linux-kernel - Re: [PATCH 4/4] mux: lan966: Add support for flexcom mux controller

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Date:   Tue, 3 May 2022 14:45:19 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Kavyasree Kotagiri <kavyasree.kotagiri@...rochip.com>,
        krzysztof.kozlowski+dt@...aro.org, nicolas.ferre@...rochip.com,
        alexandre.belloni@...tlin.com, claudiu.beznea@...rochip.com,
        peda@...ntia.se
Cc:     devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, lee.jones@...aro.org,
        linux@...linux.org.uk, Manohar.Puri@...rochip.com,
        UNGLinuxDriver@...rochip.com
Subject: Re: [PATCH 4/4] mux: lan966: Add support for flexcom mux controller

On 03/05/2022 12:55, Kavyasree Kotagiri wrote:
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/mux/driver.h>
> +#include <linux/io.h>
> +
> +#define FLEX_SHRD_MASK		0x1FFFFF
> +#define LAN966_MAX_CS		21
> +
> +static void __iomem *flx_shared_base;

Why do you have file-scope shared variable? Cannot it be passed via
private data?

> +struct mux_lan966x {
> +	u32 offset;
> +	u32 ss_pin;
> +};
> +
> +static int mux_lan966x_set(struct mux_control *mux, int state)
> +{
> +	struct mux_lan966x *mux_lan966x = mux_chip_priv(mux->chip);
> +	u32 val;
> +
> +	val = ~(1 << mux_lan966x[state].ss_pin) & FLEX_SHRD_MASK;
> +	writel(val, flx_shared_base + mux_lan966x[state].offset);
> +
> +	return 0;
> +}
> +
> +static const struct mux_control_ops mux_lan966x_ops = {
> +	.set = mux_lan966x_set,
> +};
> +
> +static const struct of_device_id mux_lan966x_dt_ids[] = {
> +	{ .compatible = "microchip,lan966-flx-mux", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, mux_lan966x_dt_ids);
> +
> +static int mux_lan966x_probe(struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct device *dev = &pdev->dev;
> +	struct mux_lan966x *mux_lan966x;
> +	struct mux_chip *mux_chip;
> +	int ret, num_fields, i;
> +
> +	ret = of_property_count_u32_elems(np, "mux-offset-pin");
> +	if (ret == 0 || ret % 2)
> +		ret = -EINVAL;
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret,
> +				     "mux-offset-pin property missing or invalid");
> +	num_fields = ret / 2;
> +
> +	mux_chip = devm_mux_chip_alloc(dev, num_fields, sizeof(*mux_lan966x));
> +	if (IS_ERR(mux_chip))
> +		return dev_err_probe(dev, PTR_ERR(mux_chip),
> +				     "failed to allocate mux_chips\n");
> +
> +	mux_lan966x = mux_chip_priv(mux_chip);
> +
> +	flx_shared_base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
> +	if (IS_ERR(flx_shared_base))
> +		return dev_err_probe(dev, PTR_ERR(flx_shared_base),
> +				     "failed to get flexcom shared base address\n");
> +
> +	for (i = 0; i < num_fields; i++) {
> +		struct mux_control *mux = &mux_chip->mux[i];
> +		u32 offset, shared_pin;
> +
> +		ret = of_property_read_u32_index(np, "mux-offset-pin",
> +						 2 * i, &offset);
> +		if (ret == 0)
> +			ret = of_property_read_u32_index(np, "mux-offset-pin",
> +							 2 * i + 1,
> +							 &shared_pin);
> +		if (ret < 0)
> +			return dev_err_probe(dev, ret,
> +					     "failed to read mux-offset-pin property: %d", i);
> +
> +		if (shared_pin >= LAN966_MAX_CS)
> +			return -EINVAL;
> +
> +		mux_lan966x[i].offset = offset;
> +		mux_lan966x[i].ss_pin = shared_pin;
> +
> +		mux->states = LAN966_MAX_CS;
> +	}
> +
> +	mux_chip->ops = &mux_lan966x_ops;
> +
> +	ret = devm_mux_chip_register(dev, mux_chip);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static struct platform_driver mux_lan966x_driver = {
> +	.driver = {
> +		.name = "lan966-mux",
> +		.of_match_table	= of_match_ptr(mux_lan966x_dt_ids),

of_match_ptr comes with maybe_unused on data structure. Are you sure it
does not have W=1 warnings during compile tests? Just drop the of_match_ptr.

> +	},
> +	.probe = mux_lan966x_probe,
> +};
> +
> +module_platform_driver(mux_lan966x_driver);

Missing MODULE() stuff.


Best regards,
Krzysztof