/**
 * dwmac-sunxi.c - Allwinner sunxi DWMAC specific glue layer
 *
 * Copyright (C) 2013 Chen-Yu Tsai
 *
 * Chen-Yu Tsai  <wens@csie.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/stmmac.h>
#include <linux/clk.h>
#include <linux/phy.h>
#include <linux/of_net.h>
#include <linux/regulator/consumer.h>

struct sunxi_priv_data {
	int interface;
	int clk_enabled;
	struct clk *tx_clk;
	struct regulator *regulator;
};

static void *sun7i_gmac_setup(struct platform_device *pdev)
{
	struct sunxi_priv_data *gmac;
	struct device *dev = &pdev->dev;

	gmac = devm_kzalloc(dev, sizeof(*gmac), GFP_KERNEL);
	if (!gmac)
		return ERR_PTR(-ENOMEM);

	gmac->interface = of_get_phy_mode(dev->of_node);

	gmac->tx_clk = devm_clk_get(dev, "allwinner_gmac_tx");
	if (IS_ERR(gmac->tx_clk)) {
		dev_err(dev, "could not get tx clock\n");
		return gmac->tx_clk;
	}

	/* Optional regulator for PHY */
	gmac->regulator = devm_regulator_get_optional(dev, "phy");
	if (IS_ERR(gmac->regulator)) {
		if (PTR_ERR(gmac->regulator) == -EPROBE_DEFER)
			return ERR_PTR(-EPROBE_DEFER);
		dev_info(dev, "no regulator found\n");
		gmac->regulator = NULL;
	}

	return gmac;
}

#define SUN7I_GMAC_GMII_RGMII_RATE	125000000
#define SUN7I_GMAC_MII_RATE		25000000

static int sun7i_gmac_init(struct platform_device *pdev, void *priv)
{
	struct sunxi_priv_data *gmac = priv;
	int ret;

	if (gmac->regulator) {
		ret = regulator_enable(gmac->regulator);
		if (ret)
			return ret;
	}

	/* Set GMAC interface port mode
	 *
	 * The GMAC TX clock lines are configured by setting the clock
	 * rate, which then uses the auto-reparenting feature of the
	 * clock driver, and enabling/disabling the clock.
	 */
	if (gmac->interface == PHY_INTERFACE_MODE_RGMII) {
		clk_set_rate(gmac->tx_clk, SUN7I_GMAC_GMII_RGMII_RATE);
		clk_prepare_enable(gmac->tx_clk);
		gmac->clk_enabled = 1;
	} else {
		clk_set_rate(gmac->tx_clk, SUN7I_GMAC_MII_RATE);
		clk_prepare(gmac->tx_clk);
	}

	return 0;
}

static void sun7i_gmac_exit(struct platform_device *pdev, void *priv)
{
	struct sunxi_priv_data *gmac = priv;

	if (gmac->clk_enabled) {
		clk_disable(gmac->tx_clk);
		gmac->clk_enabled = 0;
	}
	clk_unprepare(gmac->tx_clk);

	if (gmac->regulator)
		regulator_disable(gmac->regulator);
}

static void sun7i_fix_speed(void *priv, unsigned int speed)
{
	struct sunxi_priv_data *gmac = priv;

	/* only GMII mode requires us to reconfigure the clock lines */
	if (gmac->interface != PHY_INTERFACE_MODE_GMII)
		return;

	if (gmac->clk_enabled) {
		clk_disable(gmac->tx_clk);
		gmac->clk_enabled = 0;
	}
	clk_unprepare(gmac->tx_clk);

	if (speed == 1000) {
		clk_set_rate(gmac->tx_clk, SUN7I_GMAC_GMII_RGMII_RATE);
		clk_prepare_enable(gmac->tx_clk);
		gmac->clk_enabled = 1;
	} else {
		clk_set_rate(gmac->tx_clk, SUN7I_GMAC_MII_RATE);
		clk_prepare(gmac->tx_clk);
	}
}

/* of_data specifying hardware features and callbacks.
 * hardware features were copied from Allwinner drivers. */
const struct stmmac_of_data sun7i_gmac_data = {
	.has_gmac = 1,
	.tx_coe = 1,
	.fix_mac_speed = sun7i_fix_speed,
	.setup = sun7i_gmac_setup,
	.init = sun7i_gmac_init,
	.exit = sun7i_gmac_exit,
};