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Beniamino Galvanif8d9ca12017-10-29 10:09:00 +01001/*
2 * (C) Copyright 2017 - Beniamino Galvani <b.galvani@gmail.com>
3 *
4 * SPDX-License-Identifier: GPL-2.0+
5 */
6#include <common.h>
7#include <asm/arch/i2c.h>
8#include <asm/io.h>
9#include <dm.h>
10#include <i2c.h>
11
Beniamino Galvani8c47ab62017-11-26 17:40:55 +010012#define I2C_TIMEOUT_MS 100
Beniamino Galvanif8d9ca12017-10-29 10:09:00 +010013
14/* Control register fields */
15#define REG_CTRL_START BIT(0)
16#define REG_CTRL_ACK_IGNORE BIT(1)
17#define REG_CTRL_STATUS BIT(2)
18#define REG_CTRL_ERROR BIT(3)
19#define REG_CTRL_CLKDIV_SHIFT 12
20#define REG_CTRL_CLKDIV_MASK GENMASK(21, 12)
21#define REG_CTRL_CLKDIVEXT_SHIFT 28
22#define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28)
23
24enum {
25 TOKEN_END = 0,
26 TOKEN_START,
27 TOKEN_SLAVE_ADDR_WRITE,
28 TOKEN_SLAVE_ADDR_READ,
29 TOKEN_DATA,
30 TOKEN_DATA_LAST,
31 TOKEN_STOP,
32};
33
34struct i2c_regs {
35 u32 ctrl;
36 u32 slave_addr;
37 u32 tok_list0;
38 u32 tok_list1;
39 u32 tok_wdata0;
40 u32 tok_wdata1;
41 u32 tok_rdata0;
42 u32 tok_rdata1;
43};
44
45struct meson_i2c {
46 struct i2c_regs *regs;
Beniamino Galvani50a69092017-11-26 17:40:57 +010047 struct i2c_msg *msg; /* Current I2C message */
48 bool last; /* Whether the message is the last */
49 uint count; /* Number of bytes in the current transfer */
50 uint pos; /* Position of current transfer in message */
51 u32 tokens[2]; /* Sequence of tokens to be written */
52 uint num_tokens; /* Number of tokens to be written */
Beniamino Galvanif8d9ca12017-10-29 10:09:00 +010053};
54
55static void meson_i2c_reset_tokens(struct meson_i2c *i2c)
56{
57 i2c->tokens[0] = 0;
58 i2c->tokens[1] = 0;
59 i2c->num_tokens = 0;
60}
61
62static void meson_i2c_add_token(struct meson_i2c *i2c, int token)
63{
64 if (i2c->num_tokens < 8)
65 i2c->tokens[0] |= (token & 0xf) << (i2c->num_tokens * 4);
66 else
67 i2c->tokens[1] |= (token & 0xf) << ((i2c->num_tokens % 8) * 4);
68
69 i2c->num_tokens++;
70}
71
Beniamino Galvani50a69092017-11-26 17:40:57 +010072/*
73 * Retrieve data for the current transfer (which can be at most 8
74 * bytes) from the device internal buffer.
75 */
Beniamino Galvanif8d9ca12017-10-29 10:09:00 +010076static void meson_i2c_get_data(struct meson_i2c *i2c, u8 *buf, int len)
77{
78 u32 rdata0, rdata1;
79 int i;
80
81 rdata0 = readl(&i2c->regs->tok_rdata0);
82 rdata1 = readl(&i2c->regs->tok_rdata1);
83
84 debug("meson i2c: read data %08x %08x len %d\n", rdata0, rdata1, len);
85
86 for (i = 0; i < min(4, len); i++)
87 *buf++ = (rdata0 >> i * 8) & 0xff;
88
89 for (i = 4; i < min(8, len); i++)
90 *buf++ = (rdata1 >> (i - 4) * 8) & 0xff;
91}
92
Beniamino Galvani50a69092017-11-26 17:40:57 +010093/*
94 * Write data for the current transfer (which can be at most 8 bytes)
95 * to the device internal buffer.
96 */
Beniamino Galvanif8d9ca12017-10-29 10:09:00 +010097static void meson_i2c_put_data(struct meson_i2c *i2c, u8 *buf, int len)
98{
99 u32 wdata0 = 0, wdata1 = 0;
100 int i;
101
102 for (i = 0; i < min(4, len); i++)
103 wdata0 |= *buf++ << (i * 8);
104
105 for (i = 4; i < min(8, len); i++)
106 wdata1 |= *buf++ << ((i - 4) * 8);
107
108 writel(wdata0, &i2c->regs->tok_wdata0);
109 writel(wdata1, &i2c->regs->tok_wdata1);
110
111 debug("meson i2c: write data %08x %08x len %d\n", wdata0, wdata1, len);
112}
113
Beniamino Galvani50a69092017-11-26 17:40:57 +0100114/*
115 * Prepare the next transfer: pick the next 8 bytes in the remaining
116 * part of message and write tokens and data (if needed) to the
117 * device.
118 */
Beniamino Galvanif8d9ca12017-10-29 10:09:00 +0100119static void meson_i2c_prepare_xfer(struct meson_i2c *i2c)
120{
121 bool write = !(i2c->msg->flags & I2C_M_RD);
122 int i;
123
124 i2c->count = min(i2c->msg->len - i2c->pos, 8u);
125
126 for (i = 0; i + 1 < i2c->count; i++)
127 meson_i2c_add_token(i2c, TOKEN_DATA);
128
129 if (i2c->count) {
130 if (write || i2c->pos + i2c->count < i2c->msg->len)
131 meson_i2c_add_token(i2c, TOKEN_DATA);
132 else
133 meson_i2c_add_token(i2c, TOKEN_DATA_LAST);
134 }
135
136 if (write)
137 meson_i2c_put_data(i2c, i2c->msg->buf + i2c->pos, i2c->count);
138
139 if (i2c->last && i2c->pos + i2c->count >= i2c->msg->len)
140 meson_i2c_add_token(i2c, TOKEN_STOP);
141
142 writel(i2c->tokens[0], &i2c->regs->tok_list0);
143 writel(i2c->tokens[1], &i2c->regs->tok_list1);
144}
145
146static void meson_i2c_do_start(struct meson_i2c *i2c, struct i2c_msg *msg)
147{
148 int token;
149
150 token = (msg->flags & I2C_M_RD) ? TOKEN_SLAVE_ADDR_READ :
151 TOKEN_SLAVE_ADDR_WRITE;
152
153 writel(msg->addr << 1, &i2c->regs->slave_addr);
154 meson_i2c_add_token(i2c, TOKEN_START);
155 meson_i2c_add_token(i2c, token);
156}
157
158static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg,
159 int last)
160{
161 ulong start;
162
163 debug("meson i2c: %s addr %u len %u\n",
164 (msg->flags & I2C_M_RD) ? "read" : "write",
165 msg->addr, msg->len);
166
167 i2c->msg = msg;
168 i2c->last = last;
169 i2c->pos = 0;
170 i2c->count = 0;
171
172 meson_i2c_reset_tokens(i2c);
173 meson_i2c_do_start(i2c, msg);
174
175 do {
176 meson_i2c_prepare_xfer(i2c);
177
178 /* start the transfer */
179 setbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
180 start = get_timer(0);
181 while (readl(&i2c->regs->ctrl) & REG_CTRL_STATUS) {
182 if (get_timer(start) > I2C_TIMEOUT_MS) {
183 clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
184 debug("meson i2c: timeout\n");
185 return -ETIMEDOUT;
186 }
187 udelay(1);
188 }
189 meson_i2c_reset_tokens(i2c);
190 clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
191
192 if (readl(&i2c->regs->ctrl) & REG_CTRL_ERROR) {
193 debug("meson i2c: error\n");
Beniamino Galvani989bb922017-11-26 17:40:56 +0100194 return -EREMOTEIO;
Beniamino Galvanif8d9ca12017-10-29 10:09:00 +0100195 }
196
197 if ((msg->flags & I2C_M_RD) && i2c->count) {
198 meson_i2c_get_data(i2c, i2c->msg->buf + i2c->pos,
199 i2c->count);
200 }
201 i2c->pos += i2c->count;
202 } while (i2c->pos < msg->len);
203
204 return 0;
205}
206
207static int meson_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
208 int nmsgs)
209{
210 struct meson_i2c *i2c = dev_get_priv(bus);
211 int i, ret = 0;
212
213 for (i = 0; i < nmsgs; i++) {
214 ret = meson_i2c_xfer_msg(i2c, msg + i, i == nmsgs - 1);
215 if (ret)
Beniamino Galvani989bb922017-11-26 17:40:56 +0100216 return ret;
Beniamino Galvanif8d9ca12017-10-29 10:09:00 +0100217 }
218
219 return 0;
220}
221
222static int meson_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
223{
224 struct meson_i2c *i2c = dev_get_priv(bus);
225 unsigned int clk_rate = MESON_I2C_CLK_RATE;
226 unsigned int div;
227
228 div = DIV_ROUND_UP(clk_rate, speed * 4);
229
230 /* clock divider has 12 bits */
231 if (div >= (1 << 12)) {
232 debug("meson i2c: requested bus frequency too low\n");
233 div = (1 << 12) - 1;
234 }
235
236 clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIV_MASK,
237 (div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT);
238
239 clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIVEXT_MASK,
240 (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
241
242 debug("meson i2c: set clk %u, src %u, div %u\n", speed, clk_rate, div);
243
244 return 0;
245}
246
247static int meson_i2c_probe(struct udevice *bus)
248{
249 struct meson_i2c *i2c = dev_get_priv(bus);
250
251 i2c->regs = dev_read_addr_ptr(bus);
252 clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
253
254 return 0;
255}
256
257static const struct dm_i2c_ops meson_i2c_ops = {
258 .xfer = meson_i2c_xfer,
259 .set_bus_speed = meson_i2c_set_bus_speed,
260};
261
262static const struct udevice_id meson_i2c_ids[] = {
263 { .compatible = "amlogic,meson6-i2c" },
264 { .compatible = "amlogic,meson-gx-i2c" },
265 { .compatible = "amlogic,meson-gxbb-i2c" },
266 { }
267};
268
269U_BOOT_DRIVER(i2c_meson) = {
270 .name = "i2c_meson",
271 .id = UCLASS_I2C,
272 .of_match = meson_i2c_ids,
273 .probe = meson_i2c_probe,
274 .priv_auto_alloc_size = sizeof(struct meson_i2c),
275 .ops = &meson_i2c_ops,
276};