1/*
  2 * Copyright (C) 2014 Chen-Yu Tsai
  3 * Author: Chen-Yu Tsai <wens@csie.org>
  4 *
  5 * Allwinner A23 APB0 clock driver
  6 *
  7 * License Terms: GNU General Public License v2
  8 *
  9 * Based on clk-sun6i-apb0.c
 10 * Allwinner A31 APB0 clock driver
 11 *
 12 * Copyright (C) 2014 Free Electrons
 13 * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
 14 *
 15 */
 16
 17#include <linux/clk-provider.h>
 18#include <linux/init.h>
 19#include <linux/of.h>
 20#include <linux/of_address.h>
 21#include <linux/platform_device.h>
 22
 23static struct clk *sun8i_a23_apb0_register(struct device_node *node,
 24					   void __iomem *reg)
 25{
 26	const char *clk_name = node->name;
 27	const char *clk_parent;
 28	struct clk *clk;
 29	int ret;
 30
 31	clk_parent = of_clk_get_parent_name(node, 0);
 32	if (!clk_parent)
 33		return ERR_PTR(-EINVAL);
 34
 35	of_property_read_string(node, "clock-output-names", &clk_name);
 36
 37	/* The A23 APB0 clock is a standard 2 bit wide divider clock */
 38	clk = clk_register_divider(NULL, clk_name, clk_parent, 0, reg,
 39				   0, 2, 0, NULL);
 40	if (IS_ERR(clk))
 41		return clk;
 42
 43	ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
 44	if (ret)
 45		goto err_unregister;
 46
 47	return clk;
 48
 49err_unregister:
 50	clk_unregister_divider(clk);
 51
 52	return ERR_PTR(ret);
 53}
 54
 55static void sun8i_a23_apb0_setup(struct device_node *node)
 56{
 57	void __iomem *reg;
 58	struct resource res;
 59	struct clk *clk;
 60
 61	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
 62	if (IS_ERR(reg)) {
 63		/*
 64		 * This happens with clk nodes instantiated through mfd,
 65		 * as those do not have their resources assigned in the
 66		 * device tree. Do not print an error in this case.
 67		 */
 68		if (PTR_ERR(reg) != -EINVAL)
 69			pr_err("Could not get registers for a23-apb0-clk\n");
 70
 71		return;
 72	}
 73
 74	clk = sun8i_a23_apb0_register(node, reg);
 75	if (IS_ERR(clk))
 76		goto err_unmap;
 77
 78	return;
 79
 80err_unmap:
 81	iounmap(reg);
 82	of_address_to_resource(node, 0, &res);
 83	release_mem_region(res.start, resource_size(&res));
 84}
 85CLK_OF_DECLARE_DRIVER(sun8i_a23_apb0, "allwinner,sun8i-a23-apb0-clk",
 86		      sun8i_a23_apb0_setup);
 87
 88static int sun8i_a23_apb0_clk_probe(struct platform_device *pdev)
 89{
 90	struct device_node *np = pdev->dev.of_node;
 91	struct resource *r;
 92	void __iomem *reg;
 93	struct clk *clk;
 94
 95	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 96	reg = devm_ioremap_resource(&pdev->dev, r);
 97	if (IS_ERR(reg))
 98		return PTR_ERR(reg);
 99
100	clk = sun8i_a23_apb0_register(np, reg);
101	return PTR_ERR_OR_ZERO(clk);
102}
103
104static const struct of_device_id sun8i_a23_apb0_clk_dt_ids[] = {
105	{ .compatible = "allwinner,sun8i-a23-apb0-clk" },
106	{ /* sentinel */ }
107};
108
109static struct platform_driver sun8i_a23_apb0_clk_driver = {
110	.driver = {
111		.name = "sun8i-a23-apb0-clk",
112		.of_match_table = sun8i_a23_apb0_clk_dt_ids,
113	},
114	.probe = sun8i_a23_apb0_clk_probe,
115};
116builtin_platform_driver(sun8i_a23_apb0_clk_driver);