Subject: Re: [PATCH v2 1/3] net: phy: mdio: add IPQ40xx MDIO driver

From: Andrew Lunn <[email-masked]>
Date: Tue, 14 Apr 2020 20:43:46 +0200

Hi Robert

This is looking better

> +#include <linux/delay.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>

I don't think you need this header. There are no mutexes here.

> +#include <linux/io.h>
> +#include <linux/of_address.h>
> +#include <linux/of_mdio.h>
> +#include <linux/phy.h>
> +#include <linux/platform_device.h>
> +
> +#define MDIO_CTRL_0_REG		0x40
> +#define MDIO_CTRL_1_REG		0x44
> +#define MDIO_CTRL_2_REG		0x48
> +#define MDIO_CTRL_3_REG		0x4c
> +#define MDIO_CTRL_4_REG		0x50

So your next version will hopefully have better names.

> +static int ipq40xx_mdio_wait_busy(struct mii_bus *bus)
> +{
> +	struct ipq40xx_mdio_data *priv = bus->priv;
> +	int i;
> +
> +	for (i = 0; i < IPQ40XX_MDIO_RETRY; i++) {
> +		unsigned int busy;
> +
> +		busy = readl(priv->membase + MDIO_CTRL_4_REG) &
> +			MDIO_CTRL_4_ACCESS_BUSY;
> +		if (!busy)
> +			return 0;
> +
> +		/* BUSY might take to be cleard by 15~20 times of loop */
> +		udelay(IPQ40XX_MDIO_DELAY);
> +	}
> +
> +	dev_err(bus->parent, "MDIO operation timed out\n");
> +
> +	return -ETIMEDOUT;
> +}

You can probably make use of include/linux/iopoll.h 

    Andrew