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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 | // SPDX-License-Identifier: GPL-2.0-only /* * Copyright © 2006-2007 Intel Corporation * * Authors: * Eric Anholt <eric@anholt.net> */ #include <linux/delay.h> #include <linux/export.h> #include <linux/i2c-algo-bit.h> #include <linux/i2c.h> #include "psb_drv.h" #include "psb_intel_reg.h" /* * Intel GPIO access functions */ #define I2C_RISEFALL_TIME 20 static int get_clock(void *data) { struct gma_i2c_chan *chan = data; struct drm_device *dev = chan->drm_dev; u32 val; val = REG_READ(chan->reg); return (val & GPIO_CLOCK_VAL_IN) != 0; } static int get_data(void *data) { struct gma_i2c_chan *chan = data; struct drm_device *dev = chan->drm_dev; u32 val; val = REG_READ(chan->reg); return (val & GPIO_DATA_VAL_IN) != 0; } static void set_clock(void *data, int state_high) { struct gma_i2c_chan *chan = data; struct drm_device *dev = chan->drm_dev; u32 reserved = 0, clock_bits; /* On most chips, these bits must be preserved in software. */ reserved = REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE | GPIO_CLOCK_PULLUP_DISABLE); if (state_high) clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK; else clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK | GPIO_CLOCK_VAL_MASK; REG_WRITE(chan->reg, reserved | clock_bits); udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */ } static void set_data(void *data, int state_high) { struct gma_i2c_chan *chan = data; struct drm_device *dev = chan->drm_dev; u32 reserved = 0, data_bits; /* On most chips, these bits must be preserved in software. */ reserved = REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE | GPIO_CLOCK_PULLUP_DISABLE); if (state_high) data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK; else data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK | GPIO_DATA_VAL_MASK; REG_WRITE(chan->reg, reserved | data_bits); udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */ } /** * gma_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg * @dev: DRM device * @reg: GPIO reg to use * @name: name for this bus * * Creates and registers a new i2c bus with the Linux i2c layer, for use * in output probing and control (e.g. DDC or SDVO control functions). * * Possible values for @reg include: * %GPIOA * %GPIOB * %GPIOC * %GPIOD * %GPIOE * %GPIOF * %GPIOG * %GPIOH * see PRM for details on how these different busses are used. */ struct gma_i2c_chan *gma_i2c_create(struct drm_device *dev, const u32 reg, const char *name) { struct gma_i2c_chan *chan; chan = kzalloc(sizeof(struct gma_i2c_chan), GFP_KERNEL); if (!chan) goto out_free; chan->drm_dev = dev; chan->reg = reg; snprintf(chan->base.name, I2C_NAME_SIZE, "intel drm %s", name); chan->base.owner = THIS_MODULE; chan->base.algo_data = &chan->algo; chan->base.dev.parent = dev->dev; chan->algo.setsda = set_data; chan->algo.setscl = set_clock; chan->algo.getsda = get_data; chan->algo.getscl = get_clock; chan->algo.udelay = 20; chan->algo.timeout = usecs_to_jiffies(2200); chan->algo.data = chan; i2c_set_adapdata(&chan->base, chan); if (i2c_bit_add_bus(&chan->base)) goto out_free; /* JJJ: raise SCL and SDA? */ set_data(chan, 1); set_clock(chan, 1); udelay(20); return chan; out_free: kfree(chan); return NULL; } /** * gma_i2c_destroy - unregister and free i2c bus resources * @chan: channel to free * * Unregister the adapter from the i2c layer, then free the structure. */ void gma_i2c_destroy(struct gma_i2c_chan *chan) { if (!chan) return; i2c_del_adapter(&chan->base); kfree(chan); } |