Re: [PATCH 3/7] reset: add BCM6345 reset controller driver

["Álvaro Fernández Rojas" <noltari@gmail.com>]

Hello Philipp,

> El 9 jun 2020, a las 18:32, Philipp Zabel <p.zabel@pengutronix.de> escribió:
> 
> Hi Álvaro,
> 
> On Tue, 2020-06-09 at 17:14 +0200, Álvaro Fernández Rojas wrote:
>> Hi Philipp,
>> 
>>> El 9 jun 2020, a las 17:06, Philipp Zabel <p.zabel@pengutronix.de> escribió:
>>> 
>>> Hi Álvaro,
>>> 
>>> On Tue, 2020-06-09 at 15:42 +0200, Álvaro Fernández Rojas wrote:
>>>> Add support for resetting blocks through the Linux reset controller
>>>> subsystem for BCM63xx SoCs.
>>>> 
>>>> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
>>>> ---
>>>> drivers/reset/Kconfig         |   7 ++
>>>> drivers/reset/Makefile        |   1 +
>>>> drivers/reset/reset-bcm6345.c | 149 ++++++++++++++++++++++++++++++++++
>>>> 3 files changed, 157 insertions(+)
>>>> create mode 100644 drivers/reset/reset-bcm6345.c
>>>> 
>>>> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
>>>> index d9efbfd29646..9f1da978cef6 100644
>>>> --- a/drivers/reset/Kconfig
>>>> +++ b/drivers/reset/Kconfig
>>>> @@ -41,6 +41,13 @@ config RESET_BERLIN
>>>> 	help
>>>> 	  This enables the reset controller driver for Marvell Berlin SoCs.
>>>> 
>>>> +config RESET_BCM6345
>>>> +	bool "BCM6345 Reset Controller"
>>>> +	depends on BMIPS_GENERIC || COMPILE_TEST
>>>> +	default BMIPS_GENERIC
>>>> +	help
>>>> +	  This enables the reset controller driver for BCM6345 SoCs.
>>>> +
>>>> config RESET_BRCMSTB
>>>> 	tristate "Broadcom STB reset controller"
>>>> 	depends on ARCH_BRCMSTB || COMPILE_TEST
>>>> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
>>>> index 249ed357c997..e642aae42f0f 100644
>>>> --- a/drivers/reset/Makefile
>>>> +++ b/drivers/reset/Makefile
>>>> @@ -6,6 +6,7 @@ obj-$(CONFIG_ARCH_TEGRA) += tegra/
>>>> obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o
>>>> obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
>>>> obj-$(CONFIG_RESET_AXS10X) += reset-axs10x.o
>>>> +obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
>>>> obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
>>>> obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
>>>> obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
>>>> diff --git a/drivers/reset/reset-bcm6345.c b/drivers/reset/reset-bcm6345.c
>>>> new file mode 100644
>>>> index 000000000000..088b7fdb896b
>>>> --- /dev/null
>>>> +++ b/drivers/reset/reset-bcm6345.c
>>>> @@ -0,0 +1,149 @@
>>>> +// SPDX-License-Identifier: GPL-2.0-or-later
>>>> +/*
>>>> + * BCM6345 Reset Controller Driver
>>>> + *
>>>> + * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com>
>>>> + */
>>>> +
>>>> +#include <linux/delay.h>
>>>> +#include <linux/init.h>
>>>> +#include <linux/io.h>
>>>> +#include <linux/mod_devicetable.h>
>>>> +#include <linux/platform_device.h>
>>>> +#include <linux/reset-controller.h>
>>>> +
>>>> +#define BCM6345_RESET_NUM		32
>>>> +#define BCM6345_RESET_SLEEP_MIN_US	10000
>>>> +#define BCM6345_RESET_SLEEP_MAX_US	20000
>>>> +
>>>> +struct bcm6345_reset {
>>>> +	struct reset_controller_dev rcdev;
>>>> +	void __iomem *base;
>>>> +	spinlock_t lock;
>>>> +};
>>>> +
>>>> +static int bcm6345_reset_update(struct bcm6345_reset *bcm6345_reset,
>>>> +				unsigned long id, bool assert)
>>>> +{
>>>> +	uint32_t val;
>>>> +
>>>> +	val = __raw_readl(bcm6345_reset->base);
>>>> +	if (assert)
>>>> +		val &= ~BIT(id);
>>>> +	else
>>>> +		val |= BIT(id);
>>>> +	__raw_writel(val, bcm6345_reset->base);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int bcm6345_reset_assert(struct reset_controller_dev *rcdev,
>>>> +				unsigned long id)
>>>> +{
>>>> +	struct bcm6345_reset *bcm6345_reset =
>>>> +		container_of(rcdev, struct bcm6345_reset, rcdev);
>>>> +	unsigned long flags;
>>>> +
>>>> +	spin_lock_irqsave(&bcm6345_reset->lock, flags);
>>>> +	bcm6345_reset_update(bcm6345_reset, id, true);
>>>> +	spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev,
>>>> +				  unsigned long id)
>>>> +{
>>>> +	struct bcm6345_reset *bcm6345_reset =
>>>> +		container_of(rcdev, struct bcm6345_reset, rcdev);
>>>> +	unsigned long flags;
>>>> +
>>>> +	spin_lock_irqsave(&bcm6345_reset->lock, flags);
>>>> +	bcm6345_reset_update(bcm6345_reset, id, false);
>>>> +	spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int bcm6345_reset_reset(struct reset_controller_dev *rcdev,
>>>> +			       unsigned long id)
>>>> +{
>>>> +	struct bcm6345_reset *bcm6345_reset =
>>>> +		container_of(rcdev, struct bcm6345_reset, rcdev);
>>>> +	unsigned long flags;
>>>> +
>>>> +	spin_lock_irqsave(&bcm6345_reset->lock, flags);
>>>> +	usleep_range(BCM6345_RESET_SLEEP_MIN_US,
>>>> +		     BCM6345_RESET_SLEEP_MAX_US);
>>> 
>>> What is the purpose of sleeping before reset assertion?
>> 
>> None, I must have introduced that for testing something and then I forgot to remove it. Sorry for that...
>> 
>>> If you can do without this, with I think this driver could be made to
>>> use reset-simple.
>> 
>> Yes, but only if I can add reset support with a configurable sleep range to reset-simple. Is this possible?
> 
> I should have mentioned, support for this is on the reset/next branch:
> 
>  git://git.pengutronix.de/pza/linux.git reset/next

Yes, but reset_us was only added to reset_simple_data, so there’s no way to fill that value from reset_simple_devdata or device tree, right?

> 
> regards
> Philipp

Regards,
Álvaro.