159 lines
3.6 KiB
C
159 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright © 2006-2007 Intel Corporation
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*
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* Authors:
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* Eric Anholt <eric@anholt.net>
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*/
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#include <linux/delay.h>
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#include <linux/export.h>
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#include <linux/i2c-algo-bit.h>
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#include <linux/i2c.h>
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#include "psb_drv.h"
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#include "psb_intel_reg.h"
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/*
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* Intel GPIO access functions
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*/
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#define I2C_RISEFALL_TIME 20
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static int get_clock(void *data)
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{
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struct psb_intel_i2c_chan *chan = data;
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struct drm_device *dev = chan->drm_dev;
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u32 val;
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val = REG_READ(chan->reg);
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return (val & GPIO_CLOCK_VAL_IN) != 0;
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}
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static int get_data(void *data)
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{
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struct psb_intel_i2c_chan *chan = data;
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struct drm_device *dev = chan->drm_dev;
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u32 val;
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val = REG_READ(chan->reg);
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return (val & GPIO_DATA_VAL_IN) != 0;
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}
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static void set_clock(void *data, int state_high)
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{
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struct psb_intel_i2c_chan *chan = data;
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struct drm_device *dev = chan->drm_dev;
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u32 reserved = 0, clock_bits;
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/* On most chips, these bits must be preserved in software. */
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reserved =
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REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
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GPIO_CLOCK_PULLUP_DISABLE);
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if (state_high)
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clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
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else
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clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
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GPIO_CLOCK_VAL_MASK;
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REG_WRITE(chan->reg, reserved | clock_bits);
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udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
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}
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static void set_data(void *data, int state_high)
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{
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struct psb_intel_i2c_chan *chan = data;
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struct drm_device *dev = chan->drm_dev;
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u32 reserved = 0, data_bits;
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/* On most chips, these bits must be preserved in software. */
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reserved =
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REG_READ(chan->reg) & (GPIO_DATA_PULLUP_DISABLE |
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GPIO_CLOCK_PULLUP_DISABLE);
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if (state_high)
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data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
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else
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data_bits =
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GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
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GPIO_DATA_VAL_MASK;
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REG_WRITE(chan->reg, reserved | data_bits);
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udelay(I2C_RISEFALL_TIME); /* wait for the line to change state */
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}
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/**
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* psb_intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg
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* @dev: DRM device
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* @reg: GPIO reg to use
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* @name: name for this bus
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*
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* Creates and registers a new i2c bus with the Linux i2c layer, for use
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* in output probing and control (e.g. DDC or SDVO control functions).
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*
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* Possible values for @reg include:
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* %GPIOA
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* %GPIOB
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* %GPIOC
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* %GPIOD
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* %GPIOE
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* %GPIOF
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* %GPIOG
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* %GPIOH
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* see PRM for details on how these different busses are used.
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*/
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struct psb_intel_i2c_chan *psb_intel_i2c_create(struct drm_device *dev,
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const u32 reg, const char *name)
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{
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struct psb_intel_i2c_chan *chan;
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chan = kzalloc(sizeof(struct psb_intel_i2c_chan), GFP_KERNEL);
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if (!chan)
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goto out_free;
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chan->drm_dev = dev;
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chan->reg = reg;
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snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name);
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chan->adapter.owner = THIS_MODULE;
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chan->adapter.algo_data = &chan->algo;
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chan->adapter.dev.parent = dev->dev;
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chan->algo.setsda = set_data;
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chan->algo.setscl = set_clock;
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chan->algo.getsda = get_data;
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chan->algo.getscl = get_clock;
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chan->algo.udelay = 20;
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chan->algo.timeout = usecs_to_jiffies(2200);
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chan->algo.data = chan;
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i2c_set_adapdata(&chan->adapter, chan);
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if (i2c_bit_add_bus(&chan->adapter))
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goto out_free;
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/* JJJ: raise SCL and SDA? */
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set_data(chan, 1);
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set_clock(chan, 1);
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udelay(20);
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return chan;
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out_free:
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kfree(chan);
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return NULL;
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}
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/**
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* psb_intel_i2c_destroy - unregister and free i2c bus resources
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* @chan: channel to free
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*
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* Unregister the adapter from the i2c layer, then free the structure.
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*/
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void psb_intel_i2c_destroy(struct psb_intel_i2c_chan *chan)
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{
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if (!chan)
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return;
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i2c_del_adapter(&chan->adapter);
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kfree(chan);
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}
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