162306a36Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0-or-later
262306a36Sopenharmony_ci/*
362306a36Sopenharmony_ci * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
462306a36Sopenharmony_ci */
562306a36Sopenharmony_ci
662306a36Sopenharmony_ci#include <linux/clk.h>
762306a36Sopenharmony_ci#include <linux/i2c.h>
862306a36Sopenharmony_ci#include <linux/iopoll.h>
962306a36Sopenharmony_ci#include <linux/interrupt.h>
1062306a36Sopenharmony_ci#include <linux/io.h>
1162306a36Sopenharmony_ci#include <linux/module.h>
1262306a36Sopenharmony_ci#include <linux/platform_device.h>
1362306a36Sopenharmony_ci
1462306a36Sopenharmony_ci#define UNIPHIER_FI2C_CR	0x00	/* control register */
1562306a36Sopenharmony_ci#define     UNIPHIER_FI2C_CR_MST	BIT(3)	/* master mode */
1662306a36Sopenharmony_ci#define     UNIPHIER_FI2C_CR_STA	BIT(2)	/* start condition */
1762306a36Sopenharmony_ci#define     UNIPHIER_FI2C_CR_STO	BIT(1)	/* stop condition */
1862306a36Sopenharmony_ci#define     UNIPHIER_FI2C_CR_NACK	BIT(0)	/* do not return ACK */
1962306a36Sopenharmony_ci#define UNIPHIER_FI2C_DTTX	0x04	/* TX FIFO */
2062306a36Sopenharmony_ci#define     UNIPHIER_FI2C_DTTX_CMD	BIT(8)	/* send command (slave addr) */
2162306a36Sopenharmony_ci#define     UNIPHIER_FI2C_DTTX_RD	BIT(0)	/* read transaction */
2262306a36Sopenharmony_ci#define UNIPHIER_FI2C_DTRX	0x04	/* RX FIFO */
2362306a36Sopenharmony_ci#define UNIPHIER_FI2C_SLAD	0x0c	/* slave address */
2462306a36Sopenharmony_ci#define UNIPHIER_FI2C_CYC	0x10	/* clock cycle control */
2562306a36Sopenharmony_ci#define UNIPHIER_FI2C_LCTL	0x14	/* clock low period control */
2662306a36Sopenharmony_ci#define UNIPHIER_FI2C_SSUT	0x18	/* restart/stop setup time control */
2762306a36Sopenharmony_ci#define UNIPHIER_FI2C_DSUT	0x1c	/* data setup time control */
2862306a36Sopenharmony_ci#define UNIPHIER_FI2C_INT	0x20	/* interrupt status */
2962306a36Sopenharmony_ci#define UNIPHIER_FI2C_IE	0x24	/* interrupt enable */
3062306a36Sopenharmony_ci#define UNIPHIER_FI2C_IC	0x28	/* interrupt clear */
3162306a36Sopenharmony_ci#define     UNIPHIER_FI2C_INT_TE	BIT(9)	/* TX FIFO empty */
3262306a36Sopenharmony_ci#define     UNIPHIER_FI2C_INT_RF	BIT(8)	/* RX FIFO full */
3362306a36Sopenharmony_ci#define     UNIPHIER_FI2C_INT_TC	BIT(7)	/* send complete (STOP) */
3462306a36Sopenharmony_ci#define     UNIPHIER_FI2C_INT_RC	BIT(6)	/* receive complete (STOP) */
3562306a36Sopenharmony_ci#define     UNIPHIER_FI2C_INT_TB	BIT(5)	/* sent specified bytes */
3662306a36Sopenharmony_ci#define     UNIPHIER_FI2C_INT_RB	BIT(4)	/* received specified bytes */
3762306a36Sopenharmony_ci#define     UNIPHIER_FI2C_INT_NA	BIT(2)	/* no ACK */
3862306a36Sopenharmony_ci#define     UNIPHIER_FI2C_INT_AL	BIT(1)	/* arbitration lost */
3962306a36Sopenharmony_ci#define UNIPHIER_FI2C_SR	0x2c	/* status register */
4062306a36Sopenharmony_ci#define     UNIPHIER_FI2C_SR_DB		BIT(12)	/* device busy */
4162306a36Sopenharmony_ci#define     UNIPHIER_FI2C_SR_STS	BIT(11)	/* stop condition detected */
4262306a36Sopenharmony_ci#define     UNIPHIER_FI2C_SR_BB		BIT(8)	/* bus busy */
4362306a36Sopenharmony_ci#define     UNIPHIER_FI2C_SR_RFF	BIT(3)	/* RX FIFO full */
4462306a36Sopenharmony_ci#define     UNIPHIER_FI2C_SR_RNE	BIT(2)	/* RX FIFO not empty */
4562306a36Sopenharmony_ci#define     UNIPHIER_FI2C_SR_TNF	BIT(1)	/* TX FIFO not full */
4662306a36Sopenharmony_ci#define     UNIPHIER_FI2C_SR_TFE	BIT(0)	/* TX FIFO empty */
4762306a36Sopenharmony_ci#define UNIPHIER_FI2C_RST	0x34	/* reset control */
4862306a36Sopenharmony_ci#define     UNIPHIER_FI2C_RST_TBRST	BIT(2)	/* clear TX FIFO */
4962306a36Sopenharmony_ci#define     UNIPHIER_FI2C_RST_RBRST	BIT(1)	/* clear RX FIFO */
5062306a36Sopenharmony_ci#define     UNIPHIER_FI2C_RST_RST	BIT(0)	/* forcible bus reset */
5162306a36Sopenharmony_ci#define UNIPHIER_FI2C_BM	0x38	/* bus monitor */
5262306a36Sopenharmony_ci#define     UNIPHIER_FI2C_BM_SDAO	BIT(3)	/* output for SDA line */
5362306a36Sopenharmony_ci#define     UNIPHIER_FI2C_BM_SDAS	BIT(2)	/* readback of SDA line */
5462306a36Sopenharmony_ci#define     UNIPHIER_FI2C_BM_SCLO	BIT(1)	/* output for SCL line */
5562306a36Sopenharmony_ci#define     UNIPHIER_FI2C_BM_SCLS	BIT(0)	/* readback of SCL line */
5662306a36Sopenharmony_ci#define UNIPHIER_FI2C_NOISE	0x3c	/* noise filter control */
5762306a36Sopenharmony_ci#define UNIPHIER_FI2C_TBC	0x40	/* TX byte count setting */
5862306a36Sopenharmony_ci#define UNIPHIER_FI2C_RBC	0x44	/* RX byte count setting */
5962306a36Sopenharmony_ci#define UNIPHIER_FI2C_TBCM	0x48	/* TX byte count monitor */
6062306a36Sopenharmony_ci#define UNIPHIER_FI2C_RBCM	0x4c	/* RX byte count monitor */
6162306a36Sopenharmony_ci#define UNIPHIER_FI2C_BRST	0x50	/* bus reset */
6262306a36Sopenharmony_ci#define     UNIPHIER_FI2C_BRST_FOEN	BIT(1)	/* normal operation */
6362306a36Sopenharmony_ci#define     UNIPHIER_FI2C_BRST_RSCL	BIT(0)	/* release SCL */
6462306a36Sopenharmony_ci
6562306a36Sopenharmony_ci#define UNIPHIER_FI2C_INT_FAULTS	\
6662306a36Sopenharmony_ci				(UNIPHIER_FI2C_INT_NA | UNIPHIER_FI2C_INT_AL)
6762306a36Sopenharmony_ci#define UNIPHIER_FI2C_INT_STOP		\
6862306a36Sopenharmony_ci				(UNIPHIER_FI2C_INT_TC | UNIPHIER_FI2C_INT_RC)
6962306a36Sopenharmony_ci
7062306a36Sopenharmony_ci#define UNIPHIER_FI2C_RD		BIT(0)
7162306a36Sopenharmony_ci#define UNIPHIER_FI2C_STOP		BIT(1)
7262306a36Sopenharmony_ci#define UNIPHIER_FI2C_MANUAL_NACK	BIT(2)
7362306a36Sopenharmony_ci#define UNIPHIER_FI2C_BYTE_WISE		BIT(3)
7462306a36Sopenharmony_ci#define UNIPHIER_FI2C_DEFER_STOP_COMP	BIT(4)
7562306a36Sopenharmony_ci
7662306a36Sopenharmony_ci#define UNIPHIER_FI2C_FIFO_SIZE		8
7762306a36Sopenharmony_ci
7862306a36Sopenharmony_cistruct uniphier_fi2c_priv {
7962306a36Sopenharmony_ci	struct completion comp;
8062306a36Sopenharmony_ci	struct i2c_adapter adap;
8162306a36Sopenharmony_ci	void __iomem *membase;
8262306a36Sopenharmony_ci	struct clk *clk;
8362306a36Sopenharmony_ci	unsigned int len;
8462306a36Sopenharmony_ci	u8 *buf;
8562306a36Sopenharmony_ci	u32 enabled_irqs;
8662306a36Sopenharmony_ci	int error;
8762306a36Sopenharmony_ci	unsigned int flags;
8862306a36Sopenharmony_ci	unsigned int busy_cnt;
8962306a36Sopenharmony_ci	unsigned int clk_cycle;
9062306a36Sopenharmony_ci	spinlock_t lock;	/* IRQ synchronization */
9162306a36Sopenharmony_ci};
9262306a36Sopenharmony_ci
9362306a36Sopenharmony_cistatic void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv,
9462306a36Sopenharmony_ci				      bool first)
9562306a36Sopenharmony_ci{
9662306a36Sopenharmony_ci	int fifo_space = UNIPHIER_FI2C_FIFO_SIZE;
9762306a36Sopenharmony_ci
9862306a36Sopenharmony_ci	/*
9962306a36Sopenharmony_ci	 * TX-FIFO stores slave address in it for the first access.
10062306a36Sopenharmony_ci	 * Decrement the counter.
10162306a36Sopenharmony_ci	 */
10262306a36Sopenharmony_ci	if (first)
10362306a36Sopenharmony_ci		fifo_space--;
10462306a36Sopenharmony_ci
10562306a36Sopenharmony_ci	while (priv->len) {
10662306a36Sopenharmony_ci		if (fifo_space-- <= 0)
10762306a36Sopenharmony_ci			break;
10862306a36Sopenharmony_ci
10962306a36Sopenharmony_ci		writel(*priv->buf++, priv->membase + UNIPHIER_FI2C_DTTX);
11062306a36Sopenharmony_ci		priv->len--;
11162306a36Sopenharmony_ci	}
11262306a36Sopenharmony_ci}
11362306a36Sopenharmony_ci
11462306a36Sopenharmony_cistatic void uniphier_fi2c_drain_rxfifo(struct uniphier_fi2c_priv *priv)
11562306a36Sopenharmony_ci{
11662306a36Sopenharmony_ci	int fifo_left = priv->flags & UNIPHIER_FI2C_BYTE_WISE ?
11762306a36Sopenharmony_ci						1 : UNIPHIER_FI2C_FIFO_SIZE;
11862306a36Sopenharmony_ci
11962306a36Sopenharmony_ci	while (priv->len) {
12062306a36Sopenharmony_ci		if (fifo_left-- <= 0)
12162306a36Sopenharmony_ci			break;
12262306a36Sopenharmony_ci
12362306a36Sopenharmony_ci		*priv->buf++ = readl(priv->membase + UNIPHIER_FI2C_DTRX);
12462306a36Sopenharmony_ci		priv->len--;
12562306a36Sopenharmony_ci	}
12662306a36Sopenharmony_ci}
12762306a36Sopenharmony_ci
12862306a36Sopenharmony_cistatic void uniphier_fi2c_set_irqs(struct uniphier_fi2c_priv *priv)
12962306a36Sopenharmony_ci{
13062306a36Sopenharmony_ci	writel(priv->enabled_irqs, priv->membase + UNIPHIER_FI2C_IE);
13162306a36Sopenharmony_ci}
13262306a36Sopenharmony_ci
13362306a36Sopenharmony_cistatic void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv,
13462306a36Sopenharmony_ci				     u32 mask)
13562306a36Sopenharmony_ci{
13662306a36Sopenharmony_ci	writel(mask, priv->membase + UNIPHIER_FI2C_IC);
13762306a36Sopenharmony_ci}
13862306a36Sopenharmony_ci
13962306a36Sopenharmony_cistatic void uniphier_fi2c_stop(struct uniphier_fi2c_priv *priv)
14062306a36Sopenharmony_ci{
14162306a36Sopenharmony_ci	priv->enabled_irqs |= UNIPHIER_FI2C_INT_STOP;
14262306a36Sopenharmony_ci	uniphier_fi2c_set_irqs(priv);
14362306a36Sopenharmony_ci	writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STO,
14462306a36Sopenharmony_ci	       priv->membase + UNIPHIER_FI2C_CR);
14562306a36Sopenharmony_ci}
14662306a36Sopenharmony_ci
14762306a36Sopenharmony_cistatic irqreturn_t uniphier_fi2c_interrupt(int irq, void *dev_id)
14862306a36Sopenharmony_ci{
14962306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv = dev_id;
15062306a36Sopenharmony_ci	u32 irq_status;
15162306a36Sopenharmony_ci
15262306a36Sopenharmony_ci	spin_lock(&priv->lock);
15362306a36Sopenharmony_ci
15462306a36Sopenharmony_ci	irq_status = readl(priv->membase + UNIPHIER_FI2C_INT);
15562306a36Sopenharmony_ci	irq_status &= priv->enabled_irqs;
15662306a36Sopenharmony_ci
15762306a36Sopenharmony_ci	if (irq_status & UNIPHIER_FI2C_INT_STOP)
15862306a36Sopenharmony_ci		goto complete;
15962306a36Sopenharmony_ci
16062306a36Sopenharmony_ci	if (unlikely(irq_status & UNIPHIER_FI2C_INT_AL)) {
16162306a36Sopenharmony_ci		priv->error = -EAGAIN;
16262306a36Sopenharmony_ci		goto complete;
16362306a36Sopenharmony_ci	}
16462306a36Sopenharmony_ci
16562306a36Sopenharmony_ci	if (unlikely(irq_status & UNIPHIER_FI2C_INT_NA)) {
16662306a36Sopenharmony_ci		priv->error = -ENXIO;
16762306a36Sopenharmony_ci		if (priv->flags & UNIPHIER_FI2C_RD) {
16862306a36Sopenharmony_ci			/*
16962306a36Sopenharmony_ci			 * work around a hardware bug:
17062306a36Sopenharmony_ci			 * The receive-completed interrupt is never set even if
17162306a36Sopenharmony_ci			 * STOP condition is detected after the address phase
17262306a36Sopenharmony_ci			 * of read transaction fails to get ACK.
17362306a36Sopenharmony_ci			 * To avoid time-out error, we issue STOP here,
17462306a36Sopenharmony_ci			 * but do not wait for its completion.
17562306a36Sopenharmony_ci			 * It should be checked after exiting this handler.
17662306a36Sopenharmony_ci			 */
17762306a36Sopenharmony_ci			uniphier_fi2c_stop(priv);
17862306a36Sopenharmony_ci			priv->flags |= UNIPHIER_FI2C_DEFER_STOP_COMP;
17962306a36Sopenharmony_ci			goto complete;
18062306a36Sopenharmony_ci		}
18162306a36Sopenharmony_ci		goto stop;
18262306a36Sopenharmony_ci	}
18362306a36Sopenharmony_ci
18462306a36Sopenharmony_ci	if (irq_status & UNIPHIER_FI2C_INT_TE) {
18562306a36Sopenharmony_ci		if (!priv->len)
18662306a36Sopenharmony_ci			goto data_done;
18762306a36Sopenharmony_ci
18862306a36Sopenharmony_ci		uniphier_fi2c_fill_txfifo(priv, false);
18962306a36Sopenharmony_ci		goto handled;
19062306a36Sopenharmony_ci	}
19162306a36Sopenharmony_ci
19262306a36Sopenharmony_ci	if (irq_status & (UNIPHIER_FI2C_INT_RF | UNIPHIER_FI2C_INT_RB)) {
19362306a36Sopenharmony_ci		uniphier_fi2c_drain_rxfifo(priv);
19462306a36Sopenharmony_ci		/*
19562306a36Sopenharmony_ci		 * If the number of bytes to read is multiple of the FIFO size
19662306a36Sopenharmony_ci		 * (msg->len == 8, 16, 24, ...), the INT_RF bit is set a little
19762306a36Sopenharmony_ci		 * earlier than INT_RB. We wait for INT_RB to confirm the
19862306a36Sopenharmony_ci		 * completion of the current message.
19962306a36Sopenharmony_ci		 */
20062306a36Sopenharmony_ci		if (!priv->len && (irq_status & UNIPHIER_FI2C_INT_RB))
20162306a36Sopenharmony_ci			goto data_done;
20262306a36Sopenharmony_ci
20362306a36Sopenharmony_ci		if (unlikely(priv->flags & UNIPHIER_FI2C_MANUAL_NACK)) {
20462306a36Sopenharmony_ci			if (priv->len <= UNIPHIER_FI2C_FIFO_SIZE &&
20562306a36Sopenharmony_ci			    !(priv->flags & UNIPHIER_FI2C_BYTE_WISE)) {
20662306a36Sopenharmony_ci				priv->enabled_irqs |= UNIPHIER_FI2C_INT_RB;
20762306a36Sopenharmony_ci				uniphier_fi2c_set_irqs(priv);
20862306a36Sopenharmony_ci				priv->flags |= UNIPHIER_FI2C_BYTE_WISE;
20962306a36Sopenharmony_ci			}
21062306a36Sopenharmony_ci			if (priv->len <= 1)
21162306a36Sopenharmony_ci				writel(UNIPHIER_FI2C_CR_MST |
21262306a36Sopenharmony_ci				       UNIPHIER_FI2C_CR_NACK,
21362306a36Sopenharmony_ci				       priv->membase + UNIPHIER_FI2C_CR);
21462306a36Sopenharmony_ci		}
21562306a36Sopenharmony_ci
21662306a36Sopenharmony_ci		goto handled;
21762306a36Sopenharmony_ci	}
21862306a36Sopenharmony_ci
21962306a36Sopenharmony_ci	spin_unlock(&priv->lock);
22062306a36Sopenharmony_ci
22162306a36Sopenharmony_ci	return IRQ_NONE;
22262306a36Sopenharmony_ci
22362306a36Sopenharmony_cidata_done:
22462306a36Sopenharmony_ci	if (priv->flags & UNIPHIER_FI2C_STOP) {
22562306a36Sopenharmony_cistop:
22662306a36Sopenharmony_ci		uniphier_fi2c_stop(priv);
22762306a36Sopenharmony_ci	} else {
22862306a36Sopenharmony_cicomplete:
22962306a36Sopenharmony_ci		priv->enabled_irqs = 0;
23062306a36Sopenharmony_ci		uniphier_fi2c_set_irqs(priv);
23162306a36Sopenharmony_ci		complete(&priv->comp);
23262306a36Sopenharmony_ci	}
23362306a36Sopenharmony_ci
23462306a36Sopenharmony_cihandled:
23562306a36Sopenharmony_ci	/*
23662306a36Sopenharmony_ci	 * This controller makes a pause while any bit of the IRQ status is
23762306a36Sopenharmony_ci	 * asserted. Clear the asserted bit to kick the controller just before
23862306a36Sopenharmony_ci	 * exiting the handler.
23962306a36Sopenharmony_ci	 */
24062306a36Sopenharmony_ci	uniphier_fi2c_clear_irqs(priv, irq_status);
24162306a36Sopenharmony_ci
24262306a36Sopenharmony_ci	spin_unlock(&priv->lock);
24362306a36Sopenharmony_ci
24462306a36Sopenharmony_ci	return IRQ_HANDLED;
24562306a36Sopenharmony_ci}
24662306a36Sopenharmony_ci
24762306a36Sopenharmony_cistatic void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr,
24862306a36Sopenharmony_ci				  bool repeat)
24962306a36Sopenharmony_ci{
25062306a36Sopenharmony_ci	priv->enabled_irqs |= UNIPHIER_FI2C_INT_TE;
25162306a36Sopenharmony_ci	uniphier_fi2c_set_irqs(priv);
25262306a36Sopenharmony_ci
25362306a36Sopenharmony_ci	/* do not use TX byte counter */
25462306a36Sopenharmony_ci	writel(0, priv->membase + UNIPHIER_FI2C_TBC);
25562306a36Sopenharmony_ci	/* set slave address */
25662306a36Sopenharmony_ci	writel(UNIPHIER_FI2C_DTTX_CMD | addr << 1,
25762306a36Sopenharmony_ci	       priv->membase + UNIPHIER_FI2C_DTTX);
25862306a36Sopenharmony_ci	/*
25962306a36Sopenharmony_ci	 * First chunk of data. For a repeated START condition, do not write
26062306a36Sopenharmony_ci	 * data to the TX fifo here to avoid the timing issue.
26162306a36Sopenharmony_ci	 */
26262306a36Sopenharmony_ci	if (!repeat)
26362306a36Sopenharmony_ci		uniphier_fi2c_fill_txfifo(priv, true);
26462306a36Sopenharmony_ci}
26562306a36Sopenharmony_ci
26662306a36Sopenharmony_cistatic void uniphier_fi2c_rx_init(struct uniphier_fi2c_priv *priv, u16 addr)
26762306a36Sopenharmony_ci{
26862306a36Sopenharmony_ci	priv->flags |= UNIPHIER_FI2C_RD;
26962306a36Sopenharmony_ci
27062306a36Sopenharmony_ci	if (likely(priv->len < 256)) {
27162306a36Sopenharmony_ci		/*
27262306a36Sopenharmony_ci		 * If possible, use RX byte counter.
27362306a36Sopenharmony_ci		 * It can automatically handle NACK for the last byte.
27462306a36Sopenharmony_ci		 */
27562306a36Sopenharmony_ci		writel(priv->len, priv->membase + UNIPHIER_FI2C_RBC);
27662306a36Sopenharmony_ci		priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF |
27762306a36Sopenharmony_ci				      UNIPHIER_FI2C_INT_RB;
27862306a36Sopenharmony_ci	} else {
27962306a36Sopenharmony_ci		/*
28062306a36Sopenharmony_ci		 * The byte counter can not count over 256.  In this case,
28162306a36Sopenharmony_ci		 * do not use it at all.  Drain data when FIFO gets full,
28262306a36Sopenharmony_ci		 * but treat the last portion as a special case.
28362306a36Sopenharmony_ci		 */
28462306a36Sopenharmony_ci		writel(0, priv->membase + UNIPHIER_FI2C_RBC);
28562306a36Sopenharmony_ci		priv->flags |= UNIPHIER_FI2C_MANUAL_NACK;
28662306a36Sopenharmony_ci		priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF;
28762306a36Sopenharmony_ci	}
28862306a36Sopenharmony_ci
28962306a36Sopenharmony_ci	uniphier_fi2c_set_irqs(priv);
29062306a36Sopenharmony_ci
29162306a36Sopenharmony_ci	/* set slave address with RD bit */
29262306a36Sopenharmony_ci	writel(UNIPHIER_FI2C_DTTX_CMD | UNIPHIER_FI2C_DTTX_RD | addr << 1,
29362306a36Sopenharmony_ci	       priv->membase + UNIPHIER_FI2C_DTTX);
29462306a36Sopenharmony_ci}
29562306a36Sopenharmony_ci
29662306a36Sopenharmony_cistatic void uniphier_fi2c_reset(struct uniphier_fi2c_priv *priv)
29762306a36Sopenharmony_ci{
29862306a36Sopenharmony_ci	writel(UNIPHIER_FI2C_RST_RST, priv->membase + UNIPHIER_FI2C_RST);
29962306a36Sopenharmony_ci}
30062306a36Sopenharmony_ci
30162306a36Sopenharmony_cistatic void uniphier_fi2c_prepare_operation(struct uniphier_fi2c_priv *priv)
30262306a36Sopenharmony_ci{
30362306a36Sopenharmony_ci	writel(UNIPHIER_FI2C_BRST_FOEN | UNIPHIER_FI2C_BRST_RSCL,
30462306a36Sopenharmony_ci	       priv->membase + UNIPHIER_FI2C_BRST);
30562306a36Sopenharmony_ci}
30662306a36Sopenharmony_ci
30762306a36Sopenharmony_cistatic void uniphier_fi2c_recover(struct uniphier_fi2c_priv *priv)
30862306a36Sopenharmony_ci{
30962306a36Sopenharmony_ci	uniphier_fi2c_reset(priv);
31062306a36Sopenharmony_ci	i2c_recover_bus(&priv->adap);
31162306a36Sopenharmony_ci}
31262306a36Sopenharmony_ci
31362306a36Sopenharmony_cistatic int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
31462306a36Sopenharmony_ci					 struct i2c_msg *msg, bool repeat,
31562306a36Sopenharmony_ci					 bool stop)
31662306a36Sopenharmony_ci{
31762306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
31862306a36Sopenharmony_ci	bool is_read = msg->flags & I2C_M_RD;
31962306a36Sopenharmony_ci	unsigned long time_left, flags;
32062306a36Sopenharmony_ci
32162306a36Sopenharmony_ci	priv->len = msg->len;
32262306a36Sopenharmony_ci	priv->buf = msg->buf;
32362306a36Sopenharmony_ci	priv->enabled_irqs = UNIPHIER_FI2C_INT_FAULTS;
32462306a36Sopenharmony_ci	priv->error = 0;
32562306a36Sopenharmony_ci	priv->flags = 0;
32662306a36Sopenharmony_ci
32762306a36Sopenharmony_ci	if (stop)
32862306a36Sopenharmony_ci		priv->flags |= UNIPHIER_FI2C_STOP;
32962306a36Sopenharmony_ci
33062306a36Sopenharmony_ci	reinit_completion(&priv->comp);
33162306a36Sopenharmony_ci	uniphier_fi2c_clear_irqs(priv, U32_MAX);
33262306a36Sopenharmony_ci	writel(UNIPHIER_FI2C_RST_TBRST | UNIPHIER_FI2C_RST_RBRST,
33362306a36Sopenharmony_ci	       priv->membase + UNIPHIER_FI2C_RST);	/* reset TX/RX FIFO */
33462306a36Sopenharmony_ci
33562306a36Sopenharmony_ci	spin_lock_irqsave(&priv->lock, flags);
33662306a36Sopenharmony_ci
33762306a36Sopenharmony_ci	if (is_read)
33862306a36Sopenharmony_ci		uniphier_fi2c_rx_init(priv, msg->addr);
33962306a36Sopenharmony_ci	else
34062306a36Sopenharmony_ci		uniphier_fi2c_tx_init(priv, msg->addr, repeat);
34162306a36Sopenharmony_ci
34262306a36Sopenharmony_ci	/*
34362306a36Sopenharmony_ci	 * For a repeated START condition, writing a slave address to the FIFO
34462306a36Sopenharmony_ci	 * kicks the controller. So, the UNIPHIER_FI2C_CR register should be
34562306a36Sopenharmony_ci	 * written only for a non-repeated START condition.
34662306a36Sopenharmony_ci	 */
34762306a36Sopenharmony_ci	if (!repeat)
34862306a36Sopenharmony_ci		writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
34962306a36Sopenharmony_ci		       priv->membase + UNIPHIER_FI2C_CR);
35062306a36Sopenharmony_ci
35162306a36Sopenharmony_ci	spin_unlock_irqrestore(&priv->lock, flags);
35262306a36Sopenharmony_ci
35362306a36Sopenharmony_ci	time_left = wait_for_completion_timeout(&priv->comp, adap->timeout);
35462306a36Sopenharmony_ci
35562306a36Sopenharmony_ci	spin_lock_irqsave(&priv->lock, flags);
35662306a36Sopenharmony_ci	priv->enabled_irqs = 0;
35762306a36Sopenharmony_ci	uniphier_fi2c_set_irqs(priv);
35862306a36Sopenharmony_ci	spin_unlock_irqrestore(&priv->lock, flags);
35962306a36Sopenharmony_ci
36062306a36Sopenharmony_ci	if (!time_left) {
36162306a36Sopenharmony_ci		dev_err(&adap->dev, "transaction timeout.\n");
36262306a36Sopenharmony_ci		uniphier_fi2c_recover(priv);
36362306a36Sopenharmony_ci		return -ETIMEDOUT;
36462306a36Sopenharmony_ci	}
36562306a36Sopenharmony_ci
36662306a36Sopenharmony_ci	if (unlikely(priv->flags & UNIPHIER_FI2C_DEFER_STOP_COMP)) {
36762306a36Sopenharmony_ci		u32 status;
36862306a36Sopenharmony_ci		int ret;
36962306a36Sopenharmony_ci
37062306a36Sopenharmony_ci		ret = readl_poll_timeout(priv->membase + UNIPHIER_FI2C_SR,
37162306a36Sopenharmony_ci					 status,
37262306a36Sopenharmony_ci					 (status & UNIPHIER_FI2C_SR_STS) &&
37362306a36Sopenharmony_ci					 !(status & UNIPHIER_FI2C_SR_BB),
37462306a36Sopenharmony_ci					 1, 20);
37562306a36Sopenharmony_ci		if (ret) {
37662306a36Sopenharmony_ci			dev_err(&adap->dev,
37762306a36Sopenharmony_ci				"stop condition was not completed.\n");
37862306a36Sopenharmony_ci			uniphier_fi2c_recover(priv);
37962306a36Sopenharmony_ci			return ret;
38062306a36Sopenharmony_ci		}
38162306a36Sopenharmony_ci	}
38262306a36Sopenharmony_ci
38362306a36Sopenharmony_ci	return priv->error;
38462306a36Sopenharmony_ci}
38562306a36Sopenharmony_ci
38662306a36Sopenharmony_cistatic int uniphier_fi2c_check_bus_busy(struct i2c_adapter *adap)
38762306a36Sopenharmony_ci{
38862306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
38962306a36Sopenharmony_ci
39062306a36Sopenharmony_ci	if (readl(priv->membase + UNIPHIER_FI2C_SR) & UNIPHIER_FI2C_SR_DB) {
39162306a36Sopenharmony_ci		if (priv->busy_cnt++ > 3) {
39262306a36Sopenharmony_ci			/*
39362306a36Sopenharmony_ci			 * If bus busy continues too long, it is probably
39462306a36Sopenharmony_ci			 * in a wrong state.  Try bus recovery.
39562306a36Sopenharmony_ci			 */
39662306a36Sopenharmony_ci			uniphier_fi2c_recover(priv);
39762306a36Sopenharmony_ci			priv->busy_cnt = 0;
39862306a36Sopenharmony_ci		}
39962306a36Sopenharmony_ci
40062306a36Sopenharmony_ci		return -EAGAIN;
40162306a36Sopenharmony_ci	}
40262306a36Sopenharmony_ci
40362306a36Sopenharmony_ci	priv->busy_cnt = 0;
40462306a36Sopenharmony_ci	return 0;
40562306a36Sopenharmony_ci}
40662306a36Sopenharmony_ci
40762306a36Sopenharmony_cistatic int uniphier_fi2c_master_xfer(struct i2c_adapter *adap,
40862306a36Sopenharmony_ci				     struct i2c_msg *msgs, int num)
40962306a36Sopenharmony_ci{
41062306a36Sopenharmony_ci	struct i2c_msg *msg, *emsg = msgs + num;
41162306a36Sopenharmony_ci	bool repeat = false;
41262306a36Sopenharmony_ci	int ret;
41362306a36Sopenharmony_ci
41462306a36Sopenharmony_ci	ret = uniphier_fi2c_check_bus_busy(adap);
41562306a36Sopenharmony_ci	if (ret)
41662306a36Sopenharmony_ci		return ret;
41762306a36Sopenharmony_ci
41862306a36Sopenharmony_ci	for (msg = msgs; msg < emsg; msg++) {
41962306a36Sopenharmony_ci		/* Emit STOP if it is the last message or I2C_M_STOP is set. */
42062306a36Sopenharmony_ci		bool stop = (msg + 1 == emsg) || (msg->flags & I2C_M_STOP);
42162306a36Sopenharmony_ci
42262306a36Sopenharmony_ci		ret = uniphier_fi2c_master_xfer_one(adap, msg, repeat, stop);
42362306a36Sopenharmony_ci		if (ret)
42462306a36Sopenharmony_ci			return ret;
42562306a36Sopenharmony_ci
42662306a36Sopenharmony_ci		repeat = !stop;
42762306a36Sopenharmony_ci	}
42862306a36Sopenharmony_ci
42962306a36Sopenharmony_ci	return num;
43062306a36Sopenharmony_ci}
43162306a36Sopenharmony_ci
43262306a36Sopenharmony_cistatic u32 uniphier_fi2c_functionality(struct i2c_adapter *adap)
43362306a36Sopenharmony_ci{
43462306a36Sopenharmony_ci	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
43562306a36Sopenharmony_ci}
43662306a36Sopenharmony_ci
43762306a36Sopenharmony_cistatic const struct i2c_algorithm uniphier_fi2c_algo = {
43862306a36Sopenharmony_ci	.master_xfer = uniphier_fi2c_master_xfer,
43962306a36Sopenharmony_ci	.functionality = uniphier_fi2c_functionality,
44062306a36Sopenharmony_ci};
44162306a36Sopenharmony_ci
44262306a36Sopenharmony_cistatic int uniphier_fi2c_get_scl(struct i2c_adapter *adap)
44362306a36Sopenharmony_ci{
44462306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
44562306a36Sopenharmony_ci
44662306a36Sopenharmony_ci	return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
44762306a36Sopenharmony_ci							UNIPHIER_FI2C_BM_SCLS);
44862306a36Sopenharmony_ci}
44962306a36Sopenharmony_ci
45062306a36Sopenharmony_cistatic void uniphier_fi2c_set_scl(struct i2c_adapter *adap, int val)
45162306a36Sopenharmony_ci{
45262306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
45362306a36Sopenharmony_ci
45462306a36Sopenharmony_ci	writel(val ? UNIPHIER_FI2C_BRST_RSCL : 0,
45562306a36Sopenharmony_ci	       priv->membase + UNIPHIER_FI2C_BRST);
45662306a36Sopenharmony_ci}
45762306a36Sopenharmony_ci
45862306a36Sopenharmony_cistatic int uniphier_fi2c_get_sda(struct i2c_adapter *adap)
45962306a36Sopenharmony_ci{
46062306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
46162306a36Sopenharmony_ci
46262306a36Sopenharmony_ci	return !!(readl(priv->membase + UNIPHIER_FI2C_BM) &
46362306a36Sopenharmony_ci							UNIPHIER_FI2C_BM_SDAS);
46462306a36Sopenharmony_ci}
46562306a36Sopenharmony_ci
46662306a36Sopenharmony_cistatic void uniphier_fi2c_unprepare_recovery(struct i2c_adapter *adap)
46762306a36Sopenharmony_ci{
46862306a36Sopenharmony_ci	uniphier_fi2c_prepare_operation(i2c_get_adapdata(adap));
46962306a36Sopenharmony_ci}
47062306a36Sopenharmony_ci
47162306a36Sopenharmony_cistatic struct i2c_bus_recovery_info uniphier_fi2c_bus_recovery_info = {
47262306a36Sopenharmony_ci	.recover_bus = i2c_generic_scl_recovery,
47362306a36Sopenharmony_ci	.get_scl = uniphier_fi2c_get_scl,
47462306a36Sopenharmony_ci	.set_scl = uniphier_fi2c_set_scl,
47562306a36Sopenharmony_ci	.get_sda = uniphier_fi2c_get_sda,
47662306a36Sopenharmony_ci	.unprepare_recovery = uniphier_fi2c_unprepare_recovery,
47762306a36Sopenharmony_ci};
47862306a36Sopenharmony_ci
47962306a36Sopenharmony_cistatic void uniphier_fi2c_hw_init(struct uniphier_fi2c_priv *priv)
48062306a36Sopenharmony_ci{
48162306a36Sopenharmony_ci	unsigned int cyc = priv->clk_cycle;
48262306a36Sopenharmony_ci	u32 tmp;
48362306a36Sopenharmony_ci
48462306a36Sopenharmony_ci	tmp = readl(priv->membase + UNIPHIER_FI2C_CR);
48562306a36Sopenharmony_ci	tmp |= UNIPHIER_FI2C_CR_MST;
48662306a36Sopenharmony_ci	writel(tmp, priv->membase + UNIPHIER_FI2C_CR);
48762306a36Sopenharmony_ci
48862306a36Sopenharmony_ci	uniphier_fi2c_reset(priv);
48962306a36Sopenharmony_ci
49062306a36Sopenharmony_ci	/*
49162306a36Sopenharmony_ci	 *  Standard-mode: tLOW + tHIGH = 10 us
49262306a36Sopenharmony_ci	 *  Fast-mode:     tLOW + tHIGH = 2.5 us
49362306a36Sopenharmony_ci	 */
49462306a36Sopenharmony_ci	writel(cyc, priv->membase + UNIPHIER_FI2C_CYC);
49562306a36Sopenharmony_ci	/*
49662306a36Sopenharmony_ci	 *  Standard-mode: tLOW = 4.7 us, tHIGH = 4.0 us, tBUF = 4.7 us
49762306a36Sopenharmony_ci	 *  Fast-mode:     tLOW = 1.3 us, tHIGH = 0.6 us, tBUF = 1.3 us
49862306a36Sopenharmony_ci	 * "tLow/tHIGH = 5/4" meets both.
49962306a36Sopenharmony_ci	 */
50062306a36Sopenharmony_ci	writel(cyc * 5 / 9, priv->membase + UNIPHIER_FI2C_LCTL);
50162306a36Sopenharmony_ci	/*
50262306a36Sopenharmony_ci	 *  Standard-mode: tHD;STA = 4.0 us, tSU;STA = 4.7 us, tSU;STO = 4.0 us
50362306a36Sopenharmony_ci	 *  Fast-mode:     tHD;STA = 0.6 us, tSU;STA = 0.6 us, tSU;STO = 0.6 us
50462306a36Sopenharmony_ci	 */
50562306a36Sopenharmony_ci	writel(cyc / 2, priv->membase + UNIPHIER_FI2C_SSUT);
50662306a36Sopenharmony_ci	/*
50762306a36Sopenharmony_ci	 *  Standard-mode: tSU;DAT = 250 ns
50862306a36Sopenharmony_ci	 *  Fast-mode:     tSU;DAT = 100 ns
50962306a36Sopenharmony_ci	 */
51062306a36Sopenharmony_ci	writel(cyc / 16, priv->membase + UNIPHIER_FI2C_DSUT);
51162306a36Sopenharmony_ci
51262306a36Sopenharmony_ci	uniphier_fi2c_prepare_operation(priv);
51362306a36Sopenharmony_ci}
51462306a36Sopenharmony_ci
51562306a36Sopenharmony_cistatic int uniphier_fi2c_probe(struct platform_device *pdev)
51662306a36Sopenharmony_ci{
51762306a36Sopenharmony_ci	struct device *dev = &pdev->dev;
51862306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv;
51962306a36Sopenharmony_ci	u32 bus_speed;
52062306a36Sopenharmony_ci	unsigned long clk_rate;
52162306a36Sopenharmony_ci	int irq, ret;
52262306a36Sopenharmony_ci
52362306a36Sopenharmony_ci	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
52462306a36Sopenharmony_ci	if (!priv)
52562306a36Sopenharmony_ci		return -ENOMEM;
52662306a36Sopenharmony_ci
52762306a36Sopenharmony_ci	priv->membase = devm_platform_ioremap_resource(pdev, 0);
52862306a36Sopenharmony_ci	if (IS_ERR(priv->membase))
52962306a36Sopenharmony_ci		return PTR_ERR(priv->membase);
53062306a36Sopenharmony_ci
53162306a36Sopenharmony_ci	irq = platform_get_irq(pdev, 0);
53262306a36Sopenharmony_ci	if (irq < 0)
53362306a36Sopenharmony_ci		return irq;
53462306a36Sopenharmony_ci
53562306a36Sopenharmony_ci	if (of_property_read_u32(dev->of_node, "clock-frequency", &bus_speed))
53662306a36Sopenharmony_ci		bus_speed = I2C_MAX_STANDARD_MODE_FREQ;
53762306a36Sopenharmony_ci
53862306a36Sopenharmony_ci	if (!bus_speed || bus_speed > I2C_MAX_FAST_MODE_FREQ) {
53962306a36Sopenharmony_ci		dev_err(dev, "invalid clock-frequency %d\n", bus_speed);
54062306a36Sopenharmony_ci		return -EINVAL;
54162306a36Sopenharmony_ci	}
54262306a36Sopenharmony_ci
54362306a36Sopenharmony_ci	priv->clk = devm_clk_get_enabled(dev, NULL);
54462306a36Sopenharmony_ci	if (IS_ERR(priv->clk)) {
54562306a36Sopenharmony_ci		dev_err(dev, "failed to enable clock\n");
54662306a36Sopenharmony_ci		return PTR_ERR(priv->clk);
54762306a36Sopenharmony_ci	}
54862306a36Sopenharmony_ci
54962306a36Sopenharmony_ci	clk_rate = clk_get_rate(priv->clk);
55062306a36Sopenharmony_ci	if (!clk_rate) {
55162306a36Sopenharmony_ci		dev_err(dev, "input clock rate should not be zero\n");
55262306a36Sopenharmony_ci		return -EINVAL;
55362306a36Sopenharmony_ci	}
55462306a36Sopenharmony_ci
55562306a36Sopenharmony_ci	priv->clk_cycle = clk_rate / bus_speed;
55662306a36Sopenharmony_ci	init_completion(&priv->comp);
55762306a36Sopenharmony_ci	spin_lock_init(&priv->lock);
55862306a36Sopenharmony_ci	priv->adap.owner = THIS_MODULE;
55962306a36Sopenharmony_ci	priv->adap.algo = &uniphier_fi2c_algo;
56062306a36Sopenharmony_ci	priv->adap.dev.parent = dev;
56162306a36Sopenharmony_ci	priv->adap.dev.of_node = dev->of_node;
56262306a36Sopenharmony_ci	strscpy(priv->adap.name, "UniPhier FI2C", sizeof(priv->adap.name));
56362306a36Sopenharmony_ci	priv->adap.bus_recovery_info = &uniphier_fi2c_bus_recovery_info;
56462306a36Sopenharmony_ci	i2c_set_adapdata(&priv->adap, priv);
56562306a36Sopenharmony_ci	platform_set_drvdata(pdev, priv);
56662306a36Sopenharmony_ci
56762306a36Sopenharmony_ci	uniphier_fi2c_hw_init(priv);
56862306a36Sopenharmony_ci
56962306a36Sopenharmony_ci	ret = devm_request_irq(dev, irq, uniphier_fi2c_interrupt, 0,
57062306a36Sopenharmony_ci			       pdev->name, priv);
57162306a36Sopenharmony_ci	if (ret) {
57262306a36Sopenharmony_ci		dev_err(dev, "failed to request irq %d\n", irq);
57362306a36Sopenharmony_ci		return ret;
57462306a36Sopenharmony_ci	}
57562306a36Sopenharmony_ci
57662306a36Sopenharmony_ci	return i2c_add_adapter(&priv->adap);
57762306a36Sopenharmony_ci}
57862306a36Sopenharmony_ci
57962306a36Sopenharmony_cistatic void uniphier_fi2c_remove(struct platform_device *pdev)
58062306a36Sopenharmony_ci{
58162306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv = platform_get_drvdata(pdev);
58262306a36Sopenharmony_ci
58362306a36Sopenharmony_ci	i2c_del_adapter(&priv->adap);
58462306a36Sopenharmony_ci}
58562306a36Sopenharmony_ci
58662306a36Sopenharmony_cistatic int __maybe_unused uniphier_fi2c_suspend(struct device *dev)
58762306a36Sopenharmony_ci{
58862306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
58962306a36Sopenharmony_ci
59062306a36Sopenharmony_ci	clk_disable_unprepare(priv->clk);
59162306a36Sopenharmony_ci
59262306a36Sopenharmony_ci	return 0;
59362306a36Sopenharmony_ci}
59462306a36Sopenharmony_ci
59562306a36Sopenharmony_cistatic int __maybe_unused uniphier_fi2c_resume(struct device *dev)
59662306a36Sopenharmony_ci{
59762306a36Sopenharmony_ci	struct uniphier_fi2c_priv *priv = dev_get_drvdata(dev);
59862306a36Sopenharmony_ci	int ret;
59962306a36Sopenharmony_ci
60062306a36Sopenharmony_ci	ret = clk_prepare_enable(priv->clk);
60162306a36Sopenharmony_ci	if (ret)
60262306a36Sopenharmony_ci		return ret;
60362306a36Sopenharmony_ci
60462306a36Sopenharmony_ci	uniphier_fi2c_hw_init(priv);
60562306a36Sopenharmony_ci
60662306a36Sopenharmony_ci	return 0;
60762306a36Sopenharmony_ci}
60862306a36Sopenharmony_ci
60962306a36Sopenharmony_cistatic const struct dev_pm_ops uniphier_fi2c_pm_ops = {
61062306a36Sopenharmony_ci	SET_SYSTEM_SLEEP_PM_OPS(uniphier_fi2c_suspend, uniphier_fi2c_resume)
61162306a36Sopenharmony_ci};
61262306a36Sopenharmony_ci
61362306a36Sopenharmony_cistatic const struct of_device_id uniphier_fi2c_match[] = {
61462306a36Sopenharmony_ci	{ .compatible = "socionext,uniphier-fi2c" },
61562306a36Sopenharmony_ci	{ /* sentinel */ }
61662306a36Sopenharmony_ci};
61762306a36Sopenharmony_ciMODULE_DEVICE_TABLE(of, uniphier_fi2c_match);
61862306a36Sopenharmony_ci
61962306a36Sopenharmony_cistatic struct platform_driver uniphier_fi2c_drv = {
62062306a36Sopenharmony_ci	.probe  = uniphier_fi2c_probe,
62162306a36Sopenharmony_ci	.remove_new = uniphier_fi2c_remove,
62262306a36Sopenharmony_ci	.driver = {
62362306a36Sopenharmony_ci		.name  = "uniphier-fi2c",
62462306a36Sopenharmony_ci		.of_match_table = uniphier_fi2c_match,
62562306a36Sopenharmony_ci		.pm = &uniphier_fi2c_pm_ops,
62662306a36Sopenharmony_ci	},
62762306a36Sopenharmony_ci};
62862306a36Sopenharmony_cimodule_platform_driver(uniphier_fi2c_drv);
62962306a36Sopenharmony_ci
63062306a36Sopenharmony_ciMODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
63162306a36Sopenharmony_ciMODULE_DESCRIPTION("UniPhier FIFO-builtin I2C bus driver");
63262306a36Sopenharmony_ciMODULE_LICENSE("GPL");
633