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

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright © 2006-2007 Intel Corporation
   4 *
   5 * Authors:
   6 *      Eric Anholt <eric@anholt.net>
   7 */
   8
   9#include <linux/delay.h>
  10#include <linux/export.h>
  11#include <linux/i2c-algo-bit.h>
  12#include <linux/i2c.h>
  13
  14#include "psb_drv.h"
  15#include "psb_intel_reg.h"
  16
  17/*
  18 * Intel GPIO access functions
  19 */
  20
  21#define I2C_RISEFALL_TIME 20
  22
  23static int get_clock(void *data)
  24{
  25        struct psb_intel_i2c_chan *chan = data;
  26        struct drm_device *dev = chan->drm_dev;
  27        u32 val;
  28
  29        val = REG_READ(chan->reg);
  30        return (val & GPIO_CLOCK_VAL_IN) != 0;
  31}
  32
  33static int get_data(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_DATA_VAL_IN) != 0;
  41}
  42
  43static void set_clock(void *data, int state_high)
  44{
  45        struct psb_intel_i2c_chan *chan = data;
  46        struct drm_device *dev = chan->drm_dev;
  47        u32 reserved = 0, clock_bits;
  48
  49        /* On most chips, these bits must be preserved in software. */
  50        reserved =
  51                    REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
  52                                           GPIO_CLOCK_PULLUP_DISABLE);
  53
  54        if (state_high)
  55                clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
  56        else
  57                clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
  58                    GPIO_CLOCK_VAL_MASK;
  59        REG_WRITE(chan->reg, reserved | clock_bits);
  60        udelay(I2C_RISEFALL_TIME);      /* wait for the line to change state */
  61}
  62
  63static void set_data(void *data, int state_high)
  64{
  65        struct psb_intel_i2c_chan *chan = data;
  66        struct drm_device *dev = chan->drm_dev;
  67        u32 reserved = 0, data_bits;
  68
  69        /* On most chips, these bits must be preserved in software. */
  70        reserved =
  71                    REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
  72                                           GPIO_CLOCK_PULLUP_DISABLE);
  73
  74        if (state_high)
  75                data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
  76        else
  77                data_bits =
  78                    GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
  79                    GPIO_DATA_VAL_MASK;
  80
  81        REG_WRITE(chan->reg, reserved | data_bits);
  82        udelay(I2C_RISEFALL_TIME);      /* wait for the line to change state */
  83}
  84
  85/**
  86 * psb_intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg
  87 * @dev: DRM device
  88 * @reg: GPIO reg to use
  89 * @name: name for this bus
  90 *
  91 * Creates and registers a new i2c bus with the Linux i2c layer, for use
  92 * in output probing and control (e.g. DDC or SDVO control functions).
  93 *
  94 * Possible values for @reg include:
  95 *   %GPIOA
  96 *   %GPIOB
  97 *   %GPIOC
  98 *   %GPIOD
  99 *   %GPIOE
 100 *   %GPIOF
 101 *   %GPIOG
 102 *   %GPIOH
 103 * see PRM for details on how these different busses are used.
 104 */
 105struct psb_intel_i2c_chan *psb_intel_i2c_create(struct drm_device *dev,
 106                                        const u32 reg, const char *name)
 107{
 108        struct psb_intel_i2c_chan *chan;
 109
 110        chan = kzalloc(sizeof(struct psb_intel_i2c_chan), GFP_KERNEL);
 111        if (!chan)
 112                goto out_free;
 113
 114        chan->drm_dev = dev;
 115        chan->reg = reg;
 116        snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name);
 117        chan->adapter.owner = THIS_MODULE;
 118        chan->adapter.algo_data = &chan->algo;
 119        chan->adapter.dev.parent = dev->dev;
 120        chan->algo.setsda = set_data;
 121        chan->algo.setscl = set_clock;
 122        chan->algo.getsda = get_data;
 123        chan->algo.getscl = get_clock;
 124        chan->algo.udelay = 20;
 125        chan->algo.timeout = usecs_to_jiffies(2200);
 126        chan->algo.data = chan;
 127
 128        i2c_set_adapdata(&chan->adapter, chan);
 129
 130        if (i2c_bit_add_bus(&chan->adapter))
 131                goto out_free;
 132
 133        /* JJJ:  raise SCL and SDA? */
 134        set_data(chan, 1);
 135        set_clock(chan, 1);
 136        udelay(20);
 137
 138        return chan;
 139
 140out_free:
 141        kfree(chan);
 142        return NULL;
 143}
 144
 145/**
 146 * psb_intel_i2c_destroy - unregister and free i2c bus resources
 147 * @chan: channel to free
 148 *
 149 * Unregister the adapter from the i2c layer, then free the structure.
 150 */
 151void psb_intel_i2c_destroy(struct psb_intel_i2c_chan *chan)
 152{
 153        if (!chan)
 154                return;
 155
 156        i2c_del_adapter(&chan->adapter);
 157        kfree(chan);
 158}
 159