1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * NXP LPC32xx SoC Key Scan Interface
4 *
5 * Authors:
6 * Kevin Wells <kevin.wells@nxp.com>
7 * Roland Stigge <stigge@antcom.de>
8 *
9 * Copyright (C) 2010 NXP Semiconductors
10 * Copyright (C) 2012 Roland Stigge
11 *
12 * This controller supports square key matrices from 1x1 up to 8x8
13 */
14
15 #include <linux/module.h>
16 #include <linux/interrupt.h>
17 #include <linux/slab.h>
18 #include <linux/irq.h>
19 #include <linux/pm.h>
20 #include <linux/platform_device.h>
21 #include <linux/input.h>
22 #include <linux/clk.h>
23 #include <linux/io.h>
24 #include <linux/of.h>
25 #include <linux/input/matrix_keypad.h>
26
27 #define DRV_NAME "lpc32xx_keys"
28
29 /*
30 * Key scanner register offsets
31 */
32 #define LPC32XX_KS_DEB(x) ((x) + 0x00)
33 #define LPC32XX_KS_STATE_COND(x) ((x) + 0x04)
34 #define LPC32XX_KS_IRQ(x) ((x) + 0x08)
35 #define LPC32XX_KS_SCAN_CTL(x) ((x) + 0x0C)
36 #define LPC32XX_KS_FAST_TST(x) ((x) + 0x10)
37 #define LPC32XX_KS_MATRIX_DIM(x) ((x) + 0x14) /* 1..8 */
38 #define LPC32XX_KS_DATA(x, y) ((x) + 0x40 + ((y) << 2))
39
40 #define LPC32XX_KSCAN_DEB_NUM_DEB_PASS(n) ((n) & 0xFF)
41
42 #define LPC32XX_KSCAN_SCOND_IN_IDLE 0x0
43 #define LPC32XX_KSCAN_SCOND_IN_SCANONCE 0x1
44 #define LPC32XX_KSCAN_SCOND_IN_IRQGEN 0x2
45 #define LPC32XX_KSCAN_SCOND_IN_SCAN_MATRIX 0x3
46
47 #define LPC32XX_KSCAN_IRQ_PENDING_CLR 0x1
48
49 #define LPC32XX_KSCAN_SCTRL_SCAN_DELAY(n) ((n) & 0xFF)
50
51 #define LPC32XX_KSCAN_FTST_FORCESCANONCE 0x1
52 #define LPC32XX_KSCAN_FTST_USE32K_CLK 0x2
53
54 #define LPC32XX_KSCAN_MSEL_SELECT(n) ((n) & 0xF)
55
56 struct lpc32xx_kscan_drv {
57 struct input_dev *input;
58 struct clk *clk;
59 void __iomem *kscan_base;
60
61 u32 matrix_sz; /* Size of matrix in XxY, ie. 3 = 3x3 */
62 u32 deb_clks; /* Debounce clocks (based on 32KHz clock) */
63 u32 scan_delay; /* Scan delay (based on 32KHz clock) */
64
65 unsigned int row_shift;
66 unsigned short *keymap; /* Pointer to key map for the scan matrix */
67
68 u8 lastkeystates[8];
69 };
70
lpc32xx_mod_states(struct lpc32xx_kscan_drv * kscandat,int col)71 static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col)
72 {
73 struct input_dev *input = kscandat->input;
74 unsigned row, changed, scancode, keycode;
75 u8 key;
76
77 key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col));
78 changed = key ^ kscandat->lastkeystates[col];
79 kscandat->lastkeystates[col] = key;
80
81 for (row = 0; changed; row++, changed >>= 1) {
82 if (changed & 1) {
83 /* Key state changed, signal an event */
84 scancode = MATRIX_SCAN_CODE(row, col,
85 kscandat->row_shift);
86 keycode = kscandat->keymap[scancode];
87 input_event(input, EV_MSC, MSC_SCAN, scancode);
88 input_report_key(input, keycode, key & (1 << row));
89 }
90 }
91 }
92
lpc32xx_kscan_irq(int irq,void * dev_id)93 static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id)
94 {
95 struct lpc32xx_kscan_drv *kscandat = dev_id;
96 int i;
97
98 for (i = 0; i < kscandat->matrix_sz; i++)
99 lpc32xx_mod_states(kscandat, i);
100
101 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
102
103 input_sync(kscandat->input);
104
105 return IRQ_HANDLED;
106 }
107
lpc32xx_kscan_open(struct input_dev * dev)108 static int lpc32xx_kscan_open(struct input_dev *dev)
109 {
110 struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
111 int error;
112
113 error = clk_prepare_enable(kscandat->clk);
114 if (error)
115 return error;
116
117 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
118
119 return 0;
120 }
121
lpc32xx_kscan_close(struct input_dev * dev)122 static void lpc32xx_kscan_close(struct input_dev *dev)
123 {
124 struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
125
126 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
127 clk_disable_unprepare(kscandat->clk);
128 }
129
lpc32xx_parse_dt(struct device * dev,struct lpc32xx_kscan_drv * kscandat)130 static int lpc32xx_parse_dt(struct device *dev,
131 struct lpc32xx_kscan_drv *kscandat)
132 {
133 struct device_node *np = dev->of_node;
134 u32 rows = 0, columns = 0;
135 int err;
136
137 err = matrix_keypad_parse_properties(dev, &rows, &columns);
138 if (err)
139 return err;
140 if (rows != columns) {
141 dev_err(dev, "rows and columns must be equal!\n");
142 return -EINVAL;
143 }
144
145 kscandat->matrix_sz = rows;
146 kscandat->row_shift = get_count_order(columns);
147
148 of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks);
149 of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay);
150 if (!kscandat->deb_clks || !kscandat->scan_delay) {
151 dev_err(dev, "debounce or scan delay not specified\n");
152 return -EINVAL;
153 }
154
155 return 0;
156 }
157
lpc32xx_kscan_probe(struct platform_device * pdev)158 static int lpc32xx_kscan_probe(struct platform_device *pdev)
159 {
160 struct lpc32xx_kscan_drv *kscandat;
161 struct input_dev *input;
162 size_t keymap_size;
163 int error;
164 int irq;
165
166 irq = platform_get_irq(pdev, 0);
167 if (irq < 0)
168 return -EINVAL;
169
170 kscandat = devm_kzalloc(&pdev->dev, sizeof(*kscandat),
171 GFP_KERNEL);
172 if (!kscandat)
173 return -ENOMEM;
174
175 error = lpc32xx_parse_dt(&pdev->dev, kscandat);
176 if (error) {
177 dev_err(&pdev->dev, "failed to parse device tree\n");
178 return error;
179 }
180
181 keymap_size = sizeof(kscandat->keymap[0]) *
182 (kscandat->matrix_sz << kscandat->row_shift);
183 kscandat->keymap = devm_kzalloc(&pdev->dev, keymap_size, GFP_KERNEL);
184 if (!kscandat->keymap)
185 return -ENOMEM;
186
187 kscandat->input = input = devm_input_allocate_device(&pdev->dev);
188 if (!input) {
189 dev_err(&pdev->dev, "failed to allocate input device\n");
190 return -ENOMEM;
191 }
192
193 /* Setup key input */
194 input->name = pdev->name;
195 input->phys = "lpc32xx/input0";
196 input->id.vendor = 0x0001;
197 input->id.product = 0x0001;
198 input->id.version = 0x0100;
199 input->open = lpc32xx_kscan_open;
200 input->close = lpc32xx_kscan_close;
201 input->dev.parent = &pdev->dev;
202
203 input_set_capability(input, EV_MSC, MSC_SCAN);
204
205 error = matrix_keypad_build_keymap(NULL, NULL,
206 kscandat->matrix_sz,
207 kscandat->matrix_sz,
208 kscandat->keymap, kscandat->input);
209 if (error) {
210 dev_err(&pdev->dev, "failed to build keymap\n");
211 return error;
212 }
213
214 input_set_drvdata(kscandat->input, kscandat);
215
216 kscandat->kscan_base = devm_platform_ioremap_resource(pdev, 0);
217 if (IS_ERR(kscandat->kscan_base))
218 return PTR_ERR(kscandat->kscan_base);
219
220 /* Get the key scanner clock */
221 kscandat->clk = devm_clk_get(&pdev->dev, NULL);
222 if (IS_ERR(kscandat->clk)) {
223 dev_err(&pdev->dev, "failed to get clock\n");
224 return PTR_ERR(kscandat->clk);
225 }
226
227 /* Configure the key scanner */
228 error = clk_prepare_enable(kscandat->clk);
229 if (error)
230 return error;
231
232 writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base));
233 writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base));
234 writel(LPC32XX_KSCAN_FTST_USE32K_CLK,
235 LPC32XX_KS_FAST_TST(kscandat->kscan_base));
236 writel(kscandat->matrix_sz,
237 LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base));
238 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
239 clk_disable_unprepare(kscandat->clk);
240
241 error = devm_request_irq(&pdev->dev, irq, lpc32xx_kscan_irq, 0,
242 pdev->name, kscandat);
243 if (error) {
244 dev_err(&pdev->dev, "failed to request irq\n");
245 return error;
246 }
247
248 error = input_register_device(kscandat->input);
249 if (error) {
250 dev_err(&pdev->dev, "failed to register input device\n");
251 return error;
252 }
253
254 platform_set_drvdata(pdev, kscandat);
255
256 return 0;
257 }
258
lpc32xx_kscan_suspend(struct device * dev)259 static int lpc32xx_kscan_suspend(struct device *dev)
260 {
261 struct platform_device *pdev = to_platform_device(dev);
262 struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
263 struct input_dev *input = kscandat->input;
264
265 mutex_lock(&input->mutex);
266
267 if (input_device_enabled(input)) {
268 /* Clear IRQ and disable clock */
269 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
270 clk_disable_unprepare(kscandat->clk);
271 }
272
273 mutex_unlock(&input->mutex);
274 return 0;
275 }
276
lpc32xx_kscan_resume(struct device * dev)277 static int lpc32xx_kscan_resume(struct device *dev)
278 {
279 struct platform_device *pdev = to_platform_device(dev);
280 struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
281 struct input_dev *input = kscandat->input;
282 int retval = 0;
283
284 mutex_lock(&input->mutex);
285
286 if (input_device_enabled(input)) {
287 /* Enable clock and clear IRQ */
288 retval = clk_prepare_enable(kscandat->clk);
289 if (retval == 0)
290 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
291 }
292
293 mutex_unlock(&input->mutex);
294 return retval;
295 }
296
297 static DEFINE_SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
298 lpc32xx_kscan_resume);
299
300 static const struct of_device_id lpc32xx_kscan_match[] = {
301 { .compatible = "nxp,lpc3220-key" },
302 {},
303 };
304 MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
305
306 static struct platform_driver lpc32xx_kscan_driver = {
307 .probe = lpc32xx_kscan_probe,
308 .driver = {
309 .name = DRV_NAME,
310 .pm = pm_sleep_ptr(&lpc32xx_kscan_pm_ops),
311 .of_match_table = lpc32xx_kscan_match,
312 }
313 };
314
315 module_platform_driver(lpc32xx_kscan_driver);
316
317 MODULE_LICENSE("GPL");
318 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
319 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
320 MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");
321