clk/sunxi/clk-sun8i-apb0.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (C) 2014 Chen-Yu Tsai
0004  * Author: Chen-Yu Tsai <wens@csie.org>
0005  *
0006  * Allwinner A23 APB0 clock driver
0007  *
0008  * Based on clk-sun6i-apb0.c
0009  * Allwinner A31 APB0 clock driver
0010  *
0011  * Copyright (C) 2014 Free Electrons
0012  * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
0013  */
0014
0015 #include <linux/clk-provider.h>
0016 #include <linux/init.h>
0017 #include <linux/io.h>
0018 #include <linux/of.h>
0019 #include <linux/of_address.h>
0020 #include <linux/platform_device.h>
0021
0022 static struct clk *sun8i_a23_apb0_register(struct device_node *node,
0023                        void __iomem *reg)
0024 {
0025     const char *clk_name = node->name;
0026     const char *clk_parent;
0027     struct clk *clk;
0028     int ret;
0029
0030     clk_parent = of_clk_get_parent_name(node, 0);
0031     if (!clk_parent)
0032         return ERR_PTR(-EINVAL);
0033
0034     of_property_read_string(node, "clock-output-names", &clk_name);
0035
0036     /* The A23 APB0 clock is a standard 2 bit wide divider clock */
0037     clk = clk_register_divider(NULL, clk_name, clk_parent, 0, reg,
0038                    0, 2, 0, NULL);
0039     if (IS_ERR(clk))
0040         return clk;
0041
0042     ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
0043     if (ret)
0044         goto err_unregister;
0045
0046     return clk;
0047
0048 err_unregister:
0049     clk_unregister_divider(clk);
0050
0051     return ERR_PTR(ret);
0052 }
0053
0054 static void sun8i_a23_apb0_setup(struct device_node *node)
0055 {
0056     void __iomem *reg;
0057     struct resource res;
0058     struct clk *clk;
0059
0060     reg = of_io_request_and_map(node, 0, of_node_full_name(node));
0061     if (IS_ERR(reg)) {
0062         /*
0063          * This happens with clk nodes instantiated through mfd,
0064          * as those do not have their resources assigned in the
0065          * device tree. Do not print an error in this case.
0066          */
0067         if (PTR_ERR(reg) != -EINVAL)
0068             pr_err("Could not get registers for a23-apb0-clk\n");
0069
0070         return;
0071     }
0072
0073     clk = sun8i_a23_apb0_register(node, reg);
0074     if (IS_ERR(clk))
0075         goto err_unmap;
0076
0077     return;
0078
0079 err_unmap:
0080     iounmap(reg);
0081     of_address_to_resource(node, 0, &res);
0082     release_mem_region(res.start, resource_size(&res));
0083 }
0084 CLK_OF_DECLARE_DRIVER(sun8i_a23_apb0, "allwinner,sun8i-a23-apb0-clk",
0085               sun8i_a23_apb0_setup);
0086
0087 static int sun8i_a23_apb0_clk_probe(struct platform_device *pdev)
0088 {
0089     struct device_node *np = pdev->dev.of_node;
0090     void __iomem *reg;
0091     struct clk *clk;
0092
0093     reg = devm_platform_ioremap_resource(pdev, 0);
0094     if (IS_ERR(reg))
0095         return PTR_ERR(reg);
0096
0097     clk = sun8i_a23_apb0_register(np, reg);
0098     return PTR_ERR_OR_ZERO(clk);
0099 }
0100
0101 static const struct of_device_id sun8i_a23_apb0_clk_dt_ids[] = {
0102     { .compatible = "allwinner,sun8i-a23-apb0-clk" },
0103     { /* sentinel */ }
0104 };
0105
0106 static struct platform_driver sun8i_a23_apb0_clk_driver = {
0107     .driver = {
0108         .name = "sun8i-a23-apb0-clk",
0109         .of_match_table = sun8i_a23_apb0_clk_dt_ids,
0110     },
0111     .probe = sun8i_a23_apb0_clk_probe,
0112 };
0113 builtin_platform_driver(sun8i_a23_apb0_clk_driver);