1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * drivers/i2c/busses/i2c-mt7621.c 4 * 5 * Copyright (C) 2013 Steven Liu <steven_liu@mediatek.com> 6 * Copyright (C) 2016 Michael Lee <igvtee@gmail.com> 7 * Copyright (C) 2018 Jan Breuer <jan.breuer@jaybee.cz> 8 * 9 * Improve driver for i2cdetect from i2c-tools to detect i2c devices on the bus. 10 * (C) 2014 Sittisak <sittisaks@hotmail.com> 11 */ 12 13 #include <linux/clk.h> 14 #include <linux/delay.h> 15 #include <linux/i2c.h> 16 #include <linux/io.h> 17 #include <linux/iopoll.h> 18 #include <linux/module.h> 19 #include <linux/of.h> 20 #include <linux/platform_device.h> 21 #include <linux/reset.h> 22 23 #define REG_SM0CFG2_REG 0x28 24 #define REG_SM0CTL0_REG 0x40 25 #define REG_SM0CTL1_REG 0x44 26 #define REG_SM0D0_REG 0x50 27 #define REG_SM0D1_REG 0x54 28 #define REG_PINTEN_REG 0x5c 29 #define REG_PINTST_REG 0x60 30 #define REG_PINTCL_REG 0x64 31 32 /* REG_SM0CFG2_REG */ 33 #define SM0CFG2_IS_AUTOMODE BIT(0) 34 35 /* REG_SM0CTL0_REG */ 36 #define SM0CTL0_ODRAIN BIT(31) 37 #define SM0CTL0_CLK_DIV_MASK (0x7ff << 16) 38 #define SM0CTL0_CLK_DIV_MAX 0x7ff 39 #define SM0CTL0_CS_STATUS BIT(4) 40 #define SM0CTL0_SCL_STATE BIT(3) 41 #define SM0CTL0_SDA_STATE BIT(2) 42 #define SM0CTL0_EN BIT(1) 43 #define SM0CTL0_SCL_STRETCH BIT(0) 44 45 /* REG_SM0CTL1_REG */ 46 #define SM0CTL1_ACK_MASK (0xff << 16) 47 #define SM0CTL1_PGLEN_MASK (0x7 << 8) 48 #define SM0CTL1_PGLEN(x) ((((x) - 1) << 8) & SM0CTL1_PGLEN_MASK) 49 #define SM0CTL1_READ (5 << 4) 50 #define SM0CTL1_READ_LAST (4 << 4) 51 #define SM0CTL1_STOP (3 << 4) 52 #define SM0CTL1_WRITE (2 << 4) 53 #define SM0CTL1_START (1 << 4) 54 #define SM0CTL1_MODE_MASK (0x7 << 4) 55 #define SM0CTL1_TRI BIT(0) 56 57 /* timeout waiting for I2C devices to respond */ 58 #define TIMEOUT_MS 1000 59 60 struct mtk_i2c { 61 void __iomem *base; 62 struct device *dev; 63 struct i2c_adapter adap; 64 u32 bus_freq; 65 u32 clk_div; 66 u32 flags; 67 struct clk *clk; 68 }; 69 70 static int mtk_i2c_wait_idle(struct mtk_i2c *i2c) 71 { 72 int ret; 73 u32 val; 74 75 ret = readl_relaxed_poll_timeout(i2c->base + REG_SM0CTL1_REG, 76 val, !(val & SM0CTL1_TRI), 77 10, TIMEOUT_MS * 1000); 78 if (ret) 79 dev_dbg(i2c->dev, "idle err(%d)\n", ret); 80 81 return ret; 82 } 83 84 static void mtk_i2c_reset(struct mtk_i2c *i2c) 85 { 86 int ret; 87 88 ret = device_reset(i2c->adap.dev.parent); 89 if (ret) 90 dev_err(i2c->dev, "I2C reset failed!\n"); 91 92 /* 93 * Don't set SM0CTL0_ODRAIN as its bit meaning is inverted. To 94 * configure open-drain mode, this bit needs to be cleared. 95 */ 96 iowrite32(((i2c->clk_div << 16) & SM0CTL0_CLK_DIV_MASK) | SM0CTL0_EN | 97 SM0CTL0_SCL_STRETCH, i2c->base + REG_SM0CTL0_REG); 98 iowrite32(0, i2c->base + REG_SM0CFG2_REG); 99 } 100 101 static void mtk_i2c_dump_reg(struct mtk_i2c *i2c) 102 { 103 dev_dbg(i2c->dev, 104 "SM0CFG2 %08x, SM0CTL0 %08x, SM0CTL1 %08x, SM0D0 %08x, SM0D1 %08x\n", 105 ioread32(i2c->base + REG_SM0CFG2_REG), 106 ioread32(i2c->base + REG_SM0CTL0_REG), 107 ioread32(i2c->base + REG_SM0CTL1_REG), 108 ioread32(i2c->base + REG_SM0D0_REG), 109 ioread32(i2c->base + REG_SM0D1_REG)); 110 } 111 112 static int mtk_i2c_check_ack(struct mtk_i2c *i2c, u32 expected) 113 { 114 u32 ack = readl_relaxed(i2c->base + REG_SM0CTL1_REG); 115 u32 ack_expected = (expected << 16) & SM0CTL1_ACK_MASK; 116 117 return ((ack & ack_expected) == ack_expected) ? 0 : -ENXIO; 118 } 119 120 static int mtk_i2c_start(struct mtk_i2c *i2c) 121 { 122 iowrite32(SM0CTL1_START | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG); 123 return mtk_i2c_wait_idle(i2c); 124 } 125 126 static int mtk_i2c_stop(struct mtk_i2c *i2c) 127 { 128 iowrite32(SM0CTL1_STOP | SM0CTL1_TRI, i2c->base + REG_SM0CTL1_REG); 129 return mtk_i2c_wait_idle(i2c); 130 } 131 132 static int mtk_i2c_cmd(struct mtk_i2c *i2c, u32 cmd, int page_len) 133 { 134 iowrite32(cmd | SM0CTL1_TRI | SM0CTL1_PGLEN(page_len), 135 i2c->base + REG_SM0CTL1_REG); 136 return mtk_i2c_wait_idle(i2c); 137 } 138 139 static int mtk_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, 140 int num) 141 { 142 struct mtk_i2c *i2c; 143 struct i2c_msg *pmsg; 144 u16 addr; 145 int i, j, ret, len, page_len; 146 u32 cmd; 147 u32 data[2]; 148 149 i2c = i2c_get_adapdata(adap); 150 151 for (i = 0; i < num; i++) { 152 pmsg = &msgs[i]; 153 154 /* wait hardware idle */ 155 ret = mtk_i2c_wait_idle(i2c); 156 if (ret) 157 goto err_timeout; 158 159 /* start sequence */ 160 ret = mtk_i2c_start(i2c); 161 if (ret) 162 goto err_timeout; 163 164 /* write address */ 165 if (pmsg->flags & I2C_M_TEN) { 166 /* 10 bits address */ 167 addr = 0xf0 | ((pmsg->addr >> 7) & 0x06); 168 addr |= (pmsg->addr & 0xff) << 8; 169 if (pmsg->flags & I2C_M_RD) 170 addr |= 1; 171 iowrite32(addr, i2c->base + REG_SM0D0_REG); 172 ret = mtk_i2c_cmd(i2c, SM0CTL1_WRITE, 2); 173 if (ret) 174 goto err_timeout; 175 } else { 176 /* 7 bits address */ 177 addr = i2c_8bit_addr_from_msg(pmsg); 178 iowrite32(addr, i2c->base + REG_SM0D0_REG); 179 ret = mtk_i2c_cmd(i2c, SM0CTL1_WRITE, 1); 180 if (ret) 181 goto err_timeout; 182 } 183 184 /* check address ACK */ 185 if (!(pmsg->flags & I2C_M_IGNORE_NAK)) { 186 ret = mtk_i2c_check_ack(i2c, BIT(0)); 187 if (ret) 188 goto err_ack; 189 } 190 191 /* transfer data */ 192 for (len = pmsg->len, j = 0; len > 0; len -= 8, j += 8) { 193 page_len = (len >= 8) ? 8 : len; 194 195 if (pmsg->flags & I2C_M_RD) { 196 cmd = (len > 8) ? 197 SM0CTL1_READ : SM0CTL1_READ_LAST; 198 } else { 199 memcpy(data, &pmsg->buf[j], page_len); 200 iowrite32(data[0], i2c->base + REG_SM0D0_REG); 201 iowrite32(data[1], i2c->base + REG_SM0D1_REG); 202 cmd = SM0CTL1_WRITE; 203 } 204 205 ret = mtk_i2c_cmd(i2c, cmd, page_len); 206 if (ret) 207 goto err_timeout; 208 209 if (pmsg->flags & I2C_M_RD) { 210 data[0] = ioread32(i2c->base + REG_SM0D0_REG); 211 data[1] = ioread32(i2c->base + REG_SM0D1_REG); 212 memcpy(&pmsg->buf[j], data, page_len); 213 } else { 214 if (!(pmsg->flags & I2C_M_IGNORE_NAK)) { 215 ret = mtk_i2c_check_ack(i2c, 216 (1 << page_len) 217 - 1); 218 if (ret) 219 goto err_ack; 220 } 221 } 222 } 223 } 224 225 ret = mtk_i2c_stop(i2c); 226 if (ret) 227 goto err_timeout; 228 229 /* the return value is number of executed messages */ 230 return i; 231 232 err_ack: 233 ret = mtk_i2c_stop(i2c); 234 if (ret) 235 goto err_timeout; 236 return -ENXIO; 237 238 err_timeout: 239 mtk_i2c_dump_reg(i2c); 240 mtk_i2c_reset(i2c); 241 return ret; 242 } 243 244 static u32 mtk_i2c_func(struct i2c_adapter *a) 245 { 246 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING; 247 } 248 249 static const struct i2c_algorithm mtk_i2c_algo = { 250 .xfer = mtk_i2c_xfer, 251 .functionality = mtk_i2c_func, 252 }; 253 254 static const struct of_device_id i2c_mtk_dt_ids[] = { 255 { .compatible = "mediatek,mt7621-i2c" }, 256 { /* sentinel */ } 257 }; 258 259 MODULE_DEVICE_TABLE(of, i2c_mtk_dt_ids); 260 261 static void mtk_i2c_init(struct mtk_i2c *i2c) 262 { 263 i2c->clk_div = clk_get_rate(i2c->clk) / i2c->bus_freq - 1; 264 if (i2c->clk_div < 99) 265 i2c->clk_div = 99; 266 if (i2c->clk_div > SM0CTL0_CLK_DIV_MAX) 267 i2c->clk_div = SM0CTL0_CLK_DIV_MAX; 268 269 mtk_i2c_reset(i2c); 270 } 271 272 static int mtk_i2c_probe(struct platform_device *pdev) 273 { 274 struct mtk_i2c *i2c; 275 struct i2c_adapter *adap; 276 int ret; 277 278 i2c = devm_kzalloc(&pdev->dev, sizeof(struct mtk_i2c), GFP_KERNEL); 279 if (!i2c) 280 return -ENOMEM; 281 282 i2c->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); 283 if (IS_ERR(i2c->base)) 284 return PTR_ERR(i2c->base); 285 286 i2c->clk = devm_clk_get_enabled(&pdev->dev, NULL); 287 if (IS_ERR(i2c->clk)) { 288 dev_err(&pdev->dev, "Failed to enable clock\n"); 289 return PTR_ERR(i2c->clk); 290 } 291 292 i2c->dev = &pdev->dev; 293 294 if (of_property_read_u32(pdev->dev.of_node, "clock-frequency", 295 &i2c->bus_freq)) 296 i2c->bus_freq = I2C_MAX_STANDARD_MODE_FREQ; 297 298 if (i2c->bus_freq == 0) { 299 dev_warn(i2c->dev, "clock-frequency 0 not supported\n"); 300 return -EINVAL; 301 } 302 303 adap = &i2c->adap; 304 adap->owner = THIS_MODULE; 305 adap->algo = &mtk_i2c_algo; 306 adap->retries = 3; 307 adap->dev.parent = &pdev->dev; 308 i2c_set_adapdata(adap, i2c); 309 adap->dev.of_node = pdev->dev.of_node; 310 strscpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name)); 311 312 platform_set_drvdata(pdev, i2c); 313 314 mtk_i2c_init(i2c); 315 316 ret = i2c_add_adapter(adap); 317 if (ret < 0) 318 return ret; 319 320 dev_info(&pdev->dev, "clock %u kHz\n", i2c->bus_freq / 1000); 321 322 return 0; 323 } 324 325 static void mtk_i2c_remove(struct platform_device *pdev) 326 { 327 struct mtk_i2c *i2c = platform_get_drvdata(pdev); 328 329 i2c_del_adapter(&i2c->adap); 330 } 331 332 static struct platform_driver mtk_i2c_driver = { 333 .probe = mtk_i2c_probe, 334 .remove_new = mtk_i2c_remove, 335 .driver = { 336 .name = "i2c-mt7621", 337 .of_match_table = i2c_mtk_dt_ids, 338 }, 339 }; 340 341 module_platform_driver(mtk_i2c_driver); 342 343 MODULE_AUTHOR("Steven Liu"); 344 MODULE_DESCRIPTION("MT7621 I2C host driver"); 345 MODULE_LICENSE("GPL v2"); 346 MODULE_ALIAS("platform:MT7621-I2C"); 347