diff options
Diffstat (limited to 'drivers/staging/vme/devices/vme_pio2_gpio.c')
| -rw-r--r-- | drivers/staging/vme/devices/vme_pio2_gpio.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/staging/vme/devices/vme_pio2_gpio.c b/drivers/staging/vme/devices/vme_pio2_gpio.c new file mode 100644 index 000000000000..dc837deb99dd --- /dev/null +++ b/drivers/staging/vme/devices/vme_pio2_gpio.c @@ -0,0 +1,232 @@ +/* + * GE PIO2 GPIO Driver + * + * Author: Martyn Welch <martyn.welch@ge.com> + * Copyright 2009 GE Intelligent Platforms Embedded Systems, Inc. + * + * 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/version.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/device.h> +#include <linux/platform_device.h> +#include <linux/ctype.h> +#include <linux/gpio.h> +#include <linux/slab.h> + +#include "../vme.h" +#include "vme_pio2.h" + +static const char driver_name[] = "pio2_gpio"; + +static struct pio2_card *gpio_to_pio2_card(struct gpio_chip *chip) +{ + return container_of(chip, struct pio2_card, gc); +} + +static int pio2_gpio_get(struct gpio_chip *chip, unsigned int offset) +{ + u8 reg; + int retval; + struct pio2_card *card = gpio_to_pio2_card(chip); + + if ((card->bank[PIO2_CHANNEL_BANK[offset]].config == OUTPUT) | + (card->bank[PIO2_CHANNEL_BANK[offset]].config == NOFIT)) { + + dev_err(&card->vdev->dev, "Channel not available as input\n"); + return 0; + } + + retval = vme_master_read(card->window, ®, 1, + PIO2_REGS_DATA[PIO2_CHANNEL_BANK[offset]]); + if (retval < 0) { + dev_err(&card->vdev->dev, "Unable to read from GPIO\n"); + return 0; + } + + /* + * Remember, input on channels configured as both input and output + * are inverted! + */ + if (reg & PIO2_CHANNEL_BIT[offset]) { + if (card->bank[PIO2_CHANNEL_BANK[offset]].config != BOTH) + return 0; + else + return 1; + } else { + if (card->bank[PIO2_CHANNEL_BANK[offset]].config != BOTH) + return 1; + else + return 0; + } +} + +static void pio2_gpio_set(struct gpio_chip *chip, unsigned int offset, + int value) +{ + u8 reg; + int retval; + struct pio2_card *card = gpio_to_pio2_card(chip); + + if ((card->bank[PIO2_CHANNEL_BANK[offset]].config == INPUT) | + (card->bank[PIO2_CHANNEL_BANK[offset]].config == NOFIT)) { + + dev_err(&card->vdev->dev, "Channel not availabe as output\n"); + return; + } + + if (value) + reg = card->bank[PIO2_CHANNEL_BANK[offset]].value | + PIO2_CHANNEL_BIT[offset]; + else + reg = card->bank[PIO2_CHANNEL_BANK[offset]].value & + ~PIO2_CHANNEL_BIT[offset]; + + retval = vme_master_write(card->window, ®, 1, + PIO2_REGS_DATA[PIO2_CHANNEL_BANK[offset]]); + if (retval < 0) { + dev_err(&card->vdev->dev, "Unable to write to GPIO\n"); + return; + } + + card->bank[PIO2_CHANNEL_BANK[offset]].value = reg; +} + +/* Directionality configured at board build - send appropriate response */ +static int pio2_gpio_dir_in(struct gpio_chip *chip, unsigned offset) +{ + int data; + struct pio2_card *card = gpio_to_pio2_card(chip); + + if ((card->bank[PIO2_CHANNEL_BANK[offset]].config == OUTPUT) | + (card->bank[PIO2_CHANNEL_BANK[offset]].config == NOFIT)) { + dev_err(&card->vdev->dev, + "Channel directionality not configurable at runtine\n"); + + data = -EINVAL; + } else { + data = 0; + } + + return data; +} + +/* Directionality configured at board build - send appropriate response */ +static int pio2_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int value) +{ + int data; + struct pio2_card *card = gpio_to_pio2_card(chip); + + if ((card->bank[PIO2_CHANNEL_BANK[offset]].config == INPUT) | + (card->bank[PIO2_CHANNEL_BANK[offset]].config == NOFIT)) { + dev_err(&card->vdev->dev, + "Channel directionality not configurable at runtine\n"); + + data = -EINVAL; + } else { + data = 0; + } + + return data; +} + +/* + * We return whether this has been successful - this is used in the probe to + * ensure we have a valid card. + */ +int pio2_gpio_reset(struct pio2_card *card) +{ + int retval = 0; + int i, j; + + u8 data = 0; + + /* Zero output registers */ + for (i = 0; i < 4; i++) { + retval = vme_master_write(card->window, &data, 1, + PIO2_REGS_DATA[i]); + if (retval < 0) + return retval; + card->bank[i].value = 0; + } + + /* Set input interrupt masks */ + for (i = 0; i < 4; i++) { + retval = vme_master_write(card->window, &data, 1, + PIO2_REGS_INT_MASK[i * 2]); + if (retval < 0) + return retval; + + retval = vme_master_write(card->window, &data, 1, + PIO2_REGS_INT_MASK[(i * 2) + 1]); + if (retval < 0) + return retval; + + for (j = 0; j < 8; j++) + card->bank[i].irq[j] = NONE; + } + + /* Ensure all I/O interrupts are cleared */ + for (i = 0; i < 4; i++) { + do { + retval = vme_master_read(card->window, &data, 1, + PIO2_REGS_INT_STAT[i]); + if (retval < 0) + return retval; + } while (data != 0); + } + + return 0; +} + +int __init pio2_gpio_init(struct pio2_card *card) +{ + int retval = 0; + char *label; + + label = kmalloc(PIO2_NUM_CHANNELS, GFP_KERNEL); + if (label == NULL) { + dev_err(&card->vdev->dev, "Unable to allocate GPIO label\n"); + return -ENOMEM; + } + + sprintf(label, "%s@%s", driver_name, dev_name(&card->vdev->dev)); + card->gc.label = label; + + card->gc.ngpio = PIO2_NUM_CHANNELS; + /* Dynamic allocation of base */ + card->gc.base = -1; + /* Setup pointers to chip functions */ + card->gc.direction_input = pio2_gpio_dir_in; + card->gc.direction_output = pio2_gpio_dir_out; + card->gc.get = pio2_gpio_get; + card->gc.set = pio2_gpio_set; + + /* This function adds a memory mapped GPIO chip */ + retval = gpiochip_add(&(card->gc)); + if (retval) { + dev_err(&card->vdev->dev, "Unable to register GPIO\n"); + kfree(card->gc.label); + } + + return retval; +}; + +void __exit pio2_gpio_exit(struct pio2_card *card) +{ + const char *label = card->gc.label; + + if (gpiochip_remove(&(card->gc))) + dev_err(&card->vdev->dev, "Failed to remove GPIO"); + + kfree(label); +} + |