Re: [PATCH 1/3] reset: add driver for socfpga

[Philipp Zabel <p.zabel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>]

Hi Steffen,

a few minor issues below:

Am Freitag, den 04.04.2014, 18:31 +0200 schrieb Steffen Trumtrar:
> Add a reset-controller driver for the socfpga platform.
> The reset-controller has four banks with up to 32 entries all encapsulated in
> one module block.
> 
> Signed-off-by: Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
>  drivers/reset/Makefile        |   1 +
>  drivers/reset/reset-socfpga.c | 149 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 150 insertions(+)
>  create mode 100644 drivers/reset/reset-socfpga.c
> 
> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> index cc29832..ab64077 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -1,2 +1,3 @@
>  obj-$(CONFIG_RESET_CONTROLLER) += core.o
>  obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o
> +obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
> diff --git a/drivers/reset/reset-socfpga.c b/drivers/reset/reset-socfpga.c
> new file mode 100644
> index 0000000..b21e4e4
> --- /dev/null
> +++ b/drivers/reset/reset-socfpga.c
> @@ -0,0 +1,149 @@
> +/*
> + * Copyright 2014 Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> + *
> + * based on
> + * Allwinner SoCs Reset Controller driver
> + *
> + * Copyright 2013 Maxime Ripard
> + *
> + * Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset-controller.h>
> +#include <linux/spinlock.h>
> +#include <linux/types.h>
> +
> +#define NR_BANKS		4
> +#define MAX_BANK_WIDTH		32

Since you are using BITS_PER_LONG for bank and offset calculation, why
not just drop MAX_BANK_WIDTH and use BITS_PER_LONG directly? (Or use
MAX_BANK_WIDTH everywhere.)

> +#define OFFSET_MODRST		0x10
> +
> +struct socfpga_reset_data {
> +	spinlock_t			lock;
> +	void __iomem			*membase;
> +	struct reset_controller_dev	rcdev;
> +};
> +
> +static int socfpga_reset_assert(struct reset_controller_dev *rcdev,
> +				unsigned long id)
> +{
> +	struct socfpga_reset_data *data = container_of(rcdev,
> +						     struct socfpga_reset_data,
> +						     rcdev);
> +	int bank = id / BITS_PER_LONG;
> +	int offset = id % BITS_PER_LONG;
> +	unsigned long flags;
> +	u32 reg;
> +
> +	spin_lock_irqsave(&data->lock, flags);
> +
> +	reg = readl(data->membase + OFFSET_MODRST + (bank * NR_BANKS));
> +	writel(reg | BIT(offset), data->membase + OFFSET_MODRST +
> +				 (bank * NR_BANKS));
> +	spin_unlock_irqrestore(&data->lock, flags);
> +
> +	return 0;
> +}
> +
> +static int socfpga_reset_deassert(struct reset_controller_dev *rcdev,
> +				  unsigned long id)
> +{
> +	struct socfpga_reset_data *data = container_of(rcdev,
> +						     struct socfpga_reset_data,
> +						     rcdev);
> +
> +	int bank = id / BITS_PER_LONG;
> +	int offset = id % BITS_PER_LONG;
> +	unsigned long flags;
> +	u32 reg;
> +
> +	spin_lock_irqsave(&data->lock, flags);
> +
> +	reg = readl(data->membase + OFFSET_MODRST + (bank * NR_BANKS));
> +	writel(reg & ~BIT(offset), data->membase + OFFSET_MODRST +
> +				  (bank * NR_BANKS));
> +
> +	spin_unlock_irqrestore(&data->lock, flags);
> +
> +	return 0;
> +}
> +
> +static struct reset_control_ops socfpga_reset_ops = {
> +	.assert		= socfpga_reset_assert,
> +	.deassert	= socfpga_reset_deassert,
> +};
> +
> +static int socfpga_reset_probe(struct platform_device *pdev)
> +{
> +	struct socfpga_reset_data *data;
> +	struct resource *res;
> +	int ret;
> +
> +	/*
> +	 * The binding was mainlined without the required property.
> +	 * Do not continue, when we encounter an old DT.
> +	 */
> +	if (!of_find_property(pdev->dev.of_node, "#reset-cells", NULL)) {
> +		dev_err(&pdev->dev, "dt missing #reset-cells property\n");

Maybe also print pdev->dev.of_node->full_name here?

> +		return -EINVAL;
> +	}
> +
> +	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	data->membase = devm_ioremap_resource(&pdev->dev, res);
> +	if (!data->membase) {
> +		ret = -ENOMEM;
> +		return ret;

This should be:
	if (IS_ERR(data->membase))
		return PTR_ERR(data->membase);

> +	}
> +
> +	spin_lock_init(&data->lock);
> +
> +	data->rcdev.owner = THIS_MODULE;
> +	data->rcdev.nr_resets = NR_BANKS * MAX_BANK_WIDTH;

See above.

> +	data->rcdev.ops = &socfpga_reset_ops;
> +	data->rcdev.of_node = pdev->dev.of_node;
> +	reset_controller_register(&data->rcdev);
> +
> +	return 0;
> +}
> +
> +static int socfpga_reset_remove(struct platform_device *pdev)
> +{
> +	struct socfpga_reset_data *data = platform_get_drvdata(pdev);
> +
> +	reset_controller_unregister(&data->rcdev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id socfpga_reset_dt_ids[] = {
> +	{ .compatible = "altr,rst-mgr", },
> +	{ /* sentinel */ },
> +};
> +
> +static struct platform_driver socfpga_reset_driver = {
> +	.probe	= socfpga_reset_probe,
> +	.remove	= socfpga_reset_remove,
> +	.driver = {
> +		.name		= "socfpga-reset",
> +		.owner		= THIS_MODULE,
> +		.of_match_table	= socfpga_reset_dt_ids,
> +	},
> +};
> +module_platform_driver(socfpga_reset_driver);
> +
> +MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org");
> +MODULE_DESCRIPTION("Socfpga Reset Controller Driver");
> +MODULE_LICENSE("GPL");

regards
Philipp

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