1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au> 4 */ 5 6 #include <linux/input/matrix_keypad.h> 7 #include <linux/platform_device.h> 8 #include <linux/interrupt.h> 9 #include <linux/io.h> 10 #include <linux/delay.h> 11 #include <linux/input.h> 12 #include <linux/slab.h> 13 #include <linux/clk.h> 14 #include <linux/module.h> 15 #include <linux/of.h> 16 17 #define KEYPAD_SCAN_MODE 0x00 18 #define KEYPAD_CNTL 0x04 19 #define KEYPAD_INT 0x08 20 #define KEYPAD_INTMSK 0x0C 21 22 #define KEYPAD_DATA 0x10 23 #define KEYPAD_GPIO 0x30 24 25 #define KEYPAD_UNKNOWN_INT 0x40 26 #define KEYPAD_UNKNOWN_INT_STS 0x44 27 28 #define KEYPAD_BITMASK_COLS 11 29 #define KEYPAD_BITMASK_ROWS 8 30 31 struct nspire_keypad { 32 void __iomem *reg_base; 33 u32 int_mask; 34 35 struct input_dev *input; 36 struct clk *clk; 37 38 struct matrix_keymap_data *keymap; 39 int row_shift; 40 41 /* Maximum delay estimated assuming 33MHz APB */ 42 u32 scan_interval; /* In microseconds (~2000us max) */ 43 u32 row_delay; /* In microseconds (~500us max) */ 44 45 u16 state[KEYPAD_BITMASK_ROWS]; 46 47 bool active_low; 48 }; 49 50 static irqreturn_t nspire_keypad_irq(int irq, void *dev_id) 51 { 52 struct nspire_keypad *keypad = dev_id; 53 struct input_dev *input = keypad->input; 54 unsigned short *keymap = input->keycode; 55 unsigned int code; 56 int row, col; 57 u32 int_sts; 58 u16 state[8]; 59 u16 bits, changed; 60 61 int_sts = readl(keypad->reg_base + KEYPAD_INT) & keypad->int_mask; 62 if (!int_sts) 63 return IRQ_NONE; 64 65 memcpy_fromio(state, keypad->reg_base + KEYPAD_DATA, sizeof(state)); 66 67 for (row = 0; row < KEYPAD_BITMASK_ROWS; row++) { 68 bits = state[row]; 69 if (keypad->active_low) 70 bits = ~bits; 71 72 changed = bits ^ keypad->state[row]; 73 if (!changed) 74 continue; 75 76 keypad->state[row] = bits; 77 78 for (col = 0; col < KEYPAD_BITMASK_COLS; col++) { 79 if (!(changed & (1U << col))) 80 continue; 81 82 code = MATRIX_SCAN_CODE(row, col, keypad->row_shift); 83 input_event(input, EV_MSC, MSC_SCAN, code); 84 input_report_key(input, keymap[code], 85 bits & (1U << col)); 86 } 87 } 88 89 input_sync(input); 90 91 writel(0x3, keypad->reg_base + KEYPAD_INT); 92 93 return IRQ_HANDLED; 94 } 95 96 static int nspire_keypad_chip_init(struct nspire_keypad *keypad) 97 { 98 unsigned long val = 0, cycles_per_us, delay_cycles, row_delay_cycles; 99 100 cycles_per_us = (clk_get_rate(keypad->clk) / 1000000); 101 if (cycles_per_us == 0) 102 cycles_per_us = 1; 103 104 delay_cycles = cycles_per_us * keypad->scan_interval; 105 WARN_ON(delay_cycles >= (1 << 16)); /* Overflow */ 106 delay_cycles &= 0xffff; 107 108 row_delay_cycles = cycles_per_us * keypad->row_delay; 109 WARN_ON(row_delay_cycles >= (1 << 14)); /* Overflow */ 110 row_delay_cycles &= 0x3fff; 111 112 val |= 3 << 0; /* Set scan mode to 3 (continuous scan) */ 113 val |= row_delay_cycles << 2; /* Delay between scanning each row */ 114 val |= delay_cycles << 16; /* Delay between scans */ 115 writel(val, keypad->reg_base + KEYPAD_SCAN_MODE); 116 117 val = (KEYPAD_BITMASK_ROWS & 0xff) | (KEYPAD_BITMASK_COLS & 0xff)<<8; 118 writel(val, keypad->reg_base + KEYPAD_CNTL); 119 120 /* Enable interrupts */ 121 keypad->int_mask = 1 << 1; 122 writel(keypad->int_mask, keypad->reg_base + KEYPAD_INTMSK); 123 124 /* Disable GPIO interrupts to prevent hanging on touchpad */ 125 /* Possibly used to detect touchpad events */ 126 writel(0, keypad->reg_base + KEYPAD_UNKNOWN_INT); 127 /* Acknowledge existing interrupts */ 128 writel(~0, keypad->reg_base + KEYPAD_UNKNOWN_INT_STS); 129 130 return 0; 131 } 132 133 static int nspire_keypad_open(struct input_dev *input) 134 { 135 struct nspire_keypad *keypad = input_get_drvdata(input); 136 int error; 137 138 error = clk_prepare_enable(keypad->clk); 139 if (error) 140 return error; 141 142 error = nspire_keypad_chip_init(keypad); 143 if (error) { 144 clk_disable_unprepare(keypad->clk); 145 return error; 146 } 147 148 return 0; 149 } 150 151 static void nspire_keypad_close(struct input_dev *input) 152 { 153 struct nspire_keypad *keypad = input_get_drvdata(input); 154 155 clk_disable_unprepare(keypad->clk); 156 } 157 158 static int nspire_keypad_probe(struct platform_device *pdev) 159 { 160 const struct device_node *of_node = pdev->dev.of_node; 161 struct nspire_keypad *keypad; 162 struct input_dev *input; 163 struct resource *res; 164 int irq; 165 int error; 166 167 irq = platform_get_irq(pdev, 0); 168 if (irq < 0) 169 return -EINVAL; 170 171 keypad = devm_kzalloc(&pdev->dev, sizeof(struct nspire_keypad), 172 GFP_KERNEL); 173 if (!keypad) { 174 dev_err(&pdev->dev, "failed to allocate keypad memory\n"); 175 return -ENOMEM; 176 } 177 178 keypad->row_shift = get_count_order(KEYPAD_BITMASK_COLS); 179 180 error = of_property_read_u32(of_node, "scan-interval", 181 &keypad->scan_interval); 182 if (error) { 183 dev_err(&pdev->dev, "failed to get scan-interval\n"); 184 return error; 185 } 186 187 error = of_property_read_u32(of_node, "row-delay", 188 &keypad->row_delay); 189 if (error) { 190 dev_err(&pdev->dev, "failed to get row-delay\n"); 191 return error; 192 } 193 194 keypad->active_low = of_property_read_bool(of_node, "active-low"); 195 196 keypad->clk = devm_clk_get(&pdev->dev, NULL); 197 if (IS_ERR(keypad->clk)) { 198 dev_err(&pdev->dev, "unable to get clock\n"); 199 return PTR_ERR(keypad->clk); 200 } 201 202 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 203 keypad->reg_base = devm_ioremap_resource(&pdev->dev, res); 204 if (IS_ERR(keypad->reg_base)) 205 return PTR_ERR(keypad->reg_base); 206 207 keypad->input = input = devm_input_allocate_device(&pdev->dev); 208 if (!input) { 209 dev_err(&pdev->dev, "failed to allocate input device\n"); 210 return -ENOMEM; 211 } 212 213 input_set_drvdata(input, keypad); 214 215 input->id.bustype = BUS_HOST; 216 input->name = "nspire-keypad"; 217 input->open = nspire_keypad_open; 218 input->close = nspire_keypad_close; 219 220 __set_bit(EV_KEY, input->evbit); 221 __set_bit(EV_REP, input->evbit); 222 input_set_capability(input, EV_MSC, MSC_SCAN); 223 224 error = matrix_keypad_build_keymap(NULL, NULL, 225 KEYPAD_BITMASK_ROWS, 226 KEYPAD_BITMASK_COLS, 227 NULL, input); 228 if (error) { 229 dev_err(&pdev->dev, "building keymap failed\n"); 230 return error; 231 } 232 233 error = devm_request_irq(&pdev->dev, irq, nspire_keypad_irq, 0, 234 "nspire_keypad", keypad); 235 if (error) { 236 dev_err(&pdev->dev, "allocate irq %d failed\n", irq); 237 return error; 238 } 239 240 error = input_register_device(input); 241 if (error) { 242 dev_err(&pdev->dev, 243 "unable to register input device: %d\n", error); 244 return error; 245 } 246 247 dev_dbg(&pdev->dev, 248 "TI-NSPIRE keypad at %pR (scan_interval=%uus, row_delay=%uus%s)\n", 249 res, keypad->row_delay, keypad->scan_interval, 250 keypad->active_low ? ", active_low" : ""); 251 252 return 0; 253 } 254 255 static const struct of_device_id nspire_keypad_dt_match[] = { 256 { .compatible = "ti,nspire-keypad" }, 257 { }, 258 }; 259 MODULE_DEVICE_TABLE(of, nspire_keypad_dt_match); 260 261 static struct platform_driver nspire_keypad_driver = { 262 .driver = { 263 .name = "nspire-keypad", 264 .of_match_table = nspire_keypad_dt_match, 265 }, 266 .probe = nspire_keypad_probe, 267 }; 268 269 module_platform_driver(nspire_keypad_driver); 270 271 MODULE_LICENSE("GPL"); 272 MODULE_DESCRIPTION("TI-NSPIRE Keypad Driver"); 273