linux/drivers/gpio/gpio-twl6040.c
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   1/*
   2 * Access to GPOs on TWL6040 chip
   3 *
   4 * Copyright (C) 2012 Texas Instruments, Inc.
   5 *
   6 * Authors:
   7 *      Sergio Aguirre <saaguirre@ti.com>
   8 *      Peter Ujfalusi <peter.ujfalusi@ti.com>
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License as published by
  12 * the Free Software Foundation; either version 2 of the License, or
  13 * (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with this program; if not, write to the Free Software
  22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  23 */
  24
  25#include <linux/module.h>
  26#include <linux/init.h>
  27#include <linux/kthread.h>
  28#include <linux/irq.h>
  29#include <linux/gpio.h>
  30#include <linux/platform_device.h>
  31#include <linux/of.h>
  32
  33#include <linux/mfd/twl6040.h>
  34
  35static struct gpio_chip twl6040gpo_chip;
  36
  37static int twl6040gpo_get(struct gpio_chip *chip, unsigned offset)
  38{
  39        struct twl6040 *twl6040 = dev_get_drvdata(chip->dev->parent);
  40        int ret = 0;
  41
  42        ret = twl6040_reg_read(twl6040, TWL6040_REG_GPOCTL);
  43        if (ret < 0)
  44                return ret;
  45
  46        return (ret >> offset) & 1;
  47}
  48
  49static int twl6040gpo_direction_out(struct gpio_chip *chip, unsigned offset,
  50                                    int value)
  51{
  52        /* This only drives GPOs, and can't change direction */
  53        return 0;
  54}
  55
  56static void twl6040gpo_set(struct gpio_chip *chip, unsigned offset, int value)
  57{
  58        struct twl6040 *twl6040 = dev_get_drvdata(chip->dev->parent);
  59        int ret;
  60        u8 gpoctl;
  61
  62        ret = twl6040_reg_read(twl6040, TWL6040_REG_GPOCTL);
  63        if (ret < 0)
  64                return;
  65
  66        if (value)
  67                gpoctl = ret | (1 << offset);
  68        else
  69                gpoctl = ret & ~(1 << offset);
  70
  71        twl6040_reg_write(twl6040, TWL6040_REG_GPOCTL, gpoctl);
  72}
  73
  74static struct gpio_chip twl6040gpo_chip = {
  75        .label                  = "twl6040",
  76        .owner                  = THIS_MODULE,
  77        .get                    = twl6040gpo_get,
  78        .direction_output       = twl6040gpo_direction_out,
  79        .set                    = twl6040gpo_set,
  80        .can_sleep              = 1,
  81};
  82
  83/*----------------------------------------------------------------------*/
  84
  85static int gpo_twl6040_probe(struct platform_device *pdev)
  86{
  87        struct device *twl6040_core_dev = pdev->dev.parent;
  88        struct twl6040 *twl6040 = dev_get_drvdata(twl6040_core_dev);
  89        int ret;
  90
  91        twl6040gpo_chip.base = -1;
  92
  93        if (twl6040_get_revid(twl6040) < TWL6041_REV_ES2_0)
  94                twl6040gpo_chip.ngpio = 3; /* twl6040 have 3 GPO */
  95        else
  96                twl6040gpo_chip.ngpio = 1; /* twl6041 have 1 GPO */
  97
  98        twl6040gpo_chip.dev = &pdev->dev;
  99#ifdef CONFIG_OF_GPIO
 100        twl6040gpo_chip.of_node = twl6040_core_dev->of_node;
 101#endif
 102
 103        ret = gpiochip_add(&twl6040gpo_chip);
 104        if (ret < 0) {
 105                dev_err(&pdev->dev, "could not register gpiochip, %d\n", ret);
 106                twl6040gpo_chip.ngpio = 0;
 107        }
 108
 109        return ret;
 110}
 111
 112static int gpo_twl6040_remove(struct platform_device *pdev)
 113{
 114        return gpiochip_remove(&twl6040gpo_chip);
 115}
 116
 117/* Note:  this hardware lives inside an I2C-based multi-function device. */
 118MODULE_ALIAS("platform:twl6040-gpo");
 119
 120static struct platform_driver gpo_twl6040_driver = {
 121        .driver = {
 122                .name   = "twl6040-gpo",
 123                .owner  = THIS_MODULE,
 124        },
 125        .probe          = gpo_twl6040_probe,
 126        .remove         = gpo_twl6040_remove,
 127};
 128
 129module_platform_driver(gpo_twl6040_driver);
 130
 131MODULE_AUTHOR("Texas Instruments, Inc.");
 132MODULE_DESCRIPTION("GPO interface for TWL6040");
 133MODULE_LICENSE("GPL");
 134
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