Mike: New page: This is a sample driver module for ''Dallas Semiconductor'' Digital Thermometer '''DS1722''':
 #include  #include  #include  #include 
2008-04-28T06:52:14Z
New page: This is a sample driver module for ''Dallas Semiconductor'' Digital Thermometer '''DS1722''': <pre> #include <linux/hwmon.h> #include <linux/init.h> #include <linux/err.h> #include <linux/...
New page
This is a sample driver module for ''Dallas Semiconductor'' Digital Thermometer '''DS1722''':

<pre>

#include <linux/hwmon.h>

#include <linux/init.h>

#include <linux/err.h>

#include <linux/spi/spi.h>

#include <linux/delay.h>



#include <asm/arch/pxa-regs.h>

#include <asm/arch/pxa2xx_spi.h>



/* defining another CE pin: sb270 p16 pin 45 */

#define DS1722_FRAME_GPIO 107



/* ds1722 CE Inactive time is 400ns - sleeping for 1ms */

#define CE_WAIT_MSEC 1

 

extern int pxa_gpio_mode(int);

extern void pxa_gpio_set_value(unsigned gpio, int value);

extern int gpio_direction_output(unsigned gpio, int value);



static int set_pxa_spi_gpio_config(void)

{

	int modes_num = 4, ret = 0, i = 0;

	int mode[] = {	GPIO23_SCLK_MD,

			GPIO24_SFRM_MD,

			GPIO25_STXD_MD,

			GPIO26_SRXD_MD };



	for (i = 0; i < modes_num; i++)

		if ((ret = pxa_gpio_mode(mode[i])) != 0)

			return ret;

	/* setting up alternative gpio frame - CE */

	return gpio_direction_output(DS1722_FRAME_GPIO, 0);

}



static int __devinit ds1722_probe(struct spi_device *spi)

{

	int ret = 0;

	u8 in[4] = { 0 };



	/* Setup spi */

	ret = spi_setup(spi);



	in[0] = 0x80; in[1] = 0x00;

	printk(KERN_INFO "\nWriting configuration to register:\t0x%x", in[0]);

	mdelay(CE_WAIT_MSEC);

	pxa_gpio_set_value(DS1722_FRAME_GPIO, 1);		/* Set CE HIGH */

	ret = spi_write(spi,in,2);

	pxa_gpio_set_value(DS1722_FRAME_GPIO, 0);		/* Set CE LOW */

	printk(KERN_INFO "\n%s:\tin\t=\t\t0x%x,0x%x", "spi_write", in[0], in[1]);

	printk(KERN_INFO "\n%s: returned\t\t\t%d\n", "spi_write", ret);

	

	in[0] = 0x00; in[1] = 0x00;

	printk(KERN_INFO "\nReading configuration from register:\t0x%x", in[0]);

	mdelay(CE_WAIT_MSEC);

	pxa_gpio_set_value(DS1722_FRAME_GPIO, 1);		/* Set CE HIGH */

	ret = spi_w8r8(spi,in[0]);

	pxa_gpio_set_value(DS1722_FRAME_GPIO, 0);		/* Set CE LOW */

	printk(KERN_INFO "\n%s: returned\t\t\t0x%x\n", "spi_w8r8", ret);

	

	in[0] = 0x02; in[1] = 0x00;

	printk(KERN_INFO "\nReading temperature MSB from register:\t0x%x", in[0]);

	mdelay(CE_WAIT_MSEC);

	pxa_gpio_set_value(DS1722_FRAME_GPIO, 1);		/* Set CE HIGH */

	ret = spi_w8r8(spi,in[0]);

	pxa_gpio_set_value(DS1722_FRAME_GPIO, 0);		/* Set CE LOW */

	printk(KERN_INFO "\n%s: returned\t\t\t%d\n", "spi_w8r8", ret);

	

	in[0] = 0x01; in[1] = 0x00;

	printk(KERN_INFO "\nReading temperature LSB from register:\t0x%x", in[0]);

	mdelay(CE_WAIT_MSEC);

	pxa_gpio_set_value(DS1722_FRAME_GPIO, 1);		/* Set CE HIGH */

	ret = spi_w8r8(spi,in[0]);

	pxa_gpio_set_value(DS1722_FRAME_GPIO, 0);		/* Set CE LOW */

	printk(KERN_INFO "\n%s: returned\t\t\t%d\n", "spi_w8r8", ret);



	return 0;

}



static int __devexit ds1722_remove(struct spi_device *spi)

{

	return 0;

}



static struct spi_driver ds1722_driver = {

	.driver = {

		.name	= "ds1722_spi",

		.bus	= &spi_bus_type,

		.owner	= THIS_MODULE,

	},

	.probe		= ds1722_probe,

	.remove		= __devexit_p(ds1722_remove),

};



static int __init ds1722_init(void)

{

	int ret = set_pxa_spi_gpio_config();

	if(ret < 0)

		return ret;

	

	return spi_register_driver(&ds1722_driver);

}

module_init(ds1722_init);



static void __exit ds1722_exit(void)

{

	spi_unregister_driver(&ds1722_driver);

}

module_exit(ds1722_exit);



MODULE_DESCRIPTION("DS1722 SPI Thermometer Driver");

MODULE_LICENSE("GPL");

</pre>

back to: [[SPI support for CM-X270]]
Ds1722.c - Revision history
