Alan Cox | 5091b7e | 2011-11-03 18:21:53 +0000 | [diff] [blame] | 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 | */ |
Dave Airlie | af3a2cf | 2011-11-16 12:13:30 +0000 | [diff] [blame] | 20 | #include <linux/export.h> |
Alan Cox | 5091b7e | 2011-11-03 18:21:53 +0000 | [diff] [blame] | 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 | |
| 33 | static 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 | |
| 43 | static 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 | |
| 53 | static 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 | |
| 73 | static 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 | */ |
| 116 | struct 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 | |
| 151 | out_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 | */ |
| 162 | void 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 | } |