drivers/bus/imx-weim.c

   1 /*
   2  * EIM driver for Freescale's i.MX chips
   3  *
   4  * Copyright (C) 2013 Freescale Semiconductor, Inc.
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2. This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  */
  10 #include <linux/module.h>
  11 #include <linux/clk.h>
  12 #include <linux/io.h>
  13 #include <linux/of_device.h>
  14
  15 struct imx_weim_devtype {
  16         unsigned int    cs_count;
  17         unsigned int    cs_regs_count;
  18         unsigned int    cs_stride;
  19 };
  20
  21 static const struct imx_weim_devtype imx1_weim_devtype = {
  22         .cs_count       = 6,
  23         .cs_regs_count  = 2,
  24         .cs_stride      = 0x08,
  25 };
  26
  27 static const struct imx_weim_devtype imx27_weim_devtype = {
  28         .cs_count       = 6,
  29         .cs_regs_count  = 3,
  30         .cs_stride      = 0x10,
  31 };
  32
  33 static const struct imx_weim_devtype imx50_weim_devtype = {
  34         .cs_count       = 4,
  35         .cs_regs_count  = 6,
  36         .cs_stride      = 0x18,
  37 };
  38
  39 static const struct imx_weim_devtype imx51_weim_devtype = {
  40         .cs_count       = 6,
  41         .cs_regs_count  = 6,
  42         .cs_stride      = 0x18,
  43 };
  44
  45 static const struct of_device_id weim_id_table[] = {
  46         /* i.MX1/21 */
  47         { .compatible = "fsl,imx1-weim", .data = &imx1_weim_devtype, },
  48         /* i.MX25/27/31/35 */
  49         { .compatible = "fsl,imx27-weim", .data = &imx27_weim_devtype, },
  50         /* i.MX50/53/6Q */
  51         { .compatible = "fsl,imx50-weim", .data = &imx50_weim_devtype, },
  52         { .compatible = "fsl,imx6q-weim", .data = &imx50_weim_devtype, },
  53         /* i.MX51 */
  54         { .compatible = "fsl,imx51-weim", .data = &imx51_weim_devtype, },
  55         { }
  56 };
  57 MODULE_DEVICE_TABLE(of, weim_id_table);
  58
  59 /* Parse and set the timing for this device. */
  60 static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
  61                                     const struct imx_weim_devtype *devtype)
  62 {
  63         u32 cs_idx, value[devtype->cs_regs_count];
  64         int i, ret;
  65
  66         /* get the CS index from this child node's "reg" property. */
  67         ret = of_property_read_u32(np, "reg", &cs_idx);
  68         if (ret)
  69                 return ret;
  70
  71         if (cs_idx >= devtype->cs_count)
  72                 return -EINVAL;
  73
  74         ret = of_property_read_u32_array(np, "fsl,weim-cs-timing",
  75                                          value, devtype->cs_regs_count);
  76         if (ret)
  77                 return ret;
  78
  79         /* set the timing for WEIM */
  80         for (i = 0; i < devtype->cs_regs_count; i++)
  81                 writel(value[i], base + cs_idx * devtype->cs_stride + i * 4);
  82
  83         return 0;
  84 }
  85
  86 static int __init weim_parse_dt(struct platform_device *pdev,
  87                                 void __iomem *base)
  88 {
  89         const struct of_device_id *of_id = of_match_device(weim_id_table,
  90                                                            &pdev->dev);
  91         const struct imx_weim_devtype *devtype = of_id->data;
  92         struct device_node *child;
  93         int ret;
  94
  95         for_each_child_of_node(pdev->dev.of_node, child) {
  96                 if (!child->name)
  97                         continue;
  98
  99                 ret = weim_timing_setup(child, base, devtype);
 100                 if (ret) {
 101                         dev_err(&pdev->dev, "%s set timing failed.\n",
 102                                 child->full_name);
 103                         return ret;
 104                 }
 105         }
 106
 107         ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
 108         if (ret)
 109                 dev_err(&pdev->dev, "%s fail to create devices.\n",
 110                         pdev->dev.of_node->full_name);
 111         return ret;
 112 }
 113
 114 static int __init weim_probe(struct platform_device *pdev)
 115 {
 116         struct resource *res;
 117         struct clk *clk;
 118         void __iomem *base;
 119         int ret;
 120
 121         /* get the resource */
 122         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 123         base = devm_ioremap_resource(&pdev->dev, res);
 124         if (IS_ERR(base))
 125                 return PTR_ERR(base);
 126
 127         /* get the clock */
 128         clk = devm_clk_get(&pdev->dev, NULL);
 129         if (IS_ERR(clk))
 130                 return PTR_ERR(clk);
 131
 132         ret = clk_prepare_enable(clk);
 133         if (ret)
 134                 return ret;
 135
 136         /* parse the device node */
 137         ret = weim_parse_dt(pdev, base);
 138         if (ret)
 139                 clk_disable_unprepare(clk);
 140         else
 141                 dev_info(&pdev->dev, "Driver registered.\n");
 142
 143         return ret;
 144 }
 145
 146 static struct platform_driver weim_driver = {
 147         .driver = {
 148                 .name           = "imx-weim",
 149                 .owner          = THIS_MODULE,
 150                 .of_match_table = weim_id_table,
 151         },
 152 };
 153 module_platform_driver_probe(weim_driver, weim_probe);
 154
 155 MODULE_AUTHOR("Freescale Semiconductor Inc.");
 156 MODULE_DESCRIPTION("i.MX EIM Controller Driver");
 157 MODULE_LICENSE("GPL");