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Commit 07901a94 authored by Alan Tull's avatar Alan Tull Committed by Linus Walleij
Browse files

gpio: gpio-dwapb: add optional reset 



Some platforms require reset to be released to allow register
access.

Signed-off-by: default avatarAlan Tull <atull@kernel.org>
Reviewed-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
[Added DT bindings oneliner for standard reset binding]
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent f76a2d9d

Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt

+1 −0
Original line number Original line Diff line number Diff line
@@ -29,6 +29,7 @@ controller. 
- interrupts : The interrupt to the parent controller raised when GPIOs

- interrupts : The interrupt to the parent controller raised when GPIOs

  generate the interrupts.

  generate the interrupts.

- snps,nr-gpios : The number of pins in the port, a single cell.

- snps,nr-gpios : The number of pins in the port, a single cell.

- resets : Reset line for the controller.





Example:

Example:

drivers/gpio/gpio-dwapb.c

+9 −0
Original line number Original line Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/of_irq.h>

#include <linux/of_irq.h>

#include <linux/platform_device.h>

#include <linux/platform_device.h>

#include <linux/property.h>

#include <linux/property.h>

#include <linux/reset.h>

#include <linux/spinlock.h>

#include <linux/spinlock.h>

#include <linux/platform_data/gpio-dwapb.h>

#include <linux/platform_data/gpio-dwapb.h>

#include <linux/slab.h>

#include <linux/slab.h>
@@ -98,6 +99,7 @@ struct dwapb_gpio { 
	unsigned int		nr_ports;

	unsigned int		nr_ports;

	struct irq_domain	*domain;

	struct irq_domain	*domain;

	unsigned int		flags;

	unsigned int		flags;

	struct reset_control	*rst;

};

};





static inline u32 gpio_reg_v2_convert(unsigned int offset)

static inline u32 gpio_reg_v2_convert(unsigned int offset)
@@ -629,6 +631,12 @@ static int dwapb_gpio_probe(struct platform_device *pdev) 
	gpio->dev = &pdev->dev;

	gpio->dev = &pdev->dev;

	gpio->nr_ports = pdata->nports;

	gpio->nr_ports = pdata->nports;





	gpio->rst = devm_reset_control_get_optional_shared(dev, NULL);

	if (IS_ERR(gpio->rst))

		return PTR_ERR(gpio->rst);



	reset_control_deassert(gpio->rst);



	gpio->ports = devm_kcalloc(&pdev->dev, gpio->nr_ports,

	gpio->ports = devm_kcalloc(&pdev->dev, gpio->nr_ports,

				   sizeof(*gpio->ports), GFP_KERNEL);

				   sizeof(*gpio->ports), GFP_KERNEL);

	if (!gpio->ports)

	if (!gpio->ports)
@@ -680,6 +688,7 @@ static int dwapb_gpio_remove(struct platform_device *pdev) 




	dwapb_gpio_unregister(gpio);

	dwapb_gpio_unregister(gpio);

	dwapb_irq_teardown(gpio);

	dwapb_irq_teardown(gpio);

	reset_control_assert(gpio->rst);





	return 0;

	return 0;

}

}