drivers/gpio/gpio-twl6040.c

   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
  35 static struct gpio_chip twl6040gpo_chip;
  36
  37 static int twl6040gpo_get(struct gpio_chip *chip, unsigned offset)
  38 {
  39         struct twl6040 *twl6040 = dev_get_drvdata(chip->parent->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
  49 static 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
  56 static void twl6040gpo_set(struct gpio_chip *chip, unsigned offset, int value)
  57 {
  58         struct twl6040 *twl6040 = dev_get_drvdata(chip->parent->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
  74 static 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              = true,
  81 };
  82
  83 /*----------------------------------------------------------------------*/
  84
  85 static 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.parent = &pdev->dev;
  99 #ifdef CONFIG_OF_GPIO
 100         twl6040gpo_chip.of_node = twl6040_core_dev->of_node;
 101 #endif
 102
 103         ret = devm_gpiochip_add_data(&pdev->dev, &twl6040gpo_chip, NULL);
 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
 112 /* Note:  this hardware lives inside an I2C-based multi-function device. */
 113 MODULE_ALIAS("platform:twl6040-gpo");
 114
 115 static struct platform_driver gpo_twl6040_driver = {
 116         .driver = {
 117                 .name   = "twl6040-gpo",
 118         },
 119         .probe          = gpo_twl6040_probe,
 120 };
 121
 122 module_platform_driver(gpo_twl6040_driver);
 123
 124 MODULE_AUTHOR("Texas Instruments, Inc.");
 125 MODULE_DESCRIPTION("GPO interface for TWL6040");
 126 MODULE_LICENSE("GPL");