mgag200_ddc.c

  1/*
  2 * Copyright 2012 Red Hat Inc.
  3 *
  4 * Permission is hereby granted, free of charge, to any person obtaining a
  5 * copy of this software and associated documentation files (the
  6 * "Software"), to deal in the Software without restriction, including
  7 * without limitation the rights to use, copy, modify, merge, publish,
  8 * distribute, sub license, and/or sell copies of the Software, and to
  9 * permit persons to whom the Software is furnished to do so, subject to
 10 * the following conditions:
 11 *
 12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 13 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 14 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 15 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 16 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 17 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 18 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 19 *
 20 * The above copyright notice and this permission notice (including the
 21 * next paragraph) shall be included in all copies or substantial portions
 22 * of the Software.
 23 *
 24 */
 25/*
 26 * Authors: Dave Airlie <airlied@redhat.com>
 27 */
 28
 29#include <linux/i2c-algo-bit.h>
 30#include <linux/i2c.h>
 31#include <linux/pci.h>
 32
 33#include <drm/drm_managed.h>
 34
 35#include "mgag200_ddc.h"
 36#include "mgag200_drv.h"
 37
 38struct mgag200_ddc {
 39	struct mga_device *mdev;
 40
 41	int data;
 42	int clock;
 43
 44	struct i2c_algo_bit_data bit;
 45	struct i2c_adapter adapter;
 46};
 47
 48static int mga_i2c_read_gpio(struct mga_device *mdev)
 49{
 50	WREG8(DAC_INDEX, MGA1064_GEN_IO_DATA);
 51	return RREG8(DAC_DATA);
 52}
 53
 54static void mga_i2c_set_gpio(struct mga_device *mdev, int mask, int val)
 55{
 56	int tmp;
 57
 58	WREG8(DAC_INDEX, MGA1064_GEN_IO_CTL);
 59	tmp = (RREG8(DAC_DATA) & mask) | val;
 60	WREG_DAC(MGA1064_GEN_IO_CTL, tmp);
 61	WREG_DAC(MGA1064_GEN_IO_DATA, 0);
 62}
 63
 64static inline void mga_i2c_set(struct mga_device *mdev, int mask, int state)
 65{
 66	if (state)
 67		state = 0;
 68	else
 69		state = mask;
 70	mga_i2c_set_gpio(mdev, ~mask, state);
 71}
 72
 73static void mgag200_ddc_algo_bit_data_setsda(void *data, int state)
 74{
 75	struct mgag200_ddc *ddc = data;
 76
 77	mga_i2c_set(ddc->mdev, ddc->data, state);
 78}
 79
 80static void mgag200_ddc_algo_bit_data_setscl(void *data, int state)
 81{
 82	struct mgag200_ddc *ddc = data;
 83
 84	mga_i2c_set(ddc->mdev, ddc->clock, state);
 85}
 86
 87static int mgag200_ddc_algo_bit_data_getsda(void *data)
 88{
 89	struct mgag200_ddc *ddc = data;
 90
 91	return (mga_i2c_read_gpio(ddc->mdev) & ddc->data) ? 1 : 0;
 92}
 93
 94static int mgag200_ddc_algo_bit_data_getscl(void *data)
 95{
 96	struct mgag200_ddc *ddc = data;
 97
 98	return (mga_i2c_read_gpio(ddc->mdev) & ddc->clock) ? 1 : 0;
 99}
100
101static int mgag200_ddc_algo_bit_data_pre_xfer(struct i2c_adapter *adapter)
102{
103	struct mgag200_ddc *ddc = i2c_get_adapdata(adapter);
104	struct mga_device *mdev = ddc->mdev;
105
106	/*
107	 * Protect access to I/O registers from concurrent modesetting
108	 * by acquiring the I/O-register lock.
109	 */
110	mutex_lock(&mdev->rmmio_lock);
111
112	return 0;
113}
114
115static void mgag200_ddc_algo_bit_data_post_xfer(struct i2c_adapter *adapter)
116{
117	struct mgag200_ddc *ddc = i2c_get_adapdata(adapter);
118	struct mga_device *mdev = ddc->mdev;
119
120	mutex_unlock(&mdev->rmmio_lock);
121}
122
123static void mgag200_ddc_release(struct drm_device *dev, void *res)
124{
125	struct mgag200_ddc *ddc = res;
126
127	i2c_del_adapter(&ddc->adapter);
128}
129
130struct i2c_adapter *mgag200_ddc_create(struct mga_device *mdev)
131{
132	struct drm_device *dev = &mdev->base;
133	const struct mgag200_device_info *info = mdev->info;
134	struct mgag200_ddc *ddc;
135	struct i2c_algo_bit_data *bit;
136	struct i2c_adapter *adapter;
137	int ret;
138
139	ddc = drmm_kzalloc(dev, sizeof(*ddc), GFP_KERNEL);
140	if (!ddc)
141		return ERR_PTR(-ENOMEM);
142
143	WREG_DAC(MGA1064_GEN_IO_CTL2, 1);
144	WREG_DAC(MGA1064_GEN_IO_DATA, 0xff);
145	WREG_DAC(MGA1064_GEN_IO_CTL, 0);
146
147	ddc->mdev = mdev;
148	ddc->data = BIT(info->i2c.data_bit);
149	ddc->clock = BIT(info->i2c.clock_bit);
150
151	bit = &ddc->bit;
152	bit->data = ddc;
153	bit->setsda = mgag200_ddc_algo_bit_data_setsda;
154	bit->setscl = mgag200_ddc_algo_bit_data_setscl;
155	bit->getsda = mgag200_ddc_algo_bit_data_getsda;
156	bit->getscl = mgag200_ddc_algo_bit_data_getscl;
157	bit->pre_xfer = mgag200_ddc_algo_bit_data_pre_xfer;
158	bit->post_xfer = mgag200_ddc_algo_bit_data_post_xfer;
159	bit->udelay = 10;
160	bit->timeout = usecs_to_jiffies(2200);
161
162	adapter = &ddc->adapter;
163	adapter->owner = THIS_MODULE;
164	adapter->algo_data = bit;
165	adapter->dev.parent = dev->dev;
166	snprintf(adapter->name, sizeof(adapter->name), "Matrox DDC bus");
167	i2c_set_adapdata(adapter, ddc);
168
169	ret = i2c_bit_add_bus(adapter);
170	if (ret)
171		return ERR_PTR(ret);
172
173	ret = drmm_add_action_or_reset(dev, mgag200_ddc_release, ddc);
174	if (ret)
175		return ERR_PTR(ret);
176
177	return adapter;
178}