diff options
| -rw-r--r-- | MAINTAINERS | 6 | ||||
| -rw-r--r-- | drivers/gpio/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/gpio/Makefile | 1 | ||||
| -rw-r--r-- | drivers/gpio/gpio-i8255.c | 287 | ||||
| -rw-r--r-- | drivers/gpio/gpio-i8255.h | 46 |
5 files changed, 352 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 3405cb36cf02..960abc07304e 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9902,6 +9902,12 @@ L: linux-fbdev@vger.kernel.org S: Maintained F: drivers/video/fbdev/i810/ +INTEL 8255 GPIO DRIVER +M: William Breathitt Gray <william.gray@linaro.org> +L: linux-gpio@vger.kernel.org +S: Maintained +F: drivers/gpio/gpio-i8255.c + INTEL ASoC DRIVERS M: Cezary Rojewski <cezary.rojewski@intel.com> M: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index cf6a2c745f3f..df484b72000d 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -824,6 +824,18 @@ endmenu menu "Port-mapped I/O GPIO drivers" depends on X86 # Unconditional I/O space access +config GPIO_I8255 + tristate + help + Enables support for the i8255 interface library functions. The i8255 + interface library provides functions to facilitate communication with + interfaces compatible with the venerable Intel 8255 Programmable + Peripheral Interface (PPI). The Intel 8255 PPI chip was first released + in the early 1970s but compatible interfaces are nowadays typically + found embedded in larger VLSI processing chips and FPGA components. + + If built as a module its name will be gpio-i8255. + config GPIO_104_DIO_48E tristate "ACCES 104-DIO-48E GPIO support" depends on PC104 diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 9d4805b2b60b..a0985d30f51b 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -67,6 +67,7 @@ obj-$(CONFIG_GPIO_GW_PLD) += gpio-gw-pld.o obj-$(CONFIG_GPIO_HISI) += gpio-hisi.o 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-$(CONFIG_GPIO_IDT3243X) += gpio-idt3243x.o obj-$(CONFIG_GPIO_IOP) += gpio-iop.o diff --git a/drivers/gpio/gpio-i8255.c b/drivers/gpio/gpio-i8255.c new file mode 100644 index 000000000000..9b97db418df1 --- /dev/null +++ b/drivers/gpio/gpio-i8255.c @@ -0,0 +1,287 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Intel 8255 Programmable Peripheral Interface + * Copyright (C) 2022 William Breathitt Gray + */ +#include <linux/bitmap.h> +#include <linux/err.h> +#include <linux/export.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/types.h> + +#include "gpio-i8255.h" + +#define I8255_CONTROL_PORTC_LOWER_DIRECTION BIT(0) +#define I8255_CONTROL_PORTB_DIRECTION BIT(1) +#define I8255_CONTROL_PORTC_UPPER_DIRECTION BIT(3) +#define I8255_CONTROL_PORTA_DIRECTION BIT(4) +#define I8255_CONTROL_MODE_SET BIT(7) +#define I8255_PORTA 0 +#define I8255_PORTB 1 +#define I8255_PORTC 2 + +static int i8255_get_port(struct i8255 __iomem *const ppi, + const unsigned long io_port, const unsigned long mask) +{ + const unsigned long bank = io_port / 3; + const unsigned long ppi_port = io_port % 3; + + return ioread8(&ppi[bank].port[ppi_port]) & mask; +} + +static u8 i8255_direction_mask(const unsigned long offset) +{ + const unsigned long port_offset = offset % 8; + const unsigned long io_port = offset / 8; + const unsigned long ppi_port = io_port % 3; + + switch (ppi_port) { + case I8255_PORTA: + return I8255_CONTROL_PORTA_DIRECTION; + case I8255_PORTB: + return I8255_CONTROL_PORTB_DIRECTION; + case I8255_PORTC: + /* Port C can be configured by nibble */ + if (port_offset >= 4) + return I8255_CONTROL_PORTC_UPPER_DIRECTION; + return I8255_CONTROL_PORTC_LOWER_DIRECTION; + default: + /* Should never reach this path */ + return 0; + } +} + +static void i8255_set_port(struct i8255 __iomem *const ppi, + struct i8255_state *const state, + const unsigned long io_port, + const unsigned long mask, const unsigned long bits) +{ + const unsigned long bank = io_port / 3; + const unsigned long ppi_port = io_port % 3; + unsigned long flags; + unsigned long out_state; + + spin_lock_irqsave(&state[bank].lock, flags); + + out_state = ioread8(&ppi[bank].port[ppi_port]); + out_state = (out_state & ~mask) | (bits & mask); + iowrite8(out_state, &ppi[bank].port[ppi_port]); + + spin_unlock_irqrestore(&state[bank].lock, flags); +} + +/** + * i8255_direction_input - configure signal offset as input + * @ppi: Intel 8255 Programmable Peripheral Interface banks + * @state: devices states of the respective PPI banks + * @offset: signal offset to configure as input + * + * Configures a signal @offset as input for the respective Intel 8255 + * Programmable Peripheral Interface (@ppi) banks. The @state control_state + * values are updated to reflect the new configuration. + */ +void i8255_direction_input(struct i8255 __iomem *const ppi, + struct i8255_state *const state, + const unsigned long offset) +{ + const unsigned long io_port = offset / 8; + const unsigned long bank = io_port / 3; + unsigned long flags; + + spin_lock_irqsave(&state[bank].lock, flags); + + state[bank].control_state |= I8255_CONTROL_MODE_SET; + state[bank].control_state |= i8255_direction_mask(offset); + + iowrite8(state[bank].control_state, &ppi[bank].control); + + spin_unlock_irqrestore(&state[bank].lock, flags); +} +EXPORT_SYMBOL_NS_GPL(i8255_direction_input, I8255); + +/** + * i8255_direction_output - configure signal offset as output + * @ppi: Intel 8255 Programmable Peripheral Interface banks + * @state: devices states of the respective PPI banks + * @offset: signal offset to configure as output + * @value: signal value to output + * + * Configures a signal @offset as output for the respective Intel 8255 + * Programmable Peripheral Interface (@ppi) banks and sets the respective signal + * output to the desired @value. The @state control_state values are updated to + * reflect the new configuration. + */ +void i8255_direction_output(struct i8255 __iomem *const ppi, + struct i8255_state *const state, + const unsigned long offset, + const unsigned long value) +{ + const unsigned long io_port = offset / 8; + const unsigned long bank = io_port / 3; + unsigned long flags; + + spin_lock_irqsave(&state[bank].lock, flags); + + state[bank].control_state |= I8255_CONTROL_MODE_SET; + state[bank].control_state &= ~i8255_direction_mask(offset); + + iowrite8(state[bank].control_state, &ppi[bank].control); + + spin_unlock_irqrestore(&state[bank].lock, flags); + + i8255_set(ppi, state, offset, value); +} +EXPORT_SYMBOL_NS_GPL(i8255_direction_output, I8255); + +/** + * i8255_get - get signal value at signal offset + * @ppi: Intel 8255 Programmable Peripheral Interface banks + * @offset: offset of signal to get + * + * Returns the signal value (0=low, 1=high) for the signal at @offset for the + * respective Intel 8255 Programmable Peripheral Interface (@ppi) banks. + */ +int i8255_get(struct i8255 __iomem *const ppi, const unsigned long offset) +{ + const unsigned long io_port = offset / 8; + const unsigned long offset_mask = BIT(offset % 8); + + return !!i8255_get_port(ppi, io_port, offset_mask); +} +EXPORT_SYMBOL_NS_GPL(i8255_get, I8255); + +/** + * i8255_get_direction - get the I/O direction for a signal offset + * @state: devices states of the respective PPI banks + * @offset: offset of signal to get direction + * + * Returns the signal direction (0=output, 1=input) for the signal at @offset. + */ +int i8255_get_direction(const struct i8255_state *const state, + const unsigned long offset) +{ + const unsigned long io_port = offset / 8; + const unsigned long bank = io_port / 3; + + return !!(state[bank].control_state & i8255_direction_mask(offset)); +} +EXPORT_SYMBOL_NS_GPL(i8255_get_direction, I8255); + +/** + * i8255_get_multiple - get multiple signal values at multiple signal offsets + * @ppi: Intel 8255 Programmable Peripheral Interface banks + * @mask: mask of signals to get + * @bits: bitmap to store signal values + * @ngpio: number of GPIO signals of the respective PPI banks + * + * Stores in @bits the values (0=low, 1=high) for the signals defined by @mask + * for the respective Intel 8255 Programmable Peripheral Interface (@ppi) banks. + */ +void i8255_get_multiple(struct i8255 __iomem *const ppi, + const unsigned long *const mask, + unsigned long *const bits, const unsigned long ngpio) +{ + unsigned long offset; + unsigned long port_mask; + unsigned long io_port; + unsigned long port_state; + + bitmap_zero(bits, ngpio); + + for_each_set_clump8(offset, port_mask, mask, ngpio) { + io_port = offset / 8; + port_state = i8255_get_port(ppi, io_port, port_mask); + + bitmap_set_value8(bits, port_state, offset); + } +} +EXPORT_SYMBOL_NS_GPL(i8255_get_multiple, I8255); + +/** + * i8255_mode0_output - configure all PPI ports to MODE 0 output mode + * @ppi: Intel 8255 Programmable Peripheral Interface bank + * + * Configures all Intel 8255 Programmable Peripheral Interface (@ppi) ports to + * MODE 0 (Basic Input/Output) output mode. + */ +void i8255_mode0_output(struct i8255 __iomem *const ppi) +{ + iowrite8(I8255_CONTROL_MODE_SET, &ppi->control); +} +EXPORT_SYMBOL_NS_GPL(i8255_mode0_output, I8255); + +/** + * i8255_set - set signal value at signal offset + * @ppi: Intel 8255 Programmable Peripheral Interface banks + * @state: devices states of the respective PPI banks + * @offset: offset of signal to set + * @value: value of signal to set + * + * Assigns output @value for the signal at @offset for the respective Intel 8255 + * Programmable Peripheral Interface (@ppi) banks. + */ +void i8255_set(struct i8255 __iomem *const ppi, struct i8255_state *const state, + const unsigned long offset, const unsigned long value) +{ + const unsigned long io_port = offset / 8; + const unsigned long port_offset = offset % 8; + const unsigned long mask = BIT(port_offset); + const unsigned long bits = value << port_offset; + + i8255_set_port(ppi, state, io_port, mask, bits); +} +EXPORT_SYMBOL_NS_GPL(i8255_set, I8255); + +/** + * i8255_set_multiple - set signal values at multiple signal offsets + * @ppi: Intel 8255 Programmable Peripheral Interface banks + * @state: devices states of the respective PPI banks + * @mask: mask of signals to set + * @bits: bitmap of signal output values + * @ngpio: number of GPIO signals of the respective PPI banks + * + * Assigns output values defined by @bits for the signals defined by @mask for + * the respective Intel 8255 Programmable Peripheral Interface (@ppi) banks. + */ +void i8255_set_multiple(struct i8255 __iomem *const ppi, + struct i8255_state *const state, + const unsigned long *const mask, + const unsigned long *const bits, + const unsigned long ngpio) +{ + unsigned long offset; + unsigned long port_mask; + unsigned long io_port; + unsigned long value; + + for_each_set_clump8(offset, port_mask, mask, ngpio) { + io_port = offset / 8; + value = bitmap_get_value8(bits, offset); + i8255_set_port(ppi, state, io_port, port_mask, value); + } +} +EXPORT_SYMBOL_NS_GPL(i8255_set_multiple, I8255); + +/** + * i8255_state_init - initialize i8255_state structure + * @state: devices states of the respective PPI banks + * @nbanks: number of Intel 8255 Programmable Peripheral Interface banks + * + * Initializes the @state of each Intel 8255 Programmable Peripheral Interface + * bank for use in i8255 library functions. + */ +void i8255_state_init(struct i8255_state *const state, + const unsigned long nbanks) +{ + unsigned long bank; + + for (bank = 0; bank < nbanks; bank++) + spin_lock_init(&state[bank].lock); +} +EXPORT_SYMBOL_NS_GPL(i8255_state_init, I8255); + +MODULE_AUTHOR("William Breathitt Gray"); +MODULE_DESCRIPTION("Intel 8255 Programmable Peripheral Interface"); +MODULE_LICENSE("GPL"); diff --git a/drivers/gpio/gpio-i8255.h b/drivers/gpio/gpio-i8255.h new file mode 100644 index 000000000000..d9084aae9446 --- /dev/null +++ b/drivers/gpio/gpio-i8255.h @@ -0,0 +1,46 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright 2022 William Breathitt Gray */ +#ifndef _I8255_H_ +#define _I8255_H_ + +#include <linux/spinlock.h> +#include <linux/types.h> + +/** + * struct i8255 - Intel 8255 register structure + * @port: Port A, B, and C + * @control: Control register + */ +struct i8255 { + u8 port[3]; + u8 control; +}; + +/** + * struct i8255_state - Intel 8255 state structure + * @lock: synchronization lock for accessing device state + * @control_state: Control register state + */ +struct i8255_state { + spinlock_t lock; + u8 control_state; +}; + +void i8255_direction_input(struct i8255 __iomem *ppi, struct i8255_state *state, + unsigned long offset); +void i8255_direction_output(struct i8255 __iomem *ppi, + struct i8255_state *state, unsigned long offset, + unsigned long value); +int i8255_get(struct i8255 __iomem *ppi, unsigned long offset); +int i8255_get_direction(const struct i8255_state *state, unsigned long offset); +void i8255_get_multiple(struct i8255 __iomem *ppi, const unsigned long *mask, + unsigned long *bits, unsigned long ngpio); +void i8255_mode0_output(struct i8255 __iomem *const ppi); +void i8255_set(struct i8255 __iomem *ppi, struct i8255_state *state, + unsigned long offset, unsigned long value); +void i8255_set_multiple(struct i8255 __iomem *ppi, struct i8255_state *state, + const unsigned long *mask, const unsigned long *bits, + unsigned long ngpio); +void i8255_state_init(struct i8255_state *const state, unsigned long nbanks); + +#endif /* _I8255_H_ */ |