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  *  based on xway_nand.c
   7  *  Copyright © 2012 John Crispin <blogic@openwrt.org>
   8  *  and oxnas_nand.c "NAND glue for Oxnas platforms"
   9  *  written by Ma Haijun <mahaijuns@gmail.com>
  10  */
  11
  12 #include <linux/mtd/nand.h>
  13 #include <linux/of_gpio.h>
  14 #include <linux/of_platform.h>
  15 #include <linux/clk.h>
  16 #include <linux/reset.h>
  17
  18 /* nand commands */
  19 #define NAND_CMD_ALE            BIT(18)
  20 #define NAND_CMD_CLE            BIT(19)
  21 #define NAND_CMD_CS             0
  22 #define NAND_CMD_RESET          0xff
  23 #define NAND_CMD                (NAND_CMD_CS | NAND_CMD_CLE)
  24 #define NAND_ADDR               (NAND_CMD_CS | NAND_CMD_ALE)
  25 #define NAND_DATA               (NAND_CMD_CS)
  26
  27 static void oxnas_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
  28 {
  29         struct nand_chip *this = mtd->priv;
  30         unsigned long nandaddr = (unsigned long) this->IO_ADDR_W;
  31
  32         if (ctrl & NAND_CTRL_CHANGE) {
  33                 nandaddr &= ~(NAND_CMD | NAND_ADDR);
  34                 if (ctrl & NAND_CLE)
  35                         nandaddr |= NAND_CMD;
  36                 else if (ctrl & NAND_ALE)
  37                         nandaddr |= NAND_ADDR;
  38                 this->IO_ADDR_W = (void __iomem *) nandaddr;
  39         }
  40
  41         if (cmd != NAND_CMD_NONE)
  42                 writeb(cmd, (void __iomem *) nandaddr);
  43 }
  44
  45 static int oxnas_nand_probe(struct platform_device *pdev)
  46 {
  47         /* enable clock and release static block reset */
  48         struct clk *clk = of_clk_get(pdev->dev.of_node, 0);
  49
  50         if (IS_ERR(clk))
  51                 return PTR_ERR(clk);
  52
  53         clk_prepare_enable(clk);
  54         device_reset(&pdev->dev);
  55
  56         return 0;
  57 }
  58
  59 /* allow users to override the partition in DT using the cmdline */
  60 static const char * part_probes[] = { "cmdlinepart", "ofpart", NULL };
  61
  62 static struct platform_nand_data oxnas_nand_data = {
  63         .chip = {
  64                 .nr_chips               = 1,
  65                 .chip_delay             = 30,
  66                 .part_probe_types       = part_probes,
  67         },
  68         .ctrl = {
  69                 .probe          = oxnas_nand_probe,
  70                 .cmd_ctrl       = oxnas_cmd_ctrl,
  71         }
  72 };
  73
  74 /*
  75  * Try to find the node inside the DT. If it is available attach out
  76  * platform_nand_data
  77  */
  78 static int __init oxnas_register_nand(void)
  79 {
  80         struct device_node *node;
  81         struct platform_device *pdev;
  82
  83         node = of_find_compatible_node(NULL, NULL, "plxtech,nand-nas782x");
  84         if (!node)
  85                 return -ENOENT;
  86         pdev = of_find_device_by_node(node);
  87         if (!pdev)
  88                 return -EINVAL;
  89         pdev->dev.platform_data = &oxnas_nand_data;
  90         of_node_put(node);
  91         return 0;
  92 }
  93
  94 subsys_initcall(oxnas_register_nand);