drivers/clk/sunxi/clk-sun6i-apb0.c

   1 /*
   2  * Copyright (C) 2014 Free Electrons
   3  *
   4  * License Terms: GNU General Public License v2
   5  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
   6  *
   7  * Allwinner A31 APB0 clock driver
   8  *
   9  */
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/init.h>
  13 #include <linux/of.h>
  14 #include <linux/platform_device.h>
  15
  16 /*
  17  * The APB0 clk has a configurable divisor.
  18  *
  19  * We must use a clk_div_table and not a regular power of 2
  20  * divisor here, because the first 2 values divide the clock
  21  * by 2.
  22  */
  23 static const struct clk_div_table sun6i_a31_apb0_divs[] = {
  24         { .val = 0, .div = 2, },
  25         { .val = 1, .div = 2, },
  26         { .val = 2, .div = 4, },
  27         { .val = 3, .div = 8, },
  28         { /* sentinel */ },
  29 };
  30
  31 static int sun6i_a31_apb0_clk_probe(struct platform_device *pdev)
  32 {
  33         struct device_node *np = pdev->dev.of_node;
  34         const char *clk_name = np->name;
  35         const char *clk_parent;
  36         struct resource *r;
  37         void __iomem *reg;
  38         struct clk *clk;
  39
  40         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  41         reg = devm_ioremap_resource(&pdev->dev, r);
  42         if (IS_ERR(reg))
  43                 return PTR_ERR(reg);
  44
  45         clk_parent = of_clk_get_parent_name(np, 0);
  46         if (!clk_parent)
  47                 return -EINVAL;
  48
  49         of_property_read_string(np, "clock-output-names", &clk_name);
  50
  51         clk = clk_register_divider_table(&pdev->dev, clk_name, clk_parent,
  52                                          0, reg, 0, 2, 0, sun6i_a31_apb0_divs,
  53                                          NULL);
  54         if (IS_ERR(clk))
  55                 return PTR_ERR(clk);
  56
  57         return of_clk_add_provider(np, of_clk_src_simple_get, clk);
  58 }
  59
  60 static const struct of_device_id sun6i_a31_apb0_clk_dt_ids[] = {
  61         { .compatible = "allwinner,sun6i-a31-apb0-clk" },
  62         { /* sentinel */ }
  63 };
  64
  65 static struct platform_driver sun6i_a31_apb0_clk_driver = {
  66         .driver = {
  67                 .name = "sun6i-a31-apb0-clk",
  68                 .of_match_table = sun6i_a31_apb0_clk_dt_ids,
  69         },
  70         .probe = sun6i_a31_apb0_clk_probe,
  71 };
  72 builtin_platform_driver(sun6i_a31_apb0_clk_driver);