/*
 * Marvell Armada AP806 System Controller
 *
 * Copyright (C) 2016 Marvell
 *
 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#define pr_fmt(fmt) "ap806-system-controller: " fmt

#include <linux/clk-provider.h>
#include <linux/mfd/syscon.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#define AP806_SAR_REG			0x400
#define AP806_SAR_CLKFREQ_MODE_MASK	0x1f

#define AP806_CLK_NUM			4

static struct clk *ap806_clks[AP806_CLK_NUM];

static struct clk_onecell_data ap806_clk_data = {
	.clks = ap806_clks,
	.clk_num = AP806_CLK_NUM,
};

static int ap806_syscon_clk_probe(struct platform_device *pdev)
{
	unsigned int freq_mode, cpuclk_freq;
	const char *name, *fixedclk_name;
	struct device_node *np = pdev->dev.of_node;
	struct regmap *regmap;
	u32 reg;
	int ret;

	regmap = syscon_node_to_regmap(np);
	if (IS_ERR(regmap)) {
		dev_err(&pdev->dev, "cannot get regmap\n");
		return PTR_ERR(regmap);
	}

	ret = regmap_read(regmap, AP806_SAR_REG, &reg);
	if (ret) {
		dev_err(&pdev->dev, "cannot read from regmap\n");
		return ret;
	}

	freq_mode = reg & AP806_SAR_CLKFREQ_MODE_MASK;
	switch (freq_mode) {
	case 0x0 ... 0x5:
		cpuclk_freq = 2000;
		break;
	case 0x6 ... 0xB:
		cpuclk_freq = 1800;
		break;
	case 0xC ... 0x11:
		cpuclk_freq = 1600;
		break;
	case 0x12 ... 0x16:
		cpuclk_freq = 1400;
		break;
	case 0x17 ... 0x19:
		cpuclk_freq = 1300;
		break;
	default:
		dev_err(&pdev->dev, "invalid SAR value\n");
		return -EINVAL;
	}

	/* Convert to hertz */
	cpuclk_freq *= 1000 * 1000;

	/* CPU clocks depend on the Sample At Reset configuration */
	of_property_read_string_index(np, "clock-output-names",
				      0, &name);
	ap806_clks[0] = clk_register_fixed_rate(&pdev->dev, name, NULL,
						0, cpuclk_freq);
	if (IS_ERR(ap806_clks[0])) {
		ret = PTR_ERR(ap806_clks[0]);
		goto fail0;
	}

	of_property_read_string_index(np, "clock-output-names",
				      1, &name);
	ap806_clks[1] = clk_register_fixed_rate(&pdev->dev, name, NULL, 0,
						cpuclk_freq);
	if (IS_ERR(ap806_clks[1])) {
		ret = PTR_ERR(ap806_clks[1]);
		goto fail1;
	}

	/* Fixed clock is always 1200 Mhz */
	of_property_read_string_index(np, "clock-output-names",
				      2, &fixedclk_name);
	ap806_clks[2] = clk_register_fixed_rate(&pdev->dev, fixedclk_name, NULL,
						0, 1200 * 1000 * 1000);
	if (IS_ERR(ap806_clks[2])) {
		ret = PTR_ERR(ap806_clks[2]);
		goto fail2;
	}

	/* MSS Clock is fixed clock divided by 6 */
	of_property_read_string_index(np, "clock-output-names",
				      3, &name);
	ap806_clks[3] = clk_register_fixed_factor(NULL, name, fixedclk_name,
						  0, 1, 6);
	if (IS_ERR(ap806_clks[3])) {
		ret = PTR_ERR(ap806_clks[3]);
		goto fail3;
	}

	ret = of_clk_add_provider(np, of_clk_src_onecell_get, &ap806_clk_data);
	if (ret)
		goto fail_clk_add;

	return 0;

fail_clk_add:
	clk_unregister_fixed_factor(ap806_clks[3]);
fail3:
	clk_unregister_fixed_rate(ap806_clks[2]);
fail2:
	clk_unregister_fixed_rate(ap806_clks[1]);
fail1:
	clk_unregister_fixed_rate(ap806_clks[0]);
fail0:
	return ret;
}

static const struct of_device_id ap806_syscon_of_match[] = {
	{ .compatible = "marvell,ap806-system-controller", },
	{ }
};

static struct platform_driver ap806_syscon_driver = {
	.probe = ap806_syscon_clk_probe,
	.driver		= {
		.name	= "marvell-ap806-system-controller",
		.of_match_table = ap806_syscon_of_match,
		.suppress_bind_attrs = true,
	},
};
builtin_platform_driver(ap806_syscon_driver);