Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 1 | /* |
| 2 | * I2C driver for the Renesas EMEV2 SoC |
| 3 | * |
| 4 | * Copyright (C) 2015 Wolfram Sang <wsa@sang-engineering.com> |
| 5 | * Copyright 2013 Codethink Ltd. |
| 6 | * Copyright 2010-2015 Renesas Electronics Corporation |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License version 2 |
| 10 | * as published by the Free Software Foundation. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/clk.h> |
| 14 | #include <linux/completion.h> |
| 15 | #include <linux/device.h> |
| 16 | #include <linux/i2c.h> |
| 17 | #include <linux/init.h> |
| 18 | #include <linux/interrupt.h> |
| 19 | #include <linux/io.h> |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/of_device.h> |
| 23 | #include <linux/platform_device.h> |
| 24 | #include <linux/sched.h> |
| 25 | |
| 26 | /* I2C Registers */ |
| 27 | #define I2C_OFS_IICACT0 0x00 /* start */ |
| 28 | #define I2C_OFS_IIC0 0x04 /* shift */ |
| 29 | #define I2C_OFS_IICC0 0x08 /* control */ |
| 30 | #define I2C_OFS_SVA0 0x0c /* slave address */ |
| 31 | #define I2C_OFS_IICCL0 0x10 /* clock select */ |
| 32 | #define I2C_OFS_IICX0 0x14 /* extension */ |
| 33 | #define I2C_OFS_IICS0 0x18 /* status */ |
| 34 | #define I2C_OFS_IICSE0 0x1c /* status For emulation */ |
| 35 | #define I2C_OFS_IICF0 0x20 /* IIC flag */ |
| 36 | |
| 37 | /* I2C IICACT0 Masks */ |
| 38 | #define I2C_BIT_IICE0 0x0001 |
| 39 | |
| 40 | /* I2C IICC0 Masks */ |
| 41 | #define I2C_BIT_LREL0 0x0040 |
| 42 | #define I2C_BIT_WREL0 0x0020 |
| 43 | #define I2C_BIT_SPIE0 0x0010 |
| 44 | #define I2C_BIT_WTIM0 0x0008 |
| 45 | #define I2C_BIT_ACKE0 0x0004 |
| 46 | #define I2C_BIT_STT0 0x0002 |
| 47 | #define I2C_BIT_SPT0 0x0001 |
| 48 | |
| 49 | /* I2C IICCL0 Masks */ |
| 50 | #define I2C_BIT_SMC0 0x0008 |
| 51 | #define I2C_BIT_DFC0 0x0004 |
| 52 | |
| 53 | /* I2C IICSE0 Masks */ |
| 54 | #define I2C_BIT_MSTS0 0x0080 |
| 55 | #define I2C_BIT_ALD0 0x0040 |
| 56 | #define I2C_BIT_EXC0 0x0020 |
| 57 | #define I2C_BIT_COI0 0x0010 |
| 58 | #define I2C_BIT_TRC0 0x0008 |
| 59 | #define I2C_BIT_ACKD0 0x0004 |
| 60 | #define I2C_BIT_STD0 0x0002 |
| 61 | #define I2C_BIT_SPD0 0x0001 |
| 62 | |
| 63 | /* I2C IICF0 Masks */ |
| 64 | #define I2C_BIT_STCF 0x0080 |
| 65 | #define I2C_BIT_IICBSY 0x0040 |
| 66 | #define I2C_BIT_STCEN 0x0002 |
| 67 | #define I2C_BIT_IICRSV 0x0001 |
| 68 | |
| 69 | struct em_i2c_device { |
| 70 | void __iomem *base; |
| 71 | struct i2c_adapter adap; |
| 72 | struct completion msg_done; |
| 73 | struct clk *sclk; |
Niklas Söderlund | c31d0a0 | 2015-12-05 18:51:31 +0100 | [diff] [blame] | 74 | struct i2c_client *slave; |
Wolfram Sang | 1fe671b | 2019-08-08 21:54:17 +0200 | [diff] [blame^] | 75 | int irq; |
Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 76 | }; |
| 77 | |
| 78 | static inline void em_clear_set_bit(struct em_i2c_device *priv, u8 clear, u8 set, u8 reg) |
| 79 | { |
| 80 | writeb((readb(priv->base + reg) & ~clear) | set, priv->base + reg); |
| 81 | } |
| 82 | |
| 83 | static int em_i2c_wait_for_event(struct em_i2c_device *priv) |
| 84 | { |
| 85 | unsigned long time_left; |
| 86 | int status; |
| 87 | |
| 88 | reinit_completion(&priv->msg_done); |
| 89 | |
| 90 | time_left = wait_for_completion_timeout(&priv->msg_done, priv->adap.timeout); |
| 91 | |
| 92 | if (!time_left) |
| 93 | return -ETIMEDOUT; |
| 94 | |
| 95 | status = readb(priv->base + I2C_OFS_IICSE0); |
| 96 | return status & I2C_BIT_ALD0 ? -EAGAIN : status; |
| 97 | } |
| 98 | |
| 99 | static void em_i2c_stop(struct em_i2c_device *priv) |
| 100 | { |
| 101 | /* Send Stop condition */ |
| 102 | em_clear_set_bit(priv, 0, I2C_BIT_SPT0 | I2C_BIT_SPIE0, I2C_OFS_IICC0); |
| 103 | |
| 104 | /* Wait for stop condition */ |
| 105 | em_i2c_wait_for_event(priv); |
| 106 | } |
| 107 | |
| 108 | static void em_i2c_reset(struct i2c_adapter *adap) |
| 109 | { |
| 110 | struct em_i2c_device *priv = i2c_get_adapdata(adap); |
| 111 | int retr; |
| 112 | |
| 113 | /* If I2C active */ |
| 114 | if (readb(priv->base + I2C_OFS_IICACT0) & I2C_BIT_IICE0) { |
| 115 | /* Disable I2C operation */ |
| 116 | writeb(0, priv->base + I2C_OFS_IICACT0); |
| 117 | |
| 118 | retr = 1000; |
| 119 | while (readb(priv->base + I2C_OFS_IICACT0) == 1 && retr) |
| 120 | retr--; |
| 121 | WARN_ON(retr == 0); |
| 122 | } |
| 123 | |
| 124 | /* Transfer mode set */ |
| 125 | writeb(I2C_BIT_DFC0, priv->base + I2C_OFS_IICCL0); |
| 126 | |
| 127 | /* Can Issue start without detecting a stop, Reservation disabled. */ |
| 128 | writeb(I2C_BIT_STCEN | I2C_BIT_IICRSV, priv->base + I2C_OFS_IICF0); |
| 129 | |
| 130 | /* I2C enable, 9 bit interrupt mode */ |
| 131 | writeb(I2C_BIT_WTIM0, priv->base + I2C_OFS_IICC0); |
| 132 | |
| 133 | /* Enable I2C operation */ |
| 134 | writeb(I2C_BIT_IICE0, priv->base + I2C_OFS_IICACT0); |
| 135 | |
| 136 | retr = 1000; |
| 137 | while (readb(priv->base + I2C_OFS_IICACT0) == 0 && retr) |
| 138 | retr--; |
| 139 | WARN_ON(retr == 0); |
| 140 | } |
| 141 | |
| 142 | static int __em_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, |
| 143 | int stop) |
| 144 | { |
| 145 | struct em_i2c_device *priv = i2c_get_adapdata(adap); |
| 146 | int count, status, read = !!(msg->flags & I2C_M_RD); |
| 147 | |
| 148 | /* Send start condition */ |
| 149 | em_clear_set_bit(priv, 0, I2C_BIT_ACKE0 | I2C_BIT_WTIM0, I2C_OFS_IICC0); |
| 150 | em_clear_set_bit(priv, 0, I2C_BIT_STT0, I2C_OFS_IICC0); |
| 151 | |
| 152 | /* Send slave address and R/W type */ |
| 153 | writeb((msg->addr << 1) | read, priv->base + I2C_OFS_IIC0); |
| 154 | |
| 155 | /* Wait for transaction */ |
| 156 | status = em_i2c_wait_for_event(priv); |
| 157 | if (status < 0) |
| 158 | goto out_reset; |
| 159 | |
| 160 | /* Received NACK (result of setting slave address and R/W) */ |
| 161 | if (!(status & I2C_BIT_ACKD0)) { |
| 162 | em_i2c_stop(priv); |
| 163 | goto out; |
| 164 | } |
| 165 | |
| 166 | /* Extra setup for read transactions */ |
| 167 | if (read) { |
| 168 | /* 8 bit interrupt mode */ |
| 169 | em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_ACKE0, I2C_OFS_IICC0); |
| 170 | em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_WREL0, I2C_OFS_IICC0); |
| 171 | |
| 172 | /* Wait for transaction */ |
| 173 | status = em_i2c_wait_for_event(priv); |
| 174 | if (status < 0) |
| 175 | goto out_reset; |
| 176 | } |
| 177 | |
| 178 | /* Send / receive data */ |
| 179 | for (count = 0; count < msg->len; count++) { |
| 180 | if (read) { /* Read transaction */ |
| 181 | msg->buf[count] = readb(priv->base + I2C_OFS_IIC0); |
| 182 | em_clear_set_bit(priv, 0, I2C_BIT_WREL0, I2C_OFS_IICC0); |
| 183 | |
| 184 | } else { /* Write transaction */ |
| 185 | /* Received NACK */ |
| 186 | if (!(status & I2C_BIT_ACKD0)) { |
| 187 | em_i2c_stop(priv); |
| 188 | goto out; |
| 189 | } |
| 190 | |
| 191 | /* Write data */ |
| 192 | writeb(msg->buf[count], priv->base + I2C_OFS_IIC0); |
| 193 | } |
| 194 | |
| 195 | /* Wait for R/W transaction */ |
| 196 | status = em_i2c_wait_for_event(priv); |
| 197 | if (status < 0) |
| 198 | goto out_reset; |
| 199 | } |
| 200 | |
| 201 | if (stop) |
| 202 | em_i2c_stop(priv); |
| 203 | |
| 204 | return count; |
| 205 | |
| 206 | out_reset: |
| 207 | em_i2c_reset(adap); |
| 208 | out: |
| 209 | return status < 0 ? status : -ENXIO; |
| 210 | } |
| 211 | |
| 212 | static int em_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, |
| 213 | int num) |
| 214 | { |
| 215 | struct em_i2c_device *priv = i2c_get_adapdata(adap); |
| 216 | int ret, i; |
| 217 | |
| 218 | if (readb(priv->base + I2C_OFS_IICF0) & I2C_BIT_IICBSY) |
| 219 | return -EAGAIN; |
| 220 | |
| 221 | for (i = 0; i < num; i++) { |
| 222 | ret = __em_i2c_xfer(adap, &msgs[i], (i == (num - 1))); |
| 223 | if (ret < 0) |
| 224 | return ret; |
| 225 | } |
| 226 | |
| 227 | /* I2C transfer completed */ |
| 228 | return num; |
| 229 | } |
| 230 | |
Niklas Söderlund | c31d0a0 | 2015-12-05 18:51:31 +0100 | [diff] [blame] | 231 | static bool em_i2c_slave_irq(struct em_i2c_device *priv) |
| 232 | { |
| 233 | u8 status, value; |
| 234 | enum i2c_slave_event event; |
| 235 | int ret; |
| 236 | |
| 237 | if (!priv->slave) |
| 238 | return false; |
| 239 | |
| 240 | status = readb(priv->base + I2C_OFS_IICSE0); |
| 241 | |
| 242 | /* Extension code, do not participate */ |
| 243 | if (status & I2C_BIT_EXC0) { |
| 244 | em_clear_set_bit(priv, 0, I2C_BIT_LREL0, I2C_OFS_IICC0); |
| 245 | return true; |
| 246 | } |
| 247 | |
| 248 | /* Stop detected, we don't know if it's for slave or master */ |
| 249 | if (status & I2C_BIT_SPD0) { |
| 250 | /* Notify slave device */ |
| 251 | i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value); |
| 252 | /* Pretend we did not handle the interrupt */ |
| 253 | return false; |
| 254 | } |
| 255 | |
| 256 | /* Only handle interrupts addressed to us */ |
| 257 | if (!(status & I2C_BIT_COI0)) |
| 258 | return false; |
| 259 | |
| 260 | /* Enable stop interrupts */ |
| 261 | em_clear_set_bit(priv, 0, I2C_BIT_SPIE0, I2C_OFS_IICC0); |
| 262 | |
| 263 | /* Transmission or Reception */ |
| 264 | if (status & I2C_BIT_TRC0) { |
| 265 | if (status & I2C_BIT_ACKD0) { |
| 266 | /* 9 bit interrupt mode */ |
| 267 | em_clear_set_bit(priv, 0, I2C_BIT_WTIM0, I2C_OFS_IICC0); |
| 268 | |
| 269 | /* Send data */ |
| 270 | event = status & I2C_BIT_STD0 ? |
| 271 | I2C_SLAVE_READ_REQUESTED : |
| 272 | I2C_SLAVE_READ_PROCESSED; |
| 273 | i2c_slave_event(priv->slave, event, &value); |
| 274 | writeb(value, priv->base + I2C_OFS_IIC0); |
| 275 | } else { |
| 276 | /* NACK, stop transmitting */ |
| 277 | em_clear_set_bit(priv, 0, I2C_BIT_LREL0, I2C_OFS_IICC0); |
| 278 | } |
| 279 | } else { |
| 280 | /* 8 bit interrupt mode */ |
| 281 | em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_ACKE0, |
| 282 | I2C_OFS_IICC0); |
| 283 | em_clear_set_bit(priv, I2C_BIT_WTIM0, I2C_BIT_WREL0, |
| 284 | I2C_OFS_IICC0); |
| 285 | |
| 286 | if (status & I2C_BIT_STD0) { |
| 287 | i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED, |
| 288 | &value); |
| 289 | } else { |
| 290 | /* Recv data */ |
| 291 | value = readb(priv->base + I2C_OFS_IIC0); |
| 292 | ret = i2c_slave_event(priv->slave, |
| 293 | I2C_SLAVE_WRITE_RECEIVED, &value); |
| 294 | if (ret < 0) |
| 295 | em_clear_set_bit(priv, I2C_BIT_ACKE0, 0, |
| 296 | I2C_OFS_IICC0); |
| 297 | } |
| 298 | } |
| 299 | |
| 300 | return true; |
| 301 | } |
| 302 | |
Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 303 | static irqreturn_t em_i2c_irq_handler(int this_irq, void *dev_id) |
| 304 | { |
| 305 | struct em_i2c_device *priv = dev_id; |
| 306 | |
Niklas Söderlund | c31d0a0 | 2015-12-05 18:51:31 +0100 | [diff] [blame] | 307 | if (em_i2c_slave_irq(priv)) |
| 308 | return IRQ_HANDLED; |
| 309 | |
Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 310 | complete(&priv->msg_done); |
Niklas Söderlund | c31d0a0 | 2015-12-05 18:51:31 +0100 | [diff] [blame] | 311 | |
Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 312 | return IRQ_HANDLED; |
| 313 | } |
| 314 | |
| 315 | static u32 em_i2c_func(struct i2c_adapter *adap) |
| 316 | { |
Niklas Söderlund | c31d0a0 | 2015-12-05 18:51:31 +0100 | [diff] [blame] | 317 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SLAVE; |
| 318 | } |
| 319 | |
| 320 | static int em_i2c_reg_slave(struct i2c_client *slave) |
| 321 | { |
| 322 | struct em_i2c_device *priv = i2c_get_adapdata(slave->adapter); |
| 323 | |
| 324 | if (priv->slave) |
| 325 | return -EBUSY; |
| 326 | |
| 327 | if (slave->flags & I2C_CLIENT_TEN) |
| 328 | return -EAFNOSUPPORT; |
| 329 | |
| 330 | priv->slave = slave; |
| 331 | |
| 332 | /* Set slave address */ |
| 333 | writeb(slave->addr << 1, priv->base + I2C_OFS_SVA0); |
| 334 | |
| 335 | return 0; |
| 336 | } |
| 337 | |
| 338 | static int em_i2c_unreg_slave(struct i2c_client *slave) |
| 339 | { |
| 340 | struct em_i2c_device *priv = i2c_get_adapdata(slave->adapter); |
| 341 | |
| 342 | WARN_ON(!priv->slave); |
| 343 | |
| 344 | writeb(0, priv->base + I2C_OFS_SVA0); |
| 345 | |
Wolfram Sang | 1fe671b | 2019-08-08 21:54:17 +0200 | [diff] [blame^] | 346 | /* |
| 347 | * Wait for interrupt to finish. New slave irqs cannot happen because we |
| 348 | * cleared the slave address and, thus, only extension codes will be |
| 349 | * detected which do not use the slave ptr. |
| 350 | */ |
| 351 | synchronize_irq(priv->irq); |
Niklas Söderlund | c31d0a0 | 2015-12-05 18:51:31 +0100 | [diff] [blame] | 352 | priv->slave = NULL; |
| 353 | |
| 354 | return 0; |
Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 355 | } |
| 356 | |
| 357 | static struct i2c_algorithm em_i2c_algo = { |
| 358 | .master_xfer = em_i2c_xfer, |
| 359 | .functionality = em_i2c_func, |
Niklas Söderlund | c31d0a0 | 2015-12-05 18:51:31 +0100 | [diff] [blame] | 360 | .reg_slave = em_i2c_reg_slave, |
| 361 | .unreg_slave = em_i2c_unreg_slave, |
Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 362 | }; |
| 363 | |
| 364 | static int em_i2c_probe(struct platform_device *pdev) |
| 365 | { |
| 366 | struct em_i2c_device *priv; |
| 367 | struct resource *r; |
Wolfram Sang | 1fe671b | 2019-08-08 21:54:17 +0200 | [diff] [blame^] | 368 | int ret; |
Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 369 | |
| 370 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
| 371 | if (!priv) |
| 372 | return -ENOMEM; |
| 373 | |
| 374 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 375 | priv->base = devm_ioremap_resource(&pdev->dev, r); |
| 376 | if (IS_ERR(priv->base)) |
| 377 | return PTR_ERR(priv->base); |
| 378 | |
| 379 | strlcpy(priv->adap.name, "EMEV2 I2C", sizeof(priv->adap.name)); |
| 380 | |
| 381 | priv->sclk = devm_clk_get(&pdev->dev, "sclk"); |
| 382 | if (IS_ERR(priv->sclk)) |
| 383 | return PTR_ERR(priv->sclk); |
| 384 | |
| 385 | clk_prepare_enable(priv->sclk); |
| 386 | |
| 387 | priv->adap.timeout = msecs_to_jiffies(100); |
| 388 | priv->adap.retries = 5; |
| 389 | priv->adap.dev.parent = &pdev->dev; |
| 390 | priv->adap.algo = &em_i2c_algo; |
| 391 | priv->adap.owner = THIS_MODULE; |
| 392 | priv->adap.dev.of_node = pdev->dev.of_node; |
| 393 | |
| 394 | init_completion(&priv->msg_done); |
| 395 | |
| 396 | platform_set_drvdata(pdev, priv); |
| 397 | i2c_set_adapdata(&priv->adap, priv); |
| 398 | |
| 399 | em_i2c_reset(&priv->adap); |
| 400 | |
Wolfram Sang | 1fe671b | 2019-08-08 21:54:17 +0200 | [diff] [blame^] | 401 | priv->irq = platform_get_irq(pdev, 0); |
| 402 | ret = devm_request_irq(&pdev->dev, priv->irq, em_i2c_irq_handler, 0, |
Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 403 | "em_i2c", priv); |
| 404 | if (ret) |
| 405 | goto err_clk; |
| 406 | |
| 407 | ret = i2c_add_adapter(&priv->adap); |
| 408 | |
| 409 | if (ret) |
| 410 | goto err_clk; |
| 411 | |
Wolfram Sang | 1fe671b | 2019-08-08 21:54:17 +0200 | [diff] [blame^] | 412 | dev_info(&pdev->dev, "Added i2c controller %d, irq %d\n", priv->adap.nr, |
| 413 | priv->irq); |
Wolfram Sang | 5faf6e1 | 2015-07-11 09:46:23 +0200 | [diff] [blame] | 414 | |
| 415 | return 0; |
| 416 | |
| 417 | err_clk: |
| 418 | clk_disable_unprepare(priv->sclk); |
| 419 | return ret; |
| 420 | } |
| 421 | |
| 422 | static int em_i2c_remove(struct platform_device *dev) |
| 423 | { |
| 424 | struct em_i2c_device *priv = platform_get_drvdata(dev); |
| 425 | |
| 426 | i2c_del_adapter(&priv->adap); |
| 427 | clk_disable_unprepare(priv->sclk); |
| 428 | |
| 429 | return 0; |
| 430 | } |
| 431 | |
| 432 | static const struct of_device_id em_i2c_ids[] = { |
| 433 | { .compatible = "renesas,iic-emev2", }, |
| 434 | { } |
| 435 | }; |
| 436 | |
| 437 | static struct platform_driver em_i2c_driver = { |
| 438 | .probe = em_i2c_probe, |
| 439 | .remove = em_i2c_remove, |
| 440 | .driver = { |
| 441 | .name = "em-i2c", |
| 442 | .of_match_table = em_i2c_ids, |
| 443 | } |
| 444 | }; |
| 445 | module_platform_driver(em_i2c_driver); |
| 446 | |
| 447 | MODULE_DESCRIPTION("EMEV2 I2C bus driver"); |
| 448 | MODULE_AUTHOR("Ian Molton and Wolfram Sang <wsa@sang-engineering.com>"); |
| 449 | MODULE_LICENSE("GPL v2"); |
| 450 | MODULE_DEVICE_TABLE(of, em_i2c_ids); |