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 500 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; 48 bool last; 49 uint count; 50 uint pos; 51 u32 tokens[2]; 52 uint num_tokens; 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 static void meson_i2c_get_data(struct meson_i2c *i2c, u8 *buf, int len) 73 { 74 u32 rdata0, rdata1; 75 int i; 76 77 rdata0 = readl(&i2c->regs->tok_rdata0); 78 rdata1 = readl(&i2c->regs->tok_rdata1); 79 80 debug("meson i2c: read data %08x %08x len %d\n", rdata0, rdata1, len); 81 82 for (i = 0; i < min(4, len); i++) 83 *buf++ = (rdata0 >> i * 8) & 0xff; 84 85 for (i = 4; i < min(8, len); i++) 86 *buf++ = (rdata1 >> (i - 4) * 8) & 0xff; 87 } 88 89 static void meson_i2c_put_data(struct meson_i2c *i2c, u8 *buf, int len) 90 { 91 u32 wdata0 = 0, wdata1 = 0; 92 int i; 93 94 for (i = 0; i < min(4, len); i++) 95 wdata0 |= *buf++ << (i * 8); 96 97 for (i = 4; i < min(8, len); i++) 98 wdata1 |= *buf++ << ((i - 4) * 8); 99 100 writel(wdata0, &i2c->regs->tok_wdata0); 101 writel(wdata1, &i2c->regs->tok_wdata1); 102 103 debug("meson i2c: write data %08x %08x len %d\n", wdata0, wdata1, len); 104 } 105 106 static void meson_i2c_prepare_xfer(struct meson_i2c *i2c) 107 { 108 bool write = !(i2c->msg->flags & I2C_M_RD); 109 int i; 110 111 i2c->count = min(i2c->msg->len - i2c->pos, 8u); 112 113 for (i = 0; i + 1 < i2c->count; i++) 114 meson_i2c_add_token(i2c, TOKEN_DATA); 115 116 if (i2c->count) { 117 if (write || i2c->pos + i2c->count < i2c->msg->len) 118 meson_i2c_add_token(i2c, TOKEN_DATA); 119 else 120 meson_i2c_add_token(i2c, TOKEN_DATA_LAST); 121 } 122 123 if (write) 124 meson_i2c_put_data(i2c, i2c->msg->buf + i2c->pos, i2c->count); 125 126 if (i2c->last && i2c->pos + i2c->count >= i2c->msg->len) 127 meson_i2c_add_token(i2c, TOKEN_STOP); 128 129 writel(i2c->tokens[0], &i2c->regs->tok_list0); 130 writel(i2c->tokens[1], &i2c->regs->tok_list1); 131 } 132 133 static void meson_i2c_do_start(struct meson_i2c *i2c, struct i2c_msg *msg) 134 { 135 int token; 136 137 token = (msg->flags & I2C_M_RD) ? TOKEN_SLAVE_ADDR_READ : 138 TOKEN_SLAVE_ADDR_WRITE; 139 140 writel(msg->addr << 1, &i2c->regs->slave_addr); 141 meson_i2c_add_token(i2c, TOKEN_START); 142 meson_i2c_add_token(i2c, token); 143 } 144 145 static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg, 146 int last) 147 { 148 ulong start; 149 150 debug("meson i2c: %s addr %u len %u\n", 151 (msg->flags & I2C_M_RD) ? "read" : "write", 152 msg->addr, msg->len); 153 154 i2c->msg = msg; 155 i2c->last = last; 156 i2c->pos = 0; 157 i2c->count = 0; 158 159 meson_i2c_reset_tokens(i2c); 160 meson_i2c_do_start(i2c, msg); 161 162 do { 163 meson_i2c_prepare_xfer(i2c); 164 165 /* start the transfer */ 166 setbits_le32(&i2c->regs->ctrl, REG_CTRL_START); 167 start = get_timer(0); 168 while (readl(&i2c->regs->ctrl) & REG_CTRL_STATUS) { 169 if (get_timer(start) > I2C_TIMEOUT_MS) { 170 clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START); 171 debug("meson i2c: timeout\n"); 172 return -ETIMEDOUT; 173 } 174 udelay(1); 175 } 176 meson_i2c_reset_tokens(i2c); 177 clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START); 178 179 if (readl(&i2c->regs->ctrl) & REG_CTRL_ERROR) { 180 debug("meson i2c: error\n"); 181 return -ENXIO; 182 } 183 184 if ((msg->flags & I2C_M_RD) && i2c->count) { 185 meson_i2c_get_data(i2c, i2c->msg->buf + i2c->pos, 186 i2c->count); 187 } 188 i2c->pos += i2c->count; 189 } while (i2c->pos < msg->len); 190 191 return 0; 192 } 193 194 static int meson_i2c_xfer(struct udevice *bus, struct i2c_msg *msg, 195 int nmsgs) 196 { 197 struct meson_i2c *i2c = dev_get_priv(bus); 198 int i, ret = 0; 199 200 for (i = 0; i < nmsgs; i++) { 201 ret = meson_i2c_xfer_msg(i2c, msg + i, i == nmsgs - 1); 202 if (ret) 203 return -EREMOTEIO; 204 } 205 206 return 0; 207 } 208 209 static int meson_i2c_set_bus_speed(struct udevice *bus, unsigned int speed) 210 { 211 struct meson_i2c *i2c = dev_get_priv(bus); 212 unsigned int clk_rate = MESON_I2C_CLK_RATE; 213 unsigned int div; 214 215 div = DIV_ROUND_UP(clk_rate, speed * 4); 216 217 /* clock divider has 12 bits */ 218 if (div >= (1 << 12)) { 219 debug("meson i2c: requested bus frequency too low\n"); 220 div = (1 << 12) - 1; 221 } 222 223 clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIV_MASK, 224 (div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT); 225 226 clrsetbits_le32(&i2c->regs->ctrl, REG_CTRL_CLKDIVEXT_MASK, 227 (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT); 228 229 debug("meson i2c: set clk %u, src %u, div %u\n", speed, clk_rate, div); 230 231 return 0; 232 } 233 234 static int meson_i2c_probe(struct udevice *bus) 235 { 236 struct meson_i2c *i2c = dev_get_priv(bus); 237 238 i2c->regs = dev_read_addr_ptr(bus); 239 clrbits_le32(&i2c->regs->ctrl, REG_CTRL_START); 240 241 return 0; 242 } 243 244 static const struct dm_i2c_ops meson_i2c_ops = { 245 .xfer = meson_i2c_xfer, 246 .set_bus_speed = meson_i2c_set_bus_speed, 247 }; 248 249 static const struct udevice_id meson_i2c_ids[] = { 250 { .compatible = "amlogic,meson6-i2c" }, 251 { .compatible = "amlogic,meson-gx-i2c" }, 252 { .compatible = "amlogic,meson-gxbb-i2c" }, 253 { } 254 }; 255 256 U_BOOT_DRIVER(i2c_meson) = { 257 .name = "i2c_meson", 258 .id = UCLASS_I2C, 259 .of_match = meson_i2c_ids, 260 .probe = meson_i2c_probe, 261 .priv_auto_alloc_size = sizeof(struct meson_i2c), 262 .ops = &meson_i2c_ops, 263 }; 264