2 * Copyright (C) 2014 Panasonic Corporation
3 * Copyright (C) 2015-2016 Socionext Inc.
4 * Author: Masahiro Yamada <yamada.masahiro@socionext.com>
6 * SPDX-License-Identifier: GPL-2.0+
11 #include <linux/types.h>
13 #include <linux/sizes.h>
14 #include <linux/errno.h>
18 struct uniphier_i2c_regs
{
19 u32 dtrm
; /* data transmission */
20 #define I2C_DTRM_STA (1 << 10)
21 #define I2C_DTRM_STO (1 << 9)
22 #define I2C_DTRM_NACK (1 << 8)
23 #define I2C_DTRM_RD (1 << 0)
24 u32 drec
; /* data reception */
25 #define I2C_DREC_STS (1 << 12)
26 #define I2C_DREC_LRB (1 << 11)
27 #define I2C_DREC_LAB (1 << 9)
28 u32 myad
; /* slave address */
29 u32 clk
; /* clock frequency control */
30 u32 brst
; /* bus reset */
31 #define I2C_BRST_FOEN (1 << 1)
32 #define I2C_BRST_BRST (1 << 0)
33 u32 hold
; /* hold time control */
34 u32 bsts
; /* bus status monitor */
35 u32 noise
; /* noise filter control */
36 u32 setup
; /* setup time control */
39 #define IOBUS_FREQ 100000000
41 struct uniphier_i2c_dev
{
42 struct uniphier_i2c_regs __iomem
*regs
; /* register base */
43 unsigned long input_clk
; /* master clock (Hz) */
44 unsigned long wait_us
; /* wait for every byte transfer (us) */
47 static int uniphier_i2c_probe(struct udevice
*dev
)
50 struct uniphier_i2c_dev
*priv
= dev_get_priv(dev
);
52 addr
= devfdt_get_addr(dev
);
53 if (addr
== FDT_ADDR_T_NONE
)
56 priv
->regs
= devm_ioremap(dev
, addr
, SZ_64
);
60 priv
->input_clk
= IOBUS_FREQ
;
63 writel(0x3, &priv
->regs
->brst
);
68 static int send_and_recv_byte(struct uniphier_i2c_dev
*dev
, u32 dtrm
)
70 writel(dtrm
, &dev
->regs
->dtrm
);
73 * This controller only provides interruption to inform the completion
74 * of each byte transfer. (No status register to poll it.)
75 * Unfortunately, U-Boot does not have a good support of interrupt.
80 return readl(&dev
->regs
->drec
);
83 static int send_byte(struct uniphier_i2c_dev
*dev
, u32 dtrm
, bool *stop
)
88 drec
= send_and_recv_byte(dev
, dtrm
);
90 if (drec
& I2C_DREC_LAB
) {
91 debug("uniphier_i2c: bus arbitration failed\n");
95 if (drec
& I2C_DREC_LRB
) {
96 debug("uniphier_i2c: slave did not return ACK\n");
102 static int uniphier_i2c_transmit(struct uniphier_i2c_dev
*dev
, uint addr
,
103 uint len
, const u8
*buf
, bool *stop
)
107 debug("%s: addr = %x, len = %d\n", __func__
, addr
, len
);
109 ret
= send_byte(dev
, I2C_DTRM_STA
| I2C_DTRM_NACK
| addr
<< 1, stop
);
114 ret
= send_byte(dev
, I2C_DTRM_NACK
| *buf
++, stop
);
121 writel(I2C_DTRM_STO
| I2C_DTRM_NACK
, &dev
->regs
->dtrm
);
126 static int uniphier_i2c_receive(struct uniphier_i2c_dev
*dev
, uint addr
,
127 uint len
, u8
*buf
, bool *stop
)
131 debug("%s: addr = %x, len = %d\n", __func__
, addr
, len
);
133 ret
= send_byte(dev
, I2C_DTRM_STA
| I2C_DTRM_NACK
|
134 I2C_DTRM_RD
| addr
<< 1, stop
);
139 *buf
++ = send_and_recv_byte(dev
, len
? 0 : I2C_DTRM_NACK
);
143 writel(I2C_DTRM_STO
| I2C_DTRM_NACK
, &dev
->regs
->dtrm
);
148 static int uniphier_i2c_xfer(struct udevice
*bus
, struct i2c_msg
*msg
,
152 struct uniphier_i2c_dev
*dev
= dev_get_priv(bus
);
155 for (; nmsgs
> 0; nmsgs
--, msg
++) {
156 /* If next message is read, skip the stop condition */
157 stop
= nmsgs
> 1 && msg
[1].flags
& I2C_M_RD
? false : true;
159 if (msg
->flags
& I2C_M_RD
)
160 ret
= uniphier_i2c_receive(dev
, msg
->addr
, msg
->len
,
163 ret
= uniphier_i2c_transmit(dev
, msg
->addr
, msg
->len
,
173 static int uniphier_i2c_set_bus_speed(struct udevice
*bus
, unsigned int speed
)
175 struct uniphier_i2c_dev
*priv
= dev_get_priv(bus
);
177 /* max supported frequency is 400 kHz */
181 /* bus reset: make sure the bus is idle when change the frequency */
182 writel(0x1, &priv
->regs
->brst
);
184 writel((priv
->input_clk
/ speed
/ 2 << 16) | (priv
->input_clk
/ speed
),
187 writel(0x3, &priv
->regs
->brst
);
190 * Theoretically, each byte can be transferred in
191 * 1000000 * 9 / speed usec. For safety, wait more than double.
193 priv
->wait_us
= 20000000 / speed
;
199 static const struct dm_i2c_ops uniphier_i2c_ops
= {
200 .xfer
= uniphier_i2c_xfer
,
201 .set_bus_speed
= uniphier_i2c_set_bus_speed
,
204 static const struct udevice_id uniphier_i2c_of_match
[] = {
205 { .compatible
= "socionext,uniphier-i2c" },
209 U_BOOT_DRIVER(uniphier_i2c
) = {
210 .name
= "uniphier-i2c",
212 .of_match
= uniphier_i2c_of_match
,
213 .probe
= uniphier_i2c_probe
,
214 .priv_auto_alloc_size
= sizeof(struct uniphier_i2c_dev
),
215 .ops
= &uniphier_i2c_ops
,