Re: [PATCH 1/5] soc: hpe: Add GXP SROM Control Register Driver

[Krzysztof Kozlowski]

On 10/01/2023 05:25, clayc@xxxxxxx wrote:
> From: Clay Chang <clayc@xxxxxxx>
> 
> The GXP SROM control register can be used to configure LPC related
> legacy I/O registers. Currently only the SROM RAM Offset Register
> (vromoff) is exported.
> 
> The GXP SOCLIB is a common library used for creating the common
> "soc" class in the kernel.
> 
> Signed-off-by: Clay Chang <clayc@xxxxxxx>
> ---
>  drivers/soc/Kconfig          |   1 +
>  drivers/soc/Makefile         |   1 +
>  drivers/soc/hpe/Kconfig      |  29 +++++++
>  drivers/soc/hpe/Makefile     |   2 +
>  drivers/soc/hpe/gxp-soclib.c |  17 +++++
>  drivers/soc/hpe/gxp-soclib.h |   9 +++
>  drivers/soc/hpe/gxp-srom.c   | 141 +++++++++++++++++++++++++++++++++++
>  7 files changed, 200 insertions(+)
>  create mode 100644 drivers/soc/hpe/Kconfig
>  create mode 100644 drivers/soc/hpe/Makefile
>  create mode 100644 drivers/soc/hpe/gxp-soclib.c
>  create mode 100644 drivers/soc/hpe/gxp-soclib.h
>  create mode 100644 drivers/soc/hpe/gxp-srom.c
> 
> diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
> index 5dbb09f843f7..faff0f036b61 100644
> --- a/drivers/soc/Kconfig
> +++ b/drivers/soc/Kconfig
> @@ -10,6 +10,7 @@ source "drivers/soc/bcm/Kconfig"
>  source "drivers/soc/canaan/Kconfig"
>  source "drivers/soc/fsl/Kconfig"
>  source "drivers/soc/fujitsu/Kconfig"
> +source "drivers/soc/hpe/Kconfig"
>  source "drivers/soc/imx/Kconfig"
>  source "drivers/soc/ixp4xx/Kconfig"
>  source "drivers/soc/litex/Kconfig"
> diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
> index fff513bd522d..d257b9d654b3 100644
> --- a/drivers/soc/Makefile
> +++ b/drivers/soc/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_MACH_DOVE)		+= dove/
>  obj-y				+= fsl/
>  obj-y				+= fujitsu/
>  obj-$(CONFIG_ARCH_GEMINI)	+= gemini/
> +obj-$(CONFIG_ARCH_HPE)		+= hpe/
>  obj-y				+= imx/
>  obj-y				+= ixp4xx/
>  obj-$(CONFIG_SOC_XWAY)		+= lantiq/
> diff --git a/drivers/soc/hpe/Kconfig b/drivers/soc/hpe/Kconfig
> new file mode 100644
> index 000000000000..88f5d46b06b6
> --- /dev/null
> +++ b/drivers/soc/hpe/Kconfig
> @@ -0,0 +1,29 @@
> +#
> +# HPE GXP SoC drivers
> +#
> +menu "HPE GXP SoC drivers"
> +	depends on ARCH_HPE || COMPILE_TEST
> +
> +config HPE_GXP_SOCLIB
> +	bool "GXP Common SoC Library"
> +	default y
> +	depends on ARCH_HPE_GXP || COMPILE_TEST
> +	help
> +	  This is for the common library for all HPE SoC drivers. It
> +	  creates the root soc class (/sys/class/soc) for all GXP SoC
> +	  drivers. It must be yes if any one of the GXP SoC drivers were
> +	  added, so the config of all GXP SoC drivers must select this.

Don't open-code Kconfig dependencies in free-form text. IOW, drop last
sentence.

> +
> +
> +config HPE_GXP_SROM
> +	bool "GXP SROM Configuration Driver"
> +	default y
> +	depends on ARCH_HPE_GXP || COMPILE_TEST
> +	select HPE_GXP_SOCLIB
> +	help
> +	  Say yes here to add support for SROM Configuration. The GXP SROM
> +	  control register can be used to configure LPC related legacy I/O
> +	  registers. Currently only the SROM RAM Offset Register (vromoff)
> +	  is exported.
> +
> +endmenu
> diff --git a/drivers/soc/hpe/Makefile b/drivers/soc/hpe/Makefile
> new file mode 100644
> index 000000000000..78de24ecb606
> --- /dev/null
> +++ b/drivers/soc/hpe/Makefile
> @@ -0,0 +1,2 @@
> +obj-$(CONFIG_HPE_GXP_SOCLIB) += gxp-soclib.o
> +obj-$(CONFIG_HPE_GXP_SROM) += gxp-srom.o
> diff --git a/drivers/soc/hpe/gxp-soclib.c b/drivers/soc/hpe/gxp-soclib.c
> new file mode 100644
> index 000000000000..11b0afe09070
> --- /dev/null
> +++ b/drivers/soc/hpe/gxp-soclib.c
> @@ -0,0 +1,17 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/* Copyright (C) 2023 Hewlett Packard Enteprise Development Company, L.P. */
> +
> +#include <linux/device.h>
> +#include <linux/module.h>
> +
> +struct class *soc_class;
> +
> +static int __init gxp_soclib_init(void)
> +{
> +	soc_class = class_create(THIS_MODULE, "soc");
> +	if (IS_ERR(soc_class))
> +		return PTR_ERR(soc_class);
> +	return 0;
> +}
> +
> +module_init(gxp_soclib_init);

I don't see a point of making it a shared object and a "kernel library".
Module inits are not libraries. Drop entire file.

> diff --git a/drivers/soc/hpe/gxp-soclib.h b/drivers/soc/hpe/gxp-soclib.h
> new file mode 100644
> index 000000000000..eb0e72b67aee
> --- /dev/null
> +++ b/drivers/soc/hpe/gxp-soclib.h
> @@ -0,0 +1,9 @@


> +
> +static int sysfs_register(struct device *parent,
> +			  struct gxp_srom_drvdata *drvdata)
> +{
> +	struct device *dev;
> +
> +	dev = device_create_with_groups(soc_class, parent, 0,
> +					drvdata, srom_groups, "srom");
> +	if (IS_ERR(dev))
> +		return PTR_ERR(dev);
> +	drvdata->dev = dev;
> +	return 0;
> +}
> +
> +static int gxp_srom_probe(struct platform_device *pdev)
> +{
> +	struct gxp_srom_drvdata *drvdata;
> +	struct resource *res;
> +	int ret;
> +
> +	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gxp_srom_drvdata),

sizeof(*)

> +				GFP_KERNEL);
> +	if (!drvdata)
> +		return -ENOMEM;
> +
> +	drvdata->pdev = pdev;
> +	platform_set_drvdata(pdev, drvdata);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res) {
> +		dev_err(&pdev->dev, "no srom resource defined\n");
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	drvdata->base = devm_ioremap_resource(&pdev->dev, res);

Combine these two. There is a helper for this.

> +	if (IS_ERR(drvdata->base)) {
> +		dev_err(&pdev->dev, "ioremap_resource error\n");
> +		ret = PTR_ERR(drvdata->base);

return dev_err_probe().
> +		goto ioremap_err;
> +	}
> +
> +	mutex_init(&drvdata->mutex);
> +
> +	ret = sysfs_register(&pdev->dev, drvdata);

Missing ABI documentation.

> +	if (ret != 0) {
> +		dev_err(&pdev->dev, "sysfs error\n");

return dev_err_probe

> +		goto sysfs_err;
> +	}
> +
> +	dev_info(&pdev->dev, "initialized\n");

Drop silly probe successes.

> +	return 0;
> +
> +sysfs_err:
> +ioremap_err:
> +	platform_set_drvdata(pdev, NULL);
> +out:
> +	if (drvdata)
> +		devm_kfree(&pdev->dev, (void *)drvdata);

1. Why? if it is here, it must be in remove() callback. If it is invalid
(because it is really not correct) for remove(), it cannot be here, right?
2. Why cast?

> +	return ret;
> +}
> +
> +static const struct of_device_id gxp_srom_of_match[] = {
> +	{ .compatible = "hpe,gxp-srom" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, gxp_srom_of_match);
> +
> +static struct platform_driver gxp_srom_driver = {
> +	.probe = gxp_srom_probe,
> +	.driver = {
> +		.name = "gxp-srom",
> +		.of_match_table = of_match_ptr(gxp_srom_of_match),

That will cause a warning. Drop of_match_ptr.

> +	},
> +};
> +module_platform_driver(gxp_srom_driver);
> +
> +MODULE_AUTHOR("Clay Chang <clayc@xxxxxxx>");
> +MODULE_DESCRIPTION("HPE GXP SROM Configuration Driver");
> +MODULE_LICENSE("GPL");

Best regards,
Krzysztof