target/linux/oxnas/files/drivers/mtd/nand/oxnas_nand.c

   1 /*
   2  *  This program is free software; you can redistribute it and/or modify it
   3  *  under the terms of the GNU General Public License version 2 as published
   4  *  by the Free Software Foundation.
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/mtd/nand.h>
   9 #include <linux/of_gpio.h>
  10 #include <linux/of_platform.h>
  11 #include <linux/clk.h>
  12 #include <linux/reset.h>
  13 #include <mach/utils.h>
  14
  15 /* nand commands */
  16 #define NAND_CMD_ALE            BIT(18)
  17 #define NAND_CMD_CLE            BIT(19)
  18 #define NAND_CMD_CS             0
  19 #define NAND_CMD_RESET          0xff
  20 #define NAND_CMD                (NAND_CMD_CS | NAND_CMD_CLE)
  21 #define NAND_ADDR               (NAND_CMD_CS | NAND_CMD_ALE)
  22 #define NAND_DATA               (NAND_CMD_CS)
  23
  24 static void oxnas_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
  25 {
  26         struct nand_chip *this = mtd->priv;
  27         unsigned long nandaddr = (unsigned long) this->IO_ADDR_W;
  28
  29         if (ctrl & NAND_CTRL_CHANGE) {
  30                 nandaddr &= ~(NAND_CMD | NAND_ADDR);
  31                 if (ctrl & NAND_CLE)
  32                         nandaddr |= NAND_CMD;
  33                 else if (ctrl & NAND_ALE)
  34                         nandaddr |= NAND_ADDR;
  35                 this->IO_ADDR_W = (void __iomem *) nandaddr;
  36         }
  37
  38         if (cmd != NAND_CMD_NONE)
  39                 writeb(cmd, (void __iomem *) nandaddr);
  40 }
  41
  42 static int oxnas_nand_probe(struct platform_device *pdev)
  43 {
  44         /* enable clock and release static block reset */
  45         struct clk *clk = of_clk_get(pdev->dev.of_node, 0);
  46
  47         if (IS_ERR(clk))
  48                 return PTR_ERR(clk);
  49
  50         clk_prepare_enable(clk);
  51         device_reset(&pdev->dev);
  52
  53         return 0;
  54 }
  55
  56 /* allow users to override the partition in DT using the cmdline */
  57 static const char * part_probes[] = { "cmdlinepart", "ofpart", NULL };
  58
  59 static struct platform_nand_data oxnas_nand_data = {
  60         .chip = {
  61                 .nr_chips               = 1,
  62                 .chip_delay             = 30,
  63                 .part_probe_types       = part_probes,
  64         },
  65         .ctrl = {
  66                 .probe          = oxnas_nand_probe,
  67                 .cmd_ctrl       = oxnas_cmd_ctrl,
  68         }
  69 };
  70
  71 /*
  72  * Try to find the node inside the DT. If it is available attach out
  73  * platform_nand_data
  74  */
  75 static int __init oxnas_register_nand(void)
  76 {
  77         struct device_node *node;
  78         struct platform_device *pdev;
  79
  80         node = of_find_compatible_node(NULL, NULL, "plxtech,nand-nas782x");
  81         if (!node)
  82                 return -ENOENT;
  83         pdev = of_find_device_by_node(node);
  84         if (!pdev)
  85                 return -EINVAL;
  86         pdev->dev.platform_data = &oxnas_nand_data;
  87         of_node_put(node);
  88         return 0;
  89 }
  90
  91 subsys_initcall(oxnas_register_nand);
  92
  93 static const struct of_device_id oxnas_nand_ids[] = {
  94         { .compatible = "plxtech,nand-nas782x"},
  95         { /* sentinel */ }
  96 };
  97 MODULE_DEVICE_TABLE(of, oxnas_nand_ids);
  98
  99 MODULE_LICENSE("GPL");
 100 MODULE_AUTHOR("Ma Haijun");
 101 MODULE_DESCRIPTION("NAND glue for Oxnas platforms");
 102 MODULE_ALIAS("platform:oxnas_nand");