1 /* 2 * CAN bus driver for the Freescale MPC5xxx embedded CPU. 3 * 4 * Copyright (C) 2004-2005 Andrey Volkov <avolkov@varma-el.com>, 5 * Varma Electronics Oy 6 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com> 7 * Copyright (C) 2009 Wolfram Sang, Pengutronix <w.sang@pengutronix.de> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the version 2 of the GNU General Public License 11 * as published by the Free Software Foundation 12 * 13 * This program is distributed in the hope that it will be useful, but 14 * WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, see <http://www.gnu.org/licenses/>. 20 */ 21 22 #include <linux/kernel.h> 23 #include <linux/module.h> 24 #include <linux/interrupt.h> 25 #include <linux/platform_device.h> 26 #include <linux/netdevice.h> 27 #include <linux/can/dev.h> 28 #include <linux/of_platform.h> 29 #include <sysdev/fsl_soc.h> 30 #include <linux/clk.h> 31 #include <linux/io.h> 32 #include <asm/mpc52xx.h> 33 34 #include "mscan.h" 35 36 #define DRV_NAME "mpc5xxx_can" 37 38 struct mpc5xxx_can_data { 39 unsigned int type; 40 u32 (*get_clock)(struct platform_device *ofdev, const char *clock_name, 41 int *mscan_clksrc); 42 void (*put_clock)(struct platform_device *ofdev); 43 }; 44 45 #ifdef CONFIG_PPC_MPC52xx 46 static const struct of_device_id mpc52xx_cdm_ids[] = { 47 { .compatible = "fsl,mpc5200-cdm", }, 48 {} 49 }; 50 51 static u32 mpc52xx_can_get_clock(struct platform_device *ofdev, 52 const char *clock_name, int *mscan_clksrc) 53 { 54 unsigned int pvr; 55 struct mpc52xx_cdm __iomem *cdm; 56 struct device_node *np_cdm; 57 unsigned int freq; 58 u32 val; 59 60 pvr = mfspr(SPRN_PVR); 61 62 /* 63 * Either the oscillator clock (SYS_XTAL_IN) or the IP bus clock 64 * (IP_CLK) can be selected as MSCAN clock source. According to 65 * the MPC5200 user's manual, the oscillator clock is the better 66 * choice as it has less jitter. For this reason, it is selected 67 * by default. Unfortunately, it can not be selected for the old 68 * MPC5200 Rev. A chips due to a hardware bug (check errata). 69 */ 70 if (clock_name && strcmp(clock_name, "ip") == 0) 71 *mscan_clksrc = MSCAN_CLKSRC_BUS; 72 else 73 *mscan_clksrc = MSCAN_CLKSRC_XTAL; 74 75 freq = mpc5xxx_get_bus_frequency(ofdev->dev.of_node); 76 if (!freq) 77 return 0; 78 79 if (*mscan_clksrc == MSCAN_CLKSRC_BUS || pvr == 0x80822011) 80 return freq; 81 82 /* Determine SYS_XTAL_IN frequency from the clock domain settings */ 83 np_cdm = of_find_matching_node(NULL, mpc52xx_cdm_ids); 84 if (!np_cdm) { 85 dev_err(&ofdev->dev, "can't get clock node!\n"); 86 return 0; 87 } 88 cdm = of_iomap(np_cdm, 0); 89 90 if (in_8(&cdm->ipb_clk_sel) & 0x1) 91 freq *= 2; 92 val = in_be32(&cdm->rstcfg); 93 94 freq *= (val & (1 << 5)) ? 8 : 4; 95 freq /= (val & (1 << 6)) ? 12 : 16; 96 97 of_node_put(np_cdm); 98 iounmap(cdm); 99 100 return freq; 101 } 102 #else /* !CONFIG_PPC_MPC52xx */ 103 static u32 mpc52xx_can_get_clock(struct platform_device *ofdev, 104 const char *clock_name, int *mscan_clksrc) 105 { 106 return 0; 107 } 108 #endif /* CONFIG_PPC_MPC52xx */ 109 110 #ifdef CONFIG_PPC_MPC512x 111 static u32 mpc512x_can_get_clock(struct platform_device *ofdev, 112 const char *clock_source, int *mscan_clksrc) 113 { 114 struct device_node *np; 115 u32 clockdiv; 116 enum { 117 CLK_FROM_AUTO, 118 CLK_FROM_IPS, 119 CLK_FROM_SYS, 120 CLK_FROM_REF, 121 } clk_from; 122 struct clk *clk_in, *clk_can; 123 unsigned long freq_calc; 124 struct mscan_priv *priv; 125 struct clk *clk_ipg; 126 127 /* the caller passed in the clock source spec that was read from 128 * the device tree, get the optional clock divider as well 129 */ 130 np = ofdev->dev.of_node; 131 clockdiv = 1; 132 of_property_read_u32(np, "fsl,mscan-clock-divider", &clockdiv); 133 dev_dbg(&ofdev->dev, "device tree specs: clk src[%s] div[%d]\n", 134 clock_source ? clock_source : "<NULL>", clockdiv); 135 136 /* when clock-source is 'ip', the CANCTL1[CLKSRC] bit needs to 137 * get set, and the 'ips' clock is the input to the MSCAN 138 * component 139 * 140 * for clock-source values of 'ref' or 'sys' the CANCTL1[CLKSRC] 141 * bit needs to get cleared, an optional clock-divider may have 142 * been specified (the default value is 1), the appropriate 143 * MSCAN related MCLK is the input to the MSCAN component 144 * 145 * in the absence of a clock-source spec, first an optimal clock 146 * gets determined based on the 'sys' clock, if that fails the 147 * 'ref' clock is used 148 */ 149 clk_from = CLK_FROM_AUTO; 150 if (clock_source) { 151 /* interpret the device tree's spec for the clock source */ 152 if (!strcmp(clock_source, "ip")) 153 clk_from = CLK_FROM_IPS; 154 else if (!strcmp(clock_source, "sys")) 155 clk_from = CLK_FROM_SYS; 156 else if (!strcmp(clock_source, "ref")) 157 clk_from = CLK_FROM_REF; 158 else 159 goto err_invalid; 160 dev_dbg(&ofdev->dev, "got a clk source spec[%d]\n", clk_from); 161 } 162 if (clk_from == CLK_FROM_AUTO) { 163 /* no spec so far, try the 'sys' clock; round to the 164 * next MHz and see if we can get a multiple of 16MHz 165 */ 166 dev_dbg(&ofdev->dev, "no clk source spec, trying SYS\n"); 167 clk_in = devm_clk_get(&ofdev->dev, "sys"); 168 if (IS_ERR(clk_in)) 169 goto err_notavail; 170 freq_calc = clk_get_rate(clk_in); 171 freq_calc += 499999; 172 freq_calc /= 1000000; 173 freq_calc *= 1000000; 174 if ((freq_calc % 16000000) == 0) { 175 clk_from = CLK_FROM_SYS; 176 clockdiv = freq_calc / 16000000; 177 dev_dbg(&ofdev->dev, 178 "clk fit, sys[%lu] div[%d] freq[%lu]\n", 179 freq_calc, clockdiv, freq_calc / clockdiv); 180 } 181 } 182 if (clk_from == CLK_FROM_AUTO) { 183 /* no spec so far, use the 'ref' clock */ 184 dev_dbg(&ofdev->dev, "no clk source spec, trying REF\n"); 185 clk_in = devm_clk_get(&ofdev->dev, "ref"); 186 if (IS_ERR(clk_in)) 187 goto err_notavail; 188 clk_from = CLK_FROM_REF; 189 freq_calc = clk_get_rate(clk_in); 190 dev_dbg(&ofdev->dev, 191 "clk fit, ref[%lu] (no div) freq[%lu]\n", 192 freq_calc, freq_calc); 193 } 194 195 /* select IPS or MCLK as the MSCAN input (returned to the caller), 196 * setup the MCLK mux source and rate if applicable, apply the 197 * optionally specified or derived above divider, and determine 198 * the actual resulting clock rate to return to the caller 199 */ 200 switch (clk_from) { 201 case CLK_FROM_IPS: 202 clk_can = devm_clk_get(&ofdev->dev, "ips"); 203 if (IS_ERR(clk_can)) 204 goto err_notavail; 205 priv = netdev_priv(dev_get_drvdata(&ofdev->dev)); 206 priv->clk_can = clk_can; 207 freq_calc = clk_get_rate(clk_can); 208 *mscan_clksrc = MSCAN_CLKSRC_IPS; 209 dev_dbg(&ofdev->dev, "clk from IPS, clksrc[%d] freq[%lu]\n", 210 *mscan_clksrc, freq_calc); 211 break; 212 case CLK_FROM_SYS: 213 case CLK_FROM_REF: 214 clk_can = devm_clk_get(&ofdev->dev, "mclk"); 215 if (IS_ERR(clk_can)) 216 goto err_notavail; 217 priv = netdev_priv(dev_get_drvdata(&ofdev->dev)); 218 priv->clk_can = clk_can; 219 if (clk_from == CLK_FROM_SYS) 220 clk_in = devm_clk_get(&ofdev->dev, "sys"); 221 if (clk_from == CLK_FROM_REF) 222 clk_in = devm_clk_get(&ofdev->dev, "ref"); 223 if (IS_ERR(clk_in)) 224 goto err_notavail; 225 clk_set_parent(clk_can, clk_in); 226 freq_calc = clk_get_rate(clk_in); 227 freq_calc /= clockdiv; 228 clk_set_rate(clk_can, freq_calc); 229 freq_calc = clk_get_rate(clk_can); 230 *mscan_clksrc = MSCAN_CLKSRC_BUS; 231 dev_dbg(&ofdev->dev, "clk from MCLK, clksrc[%d] freq[%lu]\n", 232 *mscan_clksrc, freq_calc); 233 break; 234 default: 235 goto err_invalid; 236 } 237 238 /* the above clk_can item is used for the bitrate, access to 239 * the peripheral's register set needs the clk_ipg item 240 */ 241 clk_ipg = devm_clk_get(&ofdev->dev, "ipg"); 242 if (IS_ERR(clk_ipg)) 243 goto err_notavail_ipg; 244 if (clk_prepare_enable(clk_ipg)) 245 goto err_notavail_ipg; 246 priv = netdev_priv(dev_get_drvdata(&ofdev->dev)); 247 priv->clk_ipg = clk_ipg; 248 249 /* return the determined clock source rate */ 250 return freq_calc; 251 252 err_invalid: 253 dev_err(&ofdev->dev, "invalid clock source specification\n"); 254 /* clock source rate could not get determined */ 255 return 0; 256 257 err_notavail: 258 dev_err(&ofdev->dev, "cannot acquire or setup bitrate clock source\n"); 259 /* clock source rate could not get determined */ 260 return 0; 261 262 err_notavail_ipg: 263 dev_err(&ofdev->dev, "cannot acquire or setup register clock\n"); 264 /* clock source rate could not get determined */ 265 return 0; 266 } 267 268 static void mpc512x_can_put_clock(struct platform_device *ofdev) 269 { 270 struct mscan_priv *priv; 271 272 priv = netdev_priv(dev_get_drvdata(&ofdev->dev)); 273 if (priv->clk_ipg) 274 clk_disable_unprepare(priv->clk_ipg); 275 } 276 #else /* !CONFIG_PPC_MPC512x */ 277 static u32 mpc512x_can_get_clock(struct platform_device *ofdev, 278 const char *clock_name, int *mscan_clksrc) 279 { 280 return 0; 281 } 282 #define mpc512x_can_put_clock NULL 283 #endif /* CONFIG_PPC_MPC512x */ 284 285 static const struct of_device_id mpc5xxx_can_table[]; 286 static int mpc5xxx_can_probe(struct platform_device *ofdev) 287 { 288 const struct of_device_id *match; 289 const struct mpc5xxx_can_data *data; 290 struct device_node *np = ofdev->dev.of_node; 291 struct net_device *dev; 292 struct mscan_priv *priv; 293 void __iomem *base; 294 const char *clock_name = NULL; 295 int irq, mscan_clksrc = 0; 296 int err = -ENOMEM; 297 298 match = of_match_device(mpc5xxx_can_table, &ofdev->dev); 299 if (!match) 300 return -EINVAL; 301 data = match->data; 302 303 base = of_iomap(np, 0); 304 if (!base) { 305 dev_err(&ofdev->dev, "couldn't ioremap\n"); 306 return err; 307 } 308 309 irq = irq_of_parse_and_map(np, 0); 310 if (!irq) { 311 dev_err(&ofdev->dev, "no irq found\n"); 312 err = -ENODEV; 313 goto exit_unmap_mem; 314 } 315 316 dev = alloc_mscandev(); 317 if (!dev) 318 goto exit_dispose_irq; 319 platform_set_drvdata(ofdev, dev); 320 SET_NETDEV_DEV(dev, &ofdev->dev); 321 322 priv = netdev_priv(dev); 323 priv->reg_base = base; 324 dev->irq = irq; 325 326 clock_name = of_get_property(np, "fsl,mscan-clock-source", NULL); 327 328 BUG_ON(!data); 329 priv->type = data->type; 330 priv->can.clock.freq = data->get_clock(ofdev, clock_name, 331 &mscan_clksrc); 332 if (!priv->can.clock.freq) { 333 dev_err(&ofdev->dev, "couldn't get MSCAN clock properties\n"); 334 goto exit_free_mscan; 335 } 336 337 err = register_mscandev(dev, mscan_clksrc); 338 if (err) { 339 dev_err(&ofdev->dev, "registering %s failed (err=%d)\n", 340 DRV_NAME, err); 341 goto exit_free_mscan; 342 } 343 344 dev_info(&ofdev->dev, "MSCAN at 0x%p, irq %d, clock %d Hz\n", 345 priv->reg_base, dev->irq, priv->can.clock.freq); 346 347 return 0; 348 349 exit_free_mscan: 350 free_candev(dev); 351 exit_dispose_irq: 352 irq_dispose_mapping(irq); 353 exit_unmap_mem: 354 iounmap(base); 355 356 return err; 357 } 358 359 static int mpc5xxx_can_remove(struct platform_device *ofdev) 360 { 361 const struct of_device_id *match; 362 const struct mpc5xxx_can_data *data; 363 struct net_device *dev = platform_get_drvdata(ofdev); 364 struct mscan_priv *priv = netdev_priv(dev); 365 366 match = of_match_device(mpc5xxx_can_table, &ofdev->dev); 367 data = match ? match->data : NULL; 368 369 unregister_mscandev(dev); 370 if (data && data->put_clock) 371 data->put_clock(ofdev); 372 iounmap(priv->reg_base); 373 irq_dispose_mapping(dev->irq); 374 free_candev(dev); 375 376 return 0; 377 } 378 379 #ifdef CONFIG_PM 380 static struct mscan_regs saved_regs; 381 static int mpc5xxx_can_suspend(struct platform_device *ofdev, pm_message_t state) 382 { 383 struct net_device *dev = platform_get_drvdata(ofdev); 384 struct mscan_priv *priv = netdev_priv(dev); 385 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base; 386 387 _memcpy_fromio(&saved_regs, regs, sizeof(*regs)); 388 389 return 0; 390 } 391 392 static int mpc5xxx_can_resume(struct platform_device *ofdev) 393 { 394 struct net_device *dev = platform_get_drvdata(ofdev); 395 struct mscan_priv *priv = netdev_priv(dev); 396 struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base; 397 398 regs->canctl0 |= MSCAN_INITRQ; 399 while (!(regs->canctl1 & MSCAN_INITAK)) 400 udelay(10); 401 402 regs->canctl1 = saved_regs.canctl1; 403 regs->canbtr0 = saved_regs.canbtr0; 404 regs->canbtr1 = saved_regs.canbtr1; 405 regs->canidac = saved_regs.canidac; 406 407 /* restore masks, buffers etc. */ 408 _memcpy_toio(®s->canidar1_0, (void *)&saved_regs.canidar1_0, 409 sizeof(*regs) - offsetof(struct mscan_regs, canidar1_0)); 410 411 regs->canctl0 &= ~MSCAN_INITRQ; 412 regs->cantbsel = saved_regs.cantbsel; 413 regs->canrier = saved_regs.canrier; 414 regs->cantier = saved_regs.cantier; 415 regs->canctl0 = saved_regs.canctl0; 416 417 return 0; 418 } 419 #endif 420 421 static const struct mpc5xxx_can_data mpc5200_can_data = { 422 .type = MSCAN_TYPE_MPC5200, 423 .get_clock = mpc52xx_can_get_clock, 424 /* .put_clock not applicable */ 425 }; 426 427 static const struct mpc5xxx_can_data mpc5121_can_data = { 428 .type = MSCAN_TYPE_MPC5121, 429 .get_clock = mpc512x_can_get_clock, 430 .put_clock = mpc512x_can_put_clock, 431 }; 432 433 static const struct of_device_id mpc5xxx_can_table[] = { 434 { .compatible = "fsl,mpc5200-mscan", .data = &mpc5200_can_data, }, 435 /* Note that only MPC5121 Rev. 2 (and later) is supported */ 436 { .compatible = "fsl,mpc5121-mscan", .data = &mpc5121_can_data, }, 437 {}, 438 }; 439 MODULE_DEVICE_TABLE(of, mpc5xxx_can_table); 440 441 static struct platform_driver mpc5xxx_can_driver = { 442 .driver = { 443 .name = "mpc5xxx_can", 444 .of_match_table = mpc5xxx_can_table, 445 }, 446 .probe = mpc5xxx_can_probe, 447 .remove = mpc5xxx_can_remove, 448 #ifdef CONFIG_PM 449 .suspend = mpc5xxx_can_suspend, 450 .resume = mpc5xxx_can_resume, 451 #endif 452 }; 453 454 module_platform_driver(mpc5xxx_can_driver); 455 456 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>"); 457 MODULE_DESCRIPTION("Freescale MPC5xxx CAN driver"); 458 MODULE_LICENSE("GPL v2"); 459