drivers/mfd/rpisense-core.c

   1 /*
   2  * Raspberry Pi Sense HAT core driver
   3  * http://raspberrypi.org
   4  *
   5  * Copyright (C) 2015 Raspberry Pi
   6  *
   7  * Author: Serge Schneider
   8  *
   9  *  This program is free software; you can redistribute  it and/or modify it
  10  *  under  the terms of  the GNU General  Public License as published by the
  11  *  Free Software Foundation;  either version 2 of the  License, or (at your
  12  *  option) any later version.
  13  *
  14  *  This driver is based on wm8350 implementation.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/err.h>
  20 #include <linux/init.h>
  21 #include <linux/i2c.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/mfd/rpisense/core.h>
  24 #include <linux/slab.h>
  25
  26 static struct rpisense *rpisense;
  27
  28 static void rpisense_client_dev_register(struct rpisense *rpisense,
  29                                          const char *name,
  30                                          struct platform_device **pdev)
  31 {
  32         int ret;
  33
  34         *pdev = platform_device_alloc(name, -1);
  35         if (*pdev == NULL) {
  36                 dev_err(rpisense->dev, "Failed to allocate %s\n", name);
  37                 return;
  38         }
  39
  40         (*pdev)->dev.parent = rpisense->dev;
  41         platform_set_drvdata(*pdev, rpisense);
  42         ret = platform_device_add(*pdev);
  43         if (ret != 0) {
  44                 dev_err(rpisense->dev, "Failed to register %s: %d\n",
  45                         name, ret);
  46                 platform_device_put(*pdev);
  47                 *pdev = NULL;
  48         }
  49 }
  50
  51 static int rpisense_probe(struct i2c_client *i2c,
  52                                const struct i2c_device_id *id)
  53 {
  54         int ret;
  55         struct rpisense_js *rpisense_js;
  56
  57         rpisense = devm_kzalloc(&i2c->dev, sizeof(struct rpisense), GFP_KERNEL);
  58         if (rpisense == NULL)
  59                 return -ENOMEM;
  60
  61         i2c_set_clientdata(i2c, rpisense);
  62         rpisense->dev = &i2c->dev;
  63         rpisense->i2c_client = i2c;
  64
  65         ret = rpisense_reg_read(rpisense, RPISENSE_WAI);
  66         if (ret > 0) {
  67                 if (ret != 's')
  68                         return -EINVAL;
  69         } else {
  70                 return ret;
  71         }
  72         ret = rpisense_reg_read(rpisense, RPISENSE_VER);
  73         if (ret < 0)
  74                 return ret;
  75
  76         dev_info(rpisense->dev,
  77                  "Raspberry Pi Sense HAT firmware version %i\n", ret);
  78
  79         rpisense_js = &rpisense->joystick;
  80         rpisense_js->keys_desc = devm_gpiod_get(&i2c->dev,
  81                                                 "keys-int", GPIOD_IN);
  82         if (IS_ERR(rpisense_js->keys_desc)) {
  83                 dev_warn(&i2c->dev, "Failed to get keys-int descriptor.\n");
  84                 rpisense_js->keys_desc = gpio_to_desc(23);
  85                 if (rpisense_js->keys_desc == NULL) {
  86                         dev_err(&i2c->dev, "GPIO23 fallback failed.\n");
  87                         return PTR_ERR(rpisense_js->keys_desc);
  88                 }
  89         }
  90         rpisense_client_dev_register(rpisense, "rpi-sense-js",
  91                                      &(rpisense->joystick.pdev));
  92         rpisense_client_dev_register(rpisense, "rpi-sense-fb",
  93                                      &(rpisense->framebuffer.pdev));
  94
  95         return 0;
  96 }
  97
  98 static int rpisense_remove(struct i2c_client *i2c)
  99 {
 100         struct rpisense *rpisense = i2c_get_clientdata(i2c);
 101
 102         platform_device_unregister(rpisense->joystick.pdev);
 103         return 0;
 104 }
 105
 106 struct rpisense *rpisense_get_dev(void)
 107 {
 108         return rpisense;
 109 }
 110 EXPORT_SYMBOL_GPL(rpisense_get_dev);
 111
 112 s32 rpisense_reg_read(struct rpisense *rpisense, int reg)
 113 {
 114         int ret = i2c_smbus_read_byte_data(rpisense->i2c_client, reg);
 115
 116         if (ret < 0)
 117                 dev_err(rpisense->dev, "Read from reg %d failed\n", reg);
 118         /* Due to the BCM270x I2C clock stretching bug, some values
 119          * may have MSB set. Clear it to avoid incorrect values.
 120          * */
 121         return ret & 0x7F;
 122 }
 123 EXPORT_SYMBOL_GPL(rpisense_reg_read);
 124
 125 int rpisense_block_write(struct rpisense *rpisense, const char *buf, int count)
 126 {
 127         int ret = i2c_master_send(rpisense->i2c_client, buf, count);
 128
 129         if (ret < 0)
 130                 dev_err(rpisense->dev, "Block write failed\n");
 131         return ret;
 132 }
 133 EXPORT_SYMBOL_GPL(rpisense_block_write);
 134
 135 static const struct i2c_device_id rpisense_i2c_id[] = {
 136         { "rpi-sense", 0 },
 137         { }
 138 };
 139 MODULE_DEVICE_TABLE(i2c, rpisense_i2c_id);
 140
 141
 142 static struct i2c_driver rpisense_driver = {
 143         .driver = {
 144                    .name = "rpi-sense",
 145                    .owner = THIS_MODULE,
 146         },
 147         .probe = rpisense_probe,
 148         .remove = rpisense_remove,
 149         .id_table = rpisense_i2c_id,
 150 };
 151
 152 module_i2c_driver(rpisense_driver);
 153
 154 MODULE_DESCRIPTION("Raspberry Pi Sense HAT core driver");
 155 MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>");
 156 MODULE_LICENSE("GPL");
 157