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/iopoll.h>
14 #include <linux/sizes.h>
15 #include <linux/errno.h>
19 struct uniphier_fi2c_regs
{
20 u32 cr
; /* control register */
21 #define I2C_CR_MST (1 << 3) /* master mode */
22 #define I2C_CR_STA (1 << 2) /* start condition */
23 #define I2C_CR_STO (1 << 1) /* stop condition */
24 #define I2C_CR_NACK (1 << 0) /* not ACK */
25 u32 dttx
; /* send FIFO (write-only) */
26 #define dtrx dttx /* receive FIFO (read-only) */
27 #define I2C_DTTX_CMD (1 << 8) /* send command (slave addr) */
28 #define I2C_DTTX_RD (1 << 0) /* read */
29 u32 __reserved
; /* no register at offset 0x08 */
30 u32 slad
; /* slave address */
31 u32 cyc
; /* clock cycle control */
32 u32 lctl
; /* clock low period control */
33 u32 ssut
; /* restart/stop setup time control */
34 u32 dsut
; /* data setup time control */
35 u32 intr
; /* interrupt status */
36 u32 ie
; /* interrupt enable */
37 u32 ic
; /* interrupt clear */
38 #define I2C_INT_TE (1 << 9) /* TX FIFO empty */
39 #define I2C_INT_RB (1 << 4) /* received specified bytes */
40 #define I2C_INT_NA (1 << 2) /* no answer */
41 #define I2C_INT_AL (1 << 1) /* arbitration lost */
42 u32 sr
; /* status register */
43 #define I2C_SR_DB (1 << 12) /* device busy */
44 #define I2C_SR_BB (1 << 8) /* bus busy */
45 #define I2C_SR_RFF (1 << 3) /* Rx FIFO full */
46 #define I2C_SR_RNE (1 << 2) /* Rx FIFO not empty */
47 #define I2C_SR_TNF (1 << 1) /* Tx FIFO not full */
48 #define I2C_SR_TFE (1 << 0) /* Tx FIFO empty */
49 u32 __reserved2
; /* no register at offset 0x30 */
50 u32 rst
; /* reset control */
51 #define I2C_RST_TBRST (1 << 2) /* clear Tx FIFO */
52 #define I2C_RST_RBRST (1 << 1) /* clear Rx FIFO */
53 #define I2C_RST_RST (1 << 0) /* forcible bus reset */
54 u32 bm
; /* bus monitor */
55 u32 noise
; /* noise filter control */
56 u32 tbc
; /* Tx byte count setting */
57 u32 rbc
; /* Rx byte count setting */
58 u32 tbcm
; /* Tx byte count monitor */
59 u32 rbcm
; /* Rx byte count monitor */
60 u32 brst
; /* bus reset */
61 #define I2C_BRST_FOEN (1 << 1) /* normal operation */
62 #define I2C_BRST_RSCLO (1 << 0) /* release SCL low fixing */
65 #define FIOCLK 50000000
67 struct uniphier_fi2c_dev
{
68 struct uniphier_fi2c_regs __iomem
*regs
; /* register base */
69 unsigned long fioclk
; /* internal operation clock */
70 unsigned long timeout
; /* time out (us) */
73 static int reset_bus(struct uniphier_fi2c_regs __iomem
*regs
)
78 /* bus forcible reset */
79 writel(I2C_RST_RST
, ®s
->rst
);
80 ret
= readl_poll_timeout(®s
->rst
, val
, !(val
& I2C_RST_RST
), 1);
82 debug("error: fail to reset I2C controller\n");
87 static int check_device_busy(struct uniphier_fi2c_regs __iomem
*regs
)
92 ret
= readl_poll_timeout(®s
->sr
, val
, !(val
& I2C_SR_DB
), 100);
94 debug("error: device busy too long. reset...\n");
95 ret
= reset_bus(regs
);
101 static int uniphier_fi2c_probe(struct udevice
*dev
)
104 struct uniphier_fi2c_dev
*priv
= dev_get_priv(dev
);
107 addr
= devfdt_get_addr(dev
);
108 if (addr
== FDT_ADDR_T_NONE
)
111 priv
->regs
= devm_ioremap(dev
, addr
, SZ_128
);
115 priv
->fioclk
= FIOCLK
;
117 /* bus forcible reset */
118 ret
= reset_bus(priv
->regs
);
122 writel(I2C_BRST_FOEN
| I2C_BRST_RSCLO
, &priv
->regs
->brst
);
127 static int wait_for_irq(struct uniphier_fi2c_dev
*dev
, u32 flags
,
133 ret
= readl_poll_timeout(&dev
->regs
->intr
, irq
, irq
& flags
,
136 debug("error: time out\n");
140 if (irq
& I2C_INT_AL
) {
141 debug("error: arbitration lost\n");
146 if (irq
& I2C_INT_NA
) {
147 debug("error: no answer\n");
154 static int issue_stop(struct uniphier_fi2c_dev
*dev
, int old_ret
)
158 debug("stop condition\n");
159 writel(I2C_CR_MST
| I2C_CR_STO
, &dev
->regs
->cr
);
161 ret
= check_device_busy(dev
->regs
);
163 debug("error: device busy after operation\n");
165 return old_ret
? old_ret
: ret
;
168 static int uniphier_fi2c_transmit(struct uniphier_fi2c_dev
*dev
, uint addr
,
169 uint len
, const u8
*buf
, bool *stop
)
172 const u32 irq_flags
= I2C_INT_TE
| I2C_INT_NA
| I2C_INT_AL
;
173 struct uniphier_fi2c_regs __iomem
*regs
= dev
->regs
;
175 debug("%s: addr = %x, len = %d\n", __func__
, addr
, len
);
177 writel(I2C_DTTX_CMD
| addr
<< 1, ®s
->dttx
);
179 writel(irq_flags
, ®s
->ie
);
180 writel(irq_flags
, ®s
->ic
);
182 debug("start condition\n");
183 writel(I2C_CR_MST
| I2C_CR_STA
, ®s
->cr
);
185 ret
= wait_for_irq(dev
, irq_flags
, stop
);
190 debug("sending %x\n", *buf
);
191 writel(*buf
++, ®s
->dttx
);
193 writel(irq_flags
, ®s
->ic
);
195 ret
= wait_for_irq(dev
, irq_flags
, stop
);
201 writel(irq_flags
, ®s
->ic
);
204 ret
= issue_stop(dev
, ret
);
209 static int uniphier_fi2c_receive(struct uniphier_fi2c_dev
*dev
, uint addr
,
210 uint len
, u8
*buf
, bool *stop
)
213 const u32 irq_flags
= I2C_INT_RB
| I2C_INT_NA
| I2C_INT_AL
;
214 struct uniphier_fi2c_regs __iomem
*regs
= dev
->regs
;
216 debug("%s: addr = %x, len = %d\n", __func__
, addr
, len
);
219 * In case 'len == 0', only the slave address should be sent
220 * for probing, which is covered by the transmit function.
223 return uniphier_fi2c_transmit(dev
, addr
, len
, buf
, stop
);
225 writel(I2C_DTTX_CMD
| I2C_DTTX_RD
| addr
<< 1, ®s
->dttx
);
227 writel(0, ®s
->rbc
);
228 writel(irq_flags
, ®s
->ie
);
229 writel(irq_flags
, ®s
->ic
);
231 debug("start condition\n");
232 writel(I2C_CR_MST
| I2C_CR_STA
| (len
== 1 ? I2C_CR_NACK
: 0),
236 ret
= wait_for_irq(dev
, irq_flags
, stop
);
240 *buf
++ = readl(®s
->dtrx
);
241 debug("received %x\n", *(buf
- 1));
244 writel(I2C_CR_MST
| I2C_CR_NACK
, ®s
->cr
);
246 writel(irq_flags
, ®s
->ic
);
250 writel(irq_flags
, ®s
->ic
);
253 ret
= issue_stop(dev
, ret
);
258 static int uniphier_fi2c_xfer(struct udevice
*bus
, struct i2c_msg
*msg
,
262 struct uniphier_fi2c_dev
*dev
= dev_get_priv(bus
);
265 ret
= check_device_busy(dev
->regs
);
269 for (; nmsgs
> 0; nmsgs
--, msg
++) {
270 /* If next message is read, skip the stop condition */
271 stop
= nmsgs
> 1 && msg
[1].flags
& I2C_M_RD
? false : true;
273 if (msg
->flags
& I2C_M_RD
)
274 ret
= uniphier_fi2c_receive(dev
, msg
->addr
, msg
->len
,
277 ret
= uniphier_fi2c_transmit(dev
, msg
->addr
, msg
->len
,
287 static int uniphier_fi2c_set_bus_speed(struct udevice
*bus
, unsigned int speed
)
290 unsigned int clk_count
;
291 struct uniphier_fi2c_dev
*dev
= dev_get_priv(bus
);
292 struct uniphier_fi2c_regs __iomem
*regs
= dev
->regs
;
294 /* max supported frequency is 400 kHz */
298 ret
= check_device_busy(dev
->regs
);
302 /* make sure the bus is idle when changing the frequency */
303 writel(I2C_BRST_RSCLO
, ®s
->brst
);
305 clk_count
= dev
->fioclk
/ speed
;
307 writel(clk_count
, ®s
->cyc
);
308 writel(clk_count
/ 2, ®s
->lctl
);
309 writel(clk_count
/ 2, ®s
->ssut
);
310 writel(clk_count
/ 16, ®s
->dsut
);
312 writel(I2C_BRST_FOEN
| I2C_BRST_RSCLO
, ®s
->brst
);
315 * Theoretically, each byte can be transferred in
316 * 1000000 * 9 / speed usec.
317 * This time out value is long enough.
319 dev
->timeout
= 100000000L / speed
;
324 static const struct dm_i2c_ops uniphier_fi2c_ops
= {
325 .xfer
= uniphier_fi2c_xfer
,
326 .set_bus_speed
= uniphier_fi2c_set_bus_speed
,
329 static const struct udevice_id uniphier_fi2c_of_match
[] = {
330 { .compatible
= "socionext,uniphier-fi2c" },
334 U_BOOT_DRIVER(uniphier_fi2c
) = {
335 .name
= "uniphier-fi2c",
337 .of_match
= uniphier_fi2c_of_match
,
338 .probe
= uniphier_fi2c_probe
,
339 .priv_auto_alloc_size
= sizeof(struct uniphier_fi2c_dev
),
340 .ops
= &uniphier_fi2c_ops
,