drivers/mtd/nand/gpio.c

   1 /*
   2  * drivers/mtd/nand/gpio.c
   3  *
   4  * Updated, and converted to generic GPIO based driver by Russell King.
   5  *
   6  * Written by Ben Dooks <ben@simtec.co.uk>
   7  *   Based on 2.4 version by Mark Whittaker
   8  *
   9  * © 2004 Simtec Electronics
  10  *
  11  * Device driver for NAND connected via GPIO
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License version 2 as
  15  * published by the Free Software Foundation.
  16  *
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/err.h>
  21 #include <linux/init.h>
  22 #include <linux/slab.h>
  23 #include <linux/module.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/gpio.h>
  26 #include <linux/io.h>
  27 #include <linux/mtd/mtd.h>
  28 #include <linux/mtd/nand.h>
  29 #include <linux/mtd/partitions.h>
  30 #include <linux/mtd/nand-gpio.h>
  31 #include <linux/of.h>
  32 #include <linux/of_address.h>
  33 #include <linux/of_gpio.h>
  34
  35 struct gpiomtd {
  36         void __iomem            *io_sync;
  37         struct mtd_info         mtd_info;
  38         struct nand_chip        nand_chip;
  39         struct gpio_nand_platdata plat;
  40 };
  41
  42 #define gpio_nand_getpriv(x) container_of(x, struct gpiomtd, mtd_info)
  43
  44
  45 #ifdef CONFIG_ARM
  46 /* gpio_nand_dosync()
  47  *
  48  * Make sure the GPIO state changes occur in-order with writes to NAND
  49  * memory region.
  50  * Needed on PXA due to bus-reordering within the SoC itself (see section on
  51  * I/O ordering in PXA manual (section 2.3, p35)
  52  */
  53 static void gpio_nand_dosync(struct gpiomtd *gpiomtd)
  54 {
  55         unsigned long tmp;
  56
  57         if (gpiomtd->io_sync) {
  58                 /*
  59                  * Linux memory barriers don't cater for what's required here.
  60                  * What's required is what's here - a read from a separate
  61                  * region with a dependency on that read.
  62                  */
  63                 tmp = readl(gpiomtd->io_sync);
  64                 asm volatile("mov %1, %0\n" : "=r" (tmp) : "r" (tmp));
  65         }
  66 }
  67 #else
  68 static inline void gpio_nand_dosync(struct gpiomtd *gpiomtd) {}
  69 #endif
  70
  71 static void gpio_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
  72 {
  73         struct gpiomtd *gpiomtd = gpio_nand_getpriv(mtd);
  74
  75         gpio_nand_dosync(gpiomtd);
  76
  77         if (ctrl & NAND_CTRL_CHANGE) {
  78                 gpio_set_value(gpiomtd->plat.gpio_nce, !(ctrl & NAND_NCE));
  79                 gpio_set_value(gpiomtd->plat.gpio_cle, !!(ctrl & NAND_CLE));
  80                 gpio_set_value(gpiomtd->plat.gpio_ale, !!(ctrl & NAND_ALE));
  81                 gpio_nand_dosync(gpiomtd);
  82         }
  83         if (cmd == NAND_CMD_NONE)
  84                 return;
  85
  86         writeb(cmd, gpiomtd->nand_chip.IO_ADDR_W);
  87         gpio_nand_dosync(gpiomtd);
  88 }
  89
  90 static int gpio_nand_devready(struct mtd_info *mtd)
  91 {
  92         struct gpiomtd *gpiomtd = gpio_nand_getpriv(mtd);
  93
  94         return gpio_get_value(gpiomtd->plat.gpio_rdy);
  95 }
  96
  97 #ifdef CONFIG_OF
  98 static const struct of_device_id gpio_nand_id_table[] = {
  99         { .compatible = "gpio-control-nand" },
 100         {}
 101 };
 102 MODULE_DEVICE_TABLE(of, gpio_nand_id_table);
 103
 104 static int gpio_nand_get_config_of(const struct device *dev,
 105                                    struct gpio_nand_platdata *plat)
 106 {
 107         u32 val;
 108
 109         if (!dev->of_node)
 110                 return -ENODEV;
 111
 112         if (!of_property_read_u32(dev->of_node, "bank-width", &val)) {
 113                 if (val == 2) {
 114                         plat->options |= NAND_BUSWIDTH_16;
 115                 } else if (val != 1) {
 116                         dev_err(dev, "invalid bank-width %u\n", val);
 117                         return -EINVAL;
 118                 }
 119         }
 120
 121         plat->gpio_rdy = of_get_gpio(dev->of_node, 0);
 122         plat->gpio_nce = of_get_gpio(dev->of_node, 1);
 123         plat->gpio_ale = of_get_gpio(dev->of_node, 2);
 124         plat->gpio_cle = of_get_gpio(dev->of_node, 3);
 125         plat->gpio_nwp = of_get_gpio(dev->of_node, 4);
 126
 127         if (!of_property_read_u32(dev->of_node, "chip-delay", &val))
 128                 plat->chip_delay = val;
 129
 130         return 0;
 131 }
 132
 133 static struct resource *gpio_nand_get_io_sync_of(struct platform_device *pdev)
 134 {
 135         struct resource *r;
 136         u64 addr;
 137
 138         if (of_property_read_u64(pdev->dev.of_node,
 139                                        "gpio-control-nand,io-sync-reg", &addr))
 140                 return NULL;
 141
 142         r = devm_kzalloc(&pdev->dev, sizeof(*r), GFP_KERNEL);
 143         if (!r)
 144                 return NULL;
 145
 146         r->start = addr;
 147         r->end = r->start + 0x3;
 148         r->flags = IORESOURCE_MEM;
 149
 150         return r;
 151 }
 152 #else /* CONFIG_OF */
 153 static inline int gpio_nand_get_config_of(const struct device *dev,
 154                                           struct gpio_nand_platdata *plat)
 155 {
 156         return -ENOSYS;
 157 }
 158
 159 static inline struct resource *
 160 gpio_nand_get_io_sync_of(struct platform_device *pdev)
 161 {
 162         return NULL;
 163 }
 164 #endif /* CONFIG_OF */
 165
 166 static inline int gpio_nand_get_config(const struct device *dev,
 167                                        struct gpio_nand_platdata *plat)
 168 {
 169         int ret = gpio_nand_get_config_of(dev, plat);
 170
 171         if (!ret)
 172                 return ret;
 173
 174         if (dev_get_platdata(dev)) {
 175                 memcpy(plat, dev_get_platdata(dev), sizeof(*plat));
 176                 return 0;
 177         }
 178
 179         return -EINVAL;
 180 }
 181
 182 static inline struct resource *
 183 gpio_nand_get_io_sync(struct platform_device *pdev)
 184 {
 185         struct resource *r = gpio_nand_get_io_sync_of(pdev);
 186
 187         if (r)
 188                 return r;
 189
 190         return platform_get_resource(pdev, IORESOURCE_MEM, 1);
 191 }
 192
 193 static int gpio_nand_remove(struct platform_device *pdev)
 194 {
 195         struct gpiomtd *gpiomtd = platform_get_drvdata(pdev);
 196
 197         nand_release(&gpiomtd->mtd_info);
 198
 199         if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 200                 gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
 201         gpio_set_value(gpiomtd->plat.gpio_nce, 1);
 202
 203         return 0;
 204 }
 205
 206 static int gpio_nand_probe(struct platform_device *pdev)
 207 {
 208         struct gpiomtd *gpiomtd;
 209         struct nand_chip *chip;
 210         struct resource *res;
 211         struct mtd_part_parser_data ppdata = {};
 212         int ret = 0;
 213
 214         if (!pdev->dev.of_node && !dev_get_platdata(&pdev->dev))
 215                 return -EINVAL;
 216
 217         gpiomtd = devm_kzalloc(&pdev->dev, sizeof(*gpiomtd), GFP_KERNEL);
 218         if (!gpiomtd)
 219                 return -ENOMEM;
 220
 221         chip = &gpiomtd->nand_chip;
 222
 223         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 224         chip->IO_ADDR_R = devm_ioremap_resource(&pdev->dev, res);
 225         if (IS_ERR(chip->IO_ADDR_R))
 226                 return PTR_ERR(chip->IO_ADDR_R);
 227
 228         res = gpio_nand_get_io_sync(pdev);
 229         if (res) {
 230                 gpiomtd->io_sync = devm_ioremap_resource(&pdev->dev, res);
 231                 if (IS_ERR(gpiomtd->io_sync))
 232                         return PTR_ERR(gpiomtd->io_sync);
 233         }
 234
 235         ret = gpio_nand_get_config(&pdev->dev, &gpiomtd->plat);
 236         if (ret)
 237                 return ret;
 238
 239         ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nce, "NAND NCE");
 240         if (ret)
 241                 return ret;
 242         gpio_direction_output(gpiomtd->plat.gpio_nce, 1);
 243
 244         if (gpio_is_valid(gpiomtd->plat.gpio_nwp)) {
 245                 ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_nwp,
 246                                         "NAND NWP");
 247                 if (ret)
 248                         return ret;
 249         }
 250
 251         ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_ale, "NAND ALE");
 252         if (ret)
 253                 return ret;
 254         gpio_direction_output(gpiomtd->plat.gpio_ale, 0);
 255
 256         ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_cle, "NAND CLE");
 257         if (ret)
 258                 return ret;
 259         gpio_direction_output(gpiomtd->plat.gpio_cle, 0);
 260
 261         if (gpio_is_valid(gpiomtd->plat.gpio_rdy)) {
 262                 ret = devm_gpio_request(&pdev->dev, gpiomtd->plat.gpio_rdy,
 263                                         "NAND RDY");
 264                 if (ret)
 265                         return ret;
 266                 gpio_direction_input(gpiomtd->plat.gpio_rdy);
 267                 chip->dev_ready = gpio_nand_devready;
 268         }
 269
 270         chip->IO_ADDR_W         = chip->IO_ADDR_R;
 271         chip->ecc.mode          = NAND_ECC_SOFT;
 272         chip->options           = gpiomtd->plat.options;
 273         chip->chip_delay        = gpiomtd->plat.chip_delay;
 274         chip->cmd_ctrl          = gpio_nand_cmd_ctrl;
 275
 276         gpiomtd->mtd_info.priv  = chip;
 277         gpiomtd->mtd_info.owner = THIS_MODULE;
 278
 279         platform_set_drvdata(pdev, gpiomtd);
 280
 281         if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 282                 gpio_direction_output(gpiomtd->plat.gpio_nwp, 1);
 283
 284         if (nand_scan(&gpiomtd->mtd_info, 1)) {
 285                 ret = -ENXIO;
 286                 goto err_wp;
 287         }
 288
 289         if (gpiomtd->plat.adjust_parts)
 290                 gpiomtd->plat.adjust_parts(&gpiomtd->plat,
 291                                            gpiomtd->mtd_info.size);
 292
 293         ppdata.of_node = pdev->dev.of_node;
 294         ret = mtd_device_parse_register(&gpiomtd->mtd_info, NULL, &ppdata,
 295                                         gpiomtd->plat.parts,
 296                                         gpiomtd->plat.num_parts);
 297         if (!ret)
 298                 return 0;
 299
 300 err_wp:
 301         if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
 302                 gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
 303
 304         return ret;
 305 }
 306
 307 static struct platform_driver gpio_nand_driver = {
 308         .probe          = gpio_nand_probe,
 309         .remove         = gpio_nand_remove,
 310         .driver         = {
 311                 .name   = "gpio-nand",
 312                 .owner  = THIS_MODULE,
 313                 .of_match_table = of_match_ptr(gpio_nand_id_table),
 314         },
 315 };
 316
 317 module_platform_driver(gpio_nand_driver);
 318
 319 MODULE_LICENSE("GPL");
 320 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 321 MODULE_DESCRIPTION("GPIO NAND Driver");