[PATCH v2 1/3] gpio: idio-16: Introduce the ACCES IDIO-16 GPIO library module

William Breathitt Gray
2022-09-18T19:54:21Z

Exposes consumer library functions to facilitate communication with
devices within the ACCES IDIO-16 family such as the 104-IDIO-16 and
the PCI-IDIO-16.

A CONFIG_GPIO_IDIO_16 Kconfig option is introduced by this patch.
Modules wanting access to these idio-16 library functions should select
this Kconfig option and import the GPIO_IDIO_16 symbol namespace.

Cc: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
---
MAINTAINERS | 7 ++
drivers/gpio/Kconfig | 9 +++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-idio-16.c | 146 ++++++++++++++++++++++++++++++++++++
drivers/gpio/gpio-idio-16.h | 71 ++++++++++++++++++
5 files changed, 234 insertions(+)
create mode 100644 drivers/gpio/gpio-idio-16.c
create mode 100644 drivers/gpio/gpio-idio-16.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 8a5012ba6ff9..93938b0bdb91 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -312,6 +312,13 @@ L: linux-iio@vger.kernel.org
S: Maintained
F: drivers/counter/104-quad-8.c

+ACCES IDIO-16 GPIO LIBRARY
+M: William Breathitt Gray <william.gray@linaro.org>
+L: linux-gpio@vger.kernel.org
+S: Maintained
+F: drivers/gpio/gpio-idio-16.c
+F: drivers/gpio/gpio-idio-16.h
+
ACCES PCI-IDIO-16 GPIO DRIVER
M: William Breathitt Gray <william.gray@linaro.org>
L: linux-gpio@vger.kernel.org
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index ed9e71d6713e..551351e11365 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -109,6 +109,15 @@ config GPIO_REGMAP
config GPIO_MAX730X
tristate

+config GPIO_IDIO_16
+ tristate
+ help
+ Enables support for the idio-16 library functions. The idio-16 library
+ provides functions to facilitate communication with devices within the
+ ACCES IDIO-16 family such as the 104-IDIO-16 and the PCI-IDIO-16.
+
+ If built as a module its name will be gpio-idio-16.
+
menu "Memory mapped GPIO drivers"
depends on HAS_IOMEM

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index b67e29d348cf..15abf88c167b 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_GPIO_HLWD) += gpio-hlwd.o
obj-$(CONFIG_HTC_EGPIO) += gpio-htc-egpio.o
obj-$(CONFIG_GPIO_I8255) += gpio-i8255.o
obj-$(CONFIG_GPIO_ICH) += gpio-ich.o
+obj-$(CONFIG_GPIO_IDIO_16) += gpio-idio-16.o
obj-$(CONFIG_GPIO_IDT3243X) += gpio-idt3243x.o
obj-$(CONFIG_GPIO_IMX_SCU) += gpio-imx-scu.o
obj-$(CONFIG_GPIO_IOP) += gpio-iop.o
diff --git a/drivers/gpio/gpio-idio-16.c b/drivers/gpio/gpio-idio-16.c
new file mode 100644
index 000000000000..13315242d220
--- /dev/null
+++ b/drivers/gpio/gpio-idio-16.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * GPIO library for the ACCES IDIO-16 family
+ * Copyright (C) 2022 William Breathitt Gray
+ */
+#include <linux/bitmap.h>
+#include <linux/export.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include "gpio-idio-16.h"
+
+#define DEFAULT_SYMBOL_NAMESPACE GPIO_IDIO_16
+
+/**
+ * idio_16_get - get signal value at signal offset
+ * @reg: ACCES IDIO-16 device registers
+ * @state: ACCES IDIO-16 device state
+ * @offset: offset of signal to get
+ *
+ * Returns the signal value (0=low, 1=high) for the signal at @offset.
+ */
+int idio_16_get(struct idio_16 __iomem *const reg,
+ struct idio_16_state *const state, const unsigned long offset)
+{
+ const unsigned long mask = BIT(offset);
+
+ if (offset < IDIO_16_NOUT)
+ return test_bit(offset, state->out_state);
+
+ if (offset < 24)
+ return !!(ioread8(&reg->in0_7) & (mask >> IDIO_16_NOUT));
+
+ if (offset < 32)
+ return !!(ioread8(&reg->in8_15) & (mask >> 24));
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(idio_16_get);
+
+/**
+ * idio_16_get_multiple - get multiple signal values at multiple signal offsets
+ * @reg: ACCES IDIO-16 device registers
+ * @state: ACCES IDIO-16 device state
+ * @mask: mask of signals to get
+ * @bits: bitmap to store signal values
+ *
+ * Stores in @bits the values (0=low, 1=high) for the signals defined by @mask.
+ */
+void idio_16_get_multiple(struct idio_16 __iomem *const reg,
+ struct idio_16_state *const state,
+ const unsigned long *const mask,
+ unsigned long *const bits)
+{
+ unsigned long flags;
+ const unsigned long out_mask = GENMASK(IDIO_16_NOUT - 1, 0);
+
+ spin_lock_irqsave(&state->lock, flags);
+
+ bitmap_replace(bits, bits, state->out_state, &out_mask, IDIO_16_NOUT);
+ if (*mask & GENMASK(23, 16))
+ bitmap_set_value8(bits, ioread8(&reg->in0_7), 16);
+ if (*mask & GENMASK(31, 24))
+ bitmap_set_value8(bits, ioread8(&reg->in8_15), 24);
+
+ spin_unlock_irqrestore(&state->lock, flags);
+}
+EXPORT_SYMBOL_GPL(idio_16_get_multiple);
+
+/**
+ * idio_16_set - set signal value at signal offset
+ * @reg: ACCES IDIO-16 device registers
+ * @state: ACCES IDIO-16 device state
+ * @offset: offset of signal to set
+ * @value: value of signal to set
+ *
+ * Assigns output @value for the signal at @offset.
+ */
+void idio_16_set(struct idio_16 __iomem *const reg,
+ struct idio_16_state *const state, const unsigned long offset,
+ const unsigned long value)
+{
+ unsigned long flags;
+
+ if (offset >= IDIO_16_NOUT)
+ return;
+
+ spin_lock_irqsave(&state->lock, flags);
+
+ __assign_bit(offset, state->out_state, value);
+ if (offset < 8)
+ iowrite8(bitmap_get_value8(state->out_state, 0), &reg->out0_7);
+ else
+ iowrite8(bitmap_get_value8(state->out_state, 8), &reg->out8_15);
+
+ spin_unlock_irqrestore(&state->lock, flags);
+}
+EXPORT_SYMBOL_GPL(idio_16_set);
+
+/**
+ * idio_16_set_multiple - set signal values at multiple signal offsets
+ * @reg: ACCES IDIO-16 device registers
+ * @state: ACCES IDIO-16 device state
+ * @mask: mask of signals to set
+ * @bits: bitmap of signal output values
+ *
+ * Assigns output values defined by @bits for the signals defined by @mask.
+ */
+void idio_16_set_multiple(struct idio_16 __iomem *const reg,
+ struct idio_16_state *const state,
+ const unsigned long *const mask,
+ const unsigned long *const bits)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&state->lock, flags);
+
+ bitmap_replace(state->out_state, state->out_state, bits, mask,
+ IDIO_16_NOUT);
+ if (*mask & GENMASK(7, 0))
+ iowrite8(bitmap_get_value8(state->out_state, 0), &reg->out0_7);
+ if (*mask & GENMASK(15, 8))
+ iowrite8(bitmap_get_value8(state->out_state, 8), &reg->out8_15);
+
+ spin_unlock_irqrestore(&state->lock, flags);
+}
+EXPORT_SYMBOL_GPL(idio_16_set_multiple);
+
+/**
+ * idio_16_state_init - initialize idio_16_state structure
+ * @state: ACCES IDIO-16 device state
+ *
+ * Initializes the ACCES IDIO-16 device @state for use in idio-16 library
+ * functions.
+ */
+void idio_16_state_init(struct idio_16_state *const state)
+{
+ spin_lock_init(&state->lock);
+}
+EXPORT_SYMBOL_GPL(idio_16_state_init);
+
+MODULE_AUTHOR("William Breathitt Gray");
+MODULE_DESCRIPTION("ACCES IDIO-16 GPIO Library");
+MODULE_LICENSE("GPL");
diff --git a/drivers/gpio/gpio-idio-16.h b/drivers/gpio/gpio-idio-16.h
new file mode 100644
index 000000000000..928f8251a2bd
--- /dev/null
+++ b/drivers/gpio/gpio-idio-16.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright 2022 William Breathitt Gray */
+#ifndef _IDIO_16_H_
+#define _IDIO_16_H_
+
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+/**
+ * struct idio_16 - IDIO-16 registers structure
+ * @out0_7: Read: FET Drive Outputs 0-7
+ * Write: FET Drive Outputs 0-7
+ * @in0_7: Read: Isolated Inputs 0-7
+ * Write: Clear Interrupt
+ * @irq_ctl: Read: Enable IRQ
+ * Write: Disable IRQ
+ * @filter_ctl: Read: Activate Input Filters 0-15
+ * Write: Deactivate Input Filters 0-15
+ * @out8_15: Read: FET Drive Outputs 8-15
+ * Write: FET Drive Outputs 8-15
+ * @in8_15: Read: Isolated Inputs 8-15
+ * Write: Unused
+ * @irq_status: Read: Interrupt status
+ * Write: Unused
+ */
+struct idio_16 {
+ u8 out0_7;
+ u8 in0_7;
+ u8 irq_ctl;
+ u8 filter_ctl;
+ u8 out8_15;
+ u8 in8_15;
+ u8 irq_status;
+};
+
+#define IDIO_16_NOUT 16
+
+/**
+ * struct idio_16_state - IDIO-16 state structure
+ * @lock: synchronization lock for accessing device state
+ * @out_state: output signals state
+ */
+struct idio_16_state {
+ spinlock_t lock;
+ DECLARE_BITMAP(out_state, IDIO_16_NOUT);
+};
+
+/**
+ * idio_16_get_direction - get the I/O direction for a signal offset
+ * @offset: offset of signal to get direction
+ *
+ * Returns the signal direction (0=output, 1=input) for the signal at @offset.
+ */
+static inline int idio_16_get_direction(const unsigned long offset)
+{
+ return (offset >= IDIO_16_NOUT) ? 1 : 0;
+}
+
+int idio_16_get(struct idio_16 __iomem *reg, struct idio_16_state *state,
+ unsigned long offset);
+void idio_16_get_multiple(struct idio_16 __iomem *reg,
+ struct idio_16_state *state,
+ const unsigned long *mask, unsigned long *bits);
+void idio_16_set(struct idio_16 __iomem *reg, struct idio_16_state *state,
+ unsigned long offset, unsigned long value);
+void idio_16_set_multiple(struct idio_16 __iomem *reg,
+ struct idio_16_state *state,
+ const unsigned long *mask, const unsigned long *bits);
+void idio_16_state_init(struct idio_16_state *state);
+
+#endif /* _IDIO_16_H_ */
--
2.37.3