Re: [RFC net-next 2/2] net: dsa: Add driver for Maxlinear GSW1XX switch

[Krzysztof Kozlowski]

On 25/10/2022 09:52, Camel Guo wrote:
> Add initial framework for Maxlinear's GSW1xx switch and
> currently only GSW145 in MDIO managed mode is supported.
> 
> Signed-off-by: Camel Guo <camel.guo@xxxxxxxx>
> ---

(...)

> +	priv->ds->dev = dev;
> +	priv->ds->num_ports = priv->hw_info->max_ports;
> +	priv->ds->priv = priv;
> +	priv->ds->ops = &gsw1xx_switch_ops;
> +	priv->dev = dev;
> +	version = gsw1xx_switch_r(priv, GSW1XX_IP_VERSION);
> +
> +	np = dev->of_node;
> +	switch (version) {
> +	case GSW1XX_IP_VERSION_2_3:
> +		if (!of_device_is_compatible(np, "mxl,gsw145-mdio"))
> +			return -EINVAL;
> +		break;
> +	default:
> +		dev_err(dev, "unknown GSW1XX_IP version: 0x%x", version);
> +		return -ENOENT;
> +	}
> +
> +	/* bring up the mdio bus */
> +	mdio_np = of_get_child_by_name(np, "mdio");
> +	if (!mdio_np) {
> +		dev_err(dev, "missing child mdio node\n");
> +		return -EINVAL;
> +	}
> +
> +	err = gsw1xx_mdio(priv, mdio_np);
> +	if (err) {
> +		dev_err(dev, "mdio probe failed\n");

dev_err_probe()

> +		goto put_mdio_node;
> +	}
> +
> +	err = dsa_register_switch(priv->ds);
> +	if (err) {
> +		dev_err(dev, "dsa switch register failed: %i\n", err);


dev_err_probe()

> +		goto mdio_bus;
> +	}
> +	if (!dsa_is_cpu_port(priv->ds, priv->hw_info->cpu_port)) {
> +		dev_err(dev,
> +			"wrong CPU port defined, HW only supports port: %i",
> +			priv->hw_info->cpu_port);
> +		err = -EINVAL;
> +		goto disable_switch;
> +	}
> +
> +	dev_set_drvdata(dev, priv);
> +
> +	return 0;
> +
> +disable_switch:
> +	gsw1xx_mdio_mask(priv, GSW1XX_MDIO_GLOB_ENABLE, 0, GSW1XX_MDIO_GLOB);
> +	dsa_unregister_switch(priv->ds);
> +mdio_bus:
> +	if (mdio_np) {
> +		mdiobus_unregister(priv->ds->slave_mii_bus);
> +		mdiobus_free(priv->ds->slave_mii_bus);
> +	}
> +put_mdio_node:
> +	of_node_put(mdio_np);
> +	return err;
> +}
> +EXPORT_SYMBOL(gsw1xx_probe);
> +
> +void gsw1xx_remove(struct gsw1xx_priv *priv)
> +{
> +	if (!priv)
> +		return;
> +
> +	/* disable the switch */
> +	gsw1xx_mdio_mask(priv, GSW1XX_MDIO_GLOB_ENABLE, 0, GSW1XX_MDIO_GLOB);
> +
> +	dsa_unregister_switch(priv->ds);
> +
> +	if (priv->ds->slave_mii_bus) {
> +		mdiobus_unregister(priv->ds->slave_mii_bus);
> +		of_node_put(priv->ds->slave_mii_bus->dev.of_node);
> +		mdiobus_free(priv->ds->slave_mii_bus);
> +	}
> +
> +	dev_set_drvdata(priv->dev, NULL);
> +}
> +EXPORT_SYMBOL(gsw1xx_remove);
> +
> +void gsw1xx_shutdown(struct gsw1xx_priv *priv)
> +{
> +	if (!priv)
> +		return;
> +
> +	/* disable the switch */
> +	gsw1xx_mdio_mask(priv, GSW1XX_MDIO_GLOB_ENABLE, 0, GSW1XX_MDIO_GLOB);
> +
> +	dsa_switch_shutdown(priv->ds);
> +
> +	dev_set_drvdata(priv->dev, NULL);
> +}
> +EXPORT_SYMBOL(gsw1xx_shutdown);

1. EXPORT_SYMBOL_GPL
2. Why do you do it in the first place? It's one driver, no need for
building two modules. Same applies to other places.

> +
> +static const struct regmap_range gsw1xx_valid_regs[] = {
> +	/* GSWIP Core Registers */
> +	regmap_reg_range(GSW1XX_IP_BASE_ADDR,
> +			 GSW1XX_IP_BASE_ADDR + GSW1XX_IP_REG_LEN),
> +	/* Top Level PDI Registers, MDIO Master Reigsters */
> +	regmap_reg_range(GSW1XX_MDIO_BASE_ADDR,
> +			 GSW1XX_MDIO_BASE_ADDR + GSW1XX_MDIO_REG_LEN),
> +};
> +
> +const struct regmap_access_table gsw1xx_register_set = {
> +	.yes_ranges = gsw1xx_valid_regs,
> +	.n_yes_ranges = ARRAY_SIZE(gsw1xx_valid_regs),
> +};
> +EXPORT_SYMBOL(gsw1xx_register_set);
> +
> +MODULE_AUTHOR("Camel Guo <camel.guo@xxxxxxxx>");
> +MODULE_DESCRIPTION("Core Driver for MaxLinear GSM1XX ethernet switch");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/net/dsa/gsw1xx_mdio.c b/drivers/net/dsa/gsw1xx_mdio.c
> new file mode 100644
> index 000000000000..8328001041ed
> --- /dev/null
> +++ b/drivers/net/dsa/gsw1xx_mdio.c
> @@ -0,0 +1,128 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * MaxLinear switch driver for GSW1XX in MDIO managed mode
> + */
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mdio.h>
> +#include <linux/phy.h>
> +#include <linux/of.h>
> +
> +#include "gsw1xx.h"
> +
> +#define GSW1XX_SMDIO_TARGET_BASE_ADDR_REG	0x1F
> +
> +static int gsw1xx_mdio_write(void *ctx, uint32_t reg, uint32_t val)
> +{
> +	struct mdio_device *mdiodev = (struct mdio_device *)ctx;
> +	int ret = 0;
> +
> +	mutex_lock_nested(&mdiodev->bus->mdio_lock, MDIO_MUTEX_NESTED);
> +
> +	ret = mdiodev->bus->write(mdiodev->bus, mdiodev->addr,
> +				  GSW1XX_SMDIO_TARGET_BASE_ADDR_REG, reg);
> +	if (ret < 0)
> +		goto out;
> +
> +	ret = mdiodev->bus->write(mdiodev->bus, mdiodev->addr, 0, val);
> +
> +out:
> +	mutex_unlock(&mdiodev->bus->mdio_lock);
> +
> +	return ret;
> +}
> +
> +static int gsw1xx_mdio_read(void *ctx, uint32_t reg, uint32_t *val)
> +{
> +	struct mdio_device *mdiodev = (struct mdio_device *)ctx;
> +	int ret = 0;
> +
> +	mutex_lock_nested(&mdiodev->bus->mdio_lock, MDIO_MUTEX_NESTED);
> +
> +	ret = mdiodev->bus->write(mdiodev->bus, mdiodev->addr,
> +				  GSW1XX_SMDIO_TARGET_BASE_ADDR_REG, reg);
> +	if (ret < 0)
> +		goto out;
> +
> +	*val = mdiodev->bus->read(mdiodev->bus, mdiodev->addr, 0);
> +
> +out:
> +	mutex_unlock(&mdiodev->bus->mdio_lock);
> +
> +	return ret;
> +}
> +
> +static const struct regmap_config gsw1xx_mdio_regmap_config = {
> +	.reg_bits = 16,
> +	.val_bits = 16,
> +	.reg_stride = 1,
> +
> +	.disable_locking = true,
> +
> +	.volatile_table = &gsw1xx_register_set,
> +	.wr_table = &gsw1xx_register_set,
> +	.rd_table = &gsw1xx_register_set,
> +
> +	.reg_read = gsw1xx_mdio_read,
> +	.reg_write = gsw1xx_mdio_write,
> +
> +	.cache_type = REGCACHE_NONE,
> +};
> +
> +static int gsw1xx_mdio_probe(struct mdio_device *mdiodev)
> +{
> +	struct gsw1xx_priv *priv;
> +	struct device *dev = &mdiodev->dev;
> +	int ret;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->regmap = devm_regmap_init(dev, NULL, mdiodev,
> +					&gsw1xx_mdio_regmap_config);
> +	if (IS_ERR(priv->regmap)) {
> +		ret = PTR_ERR(priv->regmap);
> +		dev_err(dev, "regmap init failed: %d\n", ret);
> +		return ret;

return dev_err_probe().

> +	}
> +
> +	return gsw1xx_probe(priv, dev);
> +}
> +
> +static void gsw1xx_mdio_remove(struct mdio_device *mdiodev)
> +{
> +	gsw1xx_remove(dev_get_drvdata(&mdiodev->dev));
> +}
> +
> +static void gsw1xx_mdio_shutdown(struct mdio_device *mdiodev)
> +{
> +	gsw1xx_shutdown(dev_get_drvdata(&mdiodev->dev));
> +}
> +
> +static const struct gsw1xx_hw_info gsw145_hw_info = {
> +	.max_ports = 6,
> +	.cpu_port = 5,
> +};
> +
> +static const struct of_device_id gsw1xx_mdio_of_match[] = {
> +	{ .compatible = "mxl,gsw145-mdio", .data = &gsw145_hw_info },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, gsw1xx_mdio_of_match);
> +
> +static struct mdio_driver gsw1xx_mdio_driver = {
> +	.probe  = gsw1xx_mdio_probe,
> +	.remove = gsw1xx_mdio_remove,
> +	.shutdown = gsw1xx_mdio_shutdown,
> +	.mdiodrv.driver = {
> +		.name = "GSW1XX_MDIO",
> +		.of_match_table = of_match_ptr(gsw1xx_mdio_of_match),

of_match_ptr requires maybe_unused. Or just drop it.

Best regards,
Krzysztof