drivers/clk/sunxi/clk-sun8i-apb0.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2014 Chen-Yu Tsai
   4  * Author: Chen-Yu Tsai <wens@csie.org>
   5  *
   6  * Allwinner A23 APB0 clock driver
   7  *
   8  * Based on clk-sun6i-apb0.c
   9  * Allwinner A31 APB0 clock driver
  10  *
  11  * Copyright (C) 2014 Free Electrons
  12  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
  13  */
  14
  15 #include <linux/clk-provider.h>
  16 #include <linux/init.h>
  17 #include <linux/io.h>
  18 #include <linux/of.h>
  19 #include <linux/of_address.h>
  20 #include <linux/platform_device.h>
  21
  22 static struct clk *sun8i_a23_apb0_register(struct device_node *node,
  23                                            void __iomem *reg)
  24 {
  25         const char *clk_name = node->name;
  26         const char *clk_parent;
  27         struct clk *clk;
  28         int ret;
  29
  30         clk_parent = of_clk_get_parent_name(node, 0);
  31         if (!clk_parent)
  32                 return ERR_PTR(-EINVAL);
  33
  34         of_property_read_string(node, "clock-output-names", &clk_name);
  35
  36         /* The A23 APB0 clock is a standard 2 bit wide divider clock */
  37         clk = clk_register_divider(NULL, clk_name, clk_parent, 0, reg,
  38                                    0, 2, 0, NULL);
  39         if (IS_ERR(clk))
  40                 return clk;
  41
  42         ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
  43         if (ret)
  44                 goto err_unregister;
  45
  46         return clk;
  47
  48 err_unregister:
  49         clk_unregister_divider(clk);
  50
  51         return ERR_PTR(ret);
  52 }
  53
  54 static void sun8i_a23_apb0_setup(struct device_node *node)
  55 {
  56         void __iomem *reg;
  57         struct resource res;
  58         struct clk *clk;
  59
  60         reg = of_io_request_and_map(node, 0, of_node_full_name(node));
  61         if (IS_ERR(reg)) {
  62                 /*
  63                  * This happens with clk nodes instantiated through mfd,
  64                  * as those do not have their resources assigned in the
  65                  * device tree. Do not print an error in this case.
  66                  */
  67                 if (PTR_ERR(reg) != -EINVAL)
  68                         pr_err("Could not get registers for a23-apb0-clk\n");
  69
  70                 return;
  71         }
  72
  73         clk = sun8i_a23_apb0_register(node, reg);
  74         if (IS_ERR(clk))
  75                 goto err_unmap;
  76
  77         return;
  78
  79 err_unmap:
  80         iounmap(reg);
  81         of_address_to_resource(node, 0, &res);
  82         release_mem_region(res.start, resource_size(&res));
  83 }
  84 CLK_OF_DECLARE_DRIVER(sun8i_a23_apb0, "allwinner,sun8i-a23-apb0-clk",
  85                       sun8i_a23_apb0_setup);
  86
  87 static int sun8i_a23_apb0_clk_probe(struct platform_device *pdev)
  88 {
  89         struct device_node *np = pdev->dev.of_node;
  90         struct resource *r;
  91         void __iomem *reg;
  92         struct clk *clk;
  93
  94         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  95         reg = devm_ioremap_resource(&pdev->dev, r);
  96         if (IS_ERR(reg))
  97                 return PTR_ERR(reg);
  98
  99         clk = sun8i_a23_apb0_register(np, reg);
 100         return PTR_ERR_OR_ZERO(clk);
 101 }
 102
 103 static const struct of_device_id sun8i_a23_apb0_clk_dt_ids[] = {
 104         { .compatible = "allwinner,sun8i-a23-apb0-clk" },
 105         { /* sentinel */ }
 106 };
 107
 108 static struct platform_driver sun8i_a23_apb0_clk_driver = {
 109         .driver = {
 110                 .name = "sun8i-a23-apb0-clk",
 111                 .of_match_table = sun8i_a23_apb0_clk_dt_ids,
 112         },
 113         .probe = sun8i_a23_apb0_clk_probe,
 114 };
 115 builtin_platform_driver(sun8i_a23_apb0_clk_driver);