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17#include <linux/err.h>
18#include <linux/init.h>
19#include <linux/input.h>
20#include <linux/interrupt.h>
21#include <linux/io.h>
22#include <linux/module.h>
23#include <linux/of_platform.h>
24#include <linux/platform_device.h>
25#include <linux/regulator/consumer.h>
26#include <linux/slab.h>
27
28#define LRADC_CTRL 0x00
29#define LRADC_INTC 0x04
30#define LRADC_INTS 0x08
31#define LRADC_DATA0 0x0c
32#define LRADC_DATA1 0x10
33
34
35#define FIRST_CONVERT_DLY(x) ((x) << 24)
36#define CHAN_SELECT(x) ((x) << 22)
37#define CONTINUE_TIME_SEL(x) ((x) << 16)
38#define KEY_MODE_SEL(x) ((x) << 12)
39#define LEVELA_B_CNT(x) ((x) << 8)
40#define HOLD_KEY_EN(x) ((x) << 7)
41#define HOLD_EN(x) ((x) << 6)
42#define LEVELB_VOL(x) ((x) << 4)
43#define SAMPLE_RATE(x) ((x) << 2)
44#define ENABLE(x) ((x) << 0)
45
46
47#define CHAN1_KEYUP_IRQ BIT(12)
48#define CHAN1_ALRDY_HOLD_IRQ BIT(11)
49#define CHAN1_HOLD_IRQ BIT(10)
50#define CHAN1_KEYDOWN_IRQ BIT(9)
51#define CHAN1_DATA_IRQ BIT(8)
52#define CHAN0_KEYUP_IRQ BIT(4)
53#define CHAN0_ALRDY_HOLD_IRQ BIT(3)
54#define CHAN0_HOLD_IRQ BIT(2)
55#define CHAN0_KEYDOWN_IRQ BIT(1)
56#define CHAN0_DATA_IRQ BIT(0)
57
58
59
60
61
62struct lradc_variant {
63 u8 divisor_numerator;
64 u8 divisor_denominator;
65};
66
67static const struct lradc_variant lradc_variant_a10 = {
68 .divisor_numerator = 2,
69 .divisor_denominator = 3
70};
71
72static const struct lradc_variant r_lradc_variant_a83t = {
73 .divisor_numerator = 3,
74 .divisor_denominator = 4
75};
76
77struct sun4i_lradc_keymap {
78 u32 voltage;
79 u32 keycode;
80};
81
82struct sun4i_lradc_data {
83 struct device *dev;
84 struct input_dev *input;
85 void __iomem *base;
86 struct regulator *vref_supply;
87 struct sun4i_lradc_keymap *chan0_map;
88 const struct lradc_variant *variant;
89 u32 chan0_map_count;
90 u32 chan0_keycode;
91 u32 vref;
92};
93
94static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
95{
96 struct sun4i_lradc_data *lradc = dev_id;
97 u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;
98
99 ints = readl(lradc->base + LRADC_INTS);
100
101
102
103
104
105
106 if (ints & CHAN0_KEYUP_IRQ) {
107 input_report_key(lradc->input, lradc->chan0_keycode, 0);
108 lradc->chan0_keycode = 0;
109 }
110
111 if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
112 val = readl(lradc->base + LRADC_DATA0) & 0x3f;
113 voltage = val * lradc->vref / 63;
114
115 for (i = 0; i < lradc->chan0_map_count; i++) {
116 diff = abs(lradc->chan0_map[i].voltage - voltage);
117 if (diff < closest) {
118 closest = diff;
119 keycode = lradc->chan0_map[i].keycode;
120 }
121 }
122
123 lradc->chan0_keycode = keycode;
124 input_report_key(lradc->input, lradc->chan0_keycode, 1);
125 }
126
127 input_sync(lradc->input);
128
129 writel(ints, lradc->base + LRADC_INTS);
130
131 return IRQ_HANDLED;
132}
133
134static int sun4i_lradc_open(struct input_dev *dev)
135{
136 struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
137 int error;
138
139 error = regulator_enable(lradc->vref_supply);
140 if (error)
141 return error;
142
143 lradc->vref = regulator_get_voltage(lradc->vref_supply) *
144 lradc->variant->divisor_numerator /
145 lradc->variant->divisor_denominator;
146
147
148
149
150 writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
151 SAMPLE_RATE(0) | ENABLE(1), lradc->base + LRADC_CTRL);
152
153 writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);
154
155 return 0;
156}
157
158static void sun4i_lradc_close(struct input_dev *dev)
159{
160 struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
161
162
163 writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
164 SAMPLE_RATE(2), lradc->base + LRADC_CTRL);
165 writel(0, lradc->base + LRADC_INTC);
166
167 regulator_disable(lradc->vref_supply);
168}
169
170static int sun4i_lradc_load_dt_keymap(struct device *dev,
171 struct sun4i_lradc_data *lradc)
172{
173 struct device_node *np, *pp;
174 int i;
175 int error;
176
177 np = dev->of_node;
178 if (!np)
179 return -EINVAL;
180
181 lradc->chan0_map_count = of_get_child_count(np);
182 if (lradc->chan0_map_count == 0) {
183 dev_err(dev, "keymap is missing in device tree\n");
184 return -EINVAL;
185 }
186
187 lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count,
188 sizeof(struct sun4i_lradc_keymap),
189 GFP_KERNEL);
190 if (!lradc->chan0_map)
191 return -ENOMEM;
192
193 i = 0;
194 for_each_child_of_node(np, pp) {
195 struct sun4i_lradc_keymap *map = &lradc->chan0_map[i];
196 u32 channel;
197
198 error = of_property_read_u32(pp, "channel", &channel);
199 if (error || channel != 0) {
200 dev_err(dev, "%pOFn: Inval channel prop\n", pp);
201 of_node_put(pp);
202 return -EINVAL;
203 }
204
205 error = of_property_read_u32(pp, "voltage", &map->voltage);
206 if (error) {
207 dev_err(dev, "%pOFn: Inval voltage prop\n", pp);
208 of_node_put(pp);
209 return -EINVAL;
210 }
211
212 error = of_property_read_u32(pp, "linux,code", &map->keycode);
213 if (error) {
214 dev_err(dev, "%pOFn: Inval linux,code prop\n", pp);
215 of_node_put(pp);
216 return -EINVAL;
217 }
218
219 i++;
220 }
221
222 return 0;
223}
224
225static int sun4i_lradc_probe(struct platform_device *pdev)
226{
227 struct sun4i_lradc_data *lradc;
228 struct device *dev = &pdev->dev;
229 int i;
230 int error;
231
232 lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
233 if (!lradc)
234 return -ENOMEM;
235
236 error = sun4i_lradc_load_dt_keymap(dev, lradc);
237 if (error)
238 return error;
239
240 lradc->variant = of_device_get_match_data(&pdev->dev);
241 if (!lradc->variant) {
242 dev_err(&pdev->dev, "Missing sun4i-a10-lradc-keys variant\n");
243 return -EINVAL;
244 }
245
246 lradc->vref_supply = devm_regulator_get(dev, "vref");
247 if (IS_ERR(lradc->vref_supply))
248 return PTR_ERR(lradc->vref_supply);
249
250 lradc->dev = dev;
251 lradc->input = devm_input_allocate_device(dev);
252 if (!lradc->input)
253 return -ENOMEM;
254
255 lradc->input->name = pdev->name;
256 lradc->input->phys = "sun4i_lradc/input0";
257 lradc->input->open = sun4i_lradc_open;
258 lradc->input->close = sun4i_lradc_close;
259 lradc->input->id.bustype = BUS_HOST;
260 lradc->input->id.vendor = 0x0001;
261 lradc->input->id.product = 0x0001;
262 lradc->input->id.version = 0x0100;
263
264 __set_bit(EV_KEY, lradc->input->evbit);
265 for (i = 0; i < lradc->chan0_map_count; i++)
266 __set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit);
267
268 input_set_drvdata(lradc->input, lradc);
269
270 lradc->base = devm_ioremap_resource(dev,
271 platform_get_resource(pdev, IORESOURCE_MEM, 0));
272 if (IS_ERR(lradc->base))
273 return PTR_ERR(lradc->base);
274
275 error = devm_request_irq(dev, platform_get_irq(pdev, 0),
276 sun4i_lradc_irq, 0,
277 "sun4i-a10-lradc-keys", lradc);
278 if (error)
279 return error;
280
281 error = input_register_device(lradc->input);
282 if (error)
283 return error;
284
285 return 0;
286}
287
288static const struct of_device_id sun4i_lradc_of_match[] = {
289 { .compatible = "allwinner,sun4i-a10-lradc-keys",
290 .data = &lradc_variant_a10 },
291 { .compatible = "allwinner,sun8i-a83t-r-lradc",
292 .data = &r_lradc_variant_a83t },
293 { }
294};
295MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
296
297static struct platform_driver sun4i_lradc_driver = {
298 .driver = {
299 .name = "sun4i-a10-lradc-keys",
300 .of_match_table = of_match_ptr(sun4i_lradc_of_match),
301 },
302 .probe = sun4i_lradc_probe,
303};
304
305module_platform_driver(sun4i_lradc_driver);
306
307MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver");
308MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
309MODULE_LICENSE("GPL");
310
