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 void __iomem *reg; 91 struct clk *clk; 92 93 reg = devm_platform_ioremap_resource(pdev, 0); 94 if (IS_ERR(reg)) 95 return PTR_ERR(reg); 96 97 clk = sun8i_a23_apb0_register(np, reg); 98 return PTR_ERR_OR_ZERO(clk); 99 } 100 101 static const struct of_device_id sun8i_a23_apb0_clk_dt_ids[] = { 102 { .compatible = "allwinner,sun8i-a23-apb0-clk" }, 103 { /* sentinel */ } 104 }; 105 106 static struct platform_driver sun8i_a23_apb0_clk_driver = { 107 .driver = { 108 .name = "sun8i-a23-apb0-clk", 109 .of_match_table = sun8i_a23_apb0_clk_dt_ids, 110 }, 111 .probe = sun8i_a23_apb0_clk_probe, 112 }; 113 builtin_platform_driver(sun8i_a23_apb0_clk_driver); 114