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linux/drivers/gpio/gpio-viperboard.c
Linus Walleij 80776df4f5 gpio: viperboard: Be sure to clamp return value 
As we want gpio_chip .get() calls to be able to return negative
error codes and propagate to drivers, we need to go over all
drivers and make sure their return values are clamped to [0,1].
We do this by using the ret = !!(val) design pattern.

Cc: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2015-12-26 22:28:32 +01:00

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/*
* Nano River Technologies viperboard GPIO lib driver
*
* (C) 2012 by Lemonage GmbH
* Author: Lars Poeschel <poeschel@lemonage.de>
* All rights reserved.
*
* 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/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/viperboard.h>
#define VPRBRD_GPIOA_CLK_1MHZ 0
#define VPRBRD_GPIOA_CLK_100KHZ 1
#define VPRBRD_GPIOA_CLK_10KHZ 2
#define VPRBRD_GPIOA_CLK_1KHZ 3
#define VPRBRD_GPIOA_CLK_100HZ 4
#define VPRBRD_GPIOA_CLK_10HZ 5
#define VPRBRD_GPIOA_FREQ_DEFAULT 1000
#define VPRBRD_GPIOA_CMD_CONT 0x00
#define VPRBRD_GPIOA_CMD_PULSE 0x01
#define VPRBRD_GPIOA_CMD_PWM 0x02
#define VPRBRD_GPIOA_CMD_SETOUT 0x03
#define VPRBRD_GPIOA_CMD_SETIN 0x04
#define VPRBRD_GPIOA_CMD_SETINT 0x05
#define VPRBRD_GPIOA_CMD_GETIN 0x06
#define VPRBRD_GPIOB_CMD_SETDIR 0x00
#define VPRBRD_GPIOB_CMD_SETVAL 0x01
struct vprbrd_gpioa_msg {
u8 cmd;
u8 clk;
u8 offset;
u8 t1;
u8 t2;
u8 invert;
u8 pwmlevel;
u8 outval;
u8 risefall;
u8 answer;
u8 __fill;
} __packed;
struct vprbrd_gpiob_msg {
u8 cmd;
u16 val;
u16 mask;
} __packed;
struct vprbrd_gpio {
struct gpio_chip gpioa; /* gpio a related things */
u32 gpioa_out;
u32 gpioa_val;
struct gpio_chip gpiob; /* gpio b related things */
u32 gpiob_out;
u32 gpiob_val;
struct vprbrd *vb;
};
/* gpioa sampling clock module parameter */
static unsigned char gpioa_clk;
static unsigned int gpioa_freq = VPRBRD_GPIOA_FREQ_DEFAULT;
module_param(gpioa_freq, uint, 0);
MODULE_PARM_DESC(gpioa_freq,
"gpio-a sampling freq in Hz (default is 1000Hz) valid values: 10, 100, 1000, 10000, 100000, 1000000");
/* ----- begin of gipo a chip -------------------------------------------- */
static int vprbrd_gpioa_get(struct gpio_chip *chip,
unsigned offset)
{
int ret, answer, error = 0;
struct vprbrd_gpio *gpio =
container_of(chip, struct vprbrd_gpio, gpioa);
struct vprbrd *vb = gpio->vb;
struct vprbrd_gpioa_msg *gamsg = (struct vprbrd_gpioa_msg *)vb->buf;
/* if io is set to output, just return the saved value */
if (gpio->gpioa_out & (1 << offset))
return !!(gpio->gpioa_val & (1 << offset));
mutex_lock(&vb->lock);
gamsg->cmd = VPRBRD_GPIOA_CMD_GETIN;
gamsg->clk = 0x00;
gamsg->offset = offset;
gamsg->t1 = 0x00;
gamsg->t2 = 0x00;
gamsg->invert = 0x00;
gamsg->pwmlevel = 0x00;
gamsg->outval = 0x00;
gamsg->risefall = 0x00;
gamsg->answer = 0x00;
gamsg->__fill = 0x00;
ret = usb_control_msg(vb->usb_dev, usb_sndctrlpipe(vb->usb_dev, 0),
VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_OUT, 0x0000,
0x0000, gamsg, sizeof(struct vprbrd_gpioa_msg),
VPRBRD_USB_TIMEOUT_MS);
if (ret != sizeof(struct vprbrd_gpioa_msg))
error = -EREMOTEIO;
ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),
VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_IN, 0x0000,
0x0000, gamsg, sizeof(struct vprbrd_gpioa_msg),
VPRBRD_USB_TIMEOUT_MS);
answer = gamsg->answer & 0x01;
mutex_unlock(&vb->lock);
if (ret != sizeof(struct vprbrd_gpioa_msg))
error = -EREMOTEIO;
if (error)
return error;
return answer;
}
static void vprbrd_gpioa_set(struct gpio_chip *chip,
unsigned offset, int value)
{
int ret;
struct vprbrd_gpio *gpio =
container_of(chip, struct vprbrd_gpio, gpioa);
struct vprbrd *vb = gpio->vb;
struct vprbrd_gpioa_msg *gamsg = (struct vprbrd_gpioa_msg *)vb->buf;
if (gpio->gpioa_out & (1 << offset)) {
if (value)
gpio->gpioa_val |= (1 << offset);
else
gpio->gpioa_val &= ~(1 << offset);
mutex_lock(&vb->lock);
gamsg->cmd = VPRBRD_GPIOA_CMD_SETOUT;
gamsg->clk = 0x00;
gamsg->offset = offset;
gamsg->t1 = 0x00;
gamsg->t2 = 0x00;
gamsg->invert = 0x00;
gamsg->pwmlevel = 0x00;
gamsg->outval = value;
gamsg->risefall = 0x00;
gamsg->answer = 0x00;
gamsg->__fill = 0x00;
ret = usb_control_msg(vb->usb_dev,
usb_sndctrlpipe(vb->usb_dev, 0),
VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_OUT,
0x0000, 0x0000, gamsg,
sizeof(struct vprbrd_gpioa_msg), VPRBRD_USB_TIMEOUT_MS);
mutex_unlock(&vb->lock);
if (ret != sizeof(struct vprbrd_gpioa_msg))
dev_err(chip->parent, "usb error setting pin value\n");
}
}
static int vprbrd_gpioa_direction_input(struct gpio_chip *chip,
unsigned offset)
{
int ret;
struct vprbrd_gpio *gpio =
container_of(chip, struct vprbrd_gpio, gpioa);
struct vprbrd *vb = gpio->vb;
struct vprbrd_gpioa_msg *gamsg = (struct vprbrd_gpioa_msg *)vb->buf;
gpio->gpioa_out &= ~(1 << offset);
mutex_lock(&vb->lock);
gamsg->cmd = VPRBRD_GPIOA_CMD_SETIN;
gamsg->clk = gpioa_clk;
gamsg->offset = offset;
gamsg->t1 = 0x00;
gamsg->t2 = 0x00;
gamsg->invert = 0x00;
gamsg->pwmlevel = 0x00;
gamsg->outval = 0x00;
gamsg->risefall = 0x00;
gamsg->answer = 0x00;
gamsg->__fill = 0x00;
ret = usb_control_msg(vb->usb_dev, usb_sndctrlpipe(vb->usb_dev, 0),
VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_OUT, 0x0000,
0x0000, gamsg, sizeof(struct vprbrd_gpioa_msg),
VPRBRD_USB_TIMEOUT_MS);
mutex_unlock(&vb->lock);
if (ret != sizeof(struct vprbrd_gpioa_msg))
return -EREMOTEIO;
return 0;
}
static int vprbrd_gpioa_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
int ret;
struct vprbrd_gpio *gpio =
container_of(chip, struct vprbrd_gpio, gpioa);
struct vprbrd *vb = gpio->vb;
struct vprbrd_gpioa_msg *gamsg = (struct vprbrd_gpioa_msg *)vb->buf;
gpio->gpioa_out |= (1 << offset);
if (value)
gpio->gpioa_val |= (1 << offset);
else
gpio->gpioa_val &= ~(1 << offset);
mutex_lock(&vb->lock);
gamsg->cmd = VPRBRD_GPIOA_CMD_SETOUT;
gamsg->clk = 0x00;
gamsg->offset = offset;
gamsg->t1 = 0x00;
gamsg->t2 = 0x00;
gamsg->invert = 0x00;
gamsg->pwmlevel = 0x00;
gamsg->outval = value;
gamsg->risefall = 0x00;
gamsg->answer = 0x00;
gamsg->__fill = 0x00;
ret = usb_control_msg(vb->usb_dev, usb_sndctrlpipe(vb->usb_dev, 0),
VPRBRD_USB_REQUEST_GPIOA, VPRBRD_USB_TYPE_OUT, 0x0000,
0x0000, gamsg, sizeof(struct vprbrd_gpioa_msg),
VPRBRD_USB_TIMEOUT_MS);
mutex_unlock(&vb->lock);
if (ret != sizeof(struct vprbrd_gpioa_msg))
return -EREMOTEIO;
return 0;
}
/* ----- end of gpio a chip ---------------------------------------------- */
/* ----- begin of gipo b chip -------------------------------------------- */
static int vprbrd_gpiob_setdir(struct vprbrd *vb, unsigned offset,
unsigned dir)
{
struct vprbrd_gpiob_msg *gbmsg = (struct vprbrd_gpiob_msg *)vb->buf;
int ret;
gbmsg->cmd = VPRBRD_GPIOB_CMD_SETDIR;
gbmsg->val = cpu_to_be16(dir << offset);
gbmsg->mask = cpu_to_be16(0x0001 << offset);
ret = usb_control_msg(vb->usb_dev, usb_sndctrlpipe(vb->usb_dev, 0),
VPRBRD_USB_REQUEST_GPIOB, VPRBRD_USB_TYPE_OUT, 0x0000,
0x0000, gbmsg, sizeof(struct vprbrd_gpiob_msg),
VPRBRD_USB_TIMEOUT_MS);
if (ret != sizeof(struct vprbrd_gpiob_msg))
return -EREMOTEIO;
return 0;
}
static int vprbrd_gpiob_get(struct gpio_chip *chip,
unsigned offset)
{
int ret;
u16 val;
struct vprbrd_gpio *gpio =
container_of(chip, struct vprbrd_gpio, gpiob);
struct vprbrd *vb = gpio->vb;
struct vprbrd_gpiob_msg *gbmsg = (struct vprbrd_gpiob_msg *)vb->buf;
/* if io is set to output, just return the saved value */
if (gpio->gpiob_out & (1 << offset))
return gpio->gpiob_val & (1 << offset);
mutex_lock(&vb->lock);
ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),
VPRBRD_USB_REQUEST_GPIOB, VPRBRD_USB_TYPE_IN, 0x0000,
0x0000, gbmsg, sizeof(struct vprbrd_gpiob_msg),
VPRBRD_USB_TIMEOUT_MS);
val = gbmsg->val;
mutex_unlock(&vb->lock);
if (ret != sizeof(struct vprbrd_gpiob_msg))
return ret;
/* cache the read values */
gpio->gpiob_val = be16_to_cpu(val);
return (gpio->gpiob_val >> offset) & 0x1;
}
static void vprbrd_gpiob_set(struct gpio_chip *chip,
unsigned offset, int value)
{
int ret;
struct vprbrd_gpio *gpio =
container_of(chip, struct vprbrd_gpio, gpiob);
struct vprbrd *vb = gpio->vb;
struct vprbrd_gpiob_msg *gbmsg = (struct vprbrd_gpiob_msg *)vb->buf;
if (gpio->gpiob_out & (1 << offset)) {
if (value)
gpio->gpiob_val |= (1 << offset);
else
gpio->gpiob_val &= ~(1 << offset);
mutex_lock(&vb->lock);
gbmsg->cmd = VPRBRD_GPIOB_CMD_SETVAL;
gbmsg->val = cpu_to_be16(value << offset);
gbmsg->mask = cpu_to_be16(0x0001 << offset);
ret = usb_control_msg(vb->usb_dev,
usb_sndctrlpipe(vb->usb_dev, 0),
VPRBRD_USB_REQUEST_GPIOB, VPRBRD_USB_TYPE_OUT,
0x0000, 0x0000, gbmsg,
sizeof(struct vprbrd_gpiob_msg), VPRBRD_USB_TIMEOUT_MS);
mutex_unlock(&vb->lock);
if (ret != sizeof(struct vprbrd_gpiob_msg))
dev_err(chip->parent, "usb error setting pin value\n");
}
}
static int vprbrd_gpiob_direction_input(struct gpio_chip *chip,
unsigned offset)
{
int ret;
struct vprbrd_gpio *gpio =
container_of(chip, struct vprbrd_gpio, gpiob);
struct vprbrd *vb = gpio->vb;
gpio->gpiob_out &= ~(1 << offset);
mutex_lock(&vb->lock);
ret = vprbrd_gpiob_setdir(vb, offset, 0);
mutex_unlock(&vb->lock);
if (ret)
dev_err(chip->parent, "usb error setting pin to input\n");
return ret;
}
static int vprbrd_gpiob_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
int ret;
struct vprbrd_gpio *gpio =
container_of(chip, struct vprbrd_gpio, gpiob);
struct vprbrd *vb = gpio->vb;
gpio->gpiob_out |= (1 << offset);
mutex_lock(&vb->lock);
ret = vprbrd_gpiob_setdir(vb, offset, 1);
if (ret)
dev_err(chip->parent, "usb error setting pin to output\n");
mutex_unlock(&vb->lock);
vprbrd_gpiob_set(chip, offset, value);
return ret;
}
/* ----- end of gpio b chip ---------------------------------------------- */
static int vprbrd_gpio_probe(struct platform_device *pdev)
{
struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
struct vprbrd_gpio *vb_gpio;
int ret;
vb_gpio = devm_kzalloc(&pdev->dev, sizeof(*vb_gpio), GFP_KERNEL);
if (vb_gpio == NULL)
return -ENOMEM;
vb_gpio->vb = vb;
/* registering gpio a */
vb_gpio->gpioa.label = "viperboard gpio a";
vb_gpio->gpioa.parent = &pdev->dev;
vb_gpio->gpioa.owner = THIS_MODULE;
vb_gpio->gpioa.base = -1;
vb_gpio->gpioa.ngpio = 16;
vb_gpio->gpioa.can_sleep = true;
vb_gpio->gpioa.set = vprbrd_gpioa_set;
vb_gpio->gpioa.get = vprbrd_gpioa_get;
vb_gpio->gpioa.direction_input = vprbrd_gpioa_direction_input;
vb_gpio->gpioa.direction_output = vprbrd_gpioa_direction_output;
ret = gpiochip_add(&vb_gpio->gpioa);
if (ret < 0) {
dev_err(vb_gpio->gpioa.parent, "could not add gpio a");
goto err_gpioa;
}
/* registering gpio b */
vb_gpio->gpiob.label = "viperboard gpio b";
vb_gpio->gpiob.parent = &pdev->dev;
vb_gpio->gpiob.owner = THIS_MODULE;
vb_gpio->gpiob.base = -1;
vb_gpio->gpiob.ngpio = 16;
vb_gpio->gpiob.can_sleep = true;
vb_gpio->gpiob.set = vprbrd_gpiob_set;
vb_gpio->gpiob.get = vprbrd_gpiob_get;
vb_gpio->gpiob.direction_input = vprbrd_gpiob_direction_input;
vb_gpio->gpiob.direction_output = vprbrd_gpiob_direction_output;
ret = gpiochip_add(&vb_gpio->gpiob);
if (ret < 0) {
dev_err(vb_gpio->gpiob.parent, "could not add gpio b");
goto err_gpiob;
}
platform_set_drvdata(pdev, vb_gpio);
return ret;
err_gpiob:
gpiochip_remove(&vb_gpio->gpioa);
err_gpioa:
return ret;
}
static int vprbrd_gpio_remove(struct platform_device *pdev)
{
struct vprbrd_gpio *vb_gpio = platform_get_drvdata(pdev);
gpiochip_remove(&vb_gpio->gpiob);
return 0;
}
static struct platform_driver vprbrd_gpio_driver = {
.driver.name = "viperboard-gpio",
.driver.owner = THIS_MODULE,
.probe = vprbrd_gpio_probe,
.remove = vprbrd_gpio_remove,
};
static int __init vprbrd_gpio_init(void)
{
switch (gpioa_freq) {
case 1000000:
gpioa_clk = VPRBRD_GPIOA_CLK_1MHZ;
break;
case 100000:
gpioa_clk = VPRBRD_GPIOA_CLK_100KHZ;
break;
case 10000:
gpioa_clk = VPRBRD_GPIOA_CLK_10KHZ;
break;
case 1000:
gpioa_clk = VPRBRD_GPIOA_CLK_1KHZ;
break;
case 100:
gpioa_clk = VPRBRD_GPIOA_CLK_100HZ;
break;
case 10:
gpioa_clk = VPRBRD_GPIOA_CLK_10HZ;
break;
default:
pr_warn("invalid gpioa_freq (%d)\n", gpioa_freq);
gpioa_clk = VPRBRD_GPIOA_CLK_1KHZ;
}
return platform_driver_register(&vprbrd_gpio_driver);
}
subsys_initcall(vprbrd_gpio_init);
static void __exit vprbrd_gpio_exit(void)
{
platform_driver_unregister(&vprbrd_gpio_driver);
}
module_exit(vprbrd_gpio_exit);
MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
MODULE_DESCRIPTION("GPIO driver for Nano River Techs Viperboard");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:viperboard-gpio");
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