// SPDX-License-Identifier: GPL-2.0-only /* * GPIO based serio bus driver for bit banging the PS/2 protocol * * Author: Danilo Krummrich <[email protected]> */ #include <linux/gpio/consumer.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/serio.h> #include <linux/slab.h> #include <linux/platform_device.h> #include <linux/workqueue.h> #include <linux/completion.h> #include <linux/mutex.h> #include <linux/preempt.h> #include <linux/property.h> #include <linux/of.h> #include <linux/jiffies.h> #include <linux/delay.h> #include <linux/timekeeping.h> #define DRIVER_NAME … #define PS2_MODE_RX … #define PS2_MODE_TX … #define PS2_START_BIT … #define PS2_DATA_BIT0 … #define PS2_DATA_BIT1 … #define PS2_DATA_BIT2 … #define PS2_DATA_BIT3 … #define PS2_DATA_BIT4 … #define PS2_DATA_BIT5 … #define PS2_DATA_BIT6 … #define PS2_DATA_BIT7 … #define PS2_PARITY_BIT … #define PS2_STOP_BIT … #define PS2_ACK_BIT … #define PS2_DEV_RET_ACK … #define PS2_DEV_RET_NACK … #define PS2_CMD_RESEND … /* * The PS2 protocol specifies a clock frequency between 10kHz and 16.7kHz, * therefore the maximal interrupt interval should be 100us and the minimum * interrupt interval should be ~60us. Let's allow +/- 20us for frequency * deviations and interrupt latency. * * The data line must be samples after ~30us to 50us after the falling edge, * since the device updates the data line at the rising edge. * * ___ ______ ______ ______ ___ * \ / \ / \ / \ / * \ / \ / \ / \ / * \______/ \______/ \______/ \______/ * * |-----------------| |--------| * 60us/100us 30us/50us */ #define PS2_CLK_FREQ_MIN_HZ … #define PS2_CLK_FREQ_MAX_HZ … #define PS2_CLK_MIN_INTERVAL_US … #define PS2_CLK_MAX_INTERVAL_US … #define PS2_IRQ_MIN_INTERVAL_US … #define PS2_IRQ_MAX_INTERVAL_US … struct ps2_gpio_data { … }; static int ps2_gpio_open(struct serio *serio) { … } static void ps2_gpio_close(struct serio *serio) { … } static int __ps2_gpio_write(struct serio *serio, unsigned char val) { … } static int ps2_gpio_write(struct serio *serio, unsigned char val) { … } static void ps2_gpio_tx_work_fn(struct work_struct *work) { … } static irqreturn_t ps2_gpio_irq_rx(struct ps2_gpio_data *drvdata) { … } static irqreturn_t ps2_gpio_irq_tx(struct ps2_gpio_data *drvdata) { … } static irqreturn_t ps2_gpio_irq(int irq, void *dev_id) { … } static int ps2_gpio_get_props(struct device *dev, struct ps2_gpio_data *drvdata) { … } static int ps2_gpio_probe(struct platform_device *pdev) { … } static void ps2_gpio_remove(struct platform_device *pdev) { … } #if defined(CONFIG_OF) static const struct of_device_id ps2_gpio_match[] = …; MODULE_DEVICE_TABLE(of, ps2_gpio_match); #endif static struct platform_driver ps2_gpio_driver = …; module_platform_driver(…) …; MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …;
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