[thirdparty/u-boot.git] / drivers / i2c / i2c-versatile.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2018 Arm Ltd.
 * Author: Liviu Dudau <liviu.dudau@foss.arm.com>
 *
 */

#include <common.h>
#include <dm.h>
#include <errno.h>
#include <i2c.h>
#include <asm/io.h>
#include <clk.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/io.h>

#define I2C_CONTROL_REG		0x00
#define I2C_SET_REG		0x00
#define I2C_CLEAR_REG		0x04

#define SCL	BIT(0)
#define SDA	BIT(1)

struct versatile_i2c_priv {
	phys_addr_t base;
	u32 delay;
};

static inline void versatile_sda_set(struct versatile_i2c_priv *priv, u8 state)
{
	writel(SDA, priv->base + (state ? I2C_SET_REG : I2C_CLEAR_REG));
	udelay(priv->delay);
}

static inline int versatile_sda_get(struct versatile_i2c_priv *priv)
{
	int v = !!(readl(priv->base + I2C_CONTROL_REG) & SDA);

	udelay(priv->delay);
	return v;
}

static inline void versatile_scl_set(struct versatile_i2c_priv *priv, u8 state)
{
	writel(SCL, priv->base + (state ? I2C_SET_REG : I2C_CLEAR_REG));
	udelay(priv->delay);
}

static inline int versatile_scl_get(struct versatile_i2c_priv *priv)
{
	int v = !!(readl(priv->base + I2C_CONTROL_REG) & SCL);

	udelay(priv->delay);
	return v;
}

/* start: SDA goes from high to low while SCL is high */
static void versatile_i2c_start(struct versatile_i2c_priv *priv)
{
	udelay(priv->delay);
	versatile_sda_set(priv, 1);
	versatile_scl_set(priv, 1);
	versatile_sda_set(priv, 0);
}

/* stop: SDA goes from low to high while SCL is high */
static void versatile_i2c_stop(struct versatile_i2c_priv *priv)
{
	versatile_scl_set(priv, 0);
	versatile_sda_set(priv, 0);
	versatile_scl_set(priv, 1);
	versatile_sda_set(priv, 1);
}

/* read a bit from the SDA line (data or ACK/NACK) */
static u8 versatile_i2c_read_bit(struct versatile_i2c_priv *priv)
{
	versatile_scl_set(priv, 0);
	versatile_sda_set(priv, 1);
	versatile_scl_set(priv, 1);
	udelay(priv->delay);
	return (u8)versatile_sda_get(priv);
}

/* write a bit on the SDA line */
static void versatile_i2c_write_bit(struct versatile_i2c_priv *priv, u8 bit)
{
	versatile_scl_set(priv, 0);
	versatile_sda_set(priv, bit);
	versatile_scl_set(priv, 1);
	udelay(priv->delay);
}

/* send a reset sequence of 9 clocks with SDA high */
static void versatile_i2c_reset_bus(struct versatile_i2c_priv *priv)
{
	int i;

	for (i = 0; i < 9; i++)
		versatile_i2c_write_bit(priv, 1);

	versatile_i2c_stop(priv);
}

/* write byte without start/stop sequence */
static int versatile_i2c_write_byte(struct versatile_i2c_priv *priv, u8 byte)
{
	u8 nak, i;

	for (i = 0; i < 8; i++) {
		versatile_i2c_write_bit(priv, byte & 0x80);
		byte <<= 1;
	}

	/* read ACK */
	nak = versatile_i2c_read_bit(priv);
	versatile_scl_set(priv, 0);

	return nak;	/* not a nack is an ack */
}

static int versatile_i2c_read_byte(struct versatile_i2c_priv *priv,
				   u8 *byte, u8 ack)
{
	u8 i;

	*byte = 0;
	for (i = 0; i < 8; i++) {
		*byte <<= 1;
		*byte |= versatile_i2c_read_bit(priv);
	}
	/* write the nack */
	versatile_i2c_write_bit(priv, ack);

	return 0;
}

static int versatile_i2c_send_slave_addr(struct versatile_i2c_priv *priv,
					 struct i2c_msg *msg)
{
	u8 addr;
	int ret;

	if (msg->flags & I2C_M_TEN) {
		/* 10-bit address, send extended address code first */
		addr = 0xf0 | ((msg->addr >> 7) & 0x06);
		ret = versatile_i2c_write_byte(priv, addr);
		if (ret) {
			versatile_i2c_stop(priv);
			return -EIO;
		}

		/* remaining bits */
		ret = versatile_i2c_write_byte(priv, msg->addr & 0xff);
		if (ret) {
			versatile_i2c_stop(priv);
			return -EIO;
		}
		/* reads need to resend the addr */
		if (msg->flags & I2C_M_RD) {
			versatile_i2c_start(priv);
			addr |= 1;
			ret = versatile_i2c_write_byte(priv, addr);
			if (ret) {
				versatile_i2c_stop(priv);
				return -EIO;
			}
		}
	} else {
		/* normal 7-bit address */
		addr = msg->addr << 1;
		if (msg->flags & I2C_M_RD)
			addr |= 1;
		ret = versatile_i2c_write_byte(priv, addr);
		if (ret) {
			versatile_i2c_stop(priv);
			return -EIO;
		}
	}

	return 0;
}

static int versatile_i2c_message_xfer(struct versatile_i2c_priv *priv,
				      struct i2c_msg *msg)
{
	int i, ret;
	u8 ack;

	versatile_i2c_start(priv);
	if (versatile_i2c_send_slave_addr(priv, msg))
		return -EIO;

	for (i = 0; i < msg->len; i++) {
		if (msg->flags & I2C_M_RD) {
			ack = (msg->len - i - 1) == 0 ? 1 : 0;
			ret = versatile_i2c_read_byte(priv, &msg->buf[i], ack);
		} else {
			ret = versatile_i2c_write_byte(priv, msg->buf[i]);
		}

		if (ret)
			break;
	}

	versatile_i2c_stop(priv);

	return ret;
}

static int versatile_i2c_xfer(struct udevice *bus,
			      struct i2c_msg *msg, int nmsgs)
{
	struct versatile_i2c_priv *priv = dev_get_priv(bus);
	int ret;

	for ( ; nmsgs > 0; nmsgs--, msg++) {
		ret = versatile_i2c_message_xfer(priv, msg);
		if (ret)
			return -EREMOTEIO;
	}

	return 0;
}

static int versatile_i2c_chip_probe(struct udevice *bus,
				    uint chip, uint chip_flags)
{
	/* probe the presence of a slave by writing a 0-size message */
	struct i2c_msg msg = { .addr = chip, .flags = chip_flags,
			       .len = 0, .buf = NULL };
	struct versatile_i2c_priv *priv = dev_get_priv(bus);

	return versatile_i2c_message_xfer(priv, &msg);
}

static int versatile_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
{
	struct versatile_i2c_priv *priv = dev_get_priv(bus);

	priv->delay = 1000000 / (speed << 2);

	versatile_i2c_reset_bus(priv);

	return 0;
}

static int versatile_i2c_probe(struct udevice *dev)
{
	struct versatile_i2c_priv *priv = dev_get_priv(dev);

	priv->base = (phys_addr_t)dev_read_addr(dev);
	priv->delay = 25;	/* 25us * 4 = 100kHz */

	return 0;
}

static const struct dm_i2c_ops versatile_i2c_ops = {
	.xfer = versatile_i2c_xfer,
	.probe_chip = versatile_i2c_chip_probe,
	.set_bus_speed = versatile_i2c_set_bus_speed,
};

static const struct udevice_id versatile_i2c_of_match[] = {
	{ .compatible = "arm,versatile-i2c" },
	{ }
};

U_BOOT_DRIVER(versatile_i2c) = {
	.name = "i2c-bus-versatile",
	.id = UCLASS_I2C,
	.of_match = versatile_i2c_of_match,
	.probe = versatile_i2c_probe,
	.priv_auto	= sizeof(struct versatile_i2c_priv),
	.ops = &versatile_i2c_ops,
};
Commit	Line	Data
86c83e84 LD	1	// SPDX-License-Identifier: GPL-2.0+
	2	/*
	3	* Copyright (c) 2018 Arm Ltd.
	4	* Author: Liviu Dudau <liviu.dudau@foss.arm.com>
	5	*
	6	*/
	7
d678a59d	8	#include <common.h>
86c83e84 LD	9	#include <dm.h>
	10	#include <errno.h>
	11	#include <i2c.h>
	12	#include <asm/io.h>
	13	#include <clk.h>
cd93d625	14	#include <linux/bitops.h>
c05ed00a	15	#include <linux/delay.h>
86c83e84 LD	16	#include <linux/io.h>
	17
	18	#define I2C_CONTROL_REG 0x00
	19	#define I2C_SET_REG 0x00
	20	#define I2C_CLEAR_REG 0x04
	21
	22	#define SCL BIT(0)
	23	#define SDA BIT(1)
	24
	25	struct versatile_i2c_priv {
	26	phys_addr_t base;
	27	u32 delay;
	28	};
	29
	30	static inline void versatile_sda_set(struct versatile_i2c_priv *priv, u8 state)
	31	{
	32	writel(SDA, priv->base + (state ? I2C_SET_REG : I2C_CLEAR_REG));
	33	udelay(priv->delay);
	34	}
	35
	36	static inline int versatile_sda_get(struct versatile_i2c_priv *priv)
	37	{
	38	int v = !!(readl(priv->base + I2C_CONTROL_REG) & SDA);
	39
	40	udelay(priv->delay);
	41	return v;
	42	}
	43
	44	static inline void versatile_scl_set(struct versatile_i2c_priv *priv, u8 state)
	45	{
	46	writel(SCL, priv->base + (state ? I2C_SET_REG : I2C_CLEAR_REG));
	47	udelay(priv->delay);
	48	}
	49
	50	static inline int versatile_scl_get(struct versatile_i2c_priv *priv)
	51	{
	52	int v = !!(readl(priv->base + I2C_CONTROL_REG) & SCL);
	53
	54	udelay(priv->delay);
	55	return v;
	56	}
	57
	58	/* start: SDA goes from high to low while SCL is high */
	59	static void versatile_i2c_start(struct versatile_i2c_priv *priv)
	60	{
	61	udelay(priv->delay);
	62	versatile_sda_set(priv, 1);
	63	versatile_scl_set(priv, 1);
	64	versatile_sda_set(priv, 0);
	65	}
	66
	67	/* stop: SDA goes from low to high while SCL is high */
	68	static void versatile_i2c_stop(struct versatile_i2c_priv *priv)
	69	{
	70	versatile_scl_set(priv, 0);
	71	versatile_sda_set(priv, 0);
	72	versatile_scl_set(priv, 1);
	73	versatile_sda_set(priv, 1);
	74	}
	75
	76	/* read a bit from the SDA line (data or ACK/NACK) */
	77	static u8 versatile_i2c_read_bit(struct versatile_i2c_priv *priv)
	78	{
	79	versatile_scl_set(priv, 0);
80	versatile_sda_set(priv, 1);
81	versatile_scl_set(priv, 1);
82	udelay(priv->delay);
83	return (u8)versatile_sda_get(priv);
84	}
85
86	/* write a bit on the SDA line */
87	static void versatile_i2c_write_bit(struct versatile_i2c_priv *priv, u8 bit)
88	{
89	versatile_scl_set(priv, 0);
90	versatile_sda_set(priv, bit);
91	versatile_scl_set(priv, 1);
92	udelay(priv->delay);
93	}
94
95	/* send a reset sequence of 9 clocks with SDA high */
96	static void versatile_i2c_reset_bus(struct versatile_i2c_priv *priv)
97	{
98	int i;
99
100	for (i = 0; i < 9; i++)
101	versatile_i2c_write_bit(priv, 1);
102
103	versatile_i2c_stop(priv);
104	}
105
106	/* write byte without start/stop sequence */
107	static int versatile_i2c_write_byte(struct versatile_i2c_priv *priv, u8 byte)
108	{
109	u8 nak, i;
110
111	for (i = 0; i < 8; i++) {
112	versatile_i2c_write_bit(priv, byte & 0x80);
113	byte <<= 1;
114	}
115
116	/* read ACK */
117	nak = versatile_i2c_read_bit(priv);
118	versatile_scl_set(priv, 0);
119
120	return nak; /* not a nack is an ack */
121	}
122
123	static int versatile_i2c_read_byte(struct versatile_i2c_priv *priv,
124	u8 *byte, u8 ack)
125	{
126	u8 i;
127
128	*byte = 0;
129	for (i = 0; i < 8; i++) {
130	*byte <<= 1;
131	*byte \|= versatile_i2c_read_bit(priv);
132	}
133	/* write the nack */
134	versatile_i2c_write_bit(priv, ack);
135
136	return 0;
137	}
138
139	static int versatile_i2c_send_slave_addr(struct versatile_i2c_priv *priv,
140	struct i2c_msg *msg)
141	{
142	u8 addr;
143	int ret;
144
145	if (msg->flags & I2C_M_TEN) {
146	/* 10-bit address, send extended address code first */
147	addr = 0xf0 \| ((msg->addr >> 7) & 0x06);
148	ret = versatile_i2c_write_byte(priv, addr);
149	if (ret) {
150	versatile_i2c_stop(priv);
151	return -EIO;
152	}
153
154	/* remaining bits */
155	ret = versatile_i2c_write_byte(priv, msg->addr & 0xff);
156	if (ret) {
157	versatile_i2c_stop(priv);
158	return -EIO;
159	}
160	/* reads need to resend the addr */
161	if (msg->flags & I2C_M_RD) {
162	versatile_i2c_start(priv);
163	addr \|= 1;
164	ret = versatile_i2c_write_byte(priv, addr);
165	if (ret) {
166	versatile_i2c_stop(priv);
167	return -EIO;
168	}
169	}
170	} else {
171	/* normal 7-bit address */
172	addr = msg->addr << 1;
173	if (msg->flags & I2C_M_RD)
174	addr \|= 1;
175	ret = versatile_i2c_write_byte(priv, addr);
176	if (ret) {
177	versatile_i2c_stop(priv);
178	return -EIO;
179	}
180	}
181
182	return 0;
183	}
184
185	static int versatile_i2c_message_xfer(struct versatile_i2c_priv *priv,
186	struct i2c_msg *msg)
187	{
188	int i, ret;
189	u8 ack;
190
191	versatile_i2c_start(priv);
192	if (versatile_i2c_send_slave_addr(priv, msg))
193	return -EIO;
194
195	for (i = 0; i < msg->len; i++) {
196	if (msg->flags & I2C_M_RD) {
197	ack = (msg->len - i - 1) == 0 ? 1 : 0;
198	ret = versatile_i2c_read_byte(priv, &msg->buf[i], ack);
199	} else {
200	ret = versatile_i2c_write_byte(priv, msg->buf[i]);
201	}
202
203	if (ret)
204	break;
205	}
206
207	versatile_i2c_stop(priv);
208
209	return ret;
210	}
211
212	static int versatile_i2c_xfer(struct udevice *bus,
213	struct i2c_msg *msg, int nmsgs)
214	{
215	struct versatile_i2c_priv *priv = dev_get_priv(bus);
216	int ret;
217
218	for ( ; nmsgs > 0; nmsgs--, msg++) {
219	ret = versatile_i2c_message_xfer(priv, msg);
220	if (ret)
221	return -EREMOTEIO;
222	}
223
224	return 0;
225	}
226
227	static int versatile_i2c_chip_probe(struct udevice *bus,
228	uint chip, uint chip_flags)
229	{
230	/* probe the presence of a slave by writing a 0-size message */
231	struct i2c_msg msg = { .addr = chip, .flags = chip_flags,
232	.len = 0, .buf = NULL };
233	struct versatile_i2c_priv *priv = dev_get_priv(bus);
234
235	return versatile_i2c_message_xfer(priv, &msg);
236	}
237
238	static int versatile_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
239	{
240	struct versatile_i2c_priv *priv = dev_get_priv(bus);
241
242	priv->delay = 1000000 / (speed << 2);
243
244	versatile_i2c_reset_bus(priv);
245
246	return 0;
247	}
248
249	static int versatile_i2c_probe(struct udevice *dev)
250	{
251	struct versatile_i2c_priv *priv = dev_get_priv(dev);
252
253	priv->base = (phys_addr_t)dev_read_addr(dev);
254	priv->delay = 25; /* 25us * 4 = 100kHz */
86c83e84 LD	255
	256	return 0;
	257	}
	258
	259	static const struct dm_i2c_ops versatile_i2c_ops = {
	260	.xfer = versatile_i2c_xfer,
	261	.probe_chip = versatile_i2c_chip_probe,
	262	.set_bus_speed = versatile_i2c_set_bus_speed,
	263	};
	264
	265	static const struct udevice_id versatile_i2c_of_match[] = {
	266	{ .compatible = "arm,versatile-i2c" },
	267	{ }
	268	};
	269
	270	U_BOOT_DRIVER(versatile_i2c) = {
	271	.name = "i2c-bus-versatile",
	272	.id = UCLASS_I2C,
	273	.of_match = versatile_i2c_of_match,
	274	.probe = versatile_i2c_probe,
41575d8e	275	.priv_auto = sizeof(struct versatile_i2c_priv),
86c83e84 LD	276	.ops = &versatile_i2c_ops,
86c83e84 LD	277	};