net: dsa: realtek: common rtl83xx module

Some code can be shared between both interface modules (MDIO and SMI)
and among variants. These interface functions migrated to a common
module:

- rtl83xx_lock
- rtl83xx_unlock
- rtl83xx_probe
- rtl83xx_register_switch
- rtl83xx_unregister_switch
- rtl83xx_shutdown
- rtl83xx_remove

The reset during probe was moved to the end of the common probe. This way,
we avoid a reset if anything else fails.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 235 insertions, 0 deletions

diff --git a/drivers/net/dsa/realtek/rtl83xx.c b/drivers/net/dsa/realtek/rtl83xx.c
new file mode 100644
index 000000000000..0f628065f456
--- /dev/null
+++ b/drivers/net/dsa/realtek/rtl83xx.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+
+#include "realtek.h"
+#include "rtl83xx.h"
+
+/**
+ * rtl83xx_lock() - Locks the mutex used by regmaps
+ * @ctx: realtek_priv pointer
+ *
+ * This function is passed to regmap to be used as the lock function.
+ * It is also used externally to block regmap before executing multiple
+ * operations that must happen in sequence (which will use
+ * realtek_priv.map_nolock instead).
+ *
+ * Context: Can sleep. Holds priv->map_lock lock.
+ * Return: nothing
+ */
+void rtl83xx_lock(void *ctx)
+{
+	struct realtek_priv *priv = ctx;
+
+	mutex_lock(&priv->map_lock);
+}
+EXPORT_SYMBOL_NS_GPL(rtl83xx_lock, REALTEK_DSA);
+
+/**
+ * rtl83xx_unlock() - Unlocks the mutex used by regmaps
+ * @ctx: realtek_priv pointer
+ *
+ * This function unlocks the lock acquired by rtl83xx_lock.
+ *
+ * Context: Releases priv->map_lock lock.
+ * Return: nothing
+ */
+void rtl83xx_unlock(void *ctx)
+{
+	struct realtek_priv *priv = ctx;
+
+	mutex_unlock(&priv->map_lock);
+}
+EXPORT_SYMBOL_NS_GPL(rtl83xx_unlock, REALTEK_DSA);
+
+/**
+ * rtl83xx_probe() - probe a Realtek switch
+ * @dev: the device being probed
+ * @interface_info: specific management interface info.
+ *
+ * This function initializes realtek_priv and reads data from the device tree
+ * node. The switch is hard resetted if a method is provided.
+ *
+ * Context: Can sleep.
+ * Return: Pointer to the realtek_priv or ERR_PTR() in case of failure.
+ *
+ * The realtek_priv pointer does not need to be freed as it is controlled by
+ * devres.
+ */
+struct realtek_priv *
+rtl83xx_probe(struct device *dev,
+	      const struct realtek_interface_info *interface_info)
+{
+	const struct realtek_variant *var;
+	struct realtek_priv *priv;
+	struct regmap_config rc = {
+		.reg_bits = 10, /* A4..A0 R4..R0 */
+		.val_bits = 16,
+		.reg_stride = 1,
+		.max_register = 0xffff,
+		.reg_format_endian = REGMAP_ENDIAN_BIG,
+		.reg_read = interface_info->reg_read,
+		.reg_write = interface_info->reg_write,
+		.cache_type = REGCACHE_NONE,
+		.lock = rtl83xx_lock,
+		.unlock = rtl83xx_unlock,
+	};
+	int ret;
+
+	var = of_device_get_match_data(dev);
+	if (!var)
+		return ERR_PTR(-EINVAL);
+
+	priv = devm_kzalloc(dev, size_add(sizeof(*priv), var->chip_data_sz),
+			    GFP_KERNEL);
+	if (!priv)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_init(&priv->map_lock);
+
+	rc.lock_arg = priv;
+	priv->map = devm_regmap_init(dev, NULL, priv, &rc);
+	if (IS_ERR(priv->map)) {
+		ret = PTR_ERR(priv->map);
+		dev_err(dev, "regmap init failed: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	rc.disable_locking = true;
+	priv->map_nolock = devm_regmap_init(dev, NULL, priv, &rc);
+	if (IS_ERR(priv->map_nolock)) {
+		ret = PTR_ERR(priv->map_nolock);
+		dev_err(dev, "regmap init failed: %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	/* Link forward and backward */
+	priv->dev = dev;
+	priv->variant = var;
+	priv->ops = var->ops;
+	priv->chip_data = (void *)priv + sizeof(*priv);
+
+	spin_lock_init(&priv->lock);
+
+	priv->leds_disabled = of_property_read_bool(dev->of_node,
+						    "realtek,disable-leds");
+
+	/* TODO: if power is software controlled, set up any regulators here */
+	priv->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(priv->reset)) {
+		dev_err(dev, "failed to get RESET GPIO\n");
+		return ERR_CAST(priv->reset);
+	}
+
+	dev_set_drvdata(dev, priv);
+
+	if (priv->reset) {
+		gpiod_set_value(priv->reset, 1);
+		dev_dbg(dev, "asserted RESET\n");
+		msleep(REALTEK_HW_STOP_DELAY);
+		gpiod_set_value(priv->reset, 0);
+		msleep(REALTEK_HW_START_DELAY);
+		dev_dbg(dev, "deasserted RESET\n");
+	}
+
+	return priv;
+}
+EXPORT_SYMBOL_NS_GPL(rtl83xx_probe, REALTEK_DSA);
+
+/**
+ * rtl83xx_register_switch() - detects and register a switch
+ * @priv: realtek_priv pointer
+ *
+ * This function first checks the switch chip ID and register a DSA
+ * switch.
+ *
+ * Context: Can sleep. Takes and releases priv->map_lock.
+ * Return: 0 on success, negative value for failure.
+ */
+int rtl83xx_register_switch(struct realtek_priv *priv)
+{
+	struct dsa_switch *ds;
+	int ret;
+
+	ret = priv->ops->detect(priv);
+	if (ret) {
+		dev_err_probe(priv->dev, ret, "unable to detect switch\n");
+		return ret;
+	}
+
+	ds = devm_kzalloc(priv->dev, sizeof(*ds), GFP_KERNEL);
+	if (!ds)
+		return -ENOMEM;
+
+	ds->priv = priv;
+	ds->dev = priv->dev;
+	ds->ops = priv->ds_ops;
+	ds->num_ports = priv->num_ports;
+	priv->ds = ds;
+
+	ret = dsa_register_switch(ds);
+	if (ret) {
+		dev_err_probe(priv->dev, ret, "unable to register switch\n");
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(rtl83xx_register_switch, REALTEK_DSA);
+
+/**
+ * rtl83xx_unregister_switch() - unregister a switch
+ * @priv: realtek_priv pointer
+ *
+ * This function unregister a DSA switch.
+ *
+ * Context: Can sleep.
+ * Return: Nothing.
+ */
+void rtl83xx_unregister_switch(struct realtek_priv *priv)
+{
+	dsa_unregister_switch(priv->ds);
+}
+EXPORT_SYMBOL_NS_GPL(rtl83xx_unregister_switch, REALTEK_DSA);
+
+/**
+ * rtl83xx_shutdown() - shutdown a switch
+ * @priv: realtek_priv pointer
+ *
+ * This function shuts down the DSA switch and cleans the platform driver data,
+ * to prevent realtek_{smi,mdio}_remove() from running afterwards, which is
+ * possible if the parent bus implements its own .shutdown() as .remove().
+ *
+ * Context: Can sleep.
+ * Return: Nothing.
+ */
+void rtl83xx_shutdown(struct realtek_priv *priv)
+{
+	dsa_switch_shutdown(priv->ds);
+
+	dev_set_drvdata(priv->dev, NULL);
+}
+EXPORT_SYMBOL_NS_GPL(rtl83xx_shutdown, REALTEK_DSA);
+
+/**
+ * rtl83xx_remove() - Cleanup a realtek switch driver
+ * @priv: realtek_priv pointer
+ *
+ * If a method is provided, this function asserts the hard reset of the switch
+ * in order to avoid leaking traffic when the driver is gone.
+ *
+ * Context: Might sleep if priv->gdev->chip->can_sleep.
+ * Return: nothing
+ */
+void rtl83xx_remove(struct realtek_priv *priv)
+{
+	/* leave the device reset asserted */
+	if (priv->reset)
+		gpiod_set_value(priv->reset, 1);
+}
+EXPORT_SYMBOL_NS_GPL(rtl83xx_remove, REALTEK_DSA);
+
+MODULE_AUTHOR("Luiz Angelo Daros de Luca <luizluca@gmail.com>");
+MODULE_DESCRIPTION("Realtek DSA switches common module");
+MODULE_LICENSE("GPL");