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         struct nvmem_config nvmem;
  38 };
  39
  40 static int imx_iim_read(void *context, unsigned int offset,
  41                           void *buf, size_t bytes)
  42 {
  43         struct iim_priv *iim = context;
  44         int i, ret;
  45         u8 *buf8 = buf;
  46
  47         ret = clk_prepare_enable(iim->clk);
  48         if (ret)
  49                 return ret;
  50
  51         for (i = offset; i < offset + bytes; i++) {
  52                 int bank = i >> 5;
  53                 int reg = i & 0x1f;
  54
  55                 *buf8++ = readl(iim->base + IIM_BANK_BASE(bank) + reg * 4);
  56         }
  57
  58         clk_disable_unprepare(iim->clk);
  59
  60         return 0;
  61 }
  62
  63 static struct imx_iim_drvdata imx27_drvdata = {
  64         .nregs = 2 * 32,
  65 };
  66
  67 static struct imx_iim_drvdata imx25_imx31_imx35_drvdata = {
  68         .nregs = 3 * 32,
  69 };
  70
  71 static struct imx_iim_drvdata imx51_drvdata = {
  72         .nregs = 4 * 32,
  73 };
  74
  75 static struct imx_iim_drvdata imx53_drvdata = {
  76         .nregs = 4 * 32 + 16,
  77 };
  78
  79 static const struct of_device_id imx_iim_dt_ids[] = {
  80         {
  81                 .compatible = "fsl,imx25-iim",
  82                 .data = &imx25_imx31_imx35_drvdata,
  83         }, {
  84                 .compatible = "fsl,imx27-iim",
  85                 .data = &imx27_drvdata,
  86         }, {
  87                 .compatible = "fsl,imx31-iim",
  88                 .data = &imx25_imx31_imx35_drvdata,
  89         }, {
  90                 .compatible = "fsl,imx35-iim",
  91                 .data = &imx25_imx31_imx35_drvdata,
  92         }, {
  93                 .compatible = "fsl,imx51-iim",
  94                 .data = &imx51_drvdata,
  95         }, {
  96                 .compatible = "fsl,imx53-iim",
  97                 .data = &imx53_drvdata,
  98         }, {
  99                 /* sentinel */
 100         },
 101 };
 102 MODULE_DEVICE_TABLE(of, imx_iim_dt_ids);
 103
 104 static int imx_iim_probe(struct platform_device *pdev)
 105 {
 106         const struct of_device_id *of_id;
 107         struct device *dev = &pdev->dev;
 108         struct resource *res;
 109         struct iim_priv *iim;
 110         struct nvmem_device *nvmem;
 111         struct nvmem_config *cfg;
 112         const struct imx_iim_drvdata *drvdata = NULL;
 113
 114         iim = devm_kzalloc(dev, sizeof(*iim), GFP_KERNEL);
 115         if (!iim)
 116                 return -ENOMEM;
 117
 118         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 119         iim->base = devm_ioremap_resource(dev, res);
 120         if (IS_ERR(iim->base))
 121                 return PTR_ERR(iim->base);
 122
 123         of_id = of_match_device(imx_iim_dt_ids, dev);
 124         if (!of_id)
 125                 return -ENODEV;
 126
 127         drvdata = of_id->data;
 128
 129         iim->clk = devm_clk_get(&pdev->dev, NULL);
 130         if (IS_ERR(iim->clk))
 131                 return PTR_ERR(iim->clk);
 132
 133         cfg = &iim->nvmem;
 134
 135         cfg->name = "imx-iim",
 136         cfg->read_only = true,
 137         cfg->word_size = 1,
 138         cfg->stride = 1,
 139         cfg->owner = THIS_MODULE,
 140         cfg->reg_read = imx_iim_read,
 141         cfg->dev = dev;
 142         cfg->size = drvdata->nregs;
 143         cfg->priv = iim;
 144
 145         nvmem = nvmem_register(cfg);
 146         if (IS_ERR(nvmem))
 147                 return PTR_ERR(nvmem);
 148
 149         platform_set_drvdata(pdev, nvmem);
 150
 151         return 0;
 152 }
 153
 154 static int imx_iim_remove(struct platform_device *pdev)
 155 {
 156         struct nvmem_device *nvmem = platform_get_drvdata(pdev);
 157
 158         return nvmem_unregister(nvmem);
 159 }
 160
 161 static struct platform_driver imx_iim_driver = {
 162         .probe  = imx_iim_probe,
 163         .remove = imx_iim_remove,
 164         .driver = {
 165                 .name   = "imx-iim",
 166                 .of_match_table = imx_iim_dt_ids,
 167         },
 168 };
 169 module_platform_driver(imx_iim_driver);
 170
 171 MODULE_AUTHOR("Michael Grzeschik <m.grzeschik@pengutronix.de>");
 172 MODULE_DESCRIPTION("i.MX IIM driver");
 173 MODULE_LICENSE("GPL v2");