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Release 4.11 drivers/gpu/drm/gma500/intel_i2c.c

/*
 * Copyright © 2006-2007 Intel Corporation
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Authors:
 *      Eric Anholt <eric@anholt.net>
 */
#include <linux/export.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.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 psb_intel_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; }

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static int get_data(void *data) { struct psb_intel_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; }

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static void set_clock(void *data, int state_high) { struct psb_intel_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 */ }

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static void set_data(void *data, int state_high) { struct psb_intel_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 */ }

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/** * psb_intel_i2c_create - instantiate an Intel i2c bus using the specified GPIO reg * @dev: DRM device * @output: driver specific output 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 psb_intel_i2c_chan *psb_intel_i2c_create(struct drm_device *dev, const u32 reg, const char *name) { struct psb_intel_i2c_chan *chan; chan = kzalloc(sizeof(struct psb_intel_i2c_chan), GFP_KERNEL); if (!chan) goto out_free; chan->drm_dev = dev; chan->reg = reg; snprintf(chan->adapter.name, I2C_NAME_SIZE, "intel drm %s", name); chan->adapter.owner = THIS_MODULE; chan->adapter.algo_data = &chan->algo; chan->adapter.dev.parent = &dev->pdev->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->adapter, chan); if (i2c_bit_add_bus(&chan->adapter)) 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; }

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/** * psb_intel_i2c_destroy - unregister and free i2c bus resources * @output: channel to free * * Unregister the adapter from the i2c layer, then free the structure. */
void psb_intel_i2c_destroy(struct psb_intel_i2c_chan *chan) { if (!chan) return; i2c_del_adapter(&chan->adapter); kfree(chan); }

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