base);
	452	goto out_master_put;
	453	}
	454
	455	irq = platform_get_irq(pdev, 0);
	456	if (irq < 0) {
	457	ret = irq;
	458	goto out_master_put;
	459	}
	460
	461	ret = devm_request_irq(&pdev->dev, irq, fsl_lpspi_isr, 0,
	462	dev_name(&pdev->dev), fsl_lpspi);
	463	if (ret) {
	464	dev_err(&pdev->dev, "can't get irq%d: %d\n", irq, ret);
	465	goto out_master_put;
	466	}
	467
	468	fsl_lpspi->clk = devm_clk_get(&pdev->dev, "ipg");
	469	if (IS_ERR(fsl_lpspi->clk)) {
	470	ret = PTR_ERR(fsl_lpspi->clk);
	471	goto out_master_put;
	472	}
	473
	474	ret = devm_spi_register_master(&pdev->dev, master);
	475	if (ret < 0) {
	476	dev_err(&pdev->dev, "spi_register_master error.\n");
	477	goto out_master_put;
	478	}
	479
	480	return 0;
	481
	482	out_master_put:
	483	spi_master_put(master);
	484
	485	return ret;
	486	}
	487
	488	static int fsl_lpspi_remove(struct platform_device *pdev)
	489	{
	490	struct spi_master *master = platform_get_drvdata(pdev);
	491	struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master);
	492
	493	clk_disable_unprepare(fsl_lpspi->clk);
	494
	495	return 0;
	496	}
	497
	498	static struct platform_driver fsl_lpspi_driver = {
	499	.driver = {
	500	.name = DRIVER_NAME,
	501	.of_match_table = fsl_lpspi_dt_ids,
	502	},
	503	.probe = fsl_lpspi_probe,
	504	.remove = fsl_lpspi_remove,
505	};
506	module_platform_driver(fsl_lpspi_driver);
507
508	MODULE_DESCRIPTION("LPSPI Master Controller driver");
509	MODULE_AUTHOR("Gao Pan <pandy.gao@nxp.com>");
510	MODULE_LICENSE("GPL v2");