LXR linux/drivers/gpu/drm/gma500/intel

   1/*
   2 * Copyright © 2006-2007 Intel Corporation
   3 *
   4 * This program is free software; you can redistribute it and/or modify it
   5 * under the terms and conditions of the GNU General Public License,
   6 * version 2, as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope it will be useful, but WITHOUT
   9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11 * more details.
  12 *
  13 * You should have received a copy of the GNU General Public License along with
  14 * this program; if not, write to the Free Software Foundation, Inc.,
  15 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  16 *
  17 * Authors:
  18 *      Eric Anholt <eric@anholt.net>
  19 */
  20#include <linux/export.h>
  21#include <linux/i2c.h>
  22#include <linux/i2c-algo-bit.h>
  23
  24#include "psb_drv.h"
  25#include "psb_intel_reg.h"
  26
  27/*
  28 * Intel GPIO access functions
  29 */
  30
  31#define I2C_RISEFALL_TIME 20
  32
  33static int get_clock(void *data)
  34{
  35        struct psb_intel_i2c_chan *chan = data;
  36        struct drm_device *dev = chan->drm_dev;
  37        u32 val;
  38
  39        val = REG_READ(chan->reg);
  40        return (val & GPIO_CLOCK_VAL_IN) != 0;
  41}
  42
  43static int get_data(void *data)
  44{
  45        struct psb_intel_i2c_chan *chan = data;
  46        struct drm_device *dev = chan->drm_dev;
  47        u32 val;
  48
  49        val = REG_READ(chan->reg);
  50        return (val & GPIO_DATA_VAL_IN) != 0;
  51}
  52
  53static void set_clock(void *data, int state_high)
  54{
  55        struct psb_intel_i2c_chan *chan = data;
  56        struct drm_device *dev = chan->drm_dev;
  57        u32 reserved = 0, clock_bits;
  58
  59        /* On most chips, these bits must be preserved in software. */
  60        reserved =
  61                    REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
  62                                           GPIO_CLOCK_PULLUP_DISABLE);
  63
  64        if (state_high)
  65                clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
  66        else
  67                clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
  68                    GPIO_CLOCK_VAL_MASK;
  69        REG_WRITE(chan->reg, reserved | clock_bits);
  70        udelay(I2C_RISEFALL_TIME);      /* wait for the line to change state */
  71}
  72
  73static void set_data(void *data, int state_high)
  74{
  75        struct psb_intel_i2c_chan *chan = data;
  76        struct drm_device *dev = chan->drm_dev;
  77        u32 reserved = 0, data_bits;
  78
  79        /* On most chips, these bits must be preserved in software. */
  80        reserved =
  81                    REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
  82                                           GPIO_CLOCK_PULLUP_DISABLE);
  83
  84        if (state_high)
  85                data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
  86        else
  87                data_bits =
  88                    GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
  89                    GPIO_DATA_VAL_MASK;
  90
  91        REG_WRITE(chan->reg, reserved | data_bits);
  92        udelay(I2C_RISEFALL_TIME);      /* wait for the line to change state */
  93}
  94
  95/**
  96 * psb_intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg
  97 * @dev: DRM device
  98 * @output: driver specific output device
  99 * @reg: GPIO reg to use
 100 * @name: name for this bus
 101 *
 102 * Creates and registers a new i2c bus with the Linux i2c layer, for use
 103 * in output probing and control (e.g. DDC or SDVO control functions).
 104 *
 105 * Possible values for @reg include:
 106 *   %GPIOA
 107 *   %GPIOB
 108 *   %GPIOC
 109 *   %GPIOD
 110 *   %GPIOE
 111 *   %GPIOF
 112 *   %GPIOG
 113 *   %GPIOH
 114 * see PRM for details on how these different busses are used.
 115 */
 116struct psb_intel_i2c_chan *psb_intel_i2c_create(struct drm_device *dev,
 117                                        const u32 reg, const char *name)
 118{
 119        struct psb_intel_i2c_chan *chan;
 120
 121        chan = kzalloc(sizeof(struct psb_intel_i2c_chan), GFP_KERNEL);
 122        if (!chan)
 123                goto out_free;
 124
 125        chan->drm_dev = dev;
 126        chan->reg = reg;
 127        snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name);
 128        chan->adapter.owner = THIS_MODULE;
 129        chan->adapter.algo_data = &chan->algo;
 130        chan->adapter.dev.parent = &dev->pdev->dev;
 131        chan->algo.setsda = set_data;
 132        chan->algo.setscl = set_clock;
 133        chan->algo.getsda = get_data;
 134        chan->algo.getscl = get_clock;
 135        chan->algo.udelay = 20;
 136        chan->algo.timeout = usecs_to_jiffies(2200);
 137        chan->algo.data = chan;
 138
 139        i2c_set_adapdata(&chan->adapter, chan);
 140
 141        if (i2c_bit_add_bus(&chan->adapter))
 142                goto out_free;
 143
 144        /* JJJ:  raise SCL and SDA? */
 145        set_data(chan, 1);
 146        set_clock(chan, 1);
 147        udelay(20);
 148
 149        return chan;
 150
 151out_free:
 152        kfree(chan);
 153        return NULL;
 154}
 155
 156/**
 157 * psb_intel_i2c_destroy - unregister and free i2c bus resources
 158 * @output: channel to free
 159 *
 160 * Unregister the adapter from the i2c layer, then free the structure.
 161 */
 162void psb_intel_i2c_destroy(struct psb_intel_i2c_chan *chan)
 163{
 164        if (!chan)
 165                return;
 166
 167        i2c_del_adapter(&chan->adapter);
 168        kfree(chan);
 169}
 170