Subject: Re: [PATCH net-next 2/2] net: phy: microchip_t1s: add support for Microchip LAN865x Rev.B0 PHYs

From: <[email-masked]>
Date: Thu, 27 Apr 2023 11:28:25 +0000

Hi Horatiu,

Thanks for reviewing my patches. Please see my comments below.

Best Regards,
Parthiban V
On 27/04/23 2:51 am, Horatiu Vultur wrote:
> The 04/26/2023 17:16, Parthiban Veerasooran wrote:
> 
> Hi Parthiban,
> 
>>
>> This patch adds support for the Microchip LAN865x Rev.B0 10BASE-T1S
>> Internal PHYs (LAN8650/1). The LAN865x combines a Media Access Controller
>> (MAC) and an internal 10BASE-T1S Ethernet PHY to access 10BASE‑T1S
>> networks.
> 
> I really thought that first we will have an internal review as we
> discussed before sending this out!
As the initial version of the microchip 10BASE-T1S PHY driver is already 
in the mainline with lan867x support, I sent these patches directly to 
apply on top of that.
Definitely for the upcoming new drivers in the pipeline, I will approach 
for the internal review with you first before going to the mainline.

Sorry if I had a miscommunication here.

Also please let me know if you have other proposal?
> 
>>
>> Signed-off-by: Parthiban Veerasooran <[email-masked]>
>> ---
>>   drivers/net/phy/microchip_t1s.c | 200 ++++++++++++++++++++++++++++++--
>>   1 file changed, 191 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/net/phy/microchip_t1s.c b/drivers/net/phy/microchip_t1s.c
>> index 793fb0210605..3d8d285b3c34 100644
>> --- a/drivers/net/phy/microchip_t1s.c
>> +++ b/drivers/net/phy/microchip_t1s.c
>> @@ -4,6 +4,7 @@
>>    *
>>    * Support: Microchip Phys:
>>    *  lan8670/1/2 Rev.B1
>> + *  lan8650/1 Rev.B0 Internal PHYs
>>    */
>>
>>   #include <linux/kernel.h>
>> @@ -11,9 +12,10 @@
>>   #include <linux/phy.h>
>>
>>   #define PHY_ID_LAN867X_REVB1 0x0007C162
>> +#define PHY_ID_LAN865X_REVB0 0x0007C1B3
>>
>> -#define LAN867X_REG_IRQ_1_CTL 0x001C
>> -#define LAN867X_REG_IRQ_2_CTL 0x001D
>> +#define LAN86XX_REG_IRQ_1_CTL 0x001C
>> +#define LAN86XX_REG_IRQ_2_CTL 0x001D
>>
>>   /* The arrays below are pulled from the following table from AN1699
>>    * Access MMD Address Value Mask
>> @@ -49,6 +51,174 @@ static const int lan867x_revb1_fixup_masks[12] = {
>>          0x0600, 0x7F00, 0x2000, 0xFFFF,
>>   };
>>
>> +/* LAN865x Rev.B0 configuration parameters from AN1760
>> + */
> 
> You can put */ on previous line.
Sure, will do.
> 
>> +static const int lan865x_revb0_fixup_registers[28] = {
>> +       0x0091, 0x0081, 0x0043, 0x0044,
>> +       0x0045, 0x0053, 0x0054, 0x0055,
>> +       0x0040, 0x0050, 0x00D0, 0x00E9,
>> +       0x00F5, 0x00F4, 0x00F8, 0x00F9,
>> +       0x00B0, 0x00B1, 0x00B2, 0x00B3,
>> +       0x00B4, 0x00B5, 0x00B6, 0x00B7,
>> +       0x00B8, 0x00B9, 0x00BA, 0x00BB,
>> +};
>> +
>> +static const int lan865x_revb0_fixup_values[28] = {
> 
> Can't this be u16? As this is used only by phy_write_mmd which gets an
> u16.
yes, will do it.
> 
>> +       0x9660, 0x00C0, 0x00FF, 0xFFFF,
>> +       0x0000, 0x00FF, 0xFFFF, 0x0000,
>> +       0x0002, 0x0002, 0x5F21, 0x9E50,
>> +       0x1CF8, 0xC020, 0x9B00, 0x4E53,
>> +       0x0103, 0x0910, 0x1D26, 0x002A,
>> +       0x0103, 0x070D, 0x1720, 0x0027,
>> +       0x0509, 0x0E13, 0x1C25, 0x002B,
>> +};
>> +
>> +/* indirect read pseudocode from AN1760
> 
> In the entire file, sometimes when you write the comment you start with
> a lower case, sometimes with an upper case, please be consistent.
Sure, I will.
> 
>> + * write_register(0x4, 0x00D8, addr)
>> + * write_register(0x4, 0x00DA, 0x2)
>> + * return (int8)(read_register(0x4, 0x00D9))
>> + */
>> +static int lan865x_revb0_indirect_read(struct phy_device *phydev, u16 addr)
>> +{
>> +       int ret;
>> +
>> +       ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, 0xD8, addr);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, 0xDA, 0x0002);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, 0xD9);
> 
> You can return phy_read_mmd, there is no point to check the ret here.
Ah good idea.
> 
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       return ret;
>> +}
>> +
>> +static int lan865x_setup_cfgparam(struct phy_device *phydev)
>> +{
>> +       s8 offset1;
>> +       s8 offset2;
>> +       s8 value;
>> +       u16 cfgparam;
>> +       int ret;
> 
> Please use reverse christmas notation
Sure, I will.
> 
>> +
>> +       ret = lan865x_revb0_indirect_read(phydev, 0x0004);
>> +       if (ret < 0)
>> +               return ret;
>> +       value = (s8)ret;
>> +       /* Calculation of configuration offset 1 from AN1760
>> +        */
> 
> Again, you can put */ on the previous line. There other places in the
> file, I will not mention all of them.
Sure, I will.
> 
>> +       if ((value & 0x10) != 0)
>> +               offset1 = value | 0xE0;
>> +       else
>> +               offset1 = value;
>> +
>> +       ret = lan865x_revb0_indirect_read(phydev, 0x0008);
>> +       if (ret < 0)
>> +               return ret;
>> +       value = (s8)ret;
>> +       /* Calculation of configuration offset 2 from AN1760
>> +        */
>> +       if ((value & 0x10) != 0)
>> +               offset2 = value | 0xE0;
>> +       else
>> +               offset2 = value;
>> +
>> +       /* calculate and write the configuration parameters in the
>> +        * 0x0084, 0x008A, 0x00AD, 0x00AE and 0x00AF registers (from AN1760)
>> +        */
>> +       ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, 0x0084);
>> +       if (ret < 0)
>> +               return ret;
>> +       cfgparam = (ret & 0xF) | (((9 + offset1) << 10) |
>> +                   ((14 + offset1) << 4));
> 
> What about using FIELD_PREP to skip all <<?
Ok noted.
> 
>> +       ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, 0x84, cfgparam);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, 0x008A);
> 
> Small thing, here you use 0x008A, and few lines bellow only 0X8A, please
> be consistent
Sure, I will.
> 
>> +       if (ret < 0)
>> +               return ret;
>> +       cfgparam = (ret & 0x3FF) | ((40 + offset2) << 10);
>> +       ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, 0x8A, cfgparam);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, 0x00AD);
>> +       if (ret < 0)
>> +               return ret;
>> +       cfgparam = (ret & 0xC0C0) | (((5 + offset1) << 8) | (9 + offset1));
>> +       ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, 0xAD, cfgparam);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, 0x00AE);
>> +       if (ret < 0)
>> +               return ret;
>> +       cfgparam = (ret & 0xC0C0) | (((9 + offset1) << 8) | (14 + offset1));
>> +       ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, 0xAE, cfgparam);
>> +       if (ret)
>> +               return ret;
>> +
>> +       ret = phy_read_mmd(phydev, MDIO_MMD_VEND2, 0x00AF);
>> +       if (ret < 0)
>> +               return ret;
>> +       cfgparam = (ret & 0xC0C0) | (((17 + offset1) << 8) | (22 + offset1));
>> +       return phy_write_mmd(phydev, MDIO_MMD_VEND2, 0xAF, cfgparam);
> 
> There are quite a lot of hardcoded values in the previous code, can you add
> some comments what they mean, or add defines for them.
Sure, I will check this.
> 
>> +}
>> +
>> +static int lan865x_revb0_config_init(struct phy_device *phydev)
>> +{
>> +       int addr;
>> +       int value;
>> +       int ret;
> 
> Please use reverse x-mas
Ok noted.
> 
>> +
>> +       /* As per AN1760, the below configuration applies only to the LAN8650/1
>> +        * hardware revision Rev.B0.
>> +        */
>> +       for (int i = 0; i < ARRAY_SIZE(lan865x_revb0_fixup_registers); i++) {
>> +               addr = lan865x_revb0_fixup_registers[i];
>> +               value = lan865x_revb0_fixup_values[i];
> 
> Doesn't seem that you need the variable value here.
Ok noted.
> 
>> +               ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, addr, value);
>> +               if (ret)
>> +                       return ret;
>> +       }
>> +       /* function to calculate and write the configuration parameters in the
>> +        * 0x0084, 0x008A, 0x00AD, 0x00AE and 0x00AF registers (from AN1760)
>> +        */
>> +       ret = lan865x_setup_cfgparam(phydev);
>> +       if (ret < 0)
>> +               return ret;
>> +
>> +       /* disable all the interrupts
>> +        */
>> +       ret = phy_write_mmd(phydev, MDIO_MMD_VEND2, LAN86XX_REG_IRQ_1_CTL, 0xFFFF);
>> +       if (ret)
>> +               return ret;
>> +       return phy_write_mmd(phydev, MDIO_MMD_VEND2, LAN86XX_REG_IRQ_2_CTL, 0xFFFF);
> 
> You can use GENMASK instead of 0xFFFF
Ok noted.
> 
>> +}
>> +
>> +static int lan865x_revb0_plca_set_cfg(struct phy_device *phydev,
>> +                                     const struct phy_plca_cfg *plca_cfg)
>> +{
>> +       int ret;
>> +
>> +       ret = genphy_c45_plca_set_cfg(phydev, plca_cfg);
>> +       if (ret)
>> +               return ret;
>> +
>> +       /* Disable the collision detection when PLCA is enabled and enable
>> +        * collision detection when CSMA/CD mode is enabled.
>> +        */
>> +       if (plca_cfg->enabled)
>> +               return phy_write_mmd(phydev, MDIO_MMD_VEND2, 0x0087, 0x0000);
>> +       else
>> +               return phy_write_mmd(phydev, MDIO_MMD_VEND2, 0x0087, 0x0083);
>> +}
>> +
>>   static int lan867x_revb1_config_init(struct phy_device *phydev)
>>   {
>>          /* HW quirk: Microchip states in the application note (AN1699) for the phy
>> @@ -90,13 +260,13 @@ static int lan867x_revb1_config_init(struct phy_device *phydev)
>>           * for it either.
>>           * So we'll just disable all interrupts on the chip.
>>           */
>> -       err = phy_write_mmd(phydev, MDIO_MMD_VEND2, LAN867X_REG_IRQ_1_CTL, 0xFFFF);
>> +       err = phy_write_mmd(phydev, MDIO_MMD_VEND2, LAN86XX_REG_IRQ_1_CTL, 0xFFFF);
>>          if (err != 0)
>>                  return err;
>> -       return phy_write_mmd(phydev, MDIO_MMD_VEND2, LAN867X_REG_IRQ_2_CTL, 0xFFFF);
>> +       return phy_write_mmd(phydev, MDIO_MMD_VEND2, LAN86XX_REG_IRQ_2_CTL, 0xFFFF);
>>   }
>>
>> -static int lan867x_read_status(struct phy_device *phydev)
>> +static int lan86xx_read_status(struct phy_device *phydev)
>>   {
>>          /* The phy has some limitations, namely:
>>           *  - always reports link up
>> @@ -111,23 +281,34 @@ static int lan867x_read_status(struct phy_device *phydev)
>>          return 0;
>>   }
>>
>> -static struct phy_driver lan867x_revb1_driver[] = {
>> +static struct phy_driver lan86xx_driver[] = {
>>          {
>>                  PHY_ID_MATCH_EXACT(PHY_ID_LAN867X_REVB1),
>>                  .name               = "LAN867X Rev.B1",
>>                  .features           = PHY_BASIC_T1S_P2MP_FEATURES,
>>                  .config_init        = lan867x_revb1_config_init,
>> -               .read_status        = lan867x_read_status,
>> +               .read_status        = lan86xx_read_status,
>>                  .get_plca_cfg       = genphy_c45_plca_get_cfg,
>>                  .set_plca_cfg       = genphy_c45_plca_set_cfg,
>>                  .get_plca_status    = genphy_c45_plca_get_status,
>> -       }
>> +       },
>> +       {
>> +               PHY_ID_MATCH_EXACT(PHY_ID_LAN865X_REVB0),
>> +               .name               = "LAN865X Rev.B0 Internal Phy",
>> +               .features           = PHY_BASIC_T1S_P2MP_FEATURES,
>> +               .config_init        = lan865x_revb0_config_init,
>> +               .read_status        = lan86xx_read_status,
>> +               .get_plca_cfg       = genphy_c45_plca_get_cfg,
>> +               .set_plca_cfg       = lan865x_revb0_plca_set_cfg,
>> +               .get_plca_status    = genphy_c45_plca_get_status,
>> +       },
>>   };
>>
>> -module_phy_driver(lan867x_revb1_driver);
>> +module_phy_driver(lan86xx_driver);
>>
>>   static struct mdio_device_id __maybe_unused tbl[] = {
>>          { PHY_ID_MATCH_EXACT(PHY_ID_LAN867X_REVB1) },
>> +       { PHY_ID_MATCH_EXACT(PHY_ID_LAN865X_REVB0) },
>>          { }
>>   };
>>
>> @@ -135,4 +316,5 @@ MODULE_DEVICE_TABLE(mdio, tbl);
>>
>>   MODULE_DESCRIPTION("Microchip 10BASE-T1S Phy driver");
>>   MODULE_AUTHOR("Ramón Nordin Rodriguez");
>> +MODULE_AUTHOR("Parthiban Veerasooran <[email-masked]>");
>>   MODULE_LICENSE("GPL");
>> --
>> 2.34.1
>>
>