On Thu, Jan 22, 2026 at 12:56:42PM +0200, Vladimir Oltean wrote:
This is the standalone variant of drivers/net/dsa/sja1105/sja1105_mdio.c.
Same kind of differences between this driver and the embedded DSA one
apply: regmap is being used for register access, and addresses are
multiplied by 4 with regmap.
In fact this is so generic that there is nothing NXP SJA1110 specific
about it at all, and just instantiates mdio-regmap. I decided to name it
mdio-regmap-simple.c in the style of drivers/mfd/simple-mfd-i2c.c which
has support for various vendor compatible strings.
...
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+#include <linux/module.h>
+#include <linux/of_mdio.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/mdio/mdio-regmap.h>
...
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+static const struct mdio_regmap_simple_data nxp_sja1110_base_tx = {
+ .valid_addr = 0,
+ .autoscan = false,
+};
Actually the { } is enough to initialise that. But if you want to be super
explicit... :-)
...
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+static int mdio_regmap_simple_probe(struct platform_device *pdev)
+{
+ const struct mdio_regmap_simple_data *data;
+ struct mdio_regmap_config config = {};
+ struct device *dev = &pdev->dev;
+ struct regmap *regmap;
+ struct mii_bus *bus;
+
+ if (!dev->of_node || !dev->parent)
dev->of_node check is not needed, see below.
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+ return -ENODEV;
+
+ regmap = dev_get_regmap(dev->parent, NULL);
+ if (!regmap)
+ return -ENODEV;
+
+ data = device_get_match_data(dev);
+
+ config.regmap = regmap;
+ config.parent = dev;
+ config.name = dev_name(dev);
+ /* The resource is optional, provided for finding the registers
+ * within a device-wide non-MMIO regmap
+ */
+ config.resource = platform_get_resource(pdev, IORESOURCE_REG, 0);
+ if (data) {
We may always require data to be present. As you use a default one anyway.
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+ config.valid_addr = data->valid_addr;
+ config.autoscan = data->autoscan;
+ }
And if it is not provided we will have a crash which is fine. It will just
point that the code was not ever been run on real HW.
+ return PTR_ERR_OR_ZERO(devm_mdio_regmap_register(dev, &config));
+}
...
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+static struct platform_driver mdio_regmap_simple_driver = {
+ .probe = mdio_regmap_simple_probe,
+ .driver = {
+ .name = "mdio-regmap-simple",
+ .of_match_table = mdio_regmap_simple_match,
+ },
+};
+
Unneeded blank line.
+module_platform_driver(mdio_regmap_simple_driver);
--
With Best Regards,
Andy Shevchenko