1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2014 Free Electrons
  4 *
  5 * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
  6 *
  7 * Allwinner A31 AR100 clock driver
  8 */
  9
 10#include <linux/bitops.h>
 11#include <linux/clk-provider.h>
 12#include <linux/init.h>
 13#include <linux/of.h>
 14#include <linux/platform_device.h>
 15#include <linux/spinlock.h>
 16
 17#include "clk-factors.h"
 18
 19/**
 20 * sun6i_get_ar100_factors - Calculates factors p, m for AR100
 21 *
 22 * AR100 rate is calculated as follows
 23 * rate = (parent_rate >> p) / (m + 1);
 24 */
 25static void sun6i_get_ar100_factors(struct factors_request *req)
 26{
 27	unsigned long div;
 28	int shift;
 29
 30	/* clock only divides */
 31	if (req->rate > req->parent_rate)
 32		req->rate = req->parent_rate;
 33
 34	div = DIV_ROUND_UP(req->parent_rate, req->rate);
 35
 36	if (div < 32)
 37		shift = 0;
 38	else if (div >> 1 < 32)
 39		shift = 1;
 40	else if (div >> 2 < 32)
 41		shift = 2;
 42	else
 43		shift = 3;
 44
 45	div >>= shift;
 46
 47	if (div > 32)
 48		div = 32;
 49
 50	req->rate = (req->parent_rate >> shift) / div;
 51	req->m = div - 1;
 52	req->p = shift;
 53}
 54
 55static const struct clk_factors_config sun6i_ar100_config = {
 56	.mwidth = 5,
 57	.mshift = 8,
 58	.pwidth = 2,
 59	.pshift = 4,
 60};
 61
 62static const struct factors_data sun6i_ar100_data = {
 63	.mux = 16,
 64	.muxmask = GENMASK(1, 0),
 65	.table = &sun6i_ar100_config,
 66	.getter = sun6i_get_ar100_factors,
 67};
 68
 69static DEFINE_SPINLOCK(sun6i_ar100_lock);
 70
 71static int sun6i_a31_ar100_clk_probe(struct platform_device *pdev)
 72{
 73	struct device_node *np = pdev->dev.of_node;
 74	struct resource *r;
 75	void __iomem *reg;
 76	struct clk *clk;
 77
 78	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 79	reg = devm_ioremap_resource(&pdev->dev, r);
 80	if (IS_ERR(reg))
 81		return PTR_ERR(reg);
 82
 83	clk = sunxi_factors_register(np, &sun6i_ar100_data, &sun6i_ar100_lock,
 84				     reg);
 85	if (!clk)
 86		return -ENOMEM;
 87
 88	platform_set_drvdata(pdev, clk);
 89
 90	return 0;
 91}
 92
 93static const struct of_device_id sun6i_a31_ar100_clk_dt_ids[] = {
 94	{ .compatible = "allwinner,sun6i-a31-ar100-clk" },
 95	{ /* sentinel */ }
 96};
 97
 98static struct platform_driver sun6i_a31_ar100_clk_driver = {
 99	.driver = {
100		.name = "sun6i-a31-ar100-clk",
101		.of_match_table = sun6i_a31_ar100_clk_dt_ids,
102		.suppress_bind_attrs = true,
103	},
104	.probe = sun6i_a31_ar100_clk_probe,
105};
106builtin_platform_driver(sun6i_a31_ar100_clk_driver);