diff options
Diffstat (limited to 'drivers/phy/phy-pistachio-usb.c')
| -rw-r--r-- | drivers/phy/phy-pistachio-usb.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/drivers/phy/phy-pistachio-usb.c b/drivers/phy/phy-pistachio-usb.c new file mode 100644 index 000000000..c6db35e6b --- /dev/null +++ b/drivers/phy/phy-pistachio-usb.c @@ -0,0 +1,206 @@ +/* + * 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"); |