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>

diff --git a/drivers/pcmcia/Kconfig b/drivers/pcmcia/Kconfig
index cbbe4a285b48905564ca3127efad8630ac8e13e3..1a257a323923fd3a3bd0a6a816f269c0361d394e 100644 (file)
--- a/drivers/pcmcia/Kconfig
+++ b/drivers/pcmcia/Kconfig
@@ -63,6 +63,9 @@ config CARDBUS
 
          If unsure, say Y.
 
+config PCMCIA_MAX1600
+       tristate
+
 comment "PC-card bridges"
 
 config YENTA

diff --git a/drivers/pcmcia/Makefile b/drivers/pcmcia/Makefile
index 28502bd159e07bca8ea8f215008808ab2a709753..01779c5c45f35dfd056e872d9101d13f4c3e9561 100644 (file)
--- a/drivers/pcmcia/Makefile
+++ b/drivers/pcmcia/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_OMAP_CF)                         += omap_cf.o
 obj-$(CONFIG_AT91_CF)                          += at91_cf.o
 obj-$(CONFIG_ELECTRA_CF)                       += electra_cf.o
 obj-$(CONFIG_PCMCIA_ALCHEMY_DEVBOARD)          += db1xxx_ss.o
+obj-$(CONFIG_PCMCIA_MAX1600)                   += max1600.o
 
 sa1111_cs-y                                    += sa1111_generic.o
 sa1111_cs-$(CONFIG_ASSABET_NEPONSET)           += sa1111_neponset.o

diff --git a/drivers/pcmcia/max1600.c b/drivers/pcmcia/max1600.c
new file mode 100644 (file)
index 0000000..379875a
--- /dev/null
+++ b/drivers/pcmcia/max1600.c
@@ -0,0 +1,122 @@
+// 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");

diff --git a/drivers/pcmcia/max1600.h b/drivers/pcmcia/max1600.h
new file mode 100644 (file)
index 0000000..00bf1a0
--- /dev/null
+++ b/drivers/pcmcia/max1600.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef MAX1600_H
+#define MAX1600_H
+
+struct gpio_desc;
+
+enum {
+       MAX1600_GPIO_0VCC = 0,
+       MAX1600_GPIO_1VCC,
+       MAX1600_GPIO_0VPP,
+       MAX1600_GPIO_1VPP,
+       MAX1600_GPIO_MAX,
+
+       MAX1600_CHAN_A,
+       MAX1600_CHAN_B,
+
+       MAX1600_CODE_LOW,
+       MAX1600_CODE_HIGH,
+};
+
+struct max1600 {
+       struct gpio_desc *gpio[MAX1600_GPIO_MAX];
+       struct device *dev;
+       unsigned int code;
+};
+
+int max1600_init(struct device *dev, struct max1600 **ptr,
+       unsigned int channel, unsigned int code);
+
+int max1600_configure(struct max1600 *, unsigned int vcc, unsigned int vpp);
+
+#endif