1 /* 2 * SuperH HSPI bus driver 3 * 4 * Copyright (C) 2011 Kuninori Morimoto 5 * 6 * Based on spi-sh.c: 7 * Based on pxa2xx_spi.c: 8 * Copyright (C) 2011 Renesas Solutions Corp. 9 * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License as published by 13 * the Free Software Foundation; version 2 of the License. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 23 * 24 */ 25 26 #include <linux/clk.h> 27 #include <linux/module.h> 28 #include <linux/kernel.h> 29 #include <linux/timer.h> 30 #include <linux/delay.h> 31 #include <linux/list.h> 32 #include <linux/interrupt.h> 33 #include <linux/platform_device.h> 34 #include <linux/pm_runtime.h> 35 #include <linux/io.h> 36 #include <linux/spi/spi.h> 37 #include <linux/spi/sh_hspi.h> 38 39 #define SPCR 0x00 40 #define SPSR 0x04 41 #define SPSCR 0x08 42 #define SPTBR 0x0C 43 #define SPRBR 0x10 44 #define SPCR2 0x14 45 46 /* SPSR */ 47 #define RXFL (1 << 2) 48 49 #define hspi2info(h) (h->dev->platform_data) 50 51 struct hspi_priv { 52 void __iomem *addr; 53 struct spi_master *master; 54 struct device *dev; 55 struct clk *clk; 56 }; 57 58 /* 59 * basic function 60 */ 61 static void hspi_write(struct hspi_priv *hspi, int reg, u32 val) 62 { 63 iowrite32(val, hspi->addr + reg); 64 } 65 66 static u32 hspi_read(struct hspi_priv *hspi, int reg) 67 { 68 return ioread32(hspi->addr + reg); 69 } 70 71 static void hspi_bit_set(struct hspi_priv *hspi, int reg, u32 mask, u32 set) 72 { 73 u32 val = hspi_read(hspi, reg); 74 75 val &= ~mask; 76 val |= set & mask; 77 78 hspi_write(hspi, reg, val); 79 } 80 81 /* 82 * transfer function 83 */ 84 static int hspi_status_check_timeout(struct hspi_priv *hspi, u32 mask, u32 val) 85 { 86 int t = 256; 87 88 while (t--) { 89 if ((mask & hspi_read(hspi, SPSR)) == val) 90 return 0; 91 92 udelay(10); 93 } 94 95 dev_err(hspi->dev, "timeout\n"); 96 return -ETIMEDOUT; 97 } 98 99 /* 100 * spi master function 101 */ 102 103 #define hspi_hw_cs_enable(hspi) hspi_hw_cs_ctrl(hspi, 0) 104 #define hspi_hw_cs_disable(hspi) hspi_hw_cs_ctrl(hspi, 1) 105 static void hspi_hw_cs_ctrl(struct hspi_priv *hspi, int hi) 106 { 107 hspi_bit_set(hspi, SPSCR, (1 << 6), (hi) << 6); 108 } 109 110 static void hspi_hw_setup(struct hspi_priv *hspi, 111 struct spi_message *msg, 112 struct spi_transfer *t) 113 { 114 struct spi_device *spi = msg->spi; 115 struct device *dev = hspi->dev; 116 u32 target_rate; 117 u32 spcr, idiv_clk; 118 u32 rate, best_rate, min, tmp; 119 120 target_rate = t ? t->speed_hz : 0; 121 if (!target_rate) 122 target_rate = spi->max_speed_hz; 123 124 /* 125 * find best IDIV/CLKCx settings 126 */ 127 min = ~0; 128 best_rate = 0; 129 spcr = 0; 130 for (idiv_clk = 0x00; idiv_clk <= 0x3F; idiv_clk++) { 131 rate = clk_get_rate(hspi->clk); 132 133 /* IDIV calculation */ 134 if (idiv_clk & (1 << 5)) 135 rate /= 128; 136 else 137 rate /= 16; 138 139 /* CLKCx calculation */ 140 rate /= (((idiv_clk & 0x1F) + 1) * 2); 141 142 /* save best settings */ 143 tmp = abs(target_rate - rate); 144 if (tmp < min) { 145 min = tmp; 146 spcr = idiv_clk; 147 best_rate = rate; 148 } 149 } 150 151 if (spi->mode & SPI_CPHA) 152 spcr |= 1 << 7; 153 if (spi->mode & SPI_CPOL) 154 spcr |= 1 << 6; 155 156 dev_dbg(dev, "speed %d/%d\n", target_rate, best_rate); 157 158 hspi_write(hspi, SPCR, spcr); 159 hspi_write(hspi, SPSR, 0x0); 160 hspi_write(hspi, SPSCR, 0x21); /* master mode / CS control */ 161 } 162 163 static int hspi_transfer_one_message(struct spi_master *master, 164 struct spi_message *msg) 165 { 166 struct hspi_priv *hspi = spi_master_get_devdata(master); 167 struct spi_transfer *t; 168 u32 tx; 169 u32 rx; 170 int ret, i; 171 unsigned int cs_change; 172 const int nsecs = 50; 173 174 dev_dbg(hspi->dev, "%s\n", __func__); 175 176 cs_change = 1; 177 ret = 0; 178 list_for_each_entry(t, &msg->transfers, transfer_list) { 179 180 if (cs_change) { 181 hspi_hw_setup(hspi, msg, t); 182 hspi_hw_cs_enable(hspi); 183 ndelay(nsecs); 184 } 185 cs_change = t->cs_change; 186 187 for (i = 0; i < t->len; i++) { 188 189 /* wait remains */ 190 ret = hspi_status_check_timeout(hspi, 0x1, 0); 191 if (ret < 0) 192 break; 193 194 tx = 0; 195 if (t->tx_buf) 196 tx = (u32)((u8 *)t->tx_buf)[i]; 197 198 hspi_write(hspi, SPTBR, tx); 199 200 /* wait receive */ 201 ret = hspi_status_check_timeout(hspi, 0x4, 0x4); 202 if (ret < 0) 203 break; 204 205 rx = hspi_read(hspi, SPRBR); 206 if (t->rx_buf) 207 ((u8 *)t->rx_buf)[i] = (u8)rx; 208 209 } 210 211 msg->actual_length += t->len; 212 213 if (t->delay_usecs) 214 udelay(t->delay_usecs); 215 216 if (cs_change) { 217 ndelay(nsecs); 218 hspi_hw_cs_disable(hspi); 219 ndelay(nsecs); 220 } 221 } 222 223 msg->status = ret; 224 if (!cs_change) { 225 ndelay(nsecs); 226 hspi_hw_cs_disable(hspi); 227 } 228 spi_finalize_current_message(master); 229 230 return ret; 231 } 232 233 static int hspi_setup(struct spi_device *spi) 234 { 235 struct hspi_priv *hspi = spi_master_get_devdata(spi->master); 236 struct device *dev = hspi->dev; 237 238 if (8 != spi->bits_per_word) { 239 dev_err(dev, "bits_per_word should be 8\n"); 240 return -EIO; 241 } 242 243 dev_dbg(dev, "%s setup\n", spi->modalias); 244 245 return 0; 246 } 247 248 static void hspi_cleanup(struct spi_device *spi) 249 { 250 struct hspi_priv *hspi = spi_master_get_devdata(spi->master); 251 struct device *dev = hspi->dev; 252 253 dev_dbg(dev, "%s cleanup\n", spi->modalias); 254 } 255 256 static int hspi_probe(struct platform_device *pdev) 257 { 258 struct resource *res; 259 struct spi_master *master; 260 struct hspi_priv *hspi; 261 struct clk *clk; 262 int ret; 263 264 /* get base addr */ 265 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 266 if (!res) { 267 dev_err(&pdev->dev, "invalid resource\n"); 268 return -EINVAL; 269 } 270 271 master = spi_alloc_master(&pdev->dev, sizeof(*hspi)); 272 if (!master) { 273 dev_err(&pdev->dev, "spi_alloc_master error.\n"); 274 return -ENOMEM; 275 } 276 277 clk = clk_get(NULL, "shyway_clk"); 278 if (IS_ERR(clk)) { 279 dev_err(&pdev->dev, "shyway_clk is required\n"); 280 ret = -EINVAL; 281 goto error0; 282 } 283 284 hspi = spi_master_get_devdata(master); 285 platform_set_drvdata(pdev, hspi); 286 287 /* init hspi */ 288 hspi->master = master; 289 hspi->dev = &pdev->dev; 290 hspi->clk = clk; 291 hspi->addr = devm_ioremap(hspi->dev, 292 res->start, resource_size(res)); 293 if (!hspi->addr) { 294 dev_err(&pdev->dev, "ioremap error.\n"); 295 ret = -ENOMEM; 296 goto error1; 297 } 298 299 pm_runtime_enable(&pdev->dev); 300 301 master->num_chipselect = 1; 302 master->bus_num = pdev->id; 303 master->setup = hspi_setup; 304 master->cleanup = hspi_cleanup; 305 master->mode_bits = SPI_CPOL | SPI_CPHA; 306 master->dev.of_node = pdev->dev.of_node; 307 master->auto_runtime_pm = true; 308 master->transfer_one_message = hspi_transfer_one_message; 309 ret = devm_spi_register_master(&pdev->dev, master); 310 if (ret < 0) { 311 dev_err(&pdev->dev, "spi_register_master error.\n"); 312 goto error1; 313 } 314 315 return 0; 316 317 error1: 318 clk_put(clk); 319 error0: 320 spi_master_put(master); 321 322 return ret; 323 } 324 325 static int hspi_remove(struct platform_device *pdev) 326 { 327 struct hspi_priv *hspi = platform_get_drvdata(pdev); 328 329 pm_runtime_disable(&pdev->dev); 330 331 clk_put(hspi->clk); 332 333 return 0; 334 } 335 336 static struct of_device_id hspi_of_match[] = { 337 { .compatible = "renesas,hspi", }, 338 { /* sentinel */ } 339 }; 340 MODULE_DEVICE_TABLE(of, hspi_of_match); 341 342 static struct platform_driver hspi_driver = { 343 .probe = hspi_probe, 344 .remove = hspi_remove, 345 .driver = { 346 .name = "sh-hspi", 347 .owner = THIS_MODULE, 348 .of_match_table = hspi_of_match, 349 }, 350 }; 351 module_platform_driver(hspi_driver); 352 353 MODULE_DESCRIPTION("SuperH HSPI bus driver"); 354 MODULE_LICENSE("GPL"); 355 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>"); 356 MODULE_ALIAS("platform:sh-hspi"); 357