tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#include <linux/amba/bus.h>
2#include <linux/amba/clcd.h>
3#include <linux/gpio/consumer.h>
4#include <linux/of.h>
5#include <linux/of_graph.h>
6#include <linux/delay.h>
7#include <linux/bitops.h>
8#include <linux/mfd/syscon.h>
9#include <linux/regmap.h>
10
11#include "amba-clcd-nomadik.h"
12
13static struct gpio_desc *grestb;
14static struct gpio_desc *scen;
15static struct gpio_desc *scl;
16static struct gpio_desc *sda;
17
18static u8 tpg110_readwrite_reg(bool write, u8 address, u8 outval)
19{
20 int i;
21 u8 inval = 0;
22
23 /* Assert SCEN */
24 gpiod_set_value_cansleep(scen, 1);
25 ndelay(150);
26 /* Hammer out the address */
27 for (i = 5; i >= 0; i--) {
28 if (address & BIT(i))
29 gpiod_set_value_cansleep(sda, 1);
30 else
31 gpiod_set_value_cansleep(sda, 0);
32 ndelay(150);
33 /* Send an SCL pulse */
34 gpiod_set_value_cansleep(scl, 1);
35 ndelay(160);
36 gpiod_set_value_cansleep(scl, 0);
37 ndelay(160);
38 }
39
40 if (write) {
41 /* WRITE */
42 gpiod_set_value_cansleep(sda, 0);
43 } else {
44 /* READ */
45 gpiod_set_value_cansleep(sda, 1);
46 }
47 ndelay(150);
48 /* Send an SCL pulse */
49 gpiod_set_value_cansleep(scl, 1);
50 ndelay(160);
51 gpiod_set_value_cansleep(scl, 0);
52 ndelay(160);
53
54 if (!write)
55 /* HiZ turn-around cycle */
56 gpiod_direction_input(sda);
57 ndelay(150);
58 /* Send an SCL pulse */
59 gpiod_set_value_cansleep(scl, 1);
60 ndelay(160);
61 gpiod_set_value_cansleep(scl, 0);
62 ndelay(160);
63
64 /* Hammer in/out the data */
65 for (i = 7; i >= 0; i--) {
66 int value;
67
68 if (write) {
69 value = !!(outval & BIT(i));
70 gpiod_set_value_cansleep(sda, value);
71 } else {
72 value = gpiod_get_value(sda);
73 if (value)
74 inval |= BIT(i);
75 }
76 ndelay(150);
77 /* Send an SCL pulse */
78 gpiod_set_value_cansleep(scl, 1);
79 ndelay(160);
80 gpiod_set_value_cansleep(scl, 0);
81 ndelay(160);
82 }
83
84 gpiod_direction_output(sda, 0);
85 /* Deassert SCEN */
86 gpiod_set_value_cansleep(scen, 0);
87 /* Satisfies SCEN pulse width */
88 udelay(1);
89
90 return inval;
91}
92
93static u8 tpg110_read_reg(u8 address)
94{
95 return tpg110_readwrite_reg(false, address, 0);
96}
97
98static void tpg110_write_reg(u8 address, u8 outval)
99{
100 tpg110_readwrite_reg(true, address, outval);
101}
102
103static void tpg110_startup(struct device *dev)
104{
105 u8 val;
106
107 dev_info(dev, "TPG110 display enable\n");
108 /* De-assert the reset signal */
109 gpiod_set_value_cansleep(grestb, 0);
110 mdelay(1);
111 dev_info(dev, "de-asserted GRESTB\n");
112
113 /* Test display communication */
114 tpg110_write_reg(0x00, 0x55);
115 val = tpg110_read_reg(0x00);
116 if (val == 0x55)
117 dev_info(dev, "passed communication test\n");
118 val = tpg110_read_reg(0x01);
119 dev_info(dev, "TPG110 chip ID: %d version: %d\n",
120 val>>4, val&0x0f);
121
122 /* Show display resolution */
123 val = tpg110_read_reg(0x02);
124 val &= 7;
125 switch (val) {
126 case 0x0:
127 dev_info(dev, "IN 400x240 RGB -> OUT 800x480 RGB (dual scan)");
128 break;
129 case 0x1:
130 dev_info(dev, "IN 480x272 RGB -> OUT 800x480 RGB (dual scan)");
131 break;
132 case 0x4:
133 dev_info(dev, "480x640 RGB");
134 break;
135 case 0x5:
136 dev_info(dev, "480x272 RGB");
137 break;
138 case 0x6:
139 dev_info(dev, "640x480 RGB");
140 break;
141 case 0x7:
142 dev_info(dev, "800x480 RGB");
143 break;
144 default:
145 dev_info(dev, "ILLEGAL RESOLUTION");
146 break;
147 }
148
149 val = tpg110_read_reg(0x03);
150 dev_info(dev, "resolution is controlled by %s\n",
151 (val & BIT(7)) ? "software" : "hardware");
152}
153
154static void tpg110_enable(struct clcd_fb *fb)
155{
156 struct device *dev = &fb->dev->dev;
157 static bool startup;
158 u8 val;
159
160 if (!startup) {
161 tpg110_startup(dev);
162 startup = true;
163 }
164
165 /* Take chip out of standby */
166 val = tpg110_read_reg(0x03);
167 val |= BIT(0);
168 tpg110_write_reg(0x03, val);
169}
170
171static void tpg110_disable(struct clcd_fb *fb)
172{
173 u8 val;
174
175 dev_info(&fb->dev->dev, "TPG110 display disable\n");
176 val = tpg110_read_reg(0x03);
177 /* Put into standby */
178 val &= ~BIT(0);
179 tpg110_write_reg(0x03, val);
180}
181
182static void tpg110_init(struct device *dev, struct device_node *np,
183 struct clcd_board *board)
184{
185 dev_info(dev, "TPG110 display init\n");
186
187 /* This asserts the GRESTB signal, putting the display into reset */
188 grestb = devm_fwnode_get_gpiod_from_child(dev, "grestb", &np->fwnode,
189 GPIOD_OUT_HIGH, "grestb");
190 if (IS_ERR(grestb)) {
191 dev_err(dev, "no GRESTB GPIO\n");
192 return;
193 }
194 scen = devm_fwnode_get_gpiod_from_child(dev, "scen", &np->fwnode,
195 GPIOD_OUT_LOW, "scen");
196 if (IS_ERR(scen)) {
197 dev_err(dev, "no SCEN GPIO\n");
198 return;
199 }
200 scl = devm_fwnode_get_gpiod_from_child(dev, "scl", &np->fwnode,
201 GPIOD_OUT_LOW, "scl");
202 if (IS_ERR(scl)) {
203 dev_err(dev, "no SCL GPIO\n");
204 return;
205 }
206 sda = devm_fwnode_get_gpiod_from_child(dev, "sda", &np->fwnode,
207 GPIOD_OUT_LOW, "sda");
208 if (IS_ERR(sda)) {
209 dev_err(dev, "no SDA GPIO\n");
210 return;
211 }
212 board->enable = tpg110_enable;
213 board->disable = tpg110_disable;
214}
215
216int nomadik_clcd_init_panel(struct clcd_fb *fb, struct device_node *panel)
217{
218 if (of_device_is_compatible(panel, "tpo,tpg110"))
219 tpg110_init(&fb->dev->dev, panel, fb->board);
220 else
221 dev_info(&fb->dev->dev, "unknown panel\n");
222
223 /* Unknown panel, fall through */
224 return 0;
225}
226EXPORT_SYMBOL_GPL(nomadik_clcd_init_panel);
227
228#define PMU_CTRL_OFFSET 0x0000
229#define PMU_CTRL_LCDNDIF BIT(26)
230
231int nomadik_clcd_init_board(struct amba_device *adev,
232 struct clcd_board *board)
233{
234 struct regmap *pmu_regmap;
235
236 dev_info(&adev->dev, "Nomadik CLCD board init\n");
237 pmu_regmap =
238 syscon_regmap_lookup_by_compatible("stericsson,nomadik-pmu");
239 if (IS_ERR(pmu_regmap)) {
240 dev_err(&adev->dev, "could not find PMU syscon regmap\n");
241 return PTR_ERR(pmu_regmap);
242 }
243 regmap_update_bits(pmu_regmap,
244 PMU_CTRL_OFFSET,
245 PMU_CTRL_LCDNDIF,
246 0);
247 dev_info(&adev->dev, "set PMU mux to CLCD mode\n");
248
249 return 0;
250}
251EXPORT_SYMBOL_GPL(nomadik_clcd_init_board);