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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright © 2006-2007 Intel Corporation4 *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 functions19 */20 21#define I2C_RISEFALL_TIME 2022 23static int get_clock(void *data)24{25 struct gma_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 gma_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 gma_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 else57 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 gma_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 else77 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 * gma_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg87 * @dev: DRM device88 * @reg: GPIO reg to use89 * @name: name for this bus90 *91 * Creates and registers a new i2c bus with the Linux i2c layer, for use92 * in output probing and control (e.g. DDC or SDVO control functions).93 *94 * Possible values for @reg include:95 * %GPIOA96 * %GPIOB97 * %GPIOC98 * %GPIOD99 * %GPIOE100 * %GPIOF101 * %GPIOG102 * %GPIOH103 * see PRM for details on how these different busses are used.104 */105struct gma_i2c_chan *gma_i2c_create(struct drm_device *dev, const u32 reg,106 const char *name)107{108 struct gma_i2c_chan *chan;109 110 chan = kzalloc(sizeof(struct gma_i2c_chan), GFP_KERNEL);111 if (!chan)112 goto out_free;113 114 chan->drm_dev = dev;115 chan->reg = reg;116 snprintf(chan->base.name, I2C_NAME_SIZE, "intel drm %s", name);117 chan->base.owner = THIS_MODULE;118 chan->base.algo_data = &chan->algo;119 chan->base.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->base, chan);129 130 if (i2c_bit_add_bus(&chan->base))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 * gma_i2c_destroy - unregister and free i2c bus resources147 * @chan: channel to free148 *149 * Unregister the adapter from the i2c layer, then free the structure.150 */151void gma_i2c_destroy(struct gma_i2c_chan *chan)152{153 if (!chan)154 return;155 156 i2c_del_adapter(&chan->base);157 kfree(chan);158}159