drivers/nvmem/imx-iim.c

   1 /*
   2  * i.MX IIM driver
   3  *
   4  * Copyright (c) 2017 Pengutronix, Michael Grzeschik <m.grzeschik@pengutronix.de>
   5  *
   6  * Based on the barebox iim driver,
   7  * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
   8  *      Orex Computed Radiography
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2
  12  * as published by the Free Software Foundation.
  13  *
  14  * http://www.opensource.org/licenses/gpl-license.html
  15  * http://www.gnu.org/copyleft/gpl.html
  16  */
  17
  18 #include <linux/device.h>
  19 #include <linux/io.h>
  20 #include <linux/module.h>
  21 #include <linux/nvmem-provider.h>
  22 #include <linux/of.h>
  23 #include <linux/of_device.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/slab.h>
  26 #include <linux/clk.h>
  27
  28 #define IIM_BANK_BASE(n)        (0x800 + 0x400 * (n))
  29
  30 struct imx_iim_drvdata {
  31         unsigned int nregs;
  32 };
  33
  34 struct iim_priv {
  35         void __iomem *base;
  36         struct clk *clk;
  37 };
  38
  39 static int imx_iim_read(void *context, unsigned int offset,
  40                           void *buf, size_t bytes)
  41 {
  42         struct iim_priv *iim = context;
  43         int i, ret;
  44         u8 *buf8 = buf;
  45
  46         ret = clk_prepare_enable(iim->clk);
  47         if (ret)
  48                 return ret;
  49
  50         for (i = offset; i < offset + bytes; i++) {
  51                 int bank = i >> 5;
  52                 int reg = i & 0x1f;
  53
  54                 *buf8++ = readl(iim->base + IIM_BANK_BASE(bank) + reg * 4);
  55         }
  56
  57         clk_disable_unprepare(iim->clk);
  58
  59         return 0;
  60 }
  61
  62 static struct imx_iim_drvdata imx27_drvdata = {
  63         .nregs = 2 * 32,
  64 };
  65
  66 static struct imx_iim_drvdata imx25_imx31_imx35_drvdata = {
  67         .nregs = 3 * 32,
  68 };
  69
  70 static struct imx_iim_drvdata imx51_drvdata = {
  71         .nregs = 4 * 32,
  72 };
  73
  74 static struct imx_iim_drvdata imx53_drvdata = {
  75         .nregs = 4 * 32 + 16,
  76 };
  77
  78 static const struct of_device_id imx_iim_dt_ids[] = {
  79         {
  80                 .compatible = "fsl,imx25-iim",
  81                 .data = &imx25_imx31_imx35_drvdata,
  82         }, {
  83                 .compatible = "fsl,imx27-iim",
  84                 .data = &imx27_drvdata,
  85         }, {
  86                 .compatible = "fsl,imx31-iim",
  87                 .data = &imx25_imx31_imx35_drvdata,
  88         }, {
  89                 .compatible = "fsl,imx35-iim",
  90                 .data = &imx25_imx31_imx35_drvdata,
  91         }, {
  92                 .compatible = "fsl,imx51-iim",
  93                 .data = &imx51_drvdata,
  94         }, {
  95                 .compatible = "fsl,imx53-iim",
  96                 .data = &imx53_drvdata,
  97         }, {
  98                 /* sentinel */
  99         },
 100 };
 101 MODULE_DEVICE_TABLE(of, imx_iim_dt_ids);
 102
 103 static int imx_iim_probe(struct platform_device *pdev)
 104 {
 105         const struct of_device_id *of_id;
 106         struct device *dev = &pdev->dev;
 107         struct resource *res;
 108         struct iim_priv *iim;
 109         struct nvmem_device *nvmem;
 110         struct nvmem_config cfg = {};
 111         const struct imx_iim_drvdata *drvdata = NULL;
 112
 113         iim = devm_kzalloc(dev, sizeof(*iim), GFP_KERNEL);
 114         if (!iim)
 115                 return -ENOMEM;
 116
 117         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 118         iim->base = devm_ioremap_resource(dev, res);
 119         if (IS_ERR(iim->base))
 120                 return PTR_ERR(iim->base);
 121
 122         of_id = of_match_device(imx_iim_dt_ids, dev);
 123         if (!of_id)
 124                 return -ENODEV;
 125
 126         drvdata = of_id->data;
 127
 128         iim->clk = devm_clk_get(dev, NULL);
 129         if (IS_ERR(iim->clk))
 130                 return PTR_ERR(iim->clk);
 131
 132         cfg.name = "imx-iim",
 133         cfg.read_only = true,
 134         cfg.word_size = 1,
 135         cfg.stride = 1,
 136         cfg.reg_read = imx_iim_read,
 137         cfg.dev = dev;
 138         cfg.size = drvdata->nregs;
 139         cfg.priv = iim;
 140
 141         nvmem = devm_nvmem_register(dev, &cfg);
 142
 143         return PTR_ERR_OR_ZERO(nvmem);
 144 }
 145
 146 static struct platform_driver imx_iim_driver = {
 147         .probe  = imx_iim_probe,
 148         .driver = {
 149                 .name   = "imx-iim",
 150                 .of_match_table = imx_iim_dt_ids,
 151         },
 152 };
 153 module_platform_driver(imx_iim_driver);
 154
 155 MODULE_AUTHOR("Michael Grzeschik <m.grzeschik@pengutronix.de>");
 156 MODULE_DESCRIPTION("i.MX IIM driver");
 157 MODULE_LICENSE("GPL v2");