net: pcs: rzn1-miic: Add PHY_LINK active-level configuration support

Add support to configure the active level of MIIC PHY_LINK status signals
on a per-converter basis using a DT property.

MIIC provides dedicated PHY_LINK signals that indicate EtherPHY link-up and
link-down status in hardware. These signals are required regardless of
whether GMAC or ETHSW is used. With GMAC, link state is retrieved via
MDC/MDIO and handled in software, while ETHSW relies on PHY_LINK pins for
both CPU-assisted operation and switch-only data paths that do not involve
the host.

Hardware PHY_LINK signals are also critical for fast reaction to link-down
events, for example when running redundancy protocols such as Device Level
Ring (DLR), where rapid detection of cable faults is required to switch to
an alternate path without software latency.

Parse the requested polarity from DT, accumulate the configuration during
probing, and apply it to the MIIC_PHY_LINK register once hardware
initialization is complete, when the registers can be safely modified.
Handle SoC-specific bit layout differences between RZ/N1 and RZ/T2H/N2H
within the driver.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://patch.msgid.link/20260112173555.1166714-3-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/pcs/pcs-rzn1-miic.c b/drivers/net/pcs/pcs-rzn1-miic.c
index 885f17c32643b2271eba7c6173b08a2ac3e56bac..8d7f82c1df2f40525dd6f6daaa2b308a6f821310 100644 (file)
--- a/drivers/net/pcs/pcs-rzn1-miic.c
+++ b/drivers/net/pcs/pcs-rzn1-miic.c
@@ -28,6 +28,8 @@
 
 #define MIIC_MODCTRL                   0x8
 
+#define MIIC_PHY_LINK                  0x14
+
 #define MIIC_CONVCTRL(port)            (0x100 + (port) * 4)
 
 #define MIIC_CONVCTRL_CONV_SPEED       GENMASK(1, 0)
@@ -177,6 +179,16 @@ static const char * const rzt2h_reset_ids[] = {
        "crst",
 };
 
+/**
+ * struct miic_phy_link_cfg - MIIC PHY_LINK configuration
+ * @mask: Mask of phy_link bits
+ * @val: Value of phy_link bits
+ */
+struct miic_phy_link_cfg {
+       u32 mask;
+       u32 val;
+};
+
 /**
  * struct miic - MII converter structure
  * @base: base address of the MII converter
@@ -184,6 +196,7 @@ static const char * const rzt2h_reset_ids[] = {
  * @lock: Lock used for read-modify-write access
  * @rsts: Reset controls for the MII converter
  * @of_data: Pointer to OF data
+ * @link_cfg: MIIC PHY_LINK configuration
  */
 struct miic {
        void __iomem *base;
@@ -191,6 +204,12 @@ struct miic {
        spinlock_t lock;
        struct reset_control_bulk_data rsts[MIIC_MAX_NUM_RSTS];
        const struct miic_of_data *of_data;
+       struct miic_phy_link_cfg link_cfg;
+};
+
+enum miic_type {
+       MIIC_TYPE_RZN1,
+       MIIC_TYPE_RZT2H,
 };
 
 /**
@@ -210,6 +229,7 @@ struct miic {
  * @init_unlock_lock_regs: Flag to indicate if registers need to be unlocked
  *  before access.
  * @miic_write: Function pointer to write a value to a MIIC register
+ * @type: Type of MIIC
  */
 struct miic_of_data {
        struct modctrl_match *match_table;
@@ -226,6 +246,7 @@ struct miic_of_data {
        u8 reset_count;
        bool init_unlock_lock_regs;
        void (*miic_write)(struct miic *miic, int offset, u32 value);
+       enum miic_type type;
 };
 
 /**
@@ -581,10 +602,79 @@ static int miic_match_dt_conf(struct miic *miic, s8 *dt_val, u32 *mode_cfg)
        return -EINVAL;
 }
 
+static void miic_configure_phy_link(struct miic *miic, u32 conf,
+                                   u32 port, bool active_low)
+{
+       bool polarity_active_high;
+       u32 mask, shift;
+
+       /* determine shift and polarity for this conf */
+       if (miic->of_data->type == MIIC_TYPE_RZN1) {
+               switch (conf) {
+               /* switch ports => bits [3:0] (shift 0), active when low */
+               case MIIC_SWITCH_PORTA:
+               case MIIC_SWITCH_PORTB:
+               case MIIC_SWITCH_PORTC:
+               case MIIC_SWITCH_PORTD:
+                       shift = 0;
+                       polarity_active_high = false;
+                       break;
+
+               /* EtherCAT ports => bits [7:4] (shift 4), active when high */
+               case MIIC_ETHERCAT_PORTA:
+               case MIIC_ETHERCAT_PORTB:
+               case MIIC_ETHERCAT_PORTC:
+                       shift = 4;
+                       polarity_active_high = true;
+                       break;
+
+               /* Sercos ports => bits [11:8] (shift 8), active when high */
+               case MIIC_SERCOS_PORTA:
+               case MIIC_SERCOS_PORTB:
+                       shift = 8;
+                       polarity_active_high = true;
+                       break;
+
+               default:
+                       return;
+               }
+       } else {
+               switch (conf) {
+               /* ETHSW ports => bits [3:0] (shift 0), active when low */
+               case ETHSS_ETHSW_PORT0:
+               case ETHSS_ETHSW_PORT1:
+               case ETHSS_ETHSW_PORT2:
+                       shift = 0;
+                       polarity_active_high = false;
+                       break;
+
+               /* ESC ports => bits [7:4] (shift 4), active when high */
+               case ETHSS_ESC_PORT0:
+               case ETHSS_ESC_PORT1:
+               case ETHSS_ESC_PORT2:
+                       shift = 4;
+                       polarity_active_high = true;
+                       break;
+
+               default:
+                       return;
+               }
+       }
+
+       mask = BIT(port + shift);
+
+       miic->link_cfg.mask |= mask;
+       if (polarity_active_high != active_low)
+               miic->link_cfg.val |= mask;
+       else
+               miic->link_cfg.val &= ~mask;
+}
+
 static int miic_parse_dt(struct miic *miic, u32 *mode_cfg)
 {
        struct device_node *np = miic->dev->of_node;
        struct device_node *conv;
+       bool active_low;
        int port, ret;
        s8 *dt_val;
        u32 conf;
@@ -603,10 +693,15 @@ static int miic_parse_dt(struct miic *miic, u32 *mode_cfg)
                if (of_property_read_u32(conv, "reg", &port))
                        continue;
 
+               if (of_property_read_u32(conv, "renesas,miic-input", &conf))
+                       continue;
+
                /* Adjust for 0 based index */
-               port += !miic->of_data->miic_port_start;
-               if (of_property_read_u32(conv, "renesas,miic-input", &conf) == 0)
-                       dt_val[port] = conf;
+               dt_val[port + !miic->of_data->miic_port_start] = conf;
+
+               active_low = of_property_read_bool(conv, "renesas,miic-phy-link-active-low");
+
+               miic_configure_phy_link(miic, conf, port, active_low);
        }
 
        ret = miic_match_dt_conf(miic, dt_val, mode_cfg);
@@ -696,6 +791,8 @@ static int miic_probe(struct platform_device *pdev)
        if (ret)
                goto disable_runtime_pm;
 
+       miic_reg_rmw(miic, MIIC_PHY_LINK, miic->link_cfg.mask, miic->link_cfg.val);
+
        /* miic_create() relies on that fact that data are attached to the
         * platform device to determine if the driver is ready so this needs to
         * be the last thing to be done after everything is initialized
@@ -729,6 +826,7 @@ static struct miic_of_data rzn1_miic_of_data = {
        .sw_mode_mask = GENMASK(4, 0),
        .init_unlock_lock_regs = true,
        .miic_write = miic_reg_writel_unlocked,
+       .type = MIIC_TYPE_RZN1,
 };
 
 static struct miic_of_data rzt2h_miic_of_data = {
@@ -745,6 +843,7 @@ static struct miic_of_data rzt2h_miic_of_data = {
        .reset_ids = rzt2h_reset_ids,
        .reset_count = ARRAY_SIZE(rzt2h_reset_ids),
        .miic_write = miic_reg_writel_locked,
+       .type = MIIC_TYPE_RZT2H,
 };
 
 static const struct of_device_id miic_of_mtable[] = {