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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Allwinner sun4i low res adc attached tablet keys driver
4 *
5 * Copyright (C) 2014 Hans de Goede <hdegoede@redhat.com>
6 */
7
8/*
9 * Allwinnner sunxi SoCs have a lradc which is specifically designed to have
10 * various (tablet) keys (ie home, back, search, etc). attached to it using
11 * a resistor network. This driver is for the keys on such boards.
12 *
13 * There are 2 channels, currently this driver only supports channel 0 since
14 * there are no boards known to use channel 1.
15 */
16
17#include <linux/clk.h>
18#include <linux/err.h>
19#include <linux/init.h>
20#include <linux/input.h>
21#include <linux/interrupt.h>
22#include <linux/io.h>
23#include <linux/module.h>
24#include <linux/of_platform.h>
25#include <linux/platform_device.h>
26#include <linux/pm_wakeirq.h>
27#include <linux/pm_wakeup.h>
28#include <linux/regulator/consumer.h>
29#include <linux/reset.h>
30#include <linux/slab.h>
31
32#define LRADC_CTRL 0x00
33#define LRADC_INTC 0x04
34#define LRADC_INTS 0x08
35#define LRADC_DATA0 0x0c
36#define LRADC_DATA1 0x10
37
38/* LRADC_CTRL bits */
39#define FIRST_CONVERT_DLY(x) ((x) << 24) /* 8 bits */
40#define CHAN_SELECT(x) ((x) << 22) /* 2 bits */
41#define CONTINUE_TIME_SEL(x) ((x) << 16) /* 4 bits */
42#define KEY_MODE_SEL(x) ((x) << 12) /* 2 bits */
43#define LEVELA_B_CNT(x) ((x) << 8) /* 4 bits */
44#define HOLD_KEY_EN(x) ((x) << 7)
45#define HOLD_EN(x) ((x) << 6)
46#define LEVELB_VOL(x) ((x) << 4) /* 2 bits */
47#define SAMPLE_RATE(x) ((x) << 2) /* 2 bits */
48#define ENABLE(x) ((x) << 0)
49
50/* LRADC_INTC and LRADC_INTS bits */
51#define CHAN1_KEYUP_IRQ BIT(12)
52#define CHAN1_ALRDY_HOLD_IRQ BIT(11)
53#define CHAN1_HOLD_IRQ BIT(10)
54#define CHAN1_KEYDOWN_IRQ BIT(9)
55#define CHAN1_DATA_IRQ BIT(8)
56#define CHAN0_KEYUP_IRQ BIT(4)
57#define CHAN0_ALRDY_HOLD_IRQ BIT(3)
58#define CHAN0_HOLD_IRQ BIT(2)
59#define CHAN0_KEYDOWN_IRQ BIT(1)
60#define CHAN0_DATA_IRQ BIT(0)
61
62/* struct lradc_variant - Describe sun4i-a10-lradc-keys hardware variant
63 * @divisor_numerator: The numerator of lradc Vref internally divisor
64 * @divisor_denominator: The denominator of lradc Vref internally divisor
65 * @has_clock_reset: If the binding requires a clock and reset
66 */
67struct lradc_variant {
68 u8 divisor_numerator;
69 u8 divisor_denominator;
70 bool has_clock_reset;
71};
72
73static const struct lradc_variant lradc_variant_a10 = {
74 .divisor_numerator = 2,
75 .divisor_denominator = 3
76};
77
78static const struct lradc_variant r_lradc_variant_a83t = {
79 .divisor_numerator = 3,
80 .divisor_denominator = 4
81};
82
83static const struct lradc_variant lradc_variant_r329 = {
84 .divisor_numerator = 3,
85 .divisor_denominator = 4,
86 .has_clock_reset = true,
87};
88
89struct sun4i_lradc_keymap {
90 u32 voltage;
91 u32 keycode;
92};
93
94struct sun4i_lradc_data {
95 struct device *dev;
96 struct input_dev *input;
97 void __iomem *base;
98 struct clk *clk;
99 struct reset_control *reset;
100 struct regulator *vref_supply;
101 struct sun4i_lradc_keymap *chan0_map;
102 const struct lradc_variant *variant;
103 u32 chan0_map_count;
104 u32 chan0_keycode;
105 u32 vref;
106};
107
108static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
109{
110 struct sun4i_lradc_data *lradc = dev_id;
111 u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;
112
113 ints = readl(lradc->base + LRADC_INTS);
114
115 /*
116 * lradc supports only one keypress at a time, release does not give
117 * any info as to which key was released, so we cache the keycode.
118 */
119
120 if (ints & CHAN0_KEYUP_IRQ) {
121 input_report_key(lradc->input, lradc->chan0_keycode, 0);
122 lradc->chan0_keycode = 0;
123 }
124
125 if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
126 val = readl(lradc->base + LRADC_DATA0) & 0x3f;
127 voltage = val * lradc->vref / 63;
128
129 for (i = 0; i < lradc->chan0_map_count; i++) {
130 diff = abs(lradc->chan0_map[i].voltage - voltage);
131 if (diff < closest) {
132 closest = diff;
133 keycode = lradc->chan0_map[i].keycode;
134 }
135 }
136
137 lradc->chan0_keycode = keycode;
138 input_report_key(lradc->input, lradc->chan0_keycode, 1);
139 }
140
141 input_sync(lradc->input);
142
143 writel(ints, lradc->base + LRADC_INTS);
144
145 return IRQ_HANDLED;
146}
147
148static int sun4i_lradc_open(struct input_dev *dev)
149{
150 struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
151 int error;
152
153 error = regulator_enable(lradc->vref_supply);
154 if (error)
155 return error;
156
157 error = reset_control_deassert(lradc->reset);
158 if (error)
159 goto err_disable_reg;
160
161 error = clk_prepare_enable(lradc->clk);
162 if (error)
163 goto err_assert_reset;
164
165 lradc->vref = regulator_get_voltage(lradc->vref_supply) *
166 lradc->variant->divisor_numerator /
167 lradc->variant->divisor_denominator;
168 /*
169 * Set sample time to 4 ms / 250 Hz. Wait 2 * 4 ms for key to
170 * stabilize on press, wait (1 + 1) * 4 ms for key release
171 */
172 writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
173 SAMPLE_RATE(0) | ENABLE(1), lradc->base + LRADC_CTRL);
174
175 writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);
176
177 return 0;
178
179err_assert_reset:
180 reset_control_assert(lradc->reset);
181err_disable_reg:
182 regulator_disable(lradc->vref_supply);
183
184 return error;
185}
186
187static void sun4i_lradc_close(struct input_dev *dev)
188{
189 struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
190
191 /* Disable lradc, leave other settings unchanged */
192 writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
193 SAMPLE_RATE(2), lradc->base + LRADC_CTRL);
194 writel(0, lradc->base + LRADC_INTC);
195
196 clk_disable_unprepare(lradc->clk);
197 reset_control_assert(lradc->reset);
198 regulator_disable(lradc->vref_supply);
199}
200
201static int sun4i_lradc_load_dt_keymap(struct device *dev,
202 struct sun4i_lradc_data *lradc)
203{
204 struct device_node *np, *pp;
205 int i;
206 int error;
207
208 np = dev->of_node;
209 if (!np)
210 return -EINVAL;
211
212 lradc->chan0_map_count = of_get_child_count(np);
213 if (lradc->chan0_map_count == 0) {
214 dev_err(dev, "keymap is missing in device tree\n");
215 return -EINVAL;
216 }
217
218 lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count,
219 sizeof(struct sun4i_lradc_keymap),
220 GFP_KERNEL);
221 if (!lradc->chan0_map)
222 return -ENOMEM;
223
224 i = 0;
225 for_each_child_of_node(np, pp) {
226 struct sun4i_lradc_keymap *map = &lradc->chan0_map[i];
227 u32 channel;
228
229 error = of_property_read_u32(pp, "channel", &channel);
230 if (error || channel != 0) {
231 dev_err(dev, "%pOFn: Inval channel prop\n", pp);
232 of_node_put(pp);
233 return -EINVAL;
234 }
235
236 error = of_property_read_u32(pp, "voltage", &map->voltage);
237 if (error) {
238 dev_err(dev, "%pOFn: Inval voltage prop\n", pp);
239 of_node_put(pp);
240 return -EINVAL;
241 }
242
243 error = of_property_read_u32(pp, "linux,code", &map->keycode);
244 if (error) {
245 dev_err(dev, "%pOFn: Inval linux,code prop\n", pp);
246 of_node_put(pp);
247 return -EINVAL;
248 }
249
250 i++;
251 }
252
253 return 0;
254}
255
256static int sun4i_lradc_probe(struct platform_device *pdev)
257{
258 struct sun4i_lradc_data *lradc;
259 struct device *dev = &pdev->dev;
260 int error, i, irq;
261
262 lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
263 if (!lradc)
264 return -ENOMEM;
265
266 error = sun4i_lradc_load_dt_keymap(dev, lradc);
267 if (error)
268 return error;
269
270 lradc->variant = of_device_get_match_data(&pdev->dev);
271 if (!lradc->variant) {
272 dev_err(&pdev->dev, "Missing sun4i-a10-lradc-keys variant\n");
273 return -EINVAL;
274 }
275
276 if (lradc->variant->has_clock_reset) {
277 lradc->clk = devm_clk_get(dev, NULL);
278 if (IS_ERR(lradc->clk))
279 return PTR_ERR(lradc->clk);
280
281 lradc->reset = devm_reset_control_get_exclusive(dev, NULL);
282 if (IS_ERR(lradc->reset))
283 return PTR_ERR(lradc->reset);
284 }
285
286 lradc->vref_supply = devm_regulator_get(dev, "vref");
287 if (IS_ERR(lradc->vref_supply))
288 return PTR_ERR(lradc->vref_supply);
289
290 lradc->dev = dev;
291 lradc->input = devm_input_allocate_device(dev);
292 if (!lradc->input)
293 return -ENOMEM;
294
295 lradc->input->name = pdev->name;
296 lradc->input->phys = "sun4i_lradc/input0";
297 lradc->input->open = sun4i_lradc_open;
298 lradc->input->close = sun4i_lradc_close;
299 lradc->input->id.bustype = BUS_HOST;
300 lradc->input->id.vendor = 0x0001;
301 lradc->input->id.product = 0x0001;
302 lradc->input->id.version = 0x0100;
303
304 __set_bit(EV_KEY, lradc->input->evbit);
305 for (i = 0; i < lradc->chan0_map_count; i++)
306 __set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit);
307
308 input_set_drvdata(lradc->input, lradc);
309
310 lradc->base = devm_ioremap_resource(dev,
311 platform_get_resource(pdev, IORESOURCE_MEM, 0));
312 if (IS_ERR(lradc->base))
313 return PTR_ERR(lradc->base);
314
315 irq = platform_get_irq(pdev, 0);
316 if (irq < 0)
317 return irq;
318
319 error = devm_request_irq(dev, irq, sun4i_lradc_irq, 0,
320 "sun4i-a10-lradc-keys", lradc);
321 if (error)
322 return error;
323
324 error = input_register_device(lradc->input);
325 if (error)
326 return error;
327
328 if (device_property_read_bool(dev, "wakeup-source")) {
329 error = dev_pm_set_wake_irq(dev, irq);
330 if (error)
331 dev_warn(dev,
332 "Failed to set IRQ %d as a wake IRQ: %d\n",
333 irq, error);
334 else
335 device_set_wakeup_capable(dev, true);
336 }
337
338 return 0;
339}
340
341static const struct of_device_id sun4i_lradc_of_match[] = {
342 { .compatible = "allwinner,sun4i-a10-lradc-keys",
343 .data = &lradc_variant_a10 },
344 { .compatible = "allwinner,sun8i-a83t-r-lradc",
345 .data = &r_lradc_variant_a83t },
346 { .compatible = "allwinner,sun50i-r329-lradc",
347 .data = &lradc_variant_r329 },
348 { /* sentinel */ }
349};
350MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
351
352static struct platform_driver sun4i_lradc_driver = {
353 .driver = {
354 .name = "sun4i-a10-lradc-keys",
355 .of_match_table = of_match_ptr(sun4i_lradc_of_match),
356 },
357 .probe = sun4i_lradc_probe,
358};
359
360module_platform_driver(sun4i_lradc_driver);
361
362MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver");
363MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
364MODULE_LICENSE("GPL");
1/*
2 * Allwinner sun4i low res adc attached tablet keys driver
3 *
4 * Copyright (C) 2014 Hans de Goede <hdegoede@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17/*
18 * Allwinnner sunxi SoCs have a lradc which is specifically designed to have
19 * various (tablet) keys (ie home, back, search, etc). attached to it using
20 * a resistor network. This driver is for the keys on such boards.
21 *
22 * There are 2 channels, currently this driver only supports channel 0 since
23 * there are no boards known to use channel 1.
24 */
25
26#include <linux/err.h>
27#include <linux/init.h>
28#include <linux/input.h>
29#include <linux/interrupt.h>
30#include <linux/io.h>
31#include <linux/module.h>
32#include <linux/of_platform.h>
33#include <linux/platform_device.h>
34#include <linux/regulator/consumer.h>
35#include <linux/slab.h>
36
37#define LRADC_CTRL 0x00
38#define LRADC_INTC 0x04
39#define LRADC_INTS 0x08
40#define LRADC_DATA0 0x0c
41#define LRADC_DATA1 0x10
42
43/* LRADC_CTRL bits */
44#define FIRST_CONVERT_DLY(x) ((x) << 24) /* 8 bits */
45#define CHAN_SELECT(x) ((x) << 22) /* 2 bits */
46#define CONTINUE_TIME_SEL(x) ((x) << 16) /* 4 bits */
47#define KEY_MODE_SEL(x) ((x) << 12) /* 2 bits */
48#define LEVELA_B_CNT(x) ((x) << 8) /* 4 bits */
49#define HOLD_EN(x) ((x) << 6)
50#define LEVELB_VOL(x) ((x) << 4) /* 2 bits */
51#define SAMPLE_RATE(x) ((x) << 2) /* 2 bits */
52#define ENABLE(x) ((x) << 0)
53
54/* LRADC_INTC and LRADC_INTS bits */
55#define CHAN1_KEYUP_IRQ BIT(12)
56#define CHAN1_ALRDY_HOLD_IRQ BIT(11)
57#define CHAN1_HOLD_IRQ BIT(10)
58#define CHAN1_KEYDOWN_IRQ BIT(9)
59#define CHAN1_DATA_IRQ BIT(8)
60#define CHAN0_KEYUP_IRQ BIT(4)
61#define CHAN0_ALRDY_HOLD_IRQ BIT(3)
62#define CHAN0_HOLD_IRQ BIT(2)
63#define CHAN0_KEYDOWN_IRQ BIT(1)
64#define CHAN0_DATA_IRQ BIT(0)
65
66struct sun4i_lradc_keymap {
67 u32 voltage;
68 u32 keycode;
69};
70
71struct sun4i_lradc_data {
72 struct device *dev;
73 struct input_dev *input;
74 void __iomem *base;
75 struct regulator *vref_supply;
76 struct sun4i_lradc_keymap *chan0_map;
77 u32 chan0_map_count;
78 u32 chan0_keycode;
79 u32 vref;
80};
81
82static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
83{
84 struct sun4i_lradc_data *lradc = dev_id;
85 u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;
86
87 ints = readl(lradc->base + LRADC_INTS);
88
89 /*
90 * lradc supports only one keypress at a time, release does not give
91 * any info as to which key was released, so we cache the keycode.
92 */
93
94 if (ints & CHAN0_KEYUP_IRQ) {
95 input_report_key(lradc->input, lradc->chan0_keycode, 0);
96 lradc->chan0_keycode = 0;
97 }
98
99 if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
100 val = readl(lradc->base + LRADC_DATA0) & 0x3f;
101 voltage = val * lradc->vref / 63;
102
103 for (i = 0; i < lradc->chan0_map_count; i++) {
104 diff = abs(lradc->chan0_map[i].voltage - voltage);
105 if (diff < closest) {
106 closest = diff;
107 keycode = lradc->chan0_map[i].keycode;
108 }
109 }
110
111 lradc->chan0_keycode = keycode;
112 input_report_key(lradc->input, lradc->chan0_keycode, 1);
113 }
114
115 input_sync(lradc->input);
116
117 writel(ints, lradc->base + LRADC_INTS);
118
119 return IRQ_HANDLED;
120}
121
122static int sun4i_lradc_open(struct input_dev *dev)
123{
124 struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
125 int error;
126
127 error = regulator_enable(lradc->vref_supply);
128 if (error)
129 return error;
130
131 /* lradc Vref internally is divided by 2/3 */
132 lradc->vref = regulator_get_voltage(lradc->vref_supply) * 2 / 3;
133
134 /*
135 * Set sample time to 4 ms / 250 Hz. Wait 2 * 4 ms for key to
136 * stabilize on press, wait (1 + 1) * 4 ms for key release
137 */
138 writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
139 SAMPLE_RATE(0) | ENABLE(1), lradc->base + LRADC_CTRL);
140
141 writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);
142
143 return 0;
144}
145
146static void sun4i_lradc_close(struct input_dev *dev)
147{
148 struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
149
150 /* Disable lradc, leave other settings unchanged */
151 writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
152 SAMPLE_RATE(2), lradc->base + LRADC_CTRL);
153 writel(0, lradc->base + LRADC_INTC);
154
155 regulator_disable(lradc->vref_supply);
156}
157
158static int sun4i_lradc_load_dt_keymap(struct device *dev,
159 struct sun4i_lradc_data *lradc)
160{
161 struct device_node *np, *pp;
162 int i;
163 int error;
164
165 np = dev->of_node;
166 if (!np)
167 return -EINVAL;
168
169 lradc->chan0_map_count = of_get_child_count(np);
170 if (lradc->chan0_map_count == 0) {
171 dev_err(dev, "keymap is missing in device tree\n");
172 return -EINVAL;
173 }
174
175 lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count,
176 sizeof(struct sun4i_lradc_keymap),
177 GFP_KERNEL);
178 if (!lradc->chan0_map)
179 return -ENOMEM;
180
181 i = 0;
182 for_each_child_of_node(np, pp) {
183 struct sun4i_lradc_keymap *map = &lradc->chan0_map[i];
184 u32 channel;
185
186 error = of_property_read_u32(pp, "channel", &channel);
187 if (error || channel != 0) {
188 dev_err(dev, "%s: Inval channel prop\n", pp->name);
189 return -EINVAL;
190 }
191
192 error = of_property_read_u32(pp, "voltage", &map->voltage);
193 if (error) {
194 dev_err(dev, "%s: Inval voltage prop\n", pp->name);
195 return -EINVAL;
196 }
197
198 error = of_property_read_u32(pp, "linux,code", &map->keycode);
199 if (error) {
200 dev_err(dev, "%s: Inval linux,code prop\n", pp->name);
201 return -EINVAL;
202 }
203
204 i++;
205 }
206
207 return 0;
208}
209
210static int sun4i_lradc_probe(struct platform_device *pdev)
211{
212 struct sun4i_lradc_data *lradc;
213 struct device *dev = &pdev->dev;
214 int i;
215 int error;
216
217 lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
218 if (!lradc)
219 return -ENOMEM;
220
221 error = sun4i_lradc_load_dt_keymap(dev, lradc);
222 if (error)
223 return error;
224
225 lradc->vref_supply = devm_regulator_get(dev, "vref");
226 if (IS_ERR(lradc->vref_supply))
227 return PTR_ERR(lradc->vref_supply);
228
229 lradc->dev = dev;
230 lradc->input = devm_input_allocate_device(dev);
231 if (!lradc->input)
232 return -ENOMEM;
233
234 lradc->input->name = pdev->name;
235 lradc->input->phys = "sun4i_lradc/input0";
236 lradc->input->open = sun4i_lradc_open;
237 lradc->input->close = sun4i_lradc_close;
238 lradc->input->id.bustype = BUS_HOST;
239 lradc->input->id.vendor = 0x0001;
240 lradc->input->id.product = 0x0001;
241 lradc->input->id.version = 0x0100;
242
243 __set_bit(EV_KEY, lradc->input->evbit);
244 for (i = 0; i < lradc->chan0_map_count; i++)
245 __set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit);
246
247 input_set_drvdata(lradc->input, lradc);
248
249 lradc->base = devm_ioremap_resource(dev,
250 platform_get_resource(pdev, IORESOURCE_MEM, 0));
251 if (IS_ERR(lradc->base))
252 return PTR_ERR(lradc->base);
253
254 error = devm_request_irq(dev, platform_get_irq(pdev, 0),
255 sun4i_lradc_irq, 0,
256 "sun4i-a10-lradc-keys", lradc);
257 if (error)
258 return error;
259
260 error = input_register_device(lradc->input);
261 if (error)
262 return error;
263
264 platform_set_drvdata(pdev, lradc);
265 return 0;
266}
267
268static const struct of_device_id sun4i_lradc_of_match[] = {
269 { .compatible = "allwinner,sun4i-a10-lradc-keys", },
270 { /* sentinel */ }
271};
272MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
273
274static struct platform_driver sun4i_lradc_driver = {
275 .driver = {
276 .name = "sun4i-a10-lradc-keys",
277 .of_match_table = of_match_ptr(sun4i_lradc_of_match),
278 },
279 .probe = sun4i_lradc_probe,
280};
281
282module_platform_driver(sun4i_lradc_driver);
283
284MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver");
285MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
286MODULE_LICENSE("GPL");