drivers/pcmcia/max1600.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * MAX1600 PCMCIA power switch library
   4  *
   5  * Copyright (C) 2016 Russell King
   6  */
   7 #include <linux/device.h>
   8 #include <linux/module.h>
   9 #include <linux/gpio/consumer.h>
  10 #include <linux/slab.h>
  11 #include "max1600.h"
  12
  13 static const char *max1600_gpio_name[2][MAX1600_GPIO_MAX] = {
  14         { "a0vcc", "a1vcc", "a0vpp", "a1vpp" },
  15         { "b0vcc", "b1vcc", "b0vpp", "b1vpp" },
  16 };
  17
  18 int max1600_init(struct device *dev, struct max1600 **ptr,
  19         unsigned int channel, unsigned int code)
  20 {
  21         struct max1600 *m;
  22         int chan;
  23         int i;
  24
  25         switch (channel) {
  26         case MAX1600_CHAN_A:
  27                 chan = 0;
  28                 break;
  29         case MAX1600_CHAN_B:
  30                 chan = 1;
  31                 break;
  32         default:
  33                 return -EINVAL;
  34         }
  35
  36         if (code != MAX1600_CODE_LOW && code != MAX1600_CODE_HIGH)
  37                 return -EINVAL;
  38
  39         m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL);
  40         if (!m)
  41                 return -ENOMEM;
  42
  43         m->dev = dev;
  44         m->code = code;
  45
  46         for (i = 0; i < MAX1600_GPIO_MAX; i++) {
  47                 const char *name;
  48
  49                 name = max1600_gpio_name[chan][i];
  50                 if (i != MAX1600_GPIO_0VPP) {
  51                         m->gpio[i] = devm_gpiod_get(dev, name, GPIOD_OUT_LOW);
  52                 } else {
  53                         m->gpio[i] = devm_gpiod_get_optional(dev, name,
  54                                                              GPIOD_OUT_LOW);
  55                         if (!m->gpio[i])
  56                                 break;
  57                 }
  58                 if (IS_ERR(m->gpio[i]))
  59                         return PTR_ERR(m->gpio[i]);
  60         }
  61
  62         *ptr = m;
  63
  64         return 0;
  65 }
  66 EXPORT_SYMBOL_GPL(max1600_init);
  67
  68 int max1600_configure(struct max1600 *m, unsigned int vcc, unsigned int vpp)
  69 {
  70         DECLARE_BITMAP(values, MAX1600_GPIO_MAX) = { 0, };
  71         int n = MAX1600_GPIO_0VPP;
  72
  73         if (m->gpio[MAX1600_GPIO_0VPP]) {
  74                 if (vpp == 0) {
  75                         __assign_bit(MAX1600_GPIO_0VPP, values, 0);
  76                         __assign_bit(MAX1600_GPIO_1VPP, values, 0);
  77                 } else if (vpp == 120) {
  78                         __assign_bit(MAX1600_GPIO_0VPP, values, 0);
  79                         __assign_bit(MAX1600_GPIO_1VPP, values, 1);
  80                 } else if (vpp == vcc) {
  81                         __assign_bit(MAX1600_GPIO_0VPP, values, 1);
  82                         __assign_bit(MAX1600_GPIO_1VPP, values, 0);
  83                 } else {
  84                         dev_err(m->dev, "unrecognised Vpp %u.%uV\n",
  85                                 vpp / 10, vpp % 10);
  86                         return -EINVAL;
  87                 }
  88                 n = MAX1600_GPIO_MAX;
  89         } else if (vpp != vcc && vpp != 0) {
  90                 dev_err(m->dev, "no VPP control\n");
  91                 return -EINVAL;
  92         }
  93
  94         if (vcc == 0) {
  95                 __assign_bit(MAX1600_GPIO_0VCC, values, 0);
  96                 __assign_bit(MAX1600_GPIO_1VCC, values, 0);
  97         } else if (vcc == 33) { /* VY */
  98                 __assign_bit(MAX1600_GPIO_0VCC, values, 1);
  99                 __assign_bit(MAX1600_GPIO_1VCC, values, 0);
 100         } else if (vcc == 50) { /* VX */
 101                 __assign_bit(MAX1600_GPIO_0VCC, values, 0);
 102                 __assign_bit(MAX1600_GPIO_1VCC, values, 1);
 103         } else {
 104                 dev_err(m->dev, "unrecognised Vcc %u.%uV\n",
 105                         vcc / 10, vcc % 10);
 106                 return -EINVAL;
 107         }
 108
 109         if (m->code == MAX1600_CODE_HIGH) {
 110                 /*
 111                  * Cirrus mode appears to be the same as Intel mode,
 112                  * except the VCC pins are inverted.
 113                  */
 114                 __change_bit(MAX1600_GPIO_0VCC, values);
 115                 __change_bit(MAX1600_GPIO_1VCC, values);
 116         }
 117
 118         return gpiod_set_array_value_cansleep(n, m->gpio, NULL, values);
 119 }
 120 EXPORT_SYMBOL_GPL(max1600_configure);
 121
 122 MODULE_LICENSE("GPL v2");