Re: [PATCH 5/5] phy: bcm-ns-usb3: add MDIO driver using proper bus layer

Kishon Vijay Abraham I
2017-06-16T06:05:10Z

Hi Rafal,

On Thursday 11 May 2017 09:59 PM, Florian Fainelli wrote:
> On 05/11/2017 06:29 AM, Rafał Miłecki wrote:
>> From: Rafał Miłecki <rafal@milecki.pl>
>>
>> As USB 3.0 PHY is attached to the MDIO bus this module should provide a
>> MDIO driver and use a proper bus layer. This is a proper (cleaner)
>> solution which doesn't require code to know this specific MDIO bus
>> details. It also allows reusing the driver with other MDIO buses.
>>
>> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
>> ---
>> drivers/phy/Kconfig | 1 +
>> drivers/phy/phy-bcm-ns-usb3.c | 98 ++++++++++++++++++++++++++++++++++++++++++-
>> 2 files changed, 98 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
>> index afaf7b643eeb..2a9186b98ae0 100644
>> --- a/drivers/phy/Kconfig
>> +++ b/drivers/phy/Kconfig
>> @@ -29,6 +29,7 @@ config PHY_BCM_NS_USB3
>> depends on ARCH_BCM_IPROC || COMPILE_TEST
>> depends on HAS_IOMEM && OF
>> select GENERIC_PHY
>> + select PHYLIB
>
> Should not this be select MDIO_DEVICE instead? 4.11 introduced the
> possibility to build support for MDIO bus/devices without requiring PHYLIB.
>
>> help
>> Enable this to support Broadcom USB 3.0 PHY connected to the USB
>> controller on Northstar family.
>> diff --git a/drivers/phy/phy-bcm-ns-usb3.c b/drivers/phy/phy-bcm-ns-usb3.c
>> index 2c9a0d5f43d8..389f5e5a6238 100644
>> --- a/drivers/phy/phy-bcm-ns-usb3.c
>> +++ b/drivers/phy/phy-bcm-ns-usb3.c
>> @@ -16,7 +16,9 @@
>> #include <linux/bcma/bcma.h>
>> #include <linux/delay.h>
>> #include <linux/err.h>
>> +#include <linux/mdio.h>
>> #include <linux/module.h>
>> +#include <linux/of_address.h>
>> #include <linux/of_platform.h>
>> #include <linux/platform_device.h>
>> #include <linux/phy/phy.h>
>> @@ -52,6 +54,7 @@ struct bcm_ns_usb3 {
>> enum bcm_ns_family family;
>> void __iomem *dmp;
>> void __iomem *ccb_mii;
>> + struct mdio_device *mdiodev;
>> struct phy *phy;
>>
>> int (*phy_write)(struct bcm_ns_usb3 *usb3, u16 reg, u16 value);
>> @@ -183,6 +186,77 @@ static const struct phy_ops ops = {
>> };
>>
>> /**************************************************
>> + * MDIO driver code
>> + **************************************************/
>> +
>> +static int bcm_ns_usb3_mdiodev_phy_write(struct bcm_ns_usb3 *usb3, u16 reg,
>> + u16 value)
>> +{
>> + struct mdio_device *mdiodev = usb3->mdiodev;
>> +
>> + return mdiobus_write(mdiodev->bus, mdiodev->addr, reg, value);
>> +}
>> +
>> +static int bcm_ns_usb3_mdio_probe(struct mdio_device *mdiodev)
>> +{
>> + struct device *dev = &mdiodev->dev;
>> + const struct of_device_id *of_id;
>> + struct phy_provider *phy_provider;
>> + struct device_node *syscon_np;
>> + struct bcm_ns_usb3 *usb3;
>> + struct resource res;
>> + int err;
>> +
>> + usb3 = devm_kzalloc(dev, sizeof(*usb3), GFP_KERNEL);
>> + if (!usb3)
>> + return -ENOMEM;
>> +
>> + usb3->dev = dev;
>> + usb3->mdiodev = mdiodev;
>> +
>> + of_id = of_match_device(bcm_ns_usb3_id_table, dev);
>> + if (!of_id)
>> + return -EINVAL;
>> + usb3->family = (enum bcm_ns_family)of_id->data;
>> +
>> + syscon_np = of_parse_phandle(dev->of_node, "usb3-dmp-syscon", 0);
>> + err = of_address_to_resource(syscon_np, 0, &res);
>> + of_node_put(syscon_np);
>> + if (err)
>> + return err;
>> +
>> + usb3->dmp = devm_ioremap_resource(dev, &res);
>> + if (IS_ERR(usb3->dmp)) {
>> + dev_err(dev, "Failed to map DMP regs\n");
>> + return PTR_ERR(usb3->dmp);
>> + }
>> +
>> + usb3->phy_write = bcm_ns_usb3_mdiodev_phy_write;
>> +
>> + usb3->phy = devm_phy_create(dev, NULL, &ops);
>> + if (IS_ERR(usb3->phy)) {
>> + dev_err(dev, "Failed to create PHY\n");
>> + return PTR_ERR(usb3->phy);
>> + }
>> +
>> + phy_set_drvdata(usb3->phy, usb3);
>> +
>> + phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
>> +
>> + return PTR_ERR_OR_ZERO(phy_provider);
>> +}
>> +
>> +static struct mdio_driver bcm_ns_usb3_mdio_driver = {
>> + .mdiodrv = {
>> + .driver = {
>> + .name = "bcm_ns_mdio_usb3",
>> + .of_match_table = bcm_ns_usb3_id_table,
>> + },
>> + },
>> + .probe = bcm_ns_usb3_mdio_probe,
>> +};
>> +
>> +/**************************************************
>> * Platform driver code
>> **************************************************/
>>
>> @@ -297,6 +371,28 @@ static struct platform_driver bcm_ns_usb3_driver = {
>> .of_match_table = bcm_ns_usb3_id_table,
>> },
>> };
>> -module_platform_driver(bcm_ns_usb3_driver);
>> +
>> +static int __init bcm_ns_usb3_module_init(void)
>> +{
>> + int err;
>> +
>> + err = mdio_driver_register(&bcm_ns_usb3_mdio_driver);
>> + if (err)
>> + return err;
>> +
>> + err = platform_driver_register(&bcm_ns_usb3_driver);
>> + if (err)
>> + mdio_driver_unregister(&bcm_ns_usb3_mdio_driver);
>> +
>> + return err;
>> +}
>> +module_init(bcm_ns_usb3_module_init);
>> +
>> +static void __exit bcm_ns_usb3_module_exit(void)
>> +{
>> + platform_driver_unregister(&bcm_ns_usb3_driver);
>> + mdio_driver_unregister(&bcm_ns_usb3_mdio_driver);
>> +}
>> +module_exit(bcm_ns_usb3_module_exit)
>
> Do we need to keep both platform device and mdio device registration
> here? Do you have a depreciation time line for when we can entirely
> switch to mdio device (assuming this is for backwards compatibility)?

I too have the same question.

Thanks
Kishon