net: pcs: rzn1-miic: Add support to handle resets

Add reset-line handling to the RZN1 MIIC driver and move reset
configuration into the SoC/OF data. Introduce MIIC_MAX_NUM_RSTS (= 2),
add storage for reset_control_bulk_data in struct miic and add
reset_ids and reset_count fields to miic_of_data.

When reset_ids are present in the OF data, the driver obtains the reset
lines with devm_reset_control_bulk_get_exclusive(), deasserts them during
probe and registers a devres action to assert them on remove or on error.

This change is preparatory work to support the RZ/T2H SoC, which exposes
two reset lines for the ETHSS IP. The driver remains backward compatible
for platforms that do not provide reset lines.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://patch.msgid.link/20250910204132.319975-8-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 f6d9c03d10f07bce24f3273e5537e160f1d84c5a..75009b30084ab39ba955e099940eeabb83828cd6 100644 (file)
--- a/drivers/net/pcs/pcs-rzn1-miic.c
+++ b/drivers/net/pcs/pcs-rzn1-miic.c
@@ -10,6 +10,7 @@
 #include <linux/bitops.h>
 #include <linux/clk.h>
 #include <linux/device.h>
+#include <linux/device/devres.h>
 #include <linux/mdio.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
@@ -17,6 +18,7 @@
 #include <linux/phylink.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <dt-bindings/net/pcs-rzn1-miic.h>
 
@@ -52,6 +54,8 @@
 #define MIIC_MODCTRL_CONF_CONV_MAX     6
 #define MIIC_MODCTRL_CONF_NONE         -1
 
+#define MIIC_MAX_NUM_RSTS              2
+
 /**
  * struct modctrl_match - Matching table entry for  convctrl configuration
  *                       See section 8.2.1 of manual.
@@ -126,12 +130,14 @@ static const char * const index_to_string[] = {
  * @base: base address of the MII converter
  * @dev: Device associated to the MII converter
  * @lock: Lock used for read-modify-write access
+ * @rsts: Reset controls for the MII converter
  * @of_data: Pointer to OF data
  */
 struct miic {
        void __iomem *base;
        struct device *dev;
        spinlock_t lock;
+       struct reset_control_bulk_data rsts[MIIC_MAX_NUM_RSTS];
        const struct miic_of_data *of_data;
 };
 
@@ -147,6 +153,8 @@ struct miic {
  * @miic_port_start: MIIC port start number
  * @miic_port_max: Maximum MIIC supported
  * @sw_mode_mask: Switch mode mask
+ * @reset_ids: Reset names array
+ * @reset_count: Number of entries in the reset_ids array
  */
 struct miic_of_data {
        struct modctrl_match *match_table;
@@ -159,6 +167,8 @@ struct miic_of_data {
        u8 miic_port_start;
        u8 miic_port_max;
        u8 sw_mode_mask;
+       const char * const *reset_ids;
+       u8 reset_count;
 };
 
 /**
@@ -523,6 +533,48 @@ static int miic_parse_dt(struct miic *miic, u32 *mode_cfg)
        return ret;
 }
 
+static void miic_reset_control_bulk_assert(void *data)
+{
+       struct miic *miic = data;
+       int ret;
+
+       ret = reset_control_bulk_assert(miic->of_data->reset_count, miic->rsts);
+       if (ret)
+               dev_err(miic->dev, "failed to assert reset lines\n");
+}
+
+static int miic_reset_control_init(struct miic *miic)
+{
+       const struct miic_of_data *of_data = miic->of_data;
+       struct device *dev = miic->dev;
+       int ret;
+       u8 i;
+
+       if (!of_data->reset_count)
+               return 0;
+
+       for (i = 0; i < of_data->reset_count; i++)
+               miic->rsts[i].id = of_data->reset_ids[i];
+
+       ret = devm_reset_control_bulk_get_exclusive(dev, of_data->reset_count,
+                                                   miic->rsts);
+       if (ret)
+               return dev_err_probe(dev, ret,
+                                    "failed to get bulk reset lines\n");
+
+       ret = reset_control_bulk_deassert(of_data->reset_count, miic->rsts);
+       if (ret)
+               return dev_err_probe(dev, ret,
+                                    "failed to deassert reset lines\n");
+
+       ret = devm_add_action_or_reset(dev, miic_reset_control_bulk_assert,
+                                      miic);
+       if (ret)
+               return dev_err_probe(dev, ret, "failed to add reset action\n");
+
+       return 0;
+}
+
 static int miic_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
@@ -546,6 +598,10 @@ static int miic_probe(struct platform_device *pdev)
        if (IS_ERR(miic->base))
                return PTR_ERR(miic->base);
 
+       ret = miic_reset_control_init(miic);
+       if (ret)
+               return ret;
+
        ret = devm_pm_runtime_enable(dev);
        if (ret < 0)
                return ret;