drivers/nvmem/imx-iim.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * i.MX IIM driver
   4  *
   5  * Copyright (c) 2017 Pengutronix, Michael Grzeschik <m.grzeschik@pengutronix.de>
   6  *
   7  * Based on the barebox iim driver,
   8  * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>,
   9  *      Orex Computed Radiography
  10  */
  11
  12 #include <linux/device.h>
  13 #include <linux/io.h>
  14 #include <linux/module.h>
  15 #include <linux/nvmem-provider.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/slab.h>
  20 #include <linux/clk.h>
  21
  22 #define IIM_BANK_BASE(n)        (0x800 + 0x400 * (n))
  23
  24 struct imx_iim_drvdata {
  25         unsigned int nregs;
  26 };
  27
  28 struct iim_priv {
  29         void __iomem *base;
  30         struct clk *clk;
  31 };
  32
  33 static int imx_iim_read(void *context, unsigned int offset,
  34                           void *buf, size_t bytes)
  35 {
  36         struct iim_priv *iim = context;
  37         int i, ret;
  38         u8 *buf8 = buf;
  39
  40         ret = clk_prepare_enable(iim->clk);
  41         if (ret)
  42                 return ret;
  43
  44         for (i = offset; i < offset + bytes; i++) {
  45                 int bank = i >> 5;
  46                 int reg = i & 0x1f;
  47
  48                 *buf8++ = readl(iim->base + IIM_BANK_BASE(bank) + reg * 4);
  49         }
  50
  51         clk_disable_unprepare(iim->clk);
  52
  53         return 0;
  54 }
  55
  56 static struct imx_iim_drvdata imx27_drvdata = {
  57         .nregs = 2 * 32,
  58 };
  59
  60 static struct imx_iim_drvdata imx25_imx31_imx35_drvdata = {
  61         .nregs = 3 * 32,
  62 };
  63
  64 static struct imx_iim_drvdata imx51_drvdata = {
  65         .nregs = 4 * 32,
  66 };
  67
  68 static struct imx_iim_drvdata imx53_drvdata = {
  69         .nregs = 4 * 32 + 16,
  70 };
  71
  72 static const struct of_device_id imx_iim_dt_ids[] = {
  73         {
  74                 .compatible = "fsl,imx25-iim",
  75                 .data = &imx25_imx31_imx35_drvdata,
  76         }, {
  77                 .compatible = "fsl,imx27-iim",
  78                 .data = &imx27_drvdata,
  79         }, {
  80                 .compatible = "fsl,imx31-iim",
  81                 .data = &imx25_imx31_imx35_drvdata,
  82         }, {
  83                 .compatible = "fsl,imx35-iim",
  84                 .data = &imx25_imx31_imx35_drvdata,
  85         }, {
  86                 .compatible = "fsl,imx51-iim",
  87                 .data = &imx51_drvdata,
  88         }, {
  89                 .compatible = "fsl,imx53-iim",
  90                 .data = &imx53_drvdata,
  91         }, {
  92                 /* sentinel */
  93         },
  94 };
  95 MODULE_DEVICE_TABLE(of, imx_iim_dt_ids);
  96
  97 static int imx_iim_probe(struct platform_device *pdev)
  98 {
  99         const struct of_device_id *of_id;
 100         struct device *dev = &pdev->dev;
 101         struct iim_priv *iim;
 102         struct nvmem_device *nvmem;
 103         struct nvmem_config cfg = {};
 104         const struct imx_iim_drvdata *drvdata = NULL;
 105
 106         iim = devm_kzalloc(dev, sizeof(*iim), GFP_KERNEL);
 107         if (!iim)
 108                 return -ENOMEM;
 109
 110         iim->base = devm_platform_ioremap_resource(pdev, 0);
 111         if (IS_ERR(iim->base))
 112                 return PTR_ERR(iim->base);
 113
 114         of_id = of_match_device(imx_iim_dt_ids, dev);
 115         if (!of_id)
 116                 return -ENODEV;
 117
 118         drvdata = of_id->data;
 119
 120         iim->clk = devm_clk_get(dev, NULL);
 121         if (IS_ERR(iim->clk))
 122                 return PTR_ERR(iim->clk);
 123
 124         cfg.name = "imx-iim",
 125         cfg.read_only = true,
 126         cfg.word_size = 1,
 127         cfg.stride = 1,
 128         cfg.reg_read = imx_iim_read,
 129         cfg.dev = dev;
 130         cfg.size = drvdata->nregs;
 131         cfg.priv = iim;
 132
 133         nvmem = devm_nvmem_register(dev, &cfg);
 134
 135         return PTR_ERR_OR_ZERO(nvmem);
 136 }
 137
 138 static struct platform_driver imx_iim_driver = {
 139         .probe  = imx_iim_probe,
 140         .driver = {
 141                 .name   = "imx-iim",
 142                 .of_match_table = imx_iim_dt_ids,
 143         },
 144 };
 145 module_platform_driver(imx_iim_driver);
 146
 147 MODULE_AUTHOR("Michael Grzeschik <m.grzeschik@pengutronix.de>");
 148 MODULE_DESCRIPTION("i.MX IIM driver");
 149 MODULE_LICENSE("GPL v2");