linux-stable/drivers/pcmcia/max1600.c
Russell King bebdf98a78 pcmcia: add MAX1600 library
Add a library for the MAX1600 PCMCIA power switch device.  This is a
dual-channel device, controlled via four GPIO signals per channel.
Two signals control the Vcc output, and two control the Vpp output.

Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2018-12-04 22:37:38 +00:00

122 lines
2.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* MAX1600 PCMCIA power switch library
*
* Copyright (C) 2016 Russell King
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/gpio/consumer.h>
#include <linux/slab.h>
#include "max1600.h"
static const char *max1600_gpio_name[2][MAX1600_GPIO_MAX] = {
{ "a0vcc", "a1vcc", "a0vpp", "a1vpp" },
{ "b0vcc", "b1vcc", "b0vpp", "b1vpp" },
};
int max1600_init(struct device *dev, struct max1600 **ptr,
unsigned int channel, unsigned int code)
{
struct max1600 *m;
int chan;
int i;
switch (channel) {
case MAX1600_CHAN_A:
chan = 0;
break;
case MAX1600_CHAN_B:
chan = 1;
break;
default:
return -EINVAL;
}
if (code != MAX1600_CODE_LOW && code != MAX1600_CODE_HIGH)
return -EINVAL;
m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL);
if (!m)
return -ENOMEM;
m->dev = dev;
m->code = code;
for (i = 0; i < MAX1600_GPIO_MAX; i++) {
const char *name;
name = max1600_gpio_name[chan][i];
if (i != MAX1600_GPIO_0VPP) {
m->gpio[i] = devm_gpiod_get(dev, name, GPIOD_OUT_LOW);
} else {
m->gpio[i] = devm_gpiod_get_optional(dev, name,
GPIOD_OUT_LOW);
if (!m->gpio[i])
break;
}
if (IS_ERR(m->gpio[i]))
return PTR_ERR(m->gpio[i]);
}
*ptr = m;
return 0;
}
EXPORT_SYMBOL_GPL(max1600_init);
int max1600_configure(struct max1600 *m, unsigned int vcc, unsigned int vpp)
{
DECLARE_BITMAP(values, MAX1600_GPIO_MAX) = { 0, };
int n = MAX1600_GPIO_0VPP;
if (m->gpio[MAX1600_GPIO_0VPP]) {
if (vpp == 0) {
__assign_bit(MAX1600_GPIO_0VPP, values, 0);
__assign_bit(MAX1600_GPIO_1VPP, values, 0);
} else if (vpp == 120) {
__assign_bit(MAX1600_GPIO_0VPP, values, 0);
__assign_bit(MAX1600_GPIO_1VPP, values, 1);
} else if (vpp == vcc) {
__assign_bit(MAX1600_GPIO_0VPP, values, 1);
__assign_bit(MAX1600_GPIO_1VPP, values, 0);
} else {
dev_err(m->dev, "unrecognised Vpp %u.%uV\n",
vpp / 10, vpp % 10);
return -EINVAL;
}
n = MAX1600_GPIO_MAX;
} else if (vpp != vcc && vpp != 0) {
dev_err(m->dev, "no VPP control\n");
return -EINVAL;
}
if (vcc == 0) {
__assign_bit(MAX1600_GPIO_0VCC, values, 0);
__assign_bit(MAX1600_GPIO_1VCC, values, 0);
} else if (vcc == 33) { /* VY */
__assign_bit(MAX1600_GPIO_0VCC, values, 1);
__assign_bit(MAX1600_GPIO_1VCC, values, 0);
} else if (vcc == 50) { /* VX */
__assign_bit(MAX1600_GPIO_0VCC, values, 0);
__assign_bit(MAX1600_GPIO_1VCC, values, 1);
} else {
dev_err(m->dev, "unrecognised Vcc %u.%uV\n",
vcc / 10, vcc % 10);
return -EINVAL;
}
if (m->code == MAX1600_CODE_HIGH) {
/*
* Cirrus mode appears to be the same as Intel mode,
* except the VCC pins are inverted.
*/
__change_bit(MAX1600_GPIO_0VCC, values);
__change_bit(MAX1600_GPIO_1VCC, values);
}
return gpiod_set_array_value_cansleep(n, m->gpio, NULL, values);
}
EXPORT_SYMBOL_GPL(max1600_configure);
MODULE_LICENSE("GPL v2");