LXR linux/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
  22static 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
  48err_unregister:
  49        clk_unregister_divider(clk);
  50
  51        return ERR_PTR(ret);
  52}
  53
  54static 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
  79err_unmap:
  80        iounmap(reg);
  81        of_address_to_resource(node, 0, &res);
  82        release_mem_region(res.start, resource_size(&res));
  83}
  84CLK_OF_DECLARE_DRIVER(sun8i_a23_apb0, "allwinner,sun8i-a23-apb0-clk",
  85                      sun8i_a23_apb0_setup);
  86
  87static 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
 103static const struct of_device_id sun8i_a23_apb0_clk_dt_ids[] = {
 104        { .compatible = "allwinner,sun8i-a23-apb0-clk" },
 105        { /* sentinel */ }
 106};
 107
 108static 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};
 115builtin_platform_driver(sun8i_a23_apb0_clk_driver);
 116