diff options
Diffstat (limited to 'ANDROID_3.4.5/drivers/input/misc/rotary_encoder.c')
| -rw-r--r-- | ANDROID_3.4.5/drivers/input/misc/rotary_encoder.c | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/ANDROID_3.4.5/drivers/input/misc/rotary_encoder.c b/ANDROID_3.4.5/drivers/input/misc/rotary_encoder.c new file mode 100644 index 00000000..f07f7841 --- /dev/null +++ b/ANDROID_3.4.5/drivers/input/misc/rotary_encoder.c @@ -0,0 +1,292 @@ +/* + * rotary_encoder.c + * + * (c) 2009 Daniel Mack <daniel@caiaq.de> + * Copyright (C) 2011 Johan Hovold <jhovold@gmail.com> + * + * state machine code inspired by code from Tim Ruetz + * + * A generic driver for rotary encoders connected to GPIO lines. + * See file:Documentation/input/rotary-encoder.txt for more information + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/input.h> +#include <linux/device.h> +#include <linux/platform_device.h> +#include <linux/gpio.h> +#include <linux/rotary_encoder.h> +#include <linux/slab.h> + +#define DRV_NAME "rotary-encoder" + +struct rotary_encoder { + struct input_dev *input; + struct rotary_encoder_platform_data *pdata; + + unsigned int axis; + unsigned int pos; + + unsigned int irq_a; + unsigned int irq_b; + + bool armed; + unsigned char dir; /* 0 - clockwise, 1 - CCW */ + + char last_stable; +}; + +static int rotary_encoder_get_state(struct rotary_encoder_platform_data *pdata) +{ + int a = !!gpio_get_value(pdata->gpio_a); + int b = !!gpio_get_value(pdata->gpio_b); + + a ^= pdata->inverted_a; + b ^= pdata->inverted_b; + + return ((a << 1) | b); +} + +static void rotary_encoder_report_event(struct rotary_encoder *encoder) +{ + struct rotary_encoder_platform_data *pdata = encoder->pdata; + + if (pdata->relative_axis) { + input_report_rel(encoder->input, + pdata->axis, encoder->dir ? -1 : 1); + } else { + unsigned int pos = encoder->pos; + + if (encoder->dir) { + /* turning counter-clockwise */ + if (pdata->rollover) + pos += pdata->steps; + if (pos) + pos--; + } else { + /* turning clockwise */ + if (pdata->rollover || pos < pdata->steps) + pos++; + } + + if (pdata->rollover) + pos %= pdata->steps; + + encoder->pos = pos; + input_report_abs(encoder->input, pdata->axis, encoder->pos); + } + + input_sync(encoder->input); +} + +static irqreturn_t rotary_encoder_irq(int irq, void *dev_id) +{ + struct rotary_encoder *encoder = dev_id; + int state; + + state = rotary_encoder_get_state(encoder->pdata); + + switch (state) { + case 0x0: + if (encoder->armed) { + rotary_encoder_report_event(encoder); + encoder->armed = false; + } + break; + + case 0x1: + case 0x2: + if (encoder->armed) + encoder->dir = state - 1; + break; + + case 0x3: + encoder->armed = true; + break; + } + + return IRQ_HANDLED; +} + +static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id) +{ + struct rotary_encoder *encoder = dev_id; + int state; + + state = rotary_encoder_get_state(encoder->pdata); + + switch (state) { + case 0x00: + case 0x03: + if (state != encoder->last_stable) { + rotary_encoder_report_event(encoder); + encoder->last_stable = state; + } + break; + + case 0x01: + case 0x02: + encoder->dir = (encoder->last_stable + state) & 0x01; + break; + } + + return IRQ_HANDLED; +} + +static int __devinit rotary_encoder_probe(struct platform_device *pdev) +{ + struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data; + struct rotary_encoder *encoder; + struct input_dev *input; + irq_handler_t handler; + int err; + + if (!pdata) { + dev_err(&pdev->dev, "missing platform data\n"); + return -ENOENT; + } + + encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL); + input = input_allocate_device(); + if (!encoder || !input) { + dev_err(&pdev->dev, "failed to allocate memory for device\n"); + err = -ENOMEM; + goto exit_free_mem; + } + + encoder->input = input; + encoder->pdata = pdata; + encoder->irq_a = gpio_to_irq(pdata->gpio_a); + encoder->irq_b = gpio_to_irq(pdata->gpio_b); + + /* create and register the input driver */ + input->name = pdev->name; + input->id.bustype = BUS_HOST; + input->dev.parent = &pdev->dev; + + if (pdata->relative_axis) { + input->evbit[0] = BIT_MASK(EV_REL); + input->relbit[0] = BIT_MASK(pdata->axis); + } else { + input->evbit[0] = BIT_MASK(EV_ABS); + input_set_abs_params(encoder->input, + pdata->axis, 0, pdata->steps, 0, 1); + } + + err = input_register_device(input); + if (err) { + dev_err(&pdev->dev, "failed to register input device\n"); + goto exit_free_mem; + } + + /* request the GPIOs */ + err = gpio_request(pdata->gpio_a, DRV_NAME); + if (err) { + dev_err(&pdev->dev, "unable to request GPIO %d\n", + pdata->gpio_a); + goto exit_unregister_input; + } + + err = gpio_direction_input(pdata->gpio_a); + if (err) { + dev_err(&pdev->dev, "unable to set GPIO %d for input\n", + pdata->gpio_a); + goto exit_unregister_input; + } + + err = gpio_request(pdata->gpio_b, DRV_NAME); + if (err) { + dev_err(&pdev->dev, "unable to request GPIO %d\n", + pdata->gpio_b); + goto exit_free_gpio_a; + } + + err = gpio_direction_input(pdata->gpio_b); + if (err) { + dev_err(&pdev->dev, "unable to set GPIO %d for input\n", + pdata->gpio_b); + goto exit_free_gpio_a; + } + + /* request the IRQs */ + if (pdata->half_period) { + handler = &rotary_encoder_half_period_irq; + encoder->last_stable = rotary_encoder_get_state(pdata); + } else { + handler = &rotary_encoder_irq; + } + + err = request_irq(encoder->irq_a, handler, + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, + DRV_NAME, encoder); + if (err) { + dev_err(&pdev->dev, "unable to request IRQ %d\n", + encoder->irq_a); + goto exit_free_gpio_b; + } + + err = request_irq(encoder->irq_b, handler, + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, + DRV_NAME, encoder); + if (err) { + dev_err(&pdev->dev, "unable to request IRQ %d\n", + encoder->irq_b); + goto exit_free_irq_a; + } + + platform_set_drvdata(pdev, encoder); + + return 0; + +exit_free_irq_a: + free_irq(encoder->irq_a, encoder); +exit_free_gpio_b: + gpio_free(pdata->gpio_b); +exit_free_gpio_a: + gpio_free(pdata->gpio_a); +exit_unregister_input: + input_unregister_device(input); + input = NULL; /* so we don't try to free it */ +exit_free_mem: + input_free_device(input); + kfree(encoder); + return err; +} + +static int __devexit rotary_encoder_remove(struct platform_device *pdev) +{ + struct rotary_encoder *encoder = platform_get_drvdata(pdev); + struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data; + + free_irq(encoder->irq_a, encoder); + free_irq(encoder->irq_b, encoder); + gpio_free(pdata->gpio_a); + gpio_free(pdata->gpio_b); + input_unregister_device(encoder->input); + platform_set_drvdata(pdev, NULL); + kfree(encoder); + + return 0; +} + +static struct platform_driver rotary_encoder_driver = { + .probe = rotary_encoder_probe, + .remove = __devexit_p(rotary_encoder_remove), + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + } +}; +module_platform_driver(rotary_encoder_driver); + +MODULE_ALIAS("platform:" DRV_NAME); +MODULE_DESCRIPTION("GPIO rotary encoder driver"); +MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold"); +MODULE_LICENSE("GPL v2"); |