drivers/clk/mvebu/armada-37xx-xtal.c

   1 /*
   2  * Marvell Armada 37xx SoC xtal clocks
   3  *
   4  * Copyright (C) 2016 Marvell
   5  *
   6  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2.  This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #include <linux/clk-provider.h>
  14 #include <linux/mfd/syscon.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/regmap.h>
  17
  18 #define NB_GPIO1_LATCH  0xC
  19 #define XTAL_MODE           BIT(31)
  20
  21 static int armada_3700_xtal_clock_probe(struct platform_device *pdev)
  22 {
  23         struct device_node *np = pdev->dev.of_node;
  24         const char *xtal_name = "xtal";
  25         struct device_node *parent;
  26         struct regmap *regmap;
  27         struct clk_hw *xtal_hw;
  28         unsigned int rate;
  29         u32 reg;
  30         int ret;
  31
  32         xtal_hw = devm_kzalloc(&pdev->dev, sizeof(*xtal_hw), GFP_KERNEL);
  33         if (!xtal_hw)
  34                 return -ENOMEM;
  35
  36         platform_set_drvdata(pdev, xtal_hw);
  37
  38         parent = np->parent;
  39         if (!parent) {
  40                 dev_err(&pdev->dev, "no parent\n");
  41                 return -ENODEV;
  42         }
  43
  44         regmap = syscon_node_to_regmap(parent);
  45         if (IS_ERR(regmap)) {
  46                 dev_err(&pdev->dev, "cannot get regmap\n");
  47                 return PTR_ERR(regmap);
  48         }
  49
  50         ret = regmap_read(regmap, NB_GPIO1_LATCH, &reg);
  51         if (ret) {
  52                 dev_err(&pdev->dev, "cannot read from regmap\n");
  53                 return ret;
  54         }
  55
  56         if (reg & XTAL_MODE)
  57                 rate = 40000000;
  58         else
  59                 rate = 25000000;
  60
  61         of_property_read_string_index(np, "clock-output-names", 0, &xtal_name);
  62         xtal_hw = clk_hw_register_fixed_rate(NULL, xtal_name, NULL, 0, rate);
  63         if (IS_ERR(xtal_hw))
  64                 return PTR_ERR(xtal_hw);
  65         ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, xtal_hw);
  66
  67         return ret;
  68 }
  69
  70 static int armada_3700_xtal_clock_remove(struct platform_device *pdev)
  71 {
  72         of_clk_del_provider(pdev->dev.of_node);
  73
  74         return 0;
  75 }
  76
  77 static const struct of_device_id armada_3700_xtal_clock_of_match[] = {
  78         { .compatible = "marvell,armada-3700-xtal-clock", },
  79         { }
  80 };
  81
  82 static struct platform_driver armada_3700_xtal_clock_driver = {
  83         .probe = armada_3700_xtal_clock_probe,
  84         .remove = armada_3700_xtal_clock_remove,
  85         .driver         = {
  86                 .name   = "marvell-armada-3700-xtal-clock",
  87                 .of_match_table = armada_3700_xtal_clock_of_match,
  88         },
  89 };
  90
  91 builtin_platform_driver(armada_3700_xtal_clock_driver);