1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2013 Aeroflex Gaisler 4 * 5 * This driver supports the APBPS2 PS/2 core available in the GRLIB 6 * VHDL IP core library. 7 * 8 * Full documentation of the APBPS2 core can be found here: 9 * http://www.gaisler.com/products/grlib/grip.pdf 10 * 11 * See "Documentation/devicetree/bindings/input/ps2keyb-mouse-apbps2.txt" for 12 * information on open firmware properties. 13 * 14 * Contributors: Daniel Hellstrom <daniel@gaisler.com> 15 */ 16 #include <linux/platform_device.h> 17 #include <linux/of_device.h> 18 #include <linux/module.h> 19 #include <linux/serio.h> 20 #include <linux/errno.h> 21 #include <linux/interrupt.h> 22 #include <linux/of_irq.h> 23 #include <linux/device.h> 24 #include <linux/delay.h> 25 #include <linux/err.h> 26 #include <linux/slab.h> 27 #include <linux/string.h> 28 #include <linux/kernel.h> 29 #include <linux/io.h> 30 31 struct apbps2_regs { 32 u32 __iomem data; /* 0x00 */ 33 u32 __iomem status; /* 0x04 */ 34 u32 __iomem ctrl; /* 0x08 */ 35 u32 __iomem reload; /* 0x0c */ 36 }; 37 38 #define APBPS2_STATUS_DR (1<<0) 39 #define APBPS2_STATUS_PE (1<<1) 40 #define APBPS2_STATUS_FE (1<<2) 41 #define APBPS2_STATUS_KI (1<<3) 42 #define APBPS2_STATUS_RF (1<<4) 43 #define APBPS2_STATUS_TF (1<<5) 44 #define APBPS2_STATUS_TCNT (0x1f<<22) 45 #define APBPS2_STATUS_RCNT (0x1f<<27) 46 47 #define APBPS2_CTRL_RE (1<<0) 48 #define APBPS2_CTRL_TE (1<<1) 49 #define APBPS2_CTRL_RI (1<<2) 50 #define APBPS2_CTRL_TI (1<<3) 51 52 struct apbps2_priv { 53 struct serio *io; 54 struct apbps2_regs __iomem *regs; 55 }; 56 57 static int apbps2_idx; 58 59 static irqreturn_t apbps2_isr(int irq, void *dev_id) 60 { 61 struct apbps2_priv *priv = dev_id; 62 unsigned long status, data, rxflags; 63 irqreturn_t ret = IRQ_NONE; 64 65 while ((status = ioread32be(&priv->regs->status)) & APBPS2_STATUS_DR) { 66 data = ioread32be(&priv->regs->data); 67 rxflags = (status & APBPS2_STATUS_PE) ? SERIO_PARITY : 0; 68 rxflags |= (status & APBPS2_STATUS_FE) ? SERIO_FRAME : 0; 69 70 /* clear error bits? */ 71 if (rxflags) 72 iowrite32be(0, &priv->regs->status); 73 74 serio_interrupt(priv->io, data, rxflags); 75 76 ret = IRQ_HANDLED; 77 } 78 79 return ret; 80 } 81 82 static int apbps2_write(struct serio *io, unsigned char val) 83 { 84 struct apbps2_priv *priv = io->port_data; 85 unsigned int tleft = 10000; /* timeout in 100ms */ 86 87 /* delay until PS/2 controller has room for more chars */ 88 while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) && tleft--) 89 udelay(10); 90 91 if ((ioread32be(&priv->regs->status) & APBPS2_STATUS_TF) == 0) { 92 iowrite32be(val, &priv->regs->data); 93 94 iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI | APBPS2_CTRL_TE, 95 &priv->regs->ctrl); 96 return 0; 97 } 98 99 return -ETIMEDOUT; 100 } 101 102 static int apbps2_open(struct serio *io) 103 { 104 struct apbps2_priv *priv = io->port_data; 105 int limit; 106 107 /* clear error flags */ 108 iowrite32be(0, &priv->regs->status); 109 110 /* Clear old data if available (unlikely) */ 111 limit = 1024; 112 while ((ioread32be(&priv->regs->status) & APBPS2_STATUS_DR) && --limit) 113 ioread32be(&priv->regs->data); 114 115 /* Enable reciever and it's interrupt */ 116 iowrite32be(APBPS2_CTRL_RE | APBPS2_CTRL_RI, &priv->regs->ctrl); 117 118 return 0; 119 } 120 121 static void apbps2_close(struct serio *io) 122 { 123 struct apbps2_priv *priv = io->port_data; 124 125 /* stop interrupts at PS/2 HW level */ 126 iowrite32be(0, &priv->regs->ctrl); 127 } 128 129 /* Initialize one APBPS2 PS/2 core */ 130 static int apbps2_of_probe(struct platform_device *ofdev) 131 { 132 struct apbps2_priv *priv; 133 int irq, err; 134 u32 freq_hz; 135 136 priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL); 137 if (!priv) { 138 dev_err(&ofdev->dev, "memory allocation failed\n"); 139 return -ENOMEM; 140 } 141 142 /* Find Device Address */ 143 priv->regs = devm_platform_get_and_ioremap_resource(ofdev, 0, NULL); 144 if (IS_ERR(priv->regs)) 145 return PTR_ERR(priv->regs); 146 147 /* Reset hardware, disable interrupt */ 148 iowrite32be(0, &priv->regs->ctrl); 149 150 /* IRQ */ 151 irq = irq_of_parse_and_map(ofdev->dev.of_node, 0); 152 err = devm_request_irq(&ofdev->dev, irq, apbps2_isr, 153 IRQF_SHARED, "apbps2", priv); 154 if (err) { 155 dev_err(&ofdev->dev, "request IRQ%d failed\n", irq); 156 return err; 157 } 158 159 /* Get core frequency */ 160 if (of_property_read_u32(ofdev->dev.of_node, "freq", &freq_hz)) { 161 dev_err(&ofdev->dev, "unable to get core frequency\n"); 162 return -EINVAL; 163 } 164 165 /* Set reload register to core freq in kHz/10 */ 166 iowrite32be(freq_hz / 10000, &priv->regs->reload); 167 168 priv->io = kzalloc(sizeof(struct serio), GFP_KERNEL); 169 if (!priv->io) 170 return -ENOMEM; 171 172 priv->io->id.type = SERIO_8042; 173 priv->io->open = apbps2_open; 174 priv->io->close = apbps2_close; 175 priv->io->write = apbps2_write; 176 priv->io->port_data = priv; 177 strscpy(priv->io->name, "APBPS2 PS/2", sizeof(priv->io->name)); 178 snprintf(priv->io->phys, sizeof(priv->io->phys), 179 "apbps2_%d", apbps2_idx++); 180 181 dev_info(&ofdev->dev, "irq = %d, base = 0x%p\n", irq, priv->regs); 182 183 serio_register_port(priv->io); 184 185 platform_set_drvdata(ofdev, priv); 186 187 return 0; 188 } 189 190 static int apbps2_of_remove(struct platform_device *of_dev) 191 { 192 struct apbps2_priv *priv = platform_get_drvdata(of_dev); 193 194 serio_unregister_port(priv->io); 195 196 return 0; 197 } 198 199 static const struct of_device_id apbps2_of_match[] = { 200 { .name = "GAISLER_APBPS2", }, 201 { .name = "01_060", }, 202 {} 203 }; 204 205 MODULE_DEVICE_TABLE(of, apbps2_of_match); 206 207 static struct platform_driver apbps2_of_driver = { 208 .driver = { 209 .name = "grlib-apbps2", 210 .of_match_table = apbps2_of_match, 211 }, 212 .probe = apbps2_of_probe, 213 .remove = apbps2_of_remove, 214 }; 215 216 module_platform_driver(apbps2_of_driver); 217 218 MODULE_AUTHOR("Aeroflex Gaisler AB."); 219 MODULE_DESCRIPTION("GRLIB APBPS2 PS/2 serial I/O"); 220 MODULE_LICENSE("GPL"); 221