1 /* 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 12 #define I2C_TIMEOUT_MS 100 13 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 24 enum { 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 34 struct 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 45 struct meson_i2c { 46 struct i2c_regs *regs; 47 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 */ 53 }; 54 55 static 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 62 static 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 72 /* 73 * Retrieve data for the current transfer (which can be at most 8 74 * bytes) from the device internal buffer. 75 */ 76 static 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 93 /* 94 * Write data for the current transfer (which can be at most 8 bytes) 95 * to the device internal buffer. 96 */ 97 static 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 } 113 114 /* 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 */ 119 static 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 } 145 146 static 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 } 157 158 static 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"); 194 return -EREMOTEIO; 195 } 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 } 206 207 static 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) 216 return ret; 217 } 218 219 return 0; 220 } 221 222 static 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 } 246 247 static 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 } 256 257 static const struct dm_i2c_ops meson_i2c_ops = { 258 .xfer = meson_i2c_xfer, 259 .set_bus_speed = meson_i2c_set_bus_speed, 260 }; 261 262 static 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 }; 268 269 U_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 }; 277