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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");
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.h>
25#include <linux/platform_device.h>
26#include <linux/pm_wakeirq.h>
27#include <linux/pm_wakeup.h>
28#include <linux/property.h>
29#include <linux/regulator/consumer.h>
30#include <linux/reset.h>
31#include <linux/slab.h>
32
33#define LRADC_CTRL 0x00
34#define LRADC_INTC 0x04
35#define LRADC_INTS 0x08
36#define LRADC_DATA0 0x0c
37#define LRADC_DATA1 0x10
38
39/* LRADC_CTRL bits */
40#define FIRST_CONVERT_DLY(x) ((x) << 24) /* 8 bits */
41#define CHAN_SELECT(x) ((x) << 22) /* 2 bits */
42#define CONTINUE_TIME_SEL(x) ((x) << 16) /* 4 bits */
43#define KEY_MODE_SEL(x) ((x) << 12) /* 2 bits */
44#define LEVELA_B_CNT(x) ((x) << 8) /* 4 bits */
45#define HOLD_KEY_EN(x) ((x) << 7)
46#define HOLD_EN(x) ((x) << 6)
47#define LEVELB_VOL(x) ((x) << 4) /* 2 bits */
48#define SAMPLE_RATE(x) ((x) << 2) /* 2 bits */
49#define ENABLE(x) ((x) << 0)
50
51/* LRADC_INTC and LRADC_INTS bits */
52#define CHAN1_KEYUP_IRQ BIT(12)
53#define CHAN1_ALRDY_HOLD_IRQ BIT(11)
54#define CHAN1_HOLD_IRQ BIT(10)
55#define CHAN1_KEYDOWN_IRQ BIT(9)
56#define CHAN1_DATA_IRQ BIT(8)
57#define CHAN0_KEYUP_IRQ BIT(4)
58#define CHAN0_ALRDY_HOLD_IRQ BIT(3)
59#define CHAN0_HOLD_IRQ BIT(2)
60#define CHAN0_KEYDOWN_IRQ BIT(1)
61#define CHAN0_DATA_IRQ BIT(0)
62
63/* struct lradc_variant - Describe sun4i-a10-lradc-keys hardware variant
64 * @divisor_numerator: The numerator of lradc Vref internally divisor
65 * @divisor_denominator: The denominator of lradc Vref internally divisor
66 * @has_clock_reset: If the binding requires a clock and reset
67 */
68struct lradc_variant {
69 u8 divisor_numerator;
70 u8 divisor_denominator;
71 bool has_clock_reset;
72};
73
74static const struct lradc_variant lradc_variant_a10 = {
75 .divisor_numerator = 2,
76 .divisor_denominator = 3
77};
78
79static const struct lradc_variant r_lradc_variant_a83t = {
80 .divisor_numerator = 3,
81 .divisor_denominator = 4
82};
83
84static const struct lradc_variant lradc_variant_r329 = {
85 .divisor_numerator = 3,
86 .divisor_denominator = 4,
87 .has_clock_reset = true,
88};
89
90struct sun4i_lradc_keymap {
91 u32 voltage;
92 u32 keycode;
93};
94
95struct sun4i_lradc_data {
96 struct device *dev;
97 struct input_dev *input;
98 void __iomem *base;
99 struct clk *clk;
100 struct reset_control *reset;
101 struct regulator *vref_supply;
102 struct sun4i_lradc_keymap *chan0_map;
103 const struct lradc_variant *variant;
104 u32 chan0_map_count;
105 u32 chan0_keycode;
106 u32 vref;
107};
108
109static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
110{
111 struct sun4i_lradc_data *lradc = dev_id;
112 u32 i, ints, val, voltage, diff, keycode = 0, closest = 0xffffffff;
113
114 ints = readl(lradc->base + LRADC_INTS);
115
116 /*
117 * lradc supports only one keypress at a time, release does not give
118 * any info as to which key was released, so we cache the keycode.
119 */
120
121 if (ints & CHAN0_KEYUP_IRQ) {
122 input_report_key(lradc->input, lradc->chan0_keycode, 0);
123 lradc->chan0_keycode = 0;
124 }
125
126 if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
127 val = readl(lradc->base + LRADC_DATA0) & 0x3f;
128 voltage = val * lradc->vref / 63;
129
130 for (i = 0; i < lradc->chan0_map_count; i++) {
131 diff = abs(lradc->chan0_map[i].voltage - voltage);
132 if (diff < closest) {
133 closest = diff;
134 keycode = lradc->chan0_map[i].keycode;
135 }
136 }
137
138 lradc->chan0_keycode = keycode;
139 input_report_key(lradc->input, lradc->chan0_keycode, 1);
140 }
141
142 input_sync(lradc->input);
143
144 writel(ints, lradc->base + LRADC_INTS);
145
146 return IRQ_HANDLED;
147}
148
149static int sun4i_lradc_open(struct input_dev *dev)
150{
151 struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
152 int error;
153
154 error = regulator_enable(lradc->vref_supply);
155 if (error)
156 return error;
157
158 error = reset_control_deassert(lradc->reset);
159 if (error)
160 goto err_disable_reg;
161
162 error = clk_prepare_enable(lradc->clk);
163 if (error)
164 goto err_assert_reset;
165
166 lradc->vref = regulator_get_voltage(lradc->vref_supply) *
167 lradc->variant->divisor_numerator /
168 lradc->variant->divisor_denominator;
169 /*
170 * Set sample time to 4 ms / 250 Hz. Wait 2 * 4 ms for key to
171 * stabilize on press, wait (1 + 1) * 4 ms for key release
172 */
173 writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
174 SAMPLE_RATE(0) | ENABLE(1), lradc->base + LRADC_CTRL);
175
176 writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);
177
178 return 0;
179
180err_assert_reset:
181 reset_control_assert(lradc->reset);
182err_disable_reg:
183 regulator_disable(lradc->vref_supply);
184
185 return error;
186}
187
188static void sun4i_lradc_close(struct input_dev *dev)
189{
190 struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
191
192 /* Disable lradc, leave other settings unchanged */
193 writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
194 SAMPLE_RATE(2), lradc->base + LRADC_CTRL);
195 writel(0, lradc->base + LRADC_INTC);
196
197 clk_disable_unprepare(lradc->clk);
198 reset_control_assert(lradc->reset);
199 regulator_disable(lradc->vref_supply);
200}
201
202static int sun4i_lradc_load_dt_keymap(struct device *dev,
203 struct sun4i_lradc_data *lradc)
204{
205 struct device_node *np, *pp;
206 int i;
207 int error;
208
209 np = dev->of_node;
210 if (!np)
211 return -EINVAL;
212
213 lradc->chan0_map_count = of_get_child_count(np);
214 if (lradc->chan0_map_count == 0) {
215 dev_err(dev, "keymap is missing in device tree\n");
216 return -EINVAL;
217 }
218
219 lradc->chan0_map = devm_kmalloc_array(dev, lradc->chan0_map_count,
220 sizeof(struct sun4i_lradc_keymap),
221 GFP_KERNEL);
222 if (!lradc->chan0_map)
223 return -ENOMEM;
224
225 i = 0;
226 for_each_child_of_node(np, pp) {
227 struct sun4i_lradc_keymap *map = &lradc->chan0_map[i];
228 u32 channel;
229
230 error = of_property_read_u32(pp, "channel", &channel);
231 if (error || channel != 0) {
232 dev_err(dev, "%pOFn: Inval channel prop\n", pp);
233 of_node_put(pp);
234 return -EINVAL;
235 }
236
237 error = of_property_read_u32(pp, "voltage", &map->voltage);
238 if (error) {
239 dev_err(dev, "%pOFn: Inval voltage prop\n", pp);
240 of_node_put(pp);
241 return -EINVAL;
242 }
243
244 error = of_property_read_u32(pp, "linux,code", &map->keycode);
245 if (error) {
246 dev_err(dev, "%pOFn: Inval linux,code prop\n", pp);
247 of_node_put(pp);
248 return -EINVAL;
249 }
250
251 i++;
252 }
253
254 return 0;
255}
256
257static int sun4i_lradc_probe(struct platform_device *pdev)
258{
259 struct sun4i_lradc_data *lradc;
260 struct device *dev = &pdev->dev;
261 int error, i, irq;
262
263 lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
264 if (!lradc)
265 return -ENOMEM;
266
267 error = sun4i_lradc_load_dt_keymap(dev, lradc);
268 if (error)
269 return error;
270
271 lradc->variant = of_device_get_match_data(&pdev->dev);
272 if (!lradc->variant) {
273 dev_err(&pdev->dev, "Missing sun4i-a10-lradc-keys variant\n");
274 return -EINVAL;
275 }
276
277 if (lradc->variant->has_clock_reset) {
278 lradc->clk = devm_clk_get(dev, NULL);
279 if (IS_ERR(lradc->clk))
280 return PTR_ERR(lradc->clk);
281
282 lradc->reset = devm_reset_control_get_exclusive(dev, NULL);
283 if (IS_ERR(lradc->reset))
284 return PTR_ERR(lradc->reset);
285 }
286
287 lradc->vref_supply = devm_regulator_get(dev, "vref");
288 if (IS_ERR(lradc->vref_supply))
289 return PTR_ERR(lradc->vref_supply);
290
291 lradc->dev = dev;
292 lradc->input = devm_input_allocate_device(dev);
293 if (!lradc->input)
294 return -ENOMEM;
295
296 lradc->input->name = pdev->name;
297 lradc->input->phys = "sun4i_lradc/input0";
298 lradc->input->open = sun4i_lradc_open;
299 lradc->input->close = sun4i_lradc_close;
300 lradc->input->id.bustype = BUS_HOST;
301 lradc->input->id.vendor = 0x0001;
302 lradc->input->id.product = 0x0001;
303 lradc->input->id.version = 0x0100;
304
305 __set_bit(EV_KEY, lradc->input->evbit);
306 for (i = 0; i < lradc->chan0_map_count; i++)
307 __set_bit(lradc->chan0_map[i].keycode, lradc->input->keybit);
308
309 input_set_drvdata(lradc->input, lradc);
310
311 lradc->base = devm_platform_ioremap_resource(pdev, 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");