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);