drivers/input/keyboard/st-keyscan.c

   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/clk.h>
  12 #include <linux/input.h>
  13 #include <linux/input/matrix_keypad.h>
  14 #include <linux/io.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/module.h>
  17 #include <linux/of.h>
  18 #include <linux/platform_device.h>
  19
  20 #define ST_KEYSCAN_MAXKEYS 16
  21
  22 #define KEYSCAN_CONFIG_OFF              0x0
  23 #define KEYSCAN_CONFIG_ENABLE           0x1
  24 #define KEYSCAN_DEBOUNCE_TIME_OFF       0x4
  25 #define KEYSCAN_MATRIX_STATE_OFF        0x8
  26 #define KEYSCAN_MATRIX_DIM_OFF          0xc
  27 #define KEYSCAN_MATRIX_DIM_X_SHIFT      0x0
  28 #define KEYSCAN_MATRIX_DIM_Y_SHIFT      0x2
  29
  30 struct st_keyscan {
  31         void __iomem *base;
  32         int irq;
  33         struct clk *clk;
  34         struct input_dev *input_dev;
  35         unsigned long last_state;
  36         unsigned int n_rows;
  37         unsigned int n_cols;
  38         unsigned int debounce_us;
  39 };
  40
  41 static irqreturn_t keyscan_isr(int irq, void *dev_id)
  42 {
  43         struct st_keyscan *keypad = dev_id;
  44         unsigned short *keycode = keypad->input_dev->keycode;
  45         unsigned long state, change;
  46         int bit_nr;
  47
  48         state = readl(keypad->base + KEYSCAN_MATRIX_STATE_OFF) & 0xffff;
  49         change = keypad->last_state ^ state;
  50         keypad->last_state = state;
  51
  52         for_each_set_bit(bit_nr, &change, BITS_PER_LONG)
  53                 input_report_key(keypad->input_dev,
  54                                  keycode[bit_nr], state & BIT(bit_nr));
  55
  56         input_sync(keypad->input_dev);
  57
  58         return IRQ_HANDLED;
  59 }
  60
  61 static int keyscan_start(struct st_keyscan *keypad)
  62 {
  63         int error;
  64
  65         error = clk_enable(keypad->clk);
  66         if (error)
  67                 return error;
  68
  69         writel(keypad->debounce_us * (clk_get_rate(keypad->clk) / 1000000),
  70                keypad->base + KEYSCAN_DEBOUNCE_TIME_OFF);
  71
  72         writel(((keypad->n_cols - 1) << KEYSCAN_MATRIX_DIM_X_SHIFT) |
  73                ((keypad->n_rows - 1) << KEYSCAN_MATRIX_DIM_Y_SHIFT),
  74                keypad->base + KEYSCAN_MATRIX_DIM_OFF);
  75
  76         writel(KEYSCAN_CONFIG_ENABLE, keypad->base + KEYSCAN_CONFIG_OFF);
  77
  78         return 0;
  79 }
  80
  81 static void keyscan_stop(struct st_keyscan *keypad)
  82 {
  83         writel(0, keypad->base + KEYSCAN_CONFIG_OFF);
  84
  85         clk_disable(keypad->clk);
  86 }
  87
  88 static int keyscan_open(struct input_dev *dev)
  89 {
  90         struct st_keyscan *keypad = input_get_drvdata(dev);
  91
  92         return keyscan_start(keypad);
  93 }
  94
  95 static void keyscan_close(struct input_dev *dev)
  96 {
  97         struct st_keyscan *keypad = input_get_drvdata(dev);
  98
  99         keyscan_stop(keypad);
 100 }
 101
 102 static int keypad_matrix_key_parse_dt(struct st_keyscan *keypad_data)
 103 {
 104         struct device *dev = keypad_data->input_dev->dev.parent;
 105         struct device_node *np = dev->of_node;
 106         int error;
 107
 108         error = matrix_keypad_parse_properties(dev, &keypad_data->n_rows,
 109                                                &keypad_data->n_cols);
 110         if (error) {
 111                 dev_err(dev, "failed to parse keypad params\n");
 112                 return error;
 113         }
 114
 115         of_property_read_u32(np, "st,debounce-us", &keypad_data->debounce_us);
 116
 117         dev_dbg(dev, "n_rows=%d n_col=%d debounce=%d\n",
 118                 keypad_data->n_rows, keypad_data->n_cols,
 119                 keypad_data->debounce_us);
 120
 121         return 0;
 122 }
 123
 124 static int keyscan_probe(struct platform_device *pdev)
 125 {
 126         struct st_keyscan *keypad_data;
 127         struct input_dev *input_dev;
 128         int error;
 129
 130         if (!pdev->dev.of_node) {
 131                 dev_err(&pdev->dev, "no DT data present\n");
 132                 return -EINVAL;
 133         }
 134
 135         keypad_data = devm_kzalloc(&pdev->dev, sizeof(*keypad_data),
 136                                    GFP_KERNEL);
 137         if (!keypad_data)
 138                 return -ENOMEM;
 139
 140         input_dev = devm_input_allocate_device(&pdev->dev);
 141         if (!input_dev) {
 142                 dev_err(&pdev->dev, "failed to allocate the input device\n");
 143                 return -ENOMEM;
 144         }
 145
 146         input_dev->name = pdev->name;
 147         input_dev->phys = "keyscan-keys/input0";
 148         input_dev->dev.parent = &pdev->dev;
 149         input_dev->open = keyscan_open;
 150         input_dev->close = keyscan_close;
 151
 152         input_dev->id.bustype = BUS_HOST;
 153
 154         keypad_data->input_dev = input_dev;
 155
 156         error = keypad_matrix_key_parse_dt(keypad_data);
 157         if (error)
 158                 return error;
 159
 160         error = matrix_keypad_build_keymap(NULL, NULL,
 161                                            keypad_data->n_rows,
 162                                            keypad_data->n_cols,
 163                                            NULL, input_dev);
 164         if (error) {
 165                 dev_err(&pdev->dev, "failed to build keymap\n");
 166                 return error;
 167         }
 168
 169         input_set_drvdata(input_dev, keypad_data);
 170
 171         keypad_data->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
 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 static int keyscan_suspend(struct device *dev)
 214 {
 215         struct platform_device *pdev = to_platform_device(dev);
 216         struct st_keyscan *keypad = platform_get_drvdata(pdev);
 217         struct input_dev *input = keypad->input_dev;
 218
 219         guard(mutex)(&input->mutex);
 220
 221         if (device_may_wakeup(dev))
 222                 enable_irq_wake(keypad->irq);
 223         else if (input_device_enabled(input))
 224                 keyscan_stop(keypad);
 225
 226         return 0;
 227 }
 228
 229 static int keyscan_resume(struct device *dev)
 230 {
 231         struct platform_device *pdev = to_platform_device(dev);
 232         struct st_keyscan *keypad = platform_get_drvdata(pdev);
 233         struct input_dev *input = keypad->input_dev;
 234         int error;
 235
 236         guard(mutex)(&input->mutex);
 237
 238         if (device_may_wakeup(dev)) {
 239                 disable_irq_wake(keypad->irq);
 240         } else if (input_device_enabled(input)) {
 241                 error = keyscan_start(keypad);
 242                 if (error)
 243                         return error;
 244         }
 245
 246         return 0;
 247 }
 248
 249 static DEFINE_SIMPLE_DEV_PM_OPS(keyscan_dev_pm_ops,
 250                                 keyscan_suspend, keyscan_resume);
 251
 252 static const struct of_device_id keyscan_of_match[] = {
 253         { .compatible = "st,sti-keyscan" },
 254         { },
 255 };
 256 MODULE_DEVICE_TABLE(of, keyscan_of_match);
 257
 258 static struct platform_driver keyscan_device_driver = {
 259         .probe          = keyscan_probe,
 260         .driver         = {
 261                 .name   = "st-keyscan",
 262                 .pm     = pm_sleep_ptr(&keyscan_dev_pm_ops),
 263                 .of_match_table = keyscan_of_match,
 264         }
 265 };
 266
 267 module_platform_driver(keyscan_device_driver);
 268
 269 MODULE_AUTHOR("Stuart Menefy <stuart.menefy@st.com>");
 270 MODULE_DESCRIPTION("STMicroelectronics keyscan device driver");
 271 MODULE_LICENSE("GPL");