1 /*
2  * Copyright (c) 2002-2010, Intel Corporation.
3  * Copyright (c) 2014 ATRON electronic GmbH
4  *   Author: Jan Safrata <jan.nikitenko@gmail.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  *
24  */
25 
26 #include <linux/delay.h>
27 #include <linux/i2c-algo-bit.h>
28 #include <linux/i2c.h>
29 #include <linux/init.h>
30 #include <linux/io.h>
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/pci.h>
34 #include <linux/types.h>
35 
36 #include "psb_drv.h"
37 #include "psb_intel_reg.h"
38 
39 
40 /*
41  * LPC GPIO based I2C bus for LVDS of Atom E6xx
42  */
43 
44 /*-----------------------------------------------------------------------------
45  * LPC Register Offsets. Used for LVDS GPIO Bit Bashing. Registers are part
46  * Atom E6xx [D31:F0]
47  ----------------------------------------------------------------------------*/
48 #define RGEN    0x20
49 #define RGIO    0x24
50 #define RGLVL   0x28
51 #define RGTPE   0x2C
52 #define RGTNE   0x30
53 #define RGGPE   0x34
54 #define RGSMI   0x38
55 #define RGTS    0x3C
56 
57 /* The LVDS GPIO clock lines are GPIOSUS[3]
58  * The LVDS GPIO data lines are GPIOSUS[4]
59  */
60 #define GPIO_CLOCK	0x08
61 #define GPIO_DATA	0x10
62 
63 #define LPC_READ_REG(chan, r) inl((chan)->reg + (r))
64 #define LPC_WRITE_REG(chan, r, val) outl((val), (chan)->reg + (r))
65 
66 static int get_clock(void *data)
67 {
68 	struct psb_intel_i2c_chan *chan = data;
69 	u32 val;
70 
71 	val = LPC_READ_REG(chan, RGIO);
72 	val |= GPIO_CLOCK;
73 	LPC_WRITE_REG(chan, RGIO, val);
74 	LPC_READ_REG(chan, RGLVL);
75 	val = (LPC_READ_REG(chan, RGLVL) & GPIO_CLOCK) ? 1 : 0;
76 
77 	return val;
78 }
79 
80 static int get_data(void *data)
81 {
82 	struct psb_intel_i2c_chan *chan = data;
83 	u32 val;
84 
85 	val = LPC_READ_REG(chan, RGIO);
86 	val |= GPIO_DATA;
87 	LPC_WRITE_REG(chan, RGIO, val);
88 	LPC_READ_REG(chan, RGLVL);
89 	val = (LPC_READ_REG(chan, RGLVL) & GPIO_DATA) ? 1 : 0;
90 
91 	return val;
92 }
93 
94 static void set_clock(void *data, int state_high)
95 {
96 	struct psb_intel_i2c_chan *chan = data;
97 	u32 val;
98 
99 	if (state_high) {
100 		val = LPC_READ_REG(chan, RGIO);
101 		val |= GPIO_CLOCK;
102 		LPC_WRITE_REG(chan, RGIO, val);
103 	} else {
104 		val = LPC_READ_REG(chan, RGIO);
105 		val &= ~GPIO_CLOCK;
106 		LPC_WRITE_REG(chan, RGIO, val);
107 		val = LPC_READ_REG(chan, RGLVL);
108 		val &= ~GPIO_CLOCK;
109 		LPC_WRITE_REG(chan, RGLVL, val);
110 	}
111 }
112 
113 static void set_data(void *data, int state_high)
114 {
115 	struct psb_intel_i2c_chan *chan = data;
116 	u32 val;
117 
118 	if (state_high) {
119 		val = LPC_READ_REG(chan, RGIO);
120 		val |= GPIO_DATA;
121 		LPC_WRITE_REG(chan, RGIO, val);
122 	} else {
123 		val = LPC_READ_REG(chan, RGIO);
124 		val &= ~GPIO_DATA;
125 		LPC_WRITE_REG(chan, RGIO, val);
126 		val = LPC_READ_REG(chan, RGLVL);
127 		val &= ~GPIO_DATA;
128 		LPC_WRITE_REG(chan, RGLVL, val);
129 	}
130 }
131 
132 void oaktrail_lvds_i2c_init(struct drm_encoder *encoder)
133 {
134 	struct drm_device *dev = encoder->dev;
135 	struct gma_encoder *gma_encoder = to_gma_encoder(encoder);
136 	struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
137 	struct psb_intel_i2c_chan *chan;
138 
139 	chan = kzalloc(sizeof(struct psb_intel_i2c_chan), GFP_KERNEL);
140 	if (!chan)
141 		return;
142 
143 	chan->drm_dev = dev;
144 	chan->reg = dev_priv->lpc_gpio_base;
145 	strncpy(chan->adapter.name, "gma500 LPC",  I2C_NAME_SIZE - 1);
146 	chan->adapter.owner = THIS_MODULE;
147 	chan->adapter.algo_data = &chan->algo;
148 	chan->adapter.dev.parent = dev->dev;
149 	chan->algo.setsda = set_data;
150 	chan->algo.setscl = set_clock;
151 	chan->algo.getsda = get_data;
152 	chan->algo.getscl = get_clock;
153 	chan->algo.udelay = 100;
154 	chan->algo.timeout = usecs_to_jiffies(2200);
155 	chan->algo.data = chan;
156 
157 	i2c_set_adapdata(&chan->adapter, chan);
158 
159 	set_data(chan, 1);
160 	set_clock(chan, 1);
161 	udelay(50);
162 
163 	if (i2c_bit_add_bus(&chan->adapter)) {
164 		kfree(chan);
165 		return;
166 	}
167 
168 	gma_encoder->ddc_bus = chan;
169 }
170