[PATCH net-next v2 7/9] net: pcs: rzn1-miic: Add support to handle resets

[Prabhakar <prabhakar.csengg@xxxxxxxxx>]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxx>
---
v1->v2:
- No change.
---
 drivers/net/pcs/pcs-rzn1-miic.c | 41 +++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/net/pcs/pcs-rzn1-miic.c b/drivers/net/pcs/pcs-rzn1-miic.c
index c0aa93fd7274..d97554e203f0 100644
--- 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;
 };
 
 /**
@@ -518,6 +528,16 @@ 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_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -541,6 +561,27 @@ static int miic_probe(struct platform_device *pdev)
 	if (IS_ERR(miic->base))
 		return PTR_ERR(miic->base);
 
+	if (miic->of_data->reset_count) {
+		u8 i;
+
+		for (i = 0; i < miic->of_data->reset_count; i++)
+			miic->rsts[i].id = miic->of_data->reset_ids[i];
+
+		ret = devm_reset_control_bulk_get_exclusive(miic->dev,
+							    miic->of_data->reset_count,
+							    miic->rsts);
+		if (ret)
+			return dev_err_probe(miic->dev, ret, "failed to get bulk reset lines\n");
+
+		ret = reset_control_bulk_deassert(miic->of_data->reset_count, miic->rsts);
+		if (ret)
+			return dev_err_probe(miic->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(miic->dev, ret, "failed to add reset action\n");
+	}
+
 	ret = devm_pm_runtime_enable(dev);
 	if (ret < 0)
 		return ret;
-- 
2.51.0