LXR linux/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
  21static 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
  70static 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
  77static const struct of_device_id armada_3700_xtal_clock_of_match[] = {
  78        { .compatible = "marvell,armada-3700-xtal-clock", },
  79        { }
  80};
  81
  82static 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
  91builtin_platform_driver(armada_3700_xtal_clock_driver);
  92