1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * STMicroelectronics Key Scanning driver
  4 *
  5 * Copyright (c) 2014 STMicroelectonics Ltd.
  6 * Author: Stuart Menefy <stuart.menefy@st.com>
  7 *
  8 * Based on sh_keysc.c, copyright 2008 Magnus Damm
  9 */
 10
 11#include <linux/module.h>
 12#include <linux/interrupt.h>
 13#include <linux/platform_device.h>
 14#include <linux/clk.h>
 15#include <linux/io.h>
 16#include <linux/input/matrix_keypad.h>
 17
 18#define ST_KEYSCAN_MAXKEYS 16
 19
 20#define KEYSCAN_CONFIG_OFF		0x0
 21#define KEYSCAN_CONFIG_ENABLE		0x1
 22#define KEYSCAN_DEBOUNCE_TIME_OFF	0x4
 23#define KEYSCAN_MATRIX_STATE_OFF	0x8
 24#define KEYSCAN_MATRIX_DIM_OFF		0xc
 25#define KEYSCAN_MATRIX_DIM_X_SHIFT	0x0
 26#define KEYSCAN_MATRIX_DIM_Y_SHIFT	0x2
 27
 28struct st_keyscan {
 29	void __iomem *base;
 30	int irq;
 31	struct clk *clk;
 32	struct input_dev *input_dev;
 33	unsigned long last_state;
 34	unsigned int n_rows;
 35	unsigned int n_cols;
 36	unsigned int debounce_us;
 37};
 38
 39static irqreturn_t keyscan_isr(int irq, void *dev_id)
 40{
 41	struct st_keyscan *keypad = dev_id;
 42	unsigned short *keycode = keypad->input_dev->keycode;
 43	unsigned long state, change;
 44	int bit_nr;
 45
 46	state = readl(keypad->base + KEYSCAN_MATRIX_STATE_OFF) & 0xffff;
 47	change = keypad->last_state ^ state;
 48	keypad->last_state = state;
 49
 50	for_each_set_bit(bit_nr, &change, BITS_PER_LONG)
 51		input_report_key(keypad->input_dev,
 52				 keycode[bit_nr], state & BIT(bit_nr));
 53
 54	input_sync(keypad->input_dev);
 55
 56	return IRQ_HANDLED;
 57}
 58
 59static int keyscan_start(struct st_keyscan *keypad)
 60{
 61	int error;
 62
 63	error = clk_enable(keypad->clk);
 64	if (error)
 65		return error;
 66
 67	writel(keypad->debounce_us * (clk_get_rate(keypad->clk) / 1000000),
 68	       keypad->base + KEYSCAN_DEBOUNCE_TIME_OFF);
 69
 70	writel(((keypad->n_cols - 1) << KEYSCAN_MATRIX_DIM_X_SHIFT) |
 71	       ((keypad->n_rows - 1) << KEYSCAN_MATRIX_DIM_Y_SHIFT),
 72	       keypad->base + KEYSCAN_MATRIX_DIM_OFF);
 73
 74	writel(KEYSCAN_CONFIG_ENABLE, keypad->base + KEYSCAN_CONFIG_OFF);
 75
 76	return 0;
 77}
 78
 79static void keyscan_stop(struct st_keyscan *keypad)
 80{
 81	writel(0, keypad->base + KEYSCAN_CONFIG_OFF);
 82
 83	clk_disable(keypad->clk);
 84}
 85
 86static int keyscan_open(struct input_dev *dev)
 87{
 88	struct st_keyscan *keypad = input_get_drvdata(dev);
 89
 90	return keyscan_start(keypad);
 91}
 92
 93static void keyscan_close(struct input_dev *dev)
 94{
 95	struct st_keyscan *keypad = input_get_drvdata(dev);
 96
 97	keyscan_stop(keypad);
 98}
 99
100static int keypad_matrix_key_parse_dt(struct st_keyscan *keypad_data)
101{
102	struct device *dev = keypad_data->input_dev->dev.parent;
103	struct device_node *np = dev->of_node;
104	int error;
105
106	error = matrix_keypad_parse_properties(dev, &keypad_data->n_rows,
107					       &keypad_data->n_cols);
108	if (error) {
109		dev_err(dev, "failed to parse keypad params\n");
110		return error;
111	}
112
113	of_property_read_u32(np, "st,debounce-us", &keypad_data->debounce_us);
114
115	dev_dbg(dev, "n_rows=%d n_col=%d debounce=%d\n",
116		keypad_data->n_rows, keypad_data->n_cols,
117		keypad_data->debounce_us);
118
119	return 0;
120}
121
122static int keyscan_probe(struct platform_device *pdev)
123{
124	struct st_keyscan *keypad_data;
125	struct input_dev *input_dev;
126	struct resource *res;
127	int error;
128
129	if (!pdev->dev.of_node) {
130		dev_err(&pdev->dev, "no DT data present\n");
131		return -EINVAL;
132	}
133
134	keypad_data = devm_kzalloc(&pdev->dev, sizeof(*keypad_data),
135				   GFP_KERNEL);
136	if (!keypad_data)
137		return -ENOMEM;
138
139	input_dev = devm_input_allocate_device(&pdev->dev);
140	if (!input_dev) {
141		dev_err(&pdev->dev, "failed to allocate the input device\n");
142		return -ENOMEM;
143	}
144
145	input_dev->name = pdev->name;
146	input_dev->phys = "keyscan-keys/input0";
147	input_dev->dev.parent = &pdev->dev;
148	input_dev->open = keyscan_open;
149	input_dev->close = keyscan_close;
150
151	input_dev->id.bustype = BUS_HOST;
152
153	keypad_data->input_dev = input_dev;
154
155	error = keypad_matrix_key_parse_dt(keypad_data);
156	if (error)
157		return error;
158
159	error = matrix_keypad_build_keymap(NULL, NULL,
160					   keypad_data->n_rows,
161					   keypad_data->n_cols,
162					   NULL, input_dev);
163	if (error) {
164		dev_err(&pdev->dev, "failed to build keymap\n");
165		return error;
166	}
167
168	input_set_drvdata(input_dev, keypad_data);
169
170	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
171	keypad_data->base = devm_ioremap_resource(&pdev->dev, res);
172	if (IS_ERR(keypad_data->base))
173		return PTR_ERR(keypad_data->base);
174
175	keypad_data->clk = devm_clk_get(&pdev->dev, NULL);
176	if (IS_ERR(keypad_data->clk)) {
177		dev_err(&pdev->dev, "cannot get clock\n");
178		return PTR_ERR(keypad_data->clk);
179	}
180
181	error = clk_enable(keypad_data->clk);
182	if (error) {
183		dev_err(&pdev->dev, "failed to enable clock\n");
184		return error;
185	}
186
187	keyscan_stop(keypad_data);
188
189	keypad_data->irq = platform_get_irq(pdev, 0);
190	if (keypad_data->irq < 0)
191		return -EINVAL;
192
193	error = devm_request_irq(&pdev->dev, keypad_data->irq, keyscan_isr, 0,
194				 pdev->name, keypad_data);
195	if (error) {
196		dev_err(&pdev->dev, "failed to request IRQ\n");
197		return error;
198	}
199
200	error = input_register_device(input_dev);
201	if (error) {
202		dev_err(&pdev->dev, "failed to register input device\n");
203		return error;
204	}
205
206	platform_set_drvdata(pdev, keypad_data);
207
208	device_set_wakeup_capable(&pdev->dev, 1);
209
210	return 0;
211}
212
213#ifdef CONFIG_PM_SLEEP
214static int keyscan_suspend(struct device *dev)
215{
216	struct platform_device *pdev = to_platform_device(dev);
217	struct st_keyscan *keypad = platform_get_drvdata(pdev);
218	struct input_dev *input = keypad->input_dev;
219
220	mutex_lock(&input->mutex);
221
222	if (device_may_wakeup(dev))
223		enable_irq_wake(keypad->irq);
224	else if (input->users)
225		keyscan_stop(keypad);
226
227	mutex_unlock(&input->mutex);
228	return 0;
229}
230
231static int keyscan_resume(struct device *dev)
232{
233	struct platform_device *pdev = to_platform_device(dev);
234	struct st_keyscan *keypad = platform_get_drvdata(pdev);
235	struct input_dev *input = keypad->input_dev;
236	int retval = 0;
237
238	mutex_lock(&input->mutex);
239
240	if (device_may_wakeup(dev))
241		disable_irq_wake(keypad->irq);
242	else if (input->users)
243		retval = keyscan_start(keypad);
244
245	mutex_unlock(&input->mutex);
246	return retval;
247}
248#endif
249
250static SIMPLE_DEV_PM_OPS(keyscan_dev_pm_ops, keyscan_suspend, keyscan_resume);
251
252static const struct of_device_id keyscan_of_match[] = {
253	{ .compatible = "st,sti-keyscan" },
254	{ },
255};
256MODULE_DEVICE_TABLE(of, keyscan_of_match);
257
258static struct platform_driver keyscan_device_driver = {
259	.probe		= keyscan_probe,
260	.driver		= {
261		.name	= "st-keyscan",
262		.pm	= &keyscan_dev_pm_ops,
263		.of_match_table = of_match_ptr(keyscan_of_match),
264	}
265};
266
267module_platform_driver(keyscan_device_driver);
268
269MODULE_AUTHOR("Stuart Menefy <stuart.menefy@st.com>");
270MODULE_DESCRIPTION("STMicroelectronics keyscan device driver");
271MODULE_LICENSE("GPL");