drivers: vtpctp/ec: add 4-bit digital i/o-driver
add vtpctp/ec specific 4-bit digital input/output-driver Signed-off-by: Ralf Gliese <gliese@elrest.de>
This commit is contained in:
Ralf Gliese
committed by
Oleg Karfich
Oleg Karfich
parent
974bd20418
commit
c8608b2fff
@@ -209,6 +209,7 @@ CONFIG_BLK_DEV_LOOP=y
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CONFIG_BLK_DEV_RAM=y
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CONFIG_BLK_DEV_RAM_SIZE=65536
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# CONFIG_ENCSW is not set
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CONFIG_DIO_SPI_DRV=m
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CONFIG_EEPROM_AT24=y
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CONFIG_EEPROM_AT25=y
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CONFIG_SCSI=y
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@@ -594,6 +594,15 @@ config DIN_SPI_DRV
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Expose digial inputs using sysfs interface, e.g.
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/sys/bus/spi/devices/spi0.0/din
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config DIO_SPI_DRV
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tristate "SPI and SYSFS based digital input/output driver"
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depends on SYSFS && GPIOLIB && SPI
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help
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This option enables the SPI and SYSFS based digital
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input/output driver for VTPCT/EC devices.
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To compile this driver as a module, choose M here: the
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module will be called dio_drv.
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source "drivers/misc/c2port/Kconfig"
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source "drivers/misc/eeprom/Kconfig"
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source "drivers/misc/cb710/Kconfig"
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@@ -70,3 +70,4 @@ obj-$(CONFIG_TPS6594_PFSM) += tps6594-pfsm.o
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obj-$(CONFIG_TI_SN74LV165A) += ti_sn74lv165a.o
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obj-$(CONFIG_DOUT_DRV) += dout_drv.o
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obj-$(CONFIG_DIN_SPI_DRV) += din_spi_drv.o
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obj-$(CONFIG_DIO_SPI_DRV) += dio_drv.o
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@@ -0,0 +1,201 @@
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//------------------------------------------------------------------------------
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/// Copyright (c) 2019-2022 WAGO GmbH & Co. KG
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///
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/// This program is free software: you can redistribute it and/or modify
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/// it under the terms of the GNU General Public License as published by
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/// the Free Software Foundation, version 2.
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///
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/// This program is distributed in the hope that it will be useful, but
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/// WITHOUT ANY WARRANTY; without even the implied warranty of
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/// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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/// General Public License for more details.
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///
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/// You should have received a copy of the GNU General Public License
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/// along with this program. If not, see <http://www.gnu.org/licenses/>.
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//------------------------------------------------------------------------------
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///------------------------------------------------------------------------------
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/// \file dio_drv.c
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///
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/// \brief Driver for "X3" (4 digital I/O) on TouchPanel devices
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///
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/// \author Ralf Gliese, elrest Automationssysteme GmbH
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///------------------------------------------------------------------------------
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/mutex.h>
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#include <linux/mod_devicetable.h>
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#include <linux/spi/spi.h>
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#include <linux/of_gpio.h>
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#include <linux/delay.h>
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struct dio_data {
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unsigned char dma_buffer[2];
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int gpio_load;
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int gpio_reset;
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struct mutex lock;
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unsigned char tx_data;
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};
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static unsigned char reverse_low_nibble(unsigned char input)
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{
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static const unsigned char lookup[] = {
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0x0, 0x8, 0x4, 0xc, 0x2, 0xa, 0x6, 0xe,
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0x1, 0x9, 0x5, 0xd, 0x3, 0xb, 0x7, 0xf
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};
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return lookup[input & 0xf] | (input & 0xf0);
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};
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/* SPI Write/Read cycle */
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static int dio_spi_exchange(struct spi_device *spi, int data)
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{
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struct dio_data *dio = spi_get_drvdata(spi);
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struct spi_message msg;
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struct spi_transfer xfer;
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int ret;
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if (data >= 0)
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dio->tx_data = reverse_low_nibble(data);
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dio->dma_buffer[0] = 0;
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dio->dma_buffer[1] = dio->tx_data;
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/* Latch input data */
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gpio_set_value(dio->gpio_load, 0);
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udelay(10);
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gpio_set_value(dio->gpio_load, 1);
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/* Initialize the SPI message and transfer data structures */
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spi_message_init(&msg);
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memset(&xfer, 0, sizeof xfer);
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xfer.tx_buf = xfer.rx_buf = dio->dma_buffer;
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xfer.len = sizeof dio->dma_buffer;
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spi_message_add_tail(&xfer, &msg);
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/* Send the message and wait for completion */
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ret = spi_sync(spi, &msg);
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if (ret != 0) {
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dev_err(&spi->dev, "SPI transmission failed\n");
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return 0;
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}
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dev_dbg(&spi->dev, "sent %02x %02x, received %02x %02x\n",
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dio->tx_data, dio->tx_data,
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dio->dma_buffer[0], dio->dma_buffer[1]);
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return reverse_low_nibble(dio->dma_buffer[0]) | dio->dma_buffer[1] << 8;
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}
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static ssize_t dio_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct dio_data *dio = spi_get_drvdata(spi);
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int ret;
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ret = mutex_lock_interruptible(&dio->lock);
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if (ret)
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return ret;
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ret = dio_spi_exchange(spi, -1);
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mutex_unlock(&dio->lock);
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return sprintf(buf, "%d\n", ret);
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}
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static ssize_t dio_store(struct device *dev, struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct dio_data *dio = spi_get_drvdata(spi);
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unsigned long data;
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int ret;
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ret = kstrtoul(buf, 0, &data);
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if (ret < 0)
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return ret;
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if (data > 0xf)
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return -EINVAL;
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ret = mutex_lock_interruptible(&dio->lock);
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if (ret)
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return ret;
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dio_spi_exchange(spi, data);
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mutex_unlock(&dio->lock);
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return count;
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}
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static DEVICE_ATTR_RW(dio);
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static int alloc_gpio(struct device *dev, const char *name)
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{
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int ret, gpio = of_get_named_gpio(dev->of_node, name, 0);
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if (gpio < 0) {
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dev_err(dev, "GPIO '%s' not found in device tree\n", name);
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return gpio;
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}
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ret = devm_gpio_request_one(dev, gpio, GPIOF_OUT_INIT_HIGH, name);
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if (ret < 0) {
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dev_err(dev, "Cannot request GPIO '%s' %d\n", name, gpio);
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return ret;
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}
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dev_dbg(dev, "GPIO '%s' has Number %d\n", name, gpio);
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return gpio;
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}
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static int dio_drv_probe(struct spi_device *spi)
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{
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struct device *dev = &spi->dev;
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struct dio_data *dio;
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dio = devm_kzalloc(dev, sizeof *dio, GFP_KERNEL);
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if (!dio)
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return -ENOMEM;
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dio->gpio_load = alloc_gpio(dev, "gpio-load");
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if (dio->gpio_load < 0)
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return dio->gpio_load;
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dio->gpio_reset = alloc_gpio(dev, "gpio-reset");
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if (dio->gpio_reset < 0)
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return dio->gpio_reset;
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mutex_init(&dio->lock);
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spi_set_drvdata(spi, dio);
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/* Initialize and enable output lines */
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dio_spi_exchange(spi, 0);
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gpio_set_value(dio->gpio_reset, 0);
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return device_create_file(dev, &dev_attr_dio);
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}
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static void dio_drv_remove(struct spi_device *spi)
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{
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struct dio_data *dio = spi_get_drvdata(spi);
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gpio_set_value(dio->gpio_reset, 1);
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device_remove_file(&spi->dev, &dev_attr_dio);
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}
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static const struct spi_device_id dio_spi_ids[] = {
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{ "dio_spi", 0 },
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{ },
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};
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MODULE_DEVICE_TABLE(spi, dio_spi_ids);
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static struct spi_driver dio_driver = {
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.driver = {
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.name = "dio_spi",
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.owner = THIS_MODULE,
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},
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.id_table = dio_spi_ids,
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.probe = dio_drv_probe,
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.remove = dio_drv_remove,
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};
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module_spi_driver(dio_driver);
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MODULE_AUTHOR("elrest");
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MODULE_DESCRIPTION("dio_spi driver");
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MODULE_LICENSE("GPL");
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