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 unsigned int irq;
61
62 u32 matrix_sz; /* Size of matrix in XxY, ie. 3 = 3x3 */
63 u32 deb_clks; /* Debounce clocks (based on 32KHz clock) */
64 u32 scan_delay; /* Scan delay (based on 32KHz clock) */
65
66 unsigned short *keymap; /* Pointer to key map for the scan matrix */
67 unsigned int row_shift;
68
69 u8 lastkeystates[8];
70 };
71
lpc32xx_mod_states(struct lpc32xx_kscan_drv * kscandat,int col)72 static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col)
73 {
74 struct input_dev *input = kscandat->input;
75 unsigned row, changed, scancode, keycode;
76 u8 key;
77
78 key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col));
79 changed = key ^ kscandat->lastkeystates[col];
80 kscandat->lastkeystates[col] = key;
81
82 for (row = 0; changed; row++, changed >>= 1) {
83 if (changed & 1) {
84 /* Key state changed, signal an event */
85 scancode = MATRIX_SCAN_CODE(row, col,
86 kscandat->row_shift);
87 keycode = kscandat->keymap[scancode];
88 input_event(input, EV_MSC, MSC_SCAN, scancode);
89 input_report_key(input, keycode, key & (1 << row));
90 }
91 }
92 }
93
lpc32xx_kscan_irq(int irq,void * dev_id)94 static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id)
95 {
96 struct lpc32xx_kscan_drv *kscandat = dev_id;
97 int i;
98
99 for (i = 0; i < kscandat->matrix_sz; i++)
100 lpc32xx_mod_states(kscandat, i);
101
102 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
103
104 input_sync(kscandat->input);
105
106 return IRQ_HANDLED;
107 }
108
lpc32xx_kscan_open(struct input_dev * dev)109 static int lpc32xx_kscan_open(struct input_dev *dev)
110 {
111 struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
112 int error;
113
114 error = clk_prepare_enable(kscandat->clk);
115 if (error)
116 return error;
117
118 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
119
120 return 0;
121 }
122
lpc32xx_kscan_close(struct input_dev * dev)123 static void lpc32xx_kscan_close(struct input_dev *dev)
124 {
125 struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
126
127 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
128 clk_disable_unprepare(kscandat->clk);
129 }
130
lpc32xx_parse_dt(struct device * dev,struct lpc32xx_kscan_drv * kscandat)131 static int lpc32xx_parse_dt(struct device *dev,
132 struct lpc32xx_kscan_drv *kscandat)
133 {
134 struct device_node *np = dev->of_node;
135 u32 rows = 0, columns = 0;
136 int err;
137
138 err = matrix_keypad_parse_properties(dev, &rows, &columns);
139 if (err)
140 return err;
141 if (rows != columns) {
142 dev_err(dev, "rows and columns must be equal!\n");
143 return -EINVAL;
144 }
145
146 kscandat->matrix_sz = rows;
147 kscandat->row_shift = get_count_order(columns);
148
149 of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks);
150 of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay);
151 if (!kscandat->deb_clks || !kscandat->scan_delay) {
152 dev_err(dev, "debounce or scan delay not specified\n");
153 return -EINVAL;
154 }
155
156 return 0;
157 }
158
lpc32xx_kscan_probe(struct platform_device * pdev)159 static int lpc32xx_kscan_probe(struct platform_device *pdev)
160 {
161 struct lpc32xx_kscan_drv *kscandat;
162 struct input_dev *input;
163 size_t keymap_size;
164 int error;
165 int irq;
166
167 irq = platform_get_irq(pdev, 0);
168 if (irq < 0)
169 return -EINVAL;
170
171 kscandat = devm_kzalloc(&pdev->dev, sizeof(*kscandat),
172 GFP_KERNEL);
173 if (!kscandat)
174 return -ENOMEM;
175
176 error = lpc32xx_parse_dt(&pdev->dev, kscandat);
177 if (error) {
178 dev_err(&pdev->dev, "failed to parse device tree\n");
179 return error;
180 }
181
182 keymap_size = sizeof(kscandat->keymap[0]) *
183 (kscandat->matrix_sz << kscandat->row_shift);
184 kscandat->keymap = devm_kzalloc(&pdev->dev, keymap_size, GFP_KERNEL);
185 if (!kscandat->keymap)
186 return -ENOMEM;
187
188 kscandat->input = input = devm_input_allocate_device(&pdev->dev);
189 if (!input) {
190 dev_err(&pdev->dev, "failed to allocate input device\n");
191 return -ENOMEM;
192 }
193
194 /* Setup key input */
195 input->name = pdev->name;
196 input->phys = "lpc32xx/input0";
197 input->id.vendor = 0x0001;
198 input->id.product = 0x0001;
199 input->id.version = 0x0100;
200 input->open = lpc32xx_kscan_open;
201 input->close = lpc32xx_kscan_close;
202 input->dev.parent = &pdev->dev;
203
204 input_set_capability(input, EV_MSC, MSC_SCAN);
205
206 error = matrix_keypad_build_keymap(NULL, NULL,
207 kscandat->matrix_sz,
208 kscandat->matrix_sz,
209 kscandat->keymap, kscandat->input);
210 if (error) {
211 dev_err(&pdev->dev, "failed to build keymap\n");
212 return error;
213 }
214
215 input_set_drvdata(kscandat->input, kscandat);
216
217 kscandat->kscan_base = devm_platform_ioremap_resource(pdev, 0);
218 if (IS_ERR(kscandat->kscan_base))
219 return PTR_ERR(kscandat->kscan_base);
220
221 /* Get the key scanner clock */
222 kscandat->clk = devm_clk_get(&pdev->dev, NULL);
223 if (IS_ERR(kscandat->clk)) {
224 dev_err(&pdev->dev, "failed to get clock\n");
225 return PTR_ERR(kscandat->clk);
226 }
227
228 /* Configure the key scanner */
229 error = clk_prepare_enable(kscandat->clk);
230 if (error)
231 return error;
232
233 writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base));
234 writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base));
235 writel(LPC32XX_KSCAN_FTST_USE32K_CLK,
236 LPC32XX_KS_FAST_TST(kscandat->kscan_base));
237 writel(kscandat->matrix_sz,
238 LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base));
239 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
240 clk_disable_unprepare(kscandat->clk);
241
242 error = devm_request_irq(&pdev->dev, irq, lpc32xx_kscan_irq, 0,
243 pdev->name, kscandat);
244 if (error) {
245 dev_err(&pdev->dev, "failed to request irq\n");
246 return error;
247 }
248
249 error = input_register_device(kscandat->input);
250 if (error) {
251 dev_err(&pdev->dev, "failed to register input device\n");
252 return error;
253 }
254
255 platform_set_drvdata(pdev, kscandat);
256
257 return 0;
258 }
259
lpc32xx_kscan_suspend(struct device * dev)260 static int lpc32xx_kscan_suspend(struct device *dev)
261 {
262 struct platform_device *pdev = to_platform_device(dev);
263 struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
264 struct input_dev *input = kscandat->input;
265
266 mutex_lock(&input->mutex);
267
268 if (input_device_enabled(input)) {
269 /* Clear IRQ and disable clock */
270 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
271 clk_disable_unprepare(kscandat->clk);
272 }
273
274 mutex_unlock(&input->mutex);
275 return 0;
276 }
277
lpc32xx_kscan_resume(struct device * dev)278 static int lpc32xx_kscan_resume(struct device *dev)
279 {
280 struct platform_device *pdev = to_platform_device(dev);
281 struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
282 struct input_dev *input = kscandat->input;
283 int retval = 0;
284
285 mutex_lock(&input->mutex);
286
287 if (input_device_enabled(input)) {
288 /* Enable clock and clear IRQ */
289 retval = clk_prepare_enable(kscandat->clk);
290 if (retval == 0)
291 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
292 }
293
294 mutex_unlock(&input->mutex);
295 return retval;
296 }
297
298 static DEFINE_SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
299 lpc32xx_kscan_resume);
300
301 static const struct of_device_id lpc32xx_kscan_match[] = {
302 { .compatible = "nxp,lpc3220-key" },
303 {},
304 };
305 MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
306
307 static struct platform_driver lpc32xx_kscan_driver = {
308 .probe = lpc32xx_kscan_probe,
309 .driver = {
310 .name = DRV_NAME,
311 .pm = pm_sleep_ptr(&lpc32xx_kscan_pm_ops),
312 .of_match_table = lpc32xx_kscan_match,
313 }
314 };
315
316 module_platform_driver(lpc32xx_kscan_driver);
317
318 MODULE_LICENSE("GPL");
319 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
320 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
321 MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");
322