diff mbox

[3/3] gpio: add support for Cypress CYUSBS234 USB-GPIO adapter

Message ID 1411378458-18424-1-git-send-email-muth@cypress.com
State Not Applicable, archived
Headers show

Commit Message

Muthu Mani Sept. 22, 2014, 9:34 a.m. UTC
Adds support for USB-GPIO interface of Cypress Semiconductor
CYUSBS234 USB-Serial Bridge controller.

The GPIO get/set can be done through vendor command
on control endpoint.

Details about the device can be found at:
http://www.cypress.com/?rID=84126

Signed-off-by: Muthu Mani <muth@cypress.com>
Signed-off-by: Rajaram Regupathy <rera@cypress.com>
---
 drivers/gpio/Kconfig          |  13 +++
 drivers/gpio/Makefile         |   1 +
 drivers/gpio/gpio-cyusbs23x.c | 190 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 204 insertions(+)
 create mode 100644 drivers/gpio/gpio-cyusbs23x.c

Comments

Johan Hovold Sept. 22, 2014, 11:43 a.m. UTC | #1
On Mon, Sep 22, 2014 at 03:04:18PM +0530, Muthu Mani wrote:
> Adds support for USB-GPIO interface of Cypress Semiconductor
> CYUSBS234 USB-Serial Bridge controller.
> 
> The GPIO get/set can be done through vendor command
> on control endpoint.
> 
> Details about the device can be found at:
> http://www.cypress.com/?rID=84126
> 
> Signed-off-by: Muthu Mani <muth@cypress.com>
> Signed-off-by: Rajaram Regupathy <rera@cypress.com>
> ---
>  drivers/gpio/Kconfig          |  13 +++
>  drivers/gpio/Makefile         |   1 +
>  drivers/gpio/gpio-cyusbs23x.c | 190 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 204 insertions(+)
>  create mode 100644 drivers/gpio/gpio-cyusbs23x.c
> 
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 9de1515..932e07c 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -886,6 +886,19 @@ config GPIO_BCM_KONA
>  
>  comment "USB GPIO expanders:"
>  
> +config GPIO_CYUSBS23X
> +	tristate "CYUSBS23x GPIO support"
> +	depends on MFD_CYUSBS23X && USB
> +	help
> +	  Say yes here to access the GPIO signals of Cypress
> +	  Semiconductor CYUSBS23x USB Serial Bridge Controller.
> +
> +	  This driver enables the GPIO interface of CYUSBS23x USB Serial
> +	  Bridge controller.
> +
> +	  This driver can also be built as a module. If so, the module will be
> +	  called gpio-cyusbs23x.
> +
>  config GPIO_VIPERBOARD
>  	tristate "Viperboard GPIO a & b support"
>  	depends on MFD_VIPERBOARD && USB
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 5d024e3..3ad89f1 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_GPIO_BT8XX)	+= gpio-bt8xx.o
>  obj-$(CONFIG_GPIO_CLPS711X)	+= gpio-clps711x.o
>  obj-$(CONFIG_GPIO_CS5535)	+= gpio-cs5535.o
>  obj-$(CONFIG_GPIO_CRYSTAL_COVE)	+= gpio-crystalcove.o
> +obj-$(CONFIG_GPIO_CYUSBS23X)	+= gpio-cyusbs23x.o
>  obj-$(CONFIG_GPIO_DA9052)	+= gpio-da9052.o
>  obj-$(CONFIG_GPIO_DA9055)	+= gpio-da9055.o
>  obj-$(CONFIG_GPIO_DAVINCI)	+= gpio-davinci.o
> diff --git a/drivers/gpio/gpio-cyusbs23x.c b/drivers/gpio/gpio-cyusbs23x.c
> new file mode 100644
> index 0000000..8aa3ab6
> --- /dev/null
> +++ b/drivers/gpio/gpio-cyusbs23x.c
> @@ -0,0 +1,190 @@
> +/*
> + * Cypress USB-Serial Bridge Controller GPIO driver
> + *
> + * Copyright (c) 2014 Cypress Semiconductor Corporation.
> + *
> + * Author:
> + *   Muthu Mani <muth@cypress.com>
> + *
> + * Additional contributors include:
> + *   Rajaram Regupathy <rera@cypress.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/errno.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/types.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +
> +#include <linux/usb.h>
> +#include <linux/gpio.h>
> +
> +#include <linux/mfd/cyusbs23x.h>
> +
> +#define CY_GPIO_GET_LEN		(2)
> +
> +struct cyusbs_gpio {
> +	struct gpio_chip gpio;
> +	struct cyusbs23x *cyusbs;
> +};
> +
> +static int cy_gpio_get(struct gpio_chip *chip,
> +			unsigned offset)
> +{
> +	int ret;
> +	char buf[CY_GPIO_GET_LEN];

Buffers used for USB (DMA) transfers cannot be allocated on the stack.
Use kmalloc and friends.

> +	__u16 wIndex, wValue;

u16 throughout.

> +	struct cyusbs_gpio *gpio =
> +				container_of(chip, struct cyusbs_gpio, gpio);
> +	struct cyusbs23x *cyusbs = gpio->cyusbs;
> +
> +	dev_dbg(&cyusbs->usb_intf->dev, "%s: %d\n", __func__,
> +		offset);
> +	wValue = offset;
> +	wIndex = 0;
> +
> +	mutex_lock(&cyusbs->lock);
> +	ret = usb_control_msg(cyusbs->usb_dev,
> +			usb_rcvctrlpipe(cyusbs->usb_dev, 0),
> +			CY_GPIO_GET_VALUE_CMD,
> +			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
> +			wValue, wIndex, buf, CY_GPIO_GET_LEN, 2000);
> +	mutex_unlock(&cyusbs->lock);
> +
> +	dev_dbg(&cyusbs->usb_intf->dev, "%s: %d %02x %02x\n", __func__,
> +		ret, buf[0], buf[1]);
> +
> +	if (ret == CY_GPIO_GET_LEN) {
> +		if (buf[0] == 0)
> +			ret = buf[1];
> +		else
> +			ret = -EINVAL;
> +	} else {
> +		ret = -EREMOTEIO;
> +	}
> +
> +	return ret;
> +}
> +
> +static void cy_gpio_set(struct gpio_chip *chip,
> +			unsigned offset, int value)
> +{
> +	int ret;
> +	__u16 wIndex, wValue;
> +	struct cyusbs_gpio *gpio =
> +			container_of(chip, struct cyusbs_gpio, gpio);
> +	struct cyusbs23x *cyusbs = gpio->cyusbs;
> +
> +	dev_dbg(&cyusbs->usb_intf->dev, "%s: %d\n", __func__,
> +		offset);
> +	wValue = offset;
> +	wIndex = value;
> +
> +	mutex_lock(&cyusbs->lock);
> +	ret = usb_control_msg(cyusbs->usb_dev,
> +			usb_sndctrlpipe(cyusbs->usb_dev, 0),
> +			CY_GPIO_SET_VALUE_CMD,
> +			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
> +			wValue, wIndex, NULL, 0, 2000);
> +	mutex_unlock(&cyusbs->lock);
> +
> +	if (ret < 0)
> +		dev_err(&cyusbs->usb_intf->dev, "error setting gpio:%d\n", ret);
> +}
> +
> +static int cy_gpio_direction_input(struct gpio_chip *chip,
> +					unsigned offset)
> +{
> +	return 0;

Aren't the GPIOs output-only?

> +}
> +
> +static int cy_gpio_direction_output(struct gpio_chip *chip,
> +					unsigned offset, int value)
> +{
> +	return 0;
> +}
> +
> +static int cyusbs23x_gpio_probe(struct platform_device *pdev)
> +{
> +	struct cyusbs23x *cyusbs;
> +	struct cyusbs_gpio *cy_gpio;
> +	int ret = 0;
> +
> +	dev_dbg(&pdev->dev, "%s\n", __func__);
> +
> +	cyusbs = dev_get_drvdata(pdev->dev.parent);
> +
> +	cy_gpio = devm_kzalloc(&pdev->dev, sizeof(*cy_gpio), GFP_KERNEL);
> +	if (cy_gpio == NULL)
> +		return -ENOMEM;
> +
> +	cy_gpio->cyusbs = cyusbs;
> +	/* registering gpio */
> +	cy_gpio->gpio.label = "cyusbs23x gpio";
> +	cy_gpio->gpio.dev = &pdev->dev;
> +	cy_gpio->gpio.owner = THIS_MODULE;
> +	cy_gpio->gpio.base = -1;
> +	cy_gpio->gpio.ngpio = 12; /* total GPIOs */

I think you need to read out the gpio config from the device eeprom and
implement a request() callback where you verify that a requested gpio is
actually available (mode dependent, and there are never more than 10
gpios availble).

> +	cy_gpio->gpio.can_sleep = true;
> +	cy_gpio->gpio.set = cy_gpio_set;
> +	cy_gpio->gpio.get = cy_gpio_get;
> +	cy_gpio->gpio.direction_input = cy_gpio_direction_input;
> +	cy_gpio->gpio.direction_output = cy_gpio_direction_output;
> +	ret = gpiochip_add(&cy_gpio->gpio);
> +	if (ret < 0) {
> +		dev_err(cy_gpio->gpio.dev, "could not add gpio");
> +		goto error;
> +	}
> +
> +	platform_set_drvdata(pdev, cy_gpio);
> +
> +	dev_dbg(&pdev->dev, "added GPIO\n");
> +	return ret;
> +
> +error:
> +	dev_dbg(&pdev->dev, "error occured %d\n", ret);
> +	return ret;
> +}
> +
> +static int cyusbs23x_gpio_remove(struct platform_device *pdev)
> +{
> +	struct cyusbs_gpio *cy_gpio = platform_get_drvdata(pdev);
> +
> +	dev_dbg(&pdev->dev, "%s\n", __func__);
> +
> +	gpiochip_remove(&cy_gpio->gpio);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver cyusbs23x_gpio_driver = {
> +	.driver.name    = "cyusbs23x-gpio",
> +	.driver.owner   = THIS_MODULE,
> +	.probe          = cyusbs23x_gpio_probe,
> +	.remove         = cyusbs23x_gpio_remove,
> +};
> +
> +static int __init cyusbs23x_gpio_init(void)
> +{
> +	return platform_driver_register(&cyusbs23x_gpio_driver);
> +}
> +subsys_initcall(cyusbs23x_gpio_init);
> +
> +static void __exit cyusbs23x_gpio_exit(void)
> +{
> +	platform_driver_unregister(&cyusbs23x_gpio_driver);
> +}
> +module_exit(cyusbs23x_gpio_exit);

module_platform_driver

> +
> +MODULE_AUTHOR("Rajaram Regupathy <rera@cypress.com>");
> +MODULE_AUTHOR("Muthu Mani <muth@cypress.com>");
> +MODULE_DESCRIPTION("gpio-cyusbs23x driver v0.1");
> +MODULE_LICENSE("GPL");

Description and license comments from i2c patch apply here as well.

> +MODULE_ALIAS("platform:cyusbs23x-gpio");
> +

Stray new line.

Johan
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Muthu Mani Sept. 25, 2014, 5:47 a.m. UTC | #2
> -----Original Message-----
> From: Johan Hovold [mailto:jhovold@gmail.com] On Behalf Of Johan Hovold
> Sent: Monday, September 22, 2014 5:14 PM
> To: Muthu Mani
> Cc: Samuel Ortiz; Lee Jones; Wolfram Sang; linux-i2c@vger.kernel.org; Linus
> Walleij; Alexandre Courbot; linux-gpio@vger.kernel.org;
> gregkh@linuxfoundation.org; linux-usb@vger.kernel.org; linux-
> kernel@vger.kernel.org; Rajaram Regupathy
> Subject: Re: [PATCH 3/3] gpio: add support for Cypress CYUSBS234 USB-GPIO
> adapter
> 
> On Mon, Sep 22, 2014 at 03:04:18PM +0530, Muthu Mani wrote:
> > Adds support for USB-GPIO interface of Cypress Semiconductor
> > CYUSBS234 USB-Serial Bridge controller.
> >
> > The GPIO get/set can be done through vendor command on control
> > endpoint.
> >
> > Details about the device can be found at:
> > http://www.cypress.com/?rID=84126
> >
> > Signed-off-by: Muthu Mani <muth@cypress.com>
> > Signed-off-by: Rajaram Regupathy <rera@cypress.com>
> > ---
> >  drivers/gpio/Kconfig          |  13 +++
> >  drivers/gpio/Makefile         |   1 +
> >  drivers/gpio/gpio-cyusbs23x.c | 190
> > ++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 204 insertions(+)
> >  create mode 100644 drivers/gpio/gpio-cyusbs23x.c
> >
> > diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index
> > 9de1515..932e07c 100644
> > --- a/drivers/gpio/Kconfig
> > +++ b/drivers/gpio/Kconfig
> > @@ -886,6 +886,19 @@ config GPIO_BCM_KONA
> >
> >  comment "USB GPIO expanders:"
> >
> > +config GPIO_CYUSBS23X
> > +     tristate "CYUSBS23x GPIO support"
> > +     depends on MFD_CYUSBS23X && USB
> > +     help
> > +       Say yes here to access the GPIO signals of Cypress
> > +       Semiconductor CYUSBS23x USB Serial Bridge Controller.
> > +
> > +       This driver enables the GPIO interface of CYUSBS23x USB Serial
> > +       Bridge controller.
> > +
> > +       This driver can also be built as a module. If so, the module will be
> > +       called gpio-cyusbs23x.
> > +
> >  config GPIO_VIPERBOARD
> >       tristate "Viperboard GPIO a & b support"
> >       depends on MFD_VIPERBOARD && USB diff --git
> > a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 5d024e3..3ad89f1
> > 100644
> > --- a/drivers/gpio/Makefile
> > +++ b/drivers/gpio/Makefile
> > @@ -23,6 +23,7 @@ obj-$(CONFIG_GPIO_BT8XX)    += gpio-bt8xx.o
> >  obj-$(CONFIG_GPIO_CLPS711X)  += gpio-clps711x.o
> >  obj-$(CONFIG_GPIO_CS5535)    += gpio-cs5535.o
> >  obj-$(CONFIG_GPIO_CRYSTAL_COVE)      += gpio-crystalcove.o
> > +obj-$(CONFIG_GPIO_CYUSBS23X) += gpio-cyusbs23x.o
> >  obj-$(CONFIG_GPIO_DA9052)    += gpio-da9052.o
> >  obj-$(CONFIG_GPIO_DA9055)    += gpio-da9055.o
> >  obj-$(CONFIG_GPIO_DAVINCI)   += gpio-davinci.o
> > diff --git a/drivers/gpio/gpio-cyusbs23x.c
> > b/drivers/gpio/gpio-cyusbs23x.c new file mode 100644 index
> > 0000000..8aa3ab6
> > --- /dev/null
> > +++ b/drivers/gpio/gpio-cyusbs23x.c
> > @@ -0,0 +1,190 @@
> > +/*
> > + * Cypress USB-Serial Bridge Controller GPIO driver
> > + *
> > + * Copyright (c) 2014 Cypress Semiconductor Corporation.
> > + *
> > + * Author:
> > + *   Muthu Mani <muth@cypress.com>
> > + *
> > + * Additional contributors include:
> > + *   Rajaram Regupathy <rera@cypress.com>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > +modify it
> > + * under the terms of the GNU General Public License version 2 as
> > +published by
> > + * the Free Software Foundation.
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/errno.h>
> > +#include <linux/module.h>
> > +#include <linux/slab.h>
> > +#include <linux/types.h>
> > +#include <linux/mutex.h>
> > +#include <linux/platform_device.h>
> > +
> > +#include <linux/usb.h>
> > +#include <linux/gpio.h>
> > +
> > +#include <linux/mfd/cyusbs23x.h>
> > +
> > +#define CY_GPIO_GET_LEN              (2)
> > +
> > +struct cyusbs_gpio {
> > +     struct gpio_chip gpio;
> > +     struct cyusbs23x *cyusbs;
> > +};
> > +
> > +static int cy_gpio_get(struct gpio_chip *chip,
> > +                     unsigned offset) {
> > +     int ret;
> > +     char buf[CY_GPIO_GET_LEN];
> 
> Buffers used for USB (DMA) transfers cannot be allocated on the stack.
> Use kmalloc and friends.

Ok, will update it.

> 
> > +     __u16 wIndex, wValue;
> 
> u16 throughout.

Ok.

> 
> > +     struct cyusbs_gpio *gpio =
> > +                             container_of(chip, struct cyusbs_gpio, gpio);
> > +     struct cyusbs23x *cyusbs = gpio->cyusbs;
> > +
> > +     dev_dbg(&cyusbs->usb_intf->dev, "%s: %d\n", __func__,
> > +             offset);
> > +     wValue = offset;
> > +     wIndex = 0;
> > +
> > +     mutex_lock(&cyusbs->lock);
> > +     ret = usb_control_msg(cyusbs->usb_dev,
> > +                     usb_rcvctrlpipe(cyusbs->usb_dev, 0),
> > +                     CY_GPIO_GET_VALUE_CMD,
> > +                     USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
> > +                     wValue, wIndex, buf, CY_GPIO_GET_LEN, 2000);
> > +     mutex_unlock(&cyusbs->lock);
> > +
> > +     dev_dbg(&cyusbs->usb_intf->dev, "%s: %d %02x %02x\n", __func__,
> > +             ret, buf[0], buf[1]);
> > +
> > +     if (ret == CY_GPIO_GET_LEN) {
> > +             if (buf[0] == 0)
> > +                     ret = buf[1];
> > +             else
> > +                     ret = -EINVAL;
> > +     } else {
> > +             ret = -EREMOTEIO;
> > +     }
> > +
> > +     return ret;
> > +}
> > +
> > +static void cy_gpio_set(struct gpio_chip *chip,
> > +                     unsigned offset, int value) {
> > +     int ret;
> > +     __u16 wIndex, wValue;
> > +     struct cyusbs_gpio *gpio =
> > +                     container_of(chip, struct cyusbs_gpio, gpio);
> > +     struct cyusbs23x *cyusbs = gpio->cyusbs;
> > +
> > +     dev_dbg(&cyusbs->usb_intf->dev, "%s: %d\n", __func__,
> > +             offset);
> > +     wValue = offset;
> > +     wIndex = value;
> > +
> > +     mutex_lock(&cyusbs->lock);
> > +     ret = usb_control_msg(cyusbs->usb_dev,
> > +                     usb_sndctrlpipe(cyusbs->usb_dev, 0),
> > +                     CY_GPIO_SET_VALUE_CMD,
> > +                     USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
> > +                     wValue, wIndex, NULL, 0, 2000);
> > +     mutex_unlock(&cyusbs->lock);
> > +
> > +     if (ret < 0)
> > +             dev_err(&cyusbs->usb_intf->dev, "error setting
> > +gpio:%d\n", ret); }
> > +
> > +static int cy_gpio_direction_input(struct gpio_chip *chip,
> > +                                     unsigned offset) {
> > +     return 0;
> 
> Aren't the GPIOs output-only?

No.

> 
> > +}
> > +
> > +static int cy_gpio_direction_output(struct gpio_chip *chip,
> > +                                     unsigned offset, int value) {
> > +     return 0;
> > +}
> > +
> > +static int cyusbs23x_gpio_probe(struct platform_device *pdev) {
> > +     struct cyusbs23x *cyusbs;
> > +     struct cyusbs_gpio *cy_gpio;
> > +     int ret = 0;
> > +
> > +     dev_dbg(&pdev->dev, "%s\n", __func__);
> > +
> > +     cyusbs = dev_get_drvdata(pdev->dev.parent);
> > +
> > +     cy_gpio = devm_kzalloc(&pdev->dev, sizeof(*cy_gpio), GFP_KERNEL);
> > +     if (cy_gpio == NULL)
> > +             return -ENOMEM;
> > +
> > +     cy_gpio->cyusbs = cyusbs;
> > +     /* registering gpio */
> > +     cy_gpio->gpio.label = "cyusbs23x gpio";
> > +     cy_gpio->gpio.dev = &pdev->dev;
> > +     cy_gpio->gpio.owner = THIS_MODULE;
> > +     cy_gpio->gpio.base = -1;
> > +     cy_gpio->gpio.ngpio = 12; /* total GPIOs */
> 
> I think you need to read out the gpio config from the device eeprom and
> implement a request() callback where you verify that a requested gpio is
> actually available (mode dependent, and there are never more than 10 gpios
> availble).

In this initial driver, all GPIOs are made available to user space.
Additional functionalities will be added in the next version of the driver.

> 
> > +     cy_gpio->gpio.can_sleep = true;
> > +     cy_gpio->gpio.set = cy_gpio_set;
> > +     cy_gpio->gpio.get = cy_gpio_get;
> > +     cy_gpio->gpio.direction_input = cy_gpio_direction_input;
> > +     cy_gpio->gpio.direction_output = cy_gpio_direction_output;
> > +     ret = gpiochip_add(&cy_gpio->gpio);
> > +     if (ret < 0) {
> > +             dev_err(cy_gpio->gpio.dev, "could not add gpio");
> > +             goto error;
> > +     }
> > +
> > +     platform_set_drvdata(pdev, cy_gpio);
> > +
> > +     dev_dbg(&pdev->dev, "added GPIO\n");
> > +     return ret;
> > +
> > +error:
> > +     dev_dbg(&pdev->dev, "error occured %d\n", ret);
> > +     return ret;
> > +}
> > +
> > +static int cyusbs23x_gpio_remove(struct platform_device *pdev) {
> > +     struct cyusbs_gpio *cy_gpio = platform_get_drvdata(pdev);
> > +
> > +     dev_dbg(&pdev->dev, "%s\n", __func__);
> > +
> > +     gpiochip_remove(&cy_gpio->gpio);
> > +
> > +     return 0;
> > +}
> > +
> > +static struct platform_driver cyusbs23x_gpio_driver = {
> > +     .driver.name    = "cyusbs23x-gpio",
> > +     .driver.owner   = THIS_MODULE,
> > +     .probe          = cyusbs23x_gpio_probe,
> > +     .remove         = cyusbs23x_gpio_remove,
> > +};
> > +
> > +static int __init cyusbs23x_gpio_init(void) {
> > +     return platform_driver_register(&cyusbs23x_gpio_driver);
> > +}
> > +subsys_initcall(cyusbs23x_gpio_init);
> > +
> > +static void __exit cyusbs23x_gpio_exit(void) {
> > +     platform_driver_unregister(&cyusbs23x_gpio_driver);
> > +}
> > +module_exit(cyusbs23x_gpio_exit);
> 
> module_platform_driver

Ok.

> 
> > +
> > +MODULE_AUTHOR("Rajaram Regupathy <rera@cypress.com>");
> > +MODULE_AUTHOR("Muthu Mani <muth@cypress.com>");
> > +MODULE_DESCRIPTION("gpio-cyusbs23x driver v0.1");
> > +MODULE_LICENSE("GPL");
> 
> Description and license comments from i2c patch apply here as well.

Ok, will update it.

> 
> > +MODULE_ALIAS("platform:cyusbs23x-gpio");
> > +
> 
> Stray new line.

Ok, will remove it.
I will send the v2 patch soon.

> 
> Johan
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Johan Hovold Sept. 30, 2014, 11:21 a.m. UTC | #3
On Thu, Sep 25, 2014 at 05:47:11AM +0000, Muthu Mani wrote:
> > -----Original Message-----
> > From: Johan Hovold [mailto:jhovold@gmail.com] On Behalf Of Johan Hovold

> > > +static int cy_gpio_direction_input(struct gpio_chip *chip,
> > > +                                     unsigned offset) {
> > > +     return 0;
> > 
> > Aren't the GPIOs output-only?
> 
> No.

Then you should implement this callback to configure the pin as an
input.

Or can the configuration only be made through your configuration tools
and stored in eeprom?

Then you need to retrieve the actual config and implement these
callbacks (e.g. fail if not matching the eeprom config) along with
get_direction().

> > > +}
> > > +
> > > +static int cy_gpio_direction_output(struct gpio_chip *chip,
> > > +                                     unsigned offset, int value) {
> > > +     return 0;
> > > +}
> > > +
> > > +static int cyusbs23x_gpio_probe(struct platform_device *pdev) {
> > > +     struct cyusbs23x *cyusbs;
> > > +     struct cyusbs_gpio *cy_gpio;
> > > +     int ret = 0;
> > > +
> > > +     dev_dbg(&pdev->dev, "%s\n", __func__);
> > > +
> > > +     cyusbs = dev_get_drvdata(pdev->dev.parent);
> > > +
> > > +     cy_gpio = devm_kzalloc(&pdev->dev, sizeof(*cy_gpio), GFP_KERNEL);
> > > +     if (cy_gpio == NULL)
> > > +             return -ENOMEM;
> > > +
> > > +     cy_gpio->cyusbs = cyusbs;
> > > +     /* registering gpio */
> > > +     cy_gpio->gpio.label = "cyusbs23x gpio";
> > > +     cy_gpio->gpio.dev = &pdev->dev;
> > > +     cy_gpio->gpio.owner = THIS_MODULE;
> > > +     cy_gpio->gpio.base = -1;
> > > +     cy_gpio->gpio.ngpio = 12; /* total GPIOs */
> > 
> > I think you need to read out the gpio config from the device eeprom and
> > implement a request() callback where you verify that a requested gpio is
> > actually available (mode dependent, and there are never more than 10 gpios
> > availble).
> 
> In this initial driver, all GPIOs are made available to user space.
> Additional functionalities will be added in the next version of the driver.

I think this needs to be implemented now. It's needed for direction
handling as well as mentioned above.

> > > +     cy_gpio->gpio.can_sleep = true;
> > > +     cy_gpio->gpio.set = cy_gpio_set;
> > > +     cy_gpio->gpio.get = cy_gpio_get;
> > > +     cy_gpio->gpio.direction_input = cy_gpio_direction_input;
> > > +     cy_gpio->gpio.direction_output = cy_gpio_direction_output;
> > > +     ret = gpiochip_add(&cy_gpio->gpio);
> > > +     if (ret < 0) {
> > > +             dev_err(cy_gpio->gpio.dev, "could not add gpio");
> > > +             goto error;
> > > +     }

Thanks,
Johan
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diff mbox

Patch

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 9de1515..932e07c 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -886,6 +886,19 @@  config GPIO_BCM_KONA
 
 comment "USB GPIO expanders:"
 
+config GPIO_CYUSBS23X
+	tristate "CYUSBS23x GPIO support"
+	depends on MFD_CYUSBS23X && USB
+	help
+	  Say yes here to access the GPIO signals of Cypress
+	  Semiconductor CYUSBS23x USB Serial Bridge Controller.
+
+	  This driver enables the GPIO interface of CYUSBS23x USB Serial
+	  Bridge controller.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called gpio-cyusbs23x.
+
 config GPIO_VIPERBOARD
 	tristate "Viperboard GPIO a & b support"
 	depends on MFD_VIPERBOARD && USB
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 5d024e3..3ad89f1 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -23,6 +23,7 @@  obj-$(CONFIG_GPIO_BT8XX)	+= gpio-bt8xx.o
 obj-$(CONFIG_GPIO_CLPS711X)	+= gpio-clps711x.o
 obj-$(CONFIG_GPIO_CS5535)	+= gpio-cs5535.o
 obj-$(CONFIG_GPIO_CRYSTAL_COVE)	+= gpio-crystalcove.o
+obj-$(CONFIG_GPIO_CYUSBS23X)	+= gpio-cyusbs23x.o
 obj-$(CONFIG_GPIO_DA9052)	+= gpio-da9052.o
 obj-$(CONFIG_GPIO_DA9055)	+= gpio-da9055.o
 obj-$(CONFIG_GPIO_DAVINCI)	+= gpio-davinci.o
diff --git a/drivers/gpio/gpio-cyusbs23x.c b/drivers/gpio/gpio-cyusbs23x.c
new file mode 100644
index 0000000..8aa3ab6
--- /dev/null
+++ b/drivers/gpio/gpio-cyusbs23x.c
@@ -0,0 +1,190 @@ 
+/*
+ * Cypress USB-Serial Bridge Controller GPIO driver
+ *
+ * Copyright (c) 2014 Cypress Semiconductor Corporation.
+ *
+ * Author:
+ *   Muthu Mani <muth@cypress.com>
+ *
+ * Additional contributors include:
+ *   Rajaram Regupathy <rera@cypress.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+
+#include <linux/usb.h>
+#include <linux/gpio.h>
+
+#include <linux/mfd/cyusbs23x.h>
+
+#define CY_GPIO_GET_LEN		(2)
+
+struct cyusbs_gpio {
+	struct gpio_chip gpio;
+	struct cyusbs23x *cyusbs;
+};
+
+static int cy_gpio_get(struct gpio_chip *chip,
+			unsigned offset)
+{
+	int ret;
+	char buf[CY_GPIO_GET_LEN];
+	__u16 wIndex, wValue;
+	struct cyusbs_gpio *gpio =
+				container_of(chip, struct cyusbs_gpio, gpio);
+	struct cyusbs23x *cyusbs = gpio->cyusbs;
+
+	dev_dbg(&cyusbs->usb_intf->dev, "%s: %d\n", __func__,
+		offset);
+	wValue = offset;
+	wIndex = 0;
+
+	mutex_lock(&cyusbs->lock);
+	ret = usb_control_msg(cyusbs->usb_dev,
+			usb_rcvctrlpipe(cyusbs->usb_dev, 0),
+			CY_GPIO_GET_VALUE_CMD,
+			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+			wValue, wIndex, buf, CY_GPIO_GET_LEN, 2000);
+	mutex_unlock(&cyusbs->lock);
+
+	dev_dbg(&cyusbs->usb_intf->dev, "%s: %d %02x %02x\n", __func__,
+		ret, buf[0], buf[1]);
+
+	if (ret == CY_GPIO_GET_LEN) {
+		if (buf[0] == 0)
+			ret = buf[1];
+		else
+			ret = -EINVAL;
+	} else {
+		ret = -EREMOTEIO;
+	}
+
+	return ret;
+}
+
+static void cy_gpio_set(struct gpio_chip *chip,
+			unsigned offset, int value)
+{
+	int ret;
+	__u16 wIndex, wValue;
+	struct cyusbs_gpio *gpio =
+			container_of(chip, struct cyusbs_gpio, gpio);
+	struct cyusbs23x *cyusbs = gpio->cyusbs;
+
+	dev_dbg(&cyusbs->usb_intf->dev, "%s: %d\n", __func__,
+		offset);
+	wValue = offset;
+	wIndex = value;
+
+	mutex_lock(&cyusbs->lock);
+	ret = usb_control_msg(cyusbs->usb_dev,
+			usb_sndctrlpipe(cyusbs->usb_dev, 0),
+			CY_GPIO_SET_VALUE_CMD,
+			USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+			wValue, wIndex, NULL, 0, 2000);
+	mutex_unlock(&cyusbs->lock);
+
+	if (ret < 0)
+		dev_err(&cyusbs->usb_intf->dev, "error setting gpio:%d\n", ret);
+}
+
+static int cy_gpio_direction_input(struct gpio_chip *chip,
+					unsigned offset)
+{
+	return 0;
+}
+
+static int cy_gpio_direction_output(struct gpio_chip *chip,
+					unsigned offset, int value)
+{
+	return 0;
+}
+
+static int cyusbs23x_gpio_probe(struct platform_device *pdev)
+{
+	struct cyusbs23x *cyusbs;
+	struct cyusbs_gpio *cy_gpio;
+	int ret = 0;
+
+	dev_dbg(&pdev->dev, "%s\n", __func__);
+
+	cyusbs = dev_get_drvdata(pdev->dev.parent);
+
+	cy_gpio = devm_kzalloc(&pdev->dev, sizeof(*cy_gpio), GFP_KERNEL);
+	if (cy_gpio == NULL)
+		return -ENOMEM;
+
+	cy_gpio->cyusbs = cyusbs;
+	/* registering gpio */
+	cy_gpio->gpio.label = "cyusbs23x gpio";
+	cy_gpio->gpio.dev = &pdev->dev;
+	cy_gpio->gpio.owner = THIS_MODULE;
+	cy_gpio->gpio.base = -1;
+	cy_gpio->gpio.ngpio = 12; /* total GPIOs */
+	cy_gpio->gpio.can_sleep = true;
+	cy_gpio->gpio.set = cy_gpio_set;
+	cy_gpio->gpio.get = cy_gpio_get;
+	cy_gpio->gpio.direction_input = cy_gpio_direction_input;
+	cy_gpio->gpio.direction_output = cy_gpio_direction_output;
+	ret = gpiochip_add(&cy_gpio->gpio);
+	if (ret < 0) {
+		dev_err(cy_gpio->gpio.dev, "could not add gpio");
+		goto error;
+	}
+
+	platform_set_drvdata(pdev, cy_gpio);
+
+	dev_dbg(&pdev->dev, "added GPIO\n");
+	return ret;
+
+error:
+	dev_dbg(&pdev->dev, "error occured %d\n", ret);
+	return ret;
+}
+
+static int cyusbs23x_gpio_remove(struct platform_device *pdev)
+{
+	struct cyusbs_gpio *cy_gpio = platform_get_drvdata(pdev);
+
+	dev_dbg(&pdev->dev, "%s\n", __func__);
+
+	gpiochip_remove(&cy_gpio->gpio);
+
+	return 0;
+}
+
+static struct platform_driver cyusbs23x_gpio_driver = {
+	.driver.name    = "cyusbs23x-gpio",
+	.driver.owner   = THIS_MODULE,
+	.probe          = cyusbs23x_gpio_probe,
+	.remove         = cyusbs23x_gpio_remove,
+};
+
+static int __init cyusbs23x_gpio_init(void)
+{
+	return platform_driver_register(&cyusbs23x_gpio_driver);
+}
+subsys_initcall(cyusbs23x_gpio_init);
+
+static void __exit cyusbs23x_gpio_exit(void)
+{
+	platform_driver_unregister(&cyusbs23x_gpio_driver);
+}
+module_exit(cyusbs23x_gpio_exit);
+
+MODULE_AUTHOR("Rajaram Regupathy <rera@cypress.com>");
+MODULE_AUTHOR("Muthu Mani <muth@cypress.com>");
+MODULE_DESCRIPTION("gpio-cyusbs23x driver v0.1");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:cyusbs23x-gpio");
+