1 // SPDX-License-Identifier: GPL-2.0+
3 * (C) Copyright 2017 - Beniamino Galvani <b.galvani@gmail.com>
11 #include <linux/err.h>
13 #define I2C_TIMEOUT_MS 100
15 /* Control register fields */
16 #define REG_CTRL_START BIT(0)
17 #define REG_CTRL_ACK_IGNORE BIT(1)
18 #define REG_CTRL_STATUS BIT(2)
19 #define REG_CTRL_ERROR BIT(3)
20 #define REG_CTRL_CLKDIV_SHIFT 12
21 #define REG_CTRL_CLKDIV_MASK GENMASK(21, 12)
22 #define REG_CTRL_CLKDIVEXT_SHIFT 28
23 #define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28)
28 TOKEN_SLAVE_ADDR_WRITE,
29 TOKEN_SLAVE_ADDR_READ,
46 struct meson_i2c_data {
47 unsigned char div_factor;
51 const struct meson_i2c_data *data;
53 struct i2c_regs *regs;
54 struct i2c_msg *msg; /* Current I2C message */
55 bool last; /* Whether the message is the last */
56 uint count; /* Number of bytes in the current transfer */
57 uint pos; /* Position of current transfer in message */
58 u32 tokens[2]; /* Sequence of tokens to be written */
59 uint num_tokens; /* Number of tokens to be written */
62 static void meson_i2c_reset_tokens(struct meson_i2c *i2c)
69 static void meson_i2c_add_token(struct meson_i2c *i2c, int token)
71 if (i2c->num_tokens < 8)
72 i2c->tokens[0] |= (token & 0xf) << (i2c->num_tokens * 4);
74 i2c->tokens[1] |= (token & 0xf) << ((i2c->num_tokens % 8) * 4);
80 * Retrieve data for the current transfer (which can be at most 8
81 * bytes) from the device internal buffer.
83 static void meson_i2c_get_data(struct meson_i2c *i2c, u8 *buf, int len)
88 rdata0 = readl(&i2c->regs->tok_rdata0);
89 rdata1 = readl(&i2c->regs->tok_rdata1);
91 debug("meson i2c: read data %08x %08x len %d\n", rdata0, rdata1, len);
93 for (i = 0; i < min(4, len); i++)
94 *buf++ = (rdata0 >> i * 8) & 0xff;
96 for (i = 4; i < min(8, len); i++)
97 *buf++ = (rdata1 >> (i - 4) * 8) & 0xff;
101 * Write data for the current transfer (which can be at most 8 bytes)
102 * to the device internal buffer.
104 static void meson_i2c_put_data(struct meson_i2c *i2c, u8 *buf, int len)
106 u32 wdata0 = 0, wdata1 = 0;
109 for (i = 0; i < min(4, len); i++)
110 wdata0 |= *buf++ << (i * 8);
112 for (i = 4; i < min(8, len); i++)
113 wdata1 |= *buf++ << ((i - 4) * 8);
115 writel(wdata0, &i2c->regs->tok_wdata0);
116 writel(wdata1, &i2c->regs->tok_wdata1);
118 debug("meson i2c: write data %08x %08x len %d\n", wdata0, wdata1, len);
122 * Prepare the next transfer: pick the next 8 bytes in the remaining
123 * part of message and write tokens and data (if needed) to the
126 static void meson_i2c_prepare_xfer(struct meson_i2c *i2c)
128 bool write = !(i2c->msg->flags & I2C_M_RD);
131 i2c->count = min(i2c->msg->len - i2c->pos, 8u);
133 for (i = 0; i + 1 < i2c->count; i++)
134 meson_i2c_add_token(i2c, TOKEN_DATA);
137 if (write || i2c->pos + i2c->count < i2c->msg->len)
138 meson_i2c_add_token(i2c, TOKEN_DATA);
140 meson_i2c_add_token(i2c, TOKEN_DATA_LAST);
144 meson_i2c_put_data(i2c, i2c->msg->buf + i2c->pos, i2c->count);
146 if (i2c->last && i2c->pos + i2c->count >= i2c->msg->len)
147 meson_i2c_add_token(i2c, TOKEN_STOP);
149 writel(i2c->tokens[0], &i2c->regs->tok_list0);
150 writel(i2c->tokens[1], &i2c->regs->tok_list1);
153 static void meson_i2c_do_start(struct meson_i2c *i2c, struct i2c_msg *msg)
157 token = (msg->flags & I2C_M_RD) ? TOKEN_SLAVE_ADDR_READ :
158 TOKEN_SLAVE_ADDR_WRITE;
160 writel(msg->addr << 1, &i2c->regs->slave_addr);
161 meson_i2c_add_token(i2c, TOKEN_START);
162 meson_i2c_add_token(i2c, token);
165 static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg,
170 debug("meson i2c: %s addr %u len %u\n",
171 (msg->flags & I2C_M_RD) ? "read" : "write",
172 msg->addr, msg->len);
179 meson_i2c_reset_tokens(i2c);
180 meson_i2c_do_start(i2c, msg);
183 meson_i2c_prepare_xfer(i2c);
185 /* start the transfer */
186 setbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
187 start = get_timer(0);
188 while (readl(&i2c->regs->ctrl) & REG_CTRL_STATUS) {
189 if (get_timer(start) > I2C_TIMEOUT_MS) {
190 clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
191 debug("meson i2c: timeout\n");
196 meson_i2c_reset_tokens(i2c);
197 clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
199 if (readl(&i2c->regs->ctrl) & REG_CTRL_ERROR) {
200 debug("meson i2c: error\n");
204 if ((msg->flags & I2C_M_RD) && i2c->count) {
205 meson_i2c_get_data(i2c, i2c->msg->buf + i2c->pos,
208 i2c->pos += i2c->count;
209 } while (i2c->pos < msg->len);
214 static int meson_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
217 struct meson_i2c *i2c = dev_get_priv(bus);
220 for (i = 0; i < nmsgs; i++) {
221 ret = meson_i2c_xfer_msg(i2c, msg + i, i == nmsgs - 1);
229 static int meson_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
231 struct meson_i2c *i2c = dev_get_priv(bus);
235 clk_rate = clk_get_rate(&i2c->clk);
236 if (IS_ERR_VALUE(clk_rate))
239 div = DIV_ROUND_UP(clk_rate, speed * i2c->data->div_factor);
241 /* clock divider has 12 bits */
242 if (div >= (1 << 12)) {
243 debug("meson i2c: requested bus frequency too low\n");
247 clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIV_MASK,
248 (div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT);
250 clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIVEXT_MASK,
251 (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
253 debug("meson i2c: set clk %u, src %lu, div %u\n", speed, clk_rate, div);
258 static int meson_i2c_probe(struct udevice *bus)
260 struct meson_i2c *i2c = dev_get_priv(bus);
263 i2c->data = (const struct meson_i2c_data *)dev_get_driver_data(bus);
265 ret = clk_get_by_index(bus, 0, &i2c->clk);
269 ret = clk_enable(&i2c->clk);
273 i2c->regs = dev_read_addr_ptr(bus);
274 clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START);
279 static const struct dm_i2c_ops meson_i2c_ops = {
280 .xfer = meson_i2c_xfer,
281 .set_bus_speed = meson_i2c_set_bus_speed,
284 static const struct meson_i2c_data i2c_meson6_data = {
288 static const struct meson_i2c_data i2c_gxbb_data = {
292 static const struct meson_i2c_data i2c_axg_data = {
296 static const struct udevice_id meson_i2c_ids[] = {
297 {.compatible = "amlogic,meson6-i2c", .data = (ulong)&i2c_meson6_data},
298 {.compatible = "amlogic,meson-gx-i2c", .data = (ulong)&i2c_gxbb_data},
299 {.compatible = "amlogic,meson-gxbb-i2c", .data = (ulong)&i2c_gxbb_data},
300 {.compatible = "amlogic,meson-axg-i2c", .data = (ulong)&i2c_axg_data},
304 U_BOOT_DRIVER(i2c_meson) = {
307 .of_match = meson_i2c_ids,
308 .probe = meson_i2c_probe,
309 .priv_auto_alloc_size = sizeof(struct meson_i2c),
310 .ops = &meson_i2c_ops,