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114 lines
2.7 KiB
C
114 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* MDIO passthrough driver for Airoha AN8855 Switch
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*/
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#include <linux/mfd/airoha-an8855-mfd.h>
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#include <linux/module.h>
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#include <linux/of_mdio.h>
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#include <linux/platform_device.h>
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static int an855_phy_restore_page(struct an8855_mfd_priv *priv,
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int phy) __must_hold(&priv->bus->mdio_lock)
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{
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/* Check PHY page only for addr shared with switch */
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if (phy != priv->switch_addr)
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return 0;
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/* Don't restore page if it's not set to switch page */
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if (priv->current_page != FIELD_GET(AN8855_PHY_PAGE,
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AN8855_PHY_PAGE_EXTENDED_4))
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return 0;
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/* Restore page to 0, PHY might change page right after but that
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* will be ignored as it won't be a switch page.
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*/
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return an8855_mii_set_page(priv, phy, AN8855_PHY_PAGE_STANDARD);
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}
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static int an8855_phy_read(struct mii_bus *bus, int phy, int regnum)
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{
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struct an8855_mfd_priv *priv = bus->priv;
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struct mii_bus *real_bus = priv->bus;
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int ret;
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mutex_lock_nested(&real_bus->mdio_lock, MDIO_MUTEX_NESTED);
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ret = an855_phy_restore_page(priv, phy);
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if (ret)
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goto exit;
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ret = __mdiobus_read(real_bus, phy, regnum);
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exit:
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mutex_unlock(&real_bus->mdio_lock);
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return ret;
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}
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static int an8855_phy_write(struct mii_bus *bus, int phy, int regnum, u16 val)
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{
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struct an8855_mfd_priv *priv = bus->priv;
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struct mii_bus *real_bus = priv->bus;
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int ret;
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mutex_lock_nested(&real_bus->mdio_lock, MDIO_MUTEX_NESTED);
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ret = an855_phy_restore_page(priv, phy);
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if (ret)
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goto exit;
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ret = __mdiobus_write(real_bus, phy, regnum, val);
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exit:
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mutex_unlock(&real_bus->mdio_lock);
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return ret;
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}
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static int an8855_mdio_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct an8855_mfd_priv *priv;
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struct mii_bus *bus;
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int ret;
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/* Get priv of MFD */
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priv = dev_get_drvdata(dev->parent);
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bus = devm_mdiobus_alloc(dev);
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if (!bus)
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return -ENOMEM;
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bus->priv = priv;
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bus->name = KBUILD_MODNAME "-mii";
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snprintf(bus->id, MII_BUS_ID_SIZE, KBUILD_MODNAME "-%d",
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priv->switch_addr);
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bus->parent = dev;
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bus->read = an8855_phy_read;
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bus->write = an8855_phy_write;
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ret = devm_of_mdiobus_register(dev, bus, dev->of_node);
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if (ret)
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return dev_err_probe(dev, ret, "failed to register MDIO bus\n");
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return ret;
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}
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static const struct of_device_id an8855_mdio_of_match[] = {
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{ .compatible = "airoha,an8855-mdio", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, an8855_mdio_of_match);
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static struct platform_driver an8855_mdio_driver = {
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.probe = an8855_mdio_probe,
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.driver = {
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.name = "an8855-mdio",
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.of_match_table = an8855_mdio_of_match,
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},
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};
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module_platform_driver(an8855_mdio_driver);
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MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>");
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MODULE_DESCRIPTION("Driver for AN8855 MDIO passthrough");
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MODULE_LICENSE("GPL");
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