#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/platform_device.h>

struct ipaq_audio_clk {
	struct clk_hw clk;
	struct clk_lookup *cl;
	struct gpio_desc *gpios[2];
};
#define to_ipaq_audio_clk(x) container_of(x, struct ipaq_audio_clk, clk)

static const char *clk_names[2] = { "clk0", "clk1" };

static unsigned long ipaq_audio_clk_rates[] = {
	12288000,
	11289600,
	4096000,
	5624500,
};

static unsigned long ipaq_audio_clk_recalc_rate(struct clk_hw *hw,
	unsigned long parent_rate)
{
	struct ipaq_audio_clk *ia = to_ipaq_audio_clk(hw);
	unsigned int clk0 = !!gpiod_get_value(ia->gpios[0]);
	unsigned int clk1 = !!gpiod_get_value(ia->gpios[1]);
	unsigned int idx = clk1 * 2 + clk0;

	return ipaq_audio_clk_rates[idx];
}

static long ipaq_audio_clk_round_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long *parent_rate)
{
	int i, best = -1;
	long diff, best_diff = LONG_MAX;

	for (i = 0; i < ARRAY_SIZE(ipaq_audio_clk_rates); i++) {
		diff = ipaq_audio_clk_rates[i] - rate;
		if (diff < 0)
			diff = -diff;
		if (diff < best_diff) {
			best_diff = diff;
			best = i;
		}
	}

	return best == -1 ? -EINVAL : ipaq_audio_clk_rates[best];
}

static int ipaq_audio_clk_set_rate(struct clk_hw *hw, unsigned long rate,
	unsigned long parent_rate)
{
	struct ipaq_audio_clk *ia = to_ipaq_audio_clk(hw);
	DECLARE_BITMAP(values, 2) = { 0, };
	int i;

	for (i = 0; i < ARRAY_SIZE(ipaq_audio_clk_rates); i++) {
		if (ipaq_audio_clk_rates[i] == rate) {
			__assign_bit(0, values, !!(i & 1));
			__assign_bit(1, values, !!(i & 2));

			gpiod_set_array_value(2, ia->gpios, NULL, values);
			return 0;
		}
	}
	return -EINVAL;
}

static const struct clk_ops ipaq_audio_clk_ops = {
	.recalc_rate = ipaq_audio_clk_recalc_rate,
	.round_rate = ipaq_audio_clk_round_rate,
	.set_rate = ipaq_audio_clk_set_rate,
};

static struct clk_init_data ipaq_audio_clk_init = {
	.name = "ipaq-audio",
	.ops = &ipaq_audio_clk_ops,
};

static int ipaq_audio_clk_probe(struct platform_device *pdev)
{
	struct ipaq_audio_clk *ia;
	int i, ret;

	ia = devm_kzalloc(&pdev->dev, sizeof(*ia), GFP_KERNEL);
	if (!ia)
		return -ENOMEM;

	for (i = 0; i < ARRAY_SIZE(clk_names); i++) {
		ia->gpios[i] = devm_gpiod_get(&pdev->dev, clk_names[i],
					      GPIOD_OUT_LOW);
		if (IS_ERR(ia->gpios[i]))
			return PTR_ERR(ia->gpios[i]);
	}

	platform_set_drvdata(pdev, ia);

	ia->clk.init = &ipaq_audio_clk_init;

	ret = devm_clk_hw_register(&pdev->dev, &ia->clk);
	if (ret)
		return ret;

	ia->cl = clkdev_hw_create(&ia->clk, "ext", "h3xxx-asoc");

	return ia->cl ? 0 : -ENOMEM;
}

static int ipaq_audio_clk_remove(struct platform_device *pdev)
{
	struct ipaq_audio_clk *ia = platform_get_drvdata(pdev);

	clkdev_drop(ia->cl);

	return 0;
}

static struct platform_driver ipaq_audio_clk_driver = {
	.probe = ipaq_audio_clk_probe,
	.remove = ipaq_audio_clk_remove,
	.driver = {
		.name = "ipaq-audio-clk",
	},
};

module_platform_driver(ipaq_audio_clk_driver);

MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
MODULE_DESCRIPTION("iPAQ Audio clock driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ipaq-audio-clock");