Re: [PATCH V2 2/2] reset: img: Add Pistachio reset controller driver

[Philipp Zabel]

Hi,

a few small issues.

Am Freitag, den 15.01.2016, 18:17 +0000 schrieb James Hartley:
> From: "Damien.Horsley" <Damien.Horsley@xxxxxxxxxx>
> 
> Add reset controller driver for Pistachio SoC
> 
> Signed-off-by: Damien.Horsley <Damien.Horsley@xxxxxxxxxx>
> Signed-off-by: James Hartley <james.hartley@xxxxxxxxxx>
> ---
>  drivers/reset/Makefile                             |    1 +
>  drivers/reset/reset-pistachio.c                    |  162 ++++++++++++++++++++
>  .../reset-controller/pistachio-resets.h            |   36 +++++
>  3 files changed, 199 insertions(+)
>  create mode 100644 drivers/reset/reset-pistachio.c
>  create mode 100644 include/dt-bindings/reset-controller/pistachio-resets.h
> 
> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> index 4d7178e..a1fc8ed 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -2,6 +2,7 @@ obj-y += core.o
>  obj-$(CONFIG_ARCH_LPC18XX) += reset-lpc18xx.o
>  obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
>  obj-$(CONFIG_ARCH_BERLIN) += reset-berlin.o
> +obj-$(CONFIG_MACH_PISTACHIO) += reset-pistachio.o
>  obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o
>  obj-$(CONFIG_ARCH_STI) += sti/
>  obj-$(CONFIG_ARCH_HISI) += hisilicon/
> diff --git a/drivers/reset/reset-pistachio.c b/drivers/reset/reset-pistachio.c
> new file mode 100644
> index 0000000..0bbc086
> --- /dev/null
> +++ b/drivers/reset/reset-pistachio.c
> @@ -0,0 +1,162 @@
> +/*
> + * Pistachio SoC Reset Controller driver
> + *
> + * Copyright (C) 2015 Imagination Technologies Ltd.
> + *
> + * Author: Damien Horsley <Damien.Horsley@xxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/reset-controller.h>
> +#include <linux/slab.h>
> +#include <linux/mfd/syscon.h>
> +
> +#include <dt-bindings/reset-controller/pistachio-resets.h>

This should be:
#include <dt-bindings/reset/pistachio-resets.h>
(see below).

> +
> +#define	PISTACHIO_SOFT_RESET		0
> +
> +struct pistachio_reset_data {
> +	struct reset_controller_dev	rcdev;
> +	struct regmap			*periph_regs;
> +};
> +
> +static inline int pistachio_reset_shift(unsigned long id)
> +{
> +	switch (id) {
> +	case PISTACHIO_RESET_I2C0:
> +	case PISTACHIO_RESET_I2C1:
> +	case PISTACHIO_RESET_I2C2:
> +	case PISTACHIO_RESET_I2C3:
> +	case PISTACHIO_RESET_I2S_IN:
> +	case PISTACHIO_RESET_PRL_OUT:
> +	case PISTACHIO_RESET_SPDIF_OUT:
> +	case PISTACHIO_RESET_SPI:
> +	case PISTACHIO_RESET_PWM_PDM:
> +	case PISTACHIO_RESET_UART0:
> +	case PISTACHIO_RESET_UART1:
> +	case PISTACHIO_RESET_QSPI:
> +	case PISTACHIO_RESET_MDC:
> +	case PISTACHIO_RESET_SDHOST:
> +	case PISTACHIO_RESET_ETHERNET:
> +	case PISTACHIO_RESET_IR:
> +	case PISTACHIO_RESET_HASH:
> +	case PISTACHIO_RESET_TIMER:
> +		return id;
> +	case PISTACHIO_RESET_I2S_OUT:
> +	case PISTACHIO_RESET_SPDIF_IN:
> +	case PISTACHIO_RESET_EVT:
> +		return id + 6;
> +	case PISTACHIO_RESET_USB_H:
> +	case PISTACHIO_RESET_USB_PR:
> +	case PISTACHIO_RESET_USB_PHY_PR:
> +	case PISTACHIO_RESET_USB_PHY_PON:
> +		return id + 7;
> +	default:
> +		return -1;

That's -EPERM. Please
		return -EINVAL;
here, since ...

> +	}
> +}
> +
> +static int pistachio_reset_assert(struct reset_controller_dev *rcdev,
> +			      unsigned long id)
> +{
> +	struct pistachio_reset_data *rd;
> +	u32 mask;
> +	int shift;
> +
> +	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
> +	shift = pistachio_reset_shift(id);
> +	if (shift < 0)
> +		return shift;

... here we return the above error value to the caller.

> +	mask = 1UL << shift;

I'd prefer
	mask = BIT(shift);
instead.

> +
> +	regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET, mask, mask);
> +
> +	return 0;

Better propagate the return value from regmap_update_bits:
	return regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET,
				  mask, mask);

> +}
> +
> +static int pistachio_reset_deassert(struct reset_controller_dev *rcdev,
> +				unsigned long id)
> +{
> +	struct pistachio_reset_data *rd;
> +	u32 mask;
> +	int shift;
> +
> +	rd = container_of(rcdev, struct pistachio_reset_data, rcdev);
> +	shift = pistachio_reset_shift(id);
> +	if (shift < 0)
> +		return shift;
> +	mask = 1UL << shift;

Same as above.

> +
> +	regmap_update_bits(rd->periph_regs, PISTACHIO_SOFT_RESET, mask, 0);
> +
> +	return 0;

Same as above.

> +}
> +
> +static struct reset_control_ops pistachio_reset_ops = {
> +	.assert		= pistachio_reset_assert,
> +	.deassert	= pistachio_reset_deassert,
> +};
> +
> +static int pistachio_reset_probe(struct platform_device *pdev)
> +{
> +	struct pistachio_reset_data *rd;
> +	int ret;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = pdev->dev.of_node;
> +
> +	rd = devm_kzalloc(dev, sizeof(*rd), GFP_KERNEL);
> +	if (!rd)
> +		return -ENOMEM;
> +
> +	rd->periph_regs = syscon_node_to_regmap(np->parent);
> +	if (IS_ERR(rd->periph_regs))
> +		return PTR_ERR(rd->periph_regs);
> +
> +	rd->rcdev.owner = THIS_MODULE;
> +	rd->rcdev.nr_resets = PISTACHIO_RESET_MAX + 1;
> +	rd->rcdev.ops = &pistachio_reset_ops;
> +	rd->rcdev.of_node = np;
> +
> +	ret = reset_controller_register(&rd->rcdev);
> +	if (ret)
> +		return ret;
> +
> +	return 0;

This is equivalent to:
	return reset_controller_register(&rd->rcdev);
Just use that instead.

> +}
> +
> +static int pistachio_reset_remove(struct platform_device *pdev)
> +{
> +	struct pistachio_reset_data *data = platform_get_drvdata(pdev);
> +
> +	reset_controller_unregister(&data->rcdev);
> +
> +	return 0;
> +}
> +
> +
> +static const struct of_device_id pistachio_reset_dt_ids[] = {
> +	 { .compatible = "img,pistachio-reset", },
> +	 { /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, pistachio_reset_dt_ids);
> +
> +static struct platform_driver pistachio_reset_driver = {
> +	.probe	= pistachio_reset_probe,
> +	.remove	= pistachio_reset_remove,
> +	.driver = {
> +		.name		= "pistachio-reset",
> +		.of_match_table	= pistachio_reset_dt_ids,
> +	},
> +};
> +module_platform_driver(pistachio_reset_driver);
> +
> +MODULE_AUTHOR("Damien Horsley <Damien.Horsley@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Pistacho Reset Controller Driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/dt-bindings/reset-controller/pistachio-resets.h b/include/dt-bindings/reset-controller/pistachio-resets.h
> new file mode 100644
> index 0000000..60a189b
> --- /dev/null
> +++ b/include/dt-bindings/reset-controller/pistachio-resets.h

Please move the header to include/dt-bindings/reset/pistachio-resets.h.

regards
Philipp