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bebdf98a78
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>
123 lines
2.8 KiB
C
123 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* MAX1600 PCMCIA power switch library
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*
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* Copyright (C) 2016 Russell King
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*/
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/gpio/consumer.h>
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#include <linux/slab.h>
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#include "max1600.h"
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static const char *max1600_gpio_name[2][MAX1600_GPIO_MAX] = {
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{ "a0vcc", "a1vcc", "a0vpp", "a1vpp" },
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{ "b0vcc", "b1vcc", "b0vpp", "b1vpp" },
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};
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int max1600_init(struct device *dev, struct max1600 **ptr,
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unsigned int channel, unsigned int code)
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{
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struct max1600 *m;
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int chan;
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int i;
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switch (channel) {
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case MAX1600_CHAN_A:
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chan = 0;
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break;
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case MAX1600_CHAN_B:
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chan = 1;
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break;
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default:
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return -EINVAL;
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}
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if (code != MAX1600_CODE_LOW && code != MAX1600_CODE_HIGH)
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return -EINVAL;
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m = devm_kzalloc(dev, sizeof(*m), GFP_KERNEL);
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if (!m)
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return -ENOMEM;
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m->dev = dev;
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m->code = code;
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for (i = 0; i < MAX1600_GPIO_MAX; i++) {
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const char *name;
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name = max1600_gpio_name[chan][i];
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if (i != MAX1600_GPIO_0VPP) {
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m->gpio[i] = devm_gpiod_get(dev, name, GPIOD_OUT_LOW);
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} else {
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m->gpio[i] = devm_gpiod_get_optional(dev, name,
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GPIOD_OUT_LOW);
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if (!m->gpio[i])
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break;
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}
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if (IS_ERR(m->gpio[i]))
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return PTR_ERR(m->gpio[i]);
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}
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*ptr = m;
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return 0;
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}
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EXPORT_SYMBOL_GPL(max1600_init);
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int max1600_configure(struct max1600 *m, unsigned int vcc, unsigned int vpp)
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{
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DECLARE_BITMAP(values, MAX1600_GPIO_MAX) = { 0, };
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int n = MAX1600_GPIO_0VPP;
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if (m->gpio[MAX1600_GPIO_0VPP]) {
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if (vpp == 0) {
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__assign_bit(MAX1600_GPIO_0VPP, values, 0);
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__assign_bit(MAX1600_GPIO_1VPP, values, 0);
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} else if (vpp == 120) {
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__assign_bit(MAX1600_GPIO_0VPP, values, 0);
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__assign_bit(MAX1600_GPIO_1VPP, values, 1);
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} else if (vpp == vcc) {
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__assign_bit(MAX1600_GPIO_0VPP, values, 1);
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__assign_bit(MAX1600_GPIO_1VPP, values, 0);
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} else {
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dev_err(m->dev, "unrecognised Vpp %u.%uV\n",
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vpp / 10, vpp % 10);
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return -EINVAL;
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}
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n = MAX1600_GPIO_MAX;
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} else if (vpp != vcc && vpp != 0) {
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dev_err(m->dev, "no VPP control\n");
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return -EINVAL;
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}
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if (vcc == 0) {
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__assign_bit(MAX1600_GPIO_0VCC, values, 0);
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__assign_bit(MAX1600_GPIO_1VCC, values, 0);
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} else if (vcc == 33) { /* VY */
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__assign_bit(MAX1600_GPIO_0VCC, values, 1);
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__assign_bit(MAX1600_GPIO_1VCC, values, 0);
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} else if (vcc == 50) { /* VX */
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__assign_bit(MAX1600_GPIO_0VCC, values, 0);
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__assign_bit(MAX1600_GPIO_1VCC, values, 1);
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} else {
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dev_err(m->dev, "unrecognised Vcc %u.%uV\n",
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vcc / 10, vcc % 10);
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return -EINVAL;
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}
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if (m->code == MAX1600_CODE_HIGH) {
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/*
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* Cirrus mode appears to be the same as Intel mode,
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* except the VCC pins are inverted.
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*/
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__change_bit(MAX1600_GPIO_0VCC, values);
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__change_bit(MAX1600_GPIO_1VCC, values);
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}
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return gpiod_set_array_value_cansleep(n, m->gpio, NULL, values);
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}
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EXPORT_SYMBOL_GPL(max1600_configure);
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MODULE_LICENSE("GPL v2");
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