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/*
* IMG Pistachio USB PHY driver
*
* Copyright (C) 2015 Google, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <dt-bindings/phy/phy-pistachio-usb.h>
#define USB_PHY_CONTROL1 0x04
#define USB_PHY_CONTROL1_FSEL_SHIFT 2
#define USB_PHY_CONTROL1_FSEL_MASK 0x7
#define USB_PHY_STRAP_CONTROL 0x10
#define USB_PHY_STRAP_CONTROL_REFCLK_SHIFT 4
#define USB_PHY_STRAP_CONTROL_REFCLK_MASK 0x3
#define USB_PHY_STATUS 0x14
#define USB_PHY_STATUS_RX_PHY_CLK BIT(9)
#define USB_PHY_STATUS_RX_UTMI_CLK BIT(8)
#define USB_PHY_STATUS_VBUS_FAULT BIT(7)
struct pistachio_usb_phy {
struct device *dev;
struct regmap *cr_top;
struct clk *phy_clk;
unsigned int refclk;
};
static const unsigned long fsel_rate_map[] = {
9600000,
10000000,
12000000,
19200000,
20000000,
24000000,
0,
50000000,
};
static int pistachio_usb_phy_power_on(struct phy *phy)
{
struct pistachio_usb_phy *p_phy = phy_get_drvdata(phy);
unsigned long timeout, rate;
unsigned int i;
int ret;
ret = clk_prepare_enable(p_phy->phy_clk);
if (ret < 0) {
dev_err(p_phy->dev, "Failed to enable PHY clock: %d\n", ret);
return ret;
}
regmap_update_bits(p_phy->cr_top, USB_PHY_STRAP_CONTROL,
USB_PHY_STRAP_CONTROL_REFCLK_MASK <<
USB_PHY_STRAP_CONTROL_REFCLK_SHIFT,
p_phy->refclk << USB_PHY_STRAP_CONTROL_REFCLK_SHIFT);
rate = clk_get_rate(p_phy->phy_clk);
if (p_phy->refclk == REFCLK_XO_CRYSTAL && rate != 12000000) {
dev_err(p_phy->dev, "Unsupported rate for XO crystal: %ld\n",
rate);
ret = -EINVAL;
goto disable_clk;
}
for (i = 0; i < ARRAY_SIZE(fsel_rate_map); i++) {
if (rate == fsel_rate_map[i])
break;
}
if (i == ARRAY_SIZE(fsel_rate_map)) {
dev_err(p_phy->dev, "Unsupported clock rate: %lu\n", rate);
ret = -EINVAL;
goto disable_clk;
}
regmap_update_bits(p_phy->cr_top, USB_PHY_CONTROL1,
USB_PHY_CONTROL1_FSEL_MASK <<
USB_PHY_CONTROL1_FSEL_SHIFT,
i << USB_PHY_CONTROL1_FSEL_SHIFT);
timeout = jiffies + msecs_to_jiffies(200);
while (time_before(jiffies, timeout)) {
unsigned int val;
regmap_read(p_phy->cr_top, USB_PHY_STATUS, &val);
if (val & USB_PHY_STATUS_VBUS_FAULT) {
dev_err(p_phy->dev, "VBUS fault detected\n");
ret = -EIO;
goto disable_clk;
}
if ((val & USB_PHY_STATUS_RX_PHY_CLK) &&
(val & USB_PHY_STATUS_RX_UTMI_CLK))
return 0;
usleep_range(1000, 1500);
}
dev_err(p_phy->dev, "Timed out waiting for PHY to power on\n");
ret = -ETIMEDOUT;
disable_clk:
clk_disable_unprepare(p_phy->phy_clk);
return ret;
}
static int pistachio_usb_phy_power_off(struct phy *phy)
{
struct pistachio_usb_phy *p_phy = phy_get_drvdata(phy);
clk_disable_unprepare(p_phy->phy_clk);
return 0;
}
static const struct phy_ops pistachio_usb_phy_ops = {
.power_on = pistachio_usb_phy_power_on,
.power_off = pistachio_usb_phy_power_off,
.owner = THIS_MODULE,
};
static int pistachio_usb_phy_probe(struct platform_device *pdev)
{
struct pistachio_usb_phy *p_phy;
struct phy_provider *provider;
struct phy *phy;
int ret;
p_phy = devm_kzalloc(&pdev->dev, sizeof(*p_phy), GFP_KERNEL);
if (!p_phy)
return -ENOMEM;
p_phy->dev = &pdev->dev;
platform_set_drvdata(pdev, p_phy);
p_phy->cr_top = syscon_regmap_lookup_by_phandle(p_phy->dev->of_node,
"img,cr-top");
if (IS_ERR(p_phy->cr_top)) {
dev_err(p_phy->dev, "Failed to get CR_TOP registers: %ld\n",
PTR_ERR(p_phy->cr_top));
return PTR_ERR(p_phy->cr_top);
}
p_phy->phy_clk = devm_clk_get(p_phy->dev, "usb_phy");
if (IS_ERR(p_phy->phy_clk)) {
dev_err(p_phy->dev, "Failed to get usb_phy clock: %ld\n",
PTR_ERR(p_phy->phy_clk));
return PTR_ERR(p_phy->phy_clk);
}
ret = of_property_read_u32(p_phy->dev->of_node, "img,refclk",
&p_phy->refclk);
if (ret < 0) {
dev_err(p_phy->dev, "No reference clock selector specified\n");
return ret;
}
phy = devm_phy_create(p_phy->dev, NULL, &pistachio_usb_phy_ops);
if (IS_ERR(phy)) {
dev_err(p_phy->dev, "Failed to create PHY: %ld\n",
PTR_ERR(phy));
return PTR_ERR(phy);
}
phy_set_drvdata(phy, p_phy);
provider = devm_of_phy_provider_register(p_phy->dev,
of_phy_simple_xlate);
if (IS_ERR(provider)) {
dev_err(p_phy->dev, "Failed to register PHY provider: %ld\n",
PTR_ERR(provider));
return PTR_ERR(provider);
}
return 0;
}
static const struct of_device_id pistachio_usb_phy_of_match[] = {
{ .compatible = "img,pistachio-usb-phy", },
{ },
};
MODULE_DEVICE_TABLE(of, pistachio_usb_phy_of_match);
static struct platform_driver pistachio_usb_phy_driver = {
.probe = pistachio_usb_phy_probe,
.driver = {
.name = "pistachio-usb-phy",
.of_match_table = pistachio_usb_phy_of_match,
},
};
module_platform_driver(pistachio_usb_phy_driver);
MODULE_AUTHOR("Andrew Bresticker <abrestic@chromium.org>");
MODULE_DESCRIPTION("IMG Pistachio USB2.0 PHY driver");
MODULE_LICENSE("GPL v2");
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