底层驱动开发

源代码在线查看: radio-maestro.c

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				/* Maestro PCI sound card radio driver for Linux support				 * (c) 2000 A. Tlalka, atlka@pg.gda.pl				 * Notes on the hardware				 *				 *  + Frequency control is done digitally 				 *  + No volume control - only mute/unmute - you have to use Aux line volume				 *  control on Maestro card to set the volume				 *  + Radio status (tuned/not_tuned and stereo/mono) is valid some time after				 *  frequency setting (>100ms) and only when the radio is unmuted.				 *  version 0.02				 *  + io port is automatically detected - only the first radio is used				 *  version 0.03				 *  + thread access locking additions				 *  version 0.04				 * + code improvements				 * + VIDEO_TUNER_LOW is permanent				 */								#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 				#include 								#define DRIVER_VERSION	"0.04"								#define PCI_VENDOR_ESS                  0x125D				#define PCI_DEVICE_ID_ESS_ESS1968       0x1968          /* Maestro 2    */				#define PCI_DEVICE_ID_ESS_ESS1978       0x1978          /* Maestro 2E   */								#define GPIO_DATA       0x60   /* port offset from ESS_IO_BASE */								#define IO_MASK		4      /* mask      register offset from GPIO_DATA								bits 1=unmask write to given bit */				#define IO_DIR		8      /* direction register offset from GPIO_DATA								bits 0/1=read/write direction */								#define GPIO6           0x0040 /* mask bits for GPIO lines */				#define GPIO7           0x0080				#define GPIO8           0x0100				#define GPIO9           0x0200								#define STR_DATA        GPIO6  /* radio TEA5757 pins and GPIO bits */				#define STR_CLK         GPIO7				#define STR_WREN        GPIO8				#define STR_MOST        GPIO9								#define FREQ_LO		 50*16000				#define FREQ_HI		150*16000								#define FREQ_IF         171200 /* 10.7*16000   */				#define FREQ_STEP       200    /* 12.5*16      */								#define FREQ2BITS(x)	((((unsigned int)(x)+FREQ_IF+(FREQ_STEP							/(FREQ_STEP								#define BITS2FREQ(x)	((x) * FREQ_STEP - FREQ_IF)								static int radio_nr = -1;				module_param(radio_nr, int, 0);								static int radio_ioctl(struct inode *inode, struct file *file,						       unsigned int cmd, unsigned long arg);								static struct file_operations maestro_fops = {					.owner		= THIS_MODULE,					.open           = video_exclusive_open,					.release        = video_exclusive_release,					.ioctl		= radio_ioctl,					.llseek         = no_llseek,				};								static struct video_device maestro_radio=				{					.owner		= THIS_MODULE,					.name		= "Maestro radio",					.type		= VID_TYPE_TUNER,					.hardware	= VID_HARDWARE_SF16MI,					.fops           = &maestro_fops,				};								static struct radio_device				{					__u16	io,	/* base of Maestro card radio io (GPIO_DATA)*/						muted,	/* VIDEO_AUDIO_MUTE */						stereo,	/* VIDEO_TUNER_STEREO_ON */							tuned;	/* signal strength (0 or 0xffff) */					struct  semaphore lock;				} radio_unit = {0, 0, 0, 0, };								static __u32 radio_bits_get(struct radio_device *dev)				{					register __u16 io=dev->io, l, rdata;					register __u32 data=0;					__u16 omask;					omask = inw(io + IO_MASK);					outw(~(STR_CLK | STR_WREN), io + IO_MASK);					outw(0, io);					udelay(16);									for (l=24;l--;) {						outw(STR_CLK, io);		/* HI state */						udelay(2);						if(!l) 							dev->tuned = inw(io) & STR_MOST ? 0 : 0xffff;						outw(0, io);			/* LO state */						udelay(2);						data 						rdata = inw(io);						if(!l)							dev->stereo =  rdata & STR_MOST ? 							0 : VIDEO_TUNER_STEREO_ON;						else							if(rdata & STR_DATA)								data++;						udelay(2);					}					if(dev->muted)						outw(STR_WREN, io);					udelay(4);					outw(omask, io + IO_MASK);					return data & 0x3ffe;				}								static void radio_bits_set(struct radio_device *dev, __u32 data)				{					register __u16 io=dev->io, l, bits;					__u16 omask, odir;					omask = inw(io + IO_MASK);					odir  = (inw(io + IO_DIR) & ~STR_DATA) | (STR_CLK | STR_WREN);					outw(odir | STR_DATA, io + IO_DIR);					outw(~(STR_DATA | STR_CLK | STR_WREN), io + IO_MASK);					udelay(16);					for (l=25;l;l--) {						bits = ((data >> 18) & STR_DATA) | STR_WREN ;						data 						outw(bits, io);			/* start strobe */						udelay(2);						outw(bits | STR_CLK, io);	/* HI level */						udelay(2);						outw(bits, io);			/* LO level */						udelay(4);					}					if(!dev->muted)						outw(0, io);					udelay(4);					outw(omask, io + IO_MASK);					outw(odir, io + IO_DIR);					msleep(125);				}								static inline int radio_function(struct inode *inode, struct file *file,								 unsigned int cmd, void *arg)				{					struct video_device *dev = video_devdata(file);					struct radio_device *card=dev->priv;										switch(cmd) {						case VIDIOCGCAP: {							struct video_capability *v = arg;							memset(v,0,sizeof(*v));							strcpy(v->name, "Maestro radio");							v->type=VID_TYPE_TUNER;							v->channels=v->audios=1;							return 0;						}						case VIDIOCGTUNER: {							struct video_tuner *v = arg;							if(v->tuner)								return -EINVAL;							(void)radio_bits_get(card);							v->flags = VIDEO_TUNER_LOW | card->stereo;							v->signal = card->tuned;							strcpy(v->name, "FM");							v->rangelow = FREQ_LO;							v->rangehigh = FREQ_HI;							v->mode = VIDEO_MODE_AUTO;						        return 0;						}						case VIDIOCSTUNER: {							struct video_tuner *v = arg;							if(v->tuner!=0)								return -EINVAL;							return 0;						}						case VIDIOCGFREQ: {							unsigned long *freq = arg;							*freq = BITS2FREQ(radio_bits_get(card));							return 0;						}						case VIDIOCSFREQ: {							unsigned long *freq = arg;							if (*freqFREQ_HI )								return -EINVAL;							radio_bits_set(card, FREQ2BITS(*freq));							return 0;						}						case VIDIOCGAUDIO: {								struct video_audio *v = arg;							memset(v,0,sizeof(*v));							strcpy(v->name, "Radio");							v->flags=VIDEO_AUDIO_MUTABLE | card->muted;							v->mode=VIDEO_SOUND_STEREO;							return 0;								}						case VIDIOCSAUDIO: {							struct video_audio *v = arg;							if(v->audio)								return -EINVAL;							{								register __u16 io=card->io;								register __u16 omask = inw(io + IO_MASK);								outw(~STR_WREN, io + IO_MASK);								outw((card->muted = v->flags & VIDEO_AUDIO_MUTE)								     ? STR_WREN : 0, io);								udelay(4);								outw(omask, io + IO_MASK);								msleep(125);								return 0;							}						}						case VIDIOCGUNIT: {							struct video_unit *v = arg;							v->video=VIDEO_NO_UNIT;							v->vbi=VIDEO_NO_UNIT;							v->radio=dev->minor;							v->audio=0;							v->teletext=VIDEO_NO_UNIT;							return 0;								}						default: return -ENOIOCTLCMD;					}				}								static int radio_ioctl(struct inode *inode, struct file *file,						       unsigned int cmd, unsigned long arg)				{					struct video_device *dev = video_devdata(file);					struct radio_device *card=dev->priv;					int ret;									down(&card->lock);					ret = video_usercopy(inode, file, cmd, arg, radio_function);					up(&card->lock);					return ret;				}								static __u16 radio_install(struct pci_dev *pcidev);								MODULE_AUTHOR("Adam Tlalka, atlka@pg.gda.pl");				MODULE_DESCRIPTION("Radio driver for the Maestro PCI sound card radio.");				MODULE_LICENSE("GPL");								static void __exit maestro_radio_exit(void)				{					video_unregister_device(&maestro_radio);				}								static int __init maestro_radio_init(void)				{					register __u16 found=0;					struct pci_dev *pcidev = NULL;					while(!found && (pcidev = pci_find_device(PCI_VENDOR_ESS, 										  PCI_DEVICE_ID_ESS_ESS1968,										  pcidev)))						found |= radio_install(pcidev);					while(!found && (pcidev = pci_find_device(PCI_VENDOR_ESS,										  PCI_DEVICE_ID_ESS_ESS1978, 										  pcidev)))						found |= radio_install(pcidev);					if(!found) {						printk(KERN_INFO "radio-maestro: no devices found.\n");						return -ENODEV;					}					return 0;				}								module_init(maestro_radio_init);				module_exit(maestro_radio_exit);								static inline __u16 radio_power_on(struct radio_device *dev)				{					register __u16 io=dev->io;					register __u32 ofreq;					__u16 omask, odir;					omask = inw(io + IO_MASK);					odir  = (inw(io + IO_DIR) & ~STR_DATA) | (STR_CLK | STR_WREN);					outw(odir & ~STR_WREN, io + IO_DIR);					dev->muted = inw(io) & STR_WREN ? 0 : VIDEO_AUDIO_MUTE;					outw(odir, io + IO_DIR);					outw(~(STR_WREN | STR_CLK), io + IO_MASK);					outw(dev->muted ? 0 : STR_WREN, io);					udelay(16);					outw(omask, io + IO_MASK);					ofreq = radio_bits_get(dev);					if((ofreqFREQ2BITS(FREQ_HI)))						ofreq = FREQ2BITS(FREQ_LO);					radio_bits_set(dev, ofreq);					return (ofreq == radio_bits_get(dev));				}								static __u16 radio_install(struct pci_dev *pcidev)				{					if(((pcidev->class >> 8) & 0xffff) != PCI_CLASS_MULTIMEDIA_AUDIO)						return 0;										radio_unit.io = pcidev->resource[0].start + GPIO_DATA;					maestro_radio.priv = &radio_unit;					init_MUTEX(&radio_unit.lock);										if(radio_power_on(&radio_unit)) {						if(video_register_device(&maestro_radio, VFL_TYPE_RADIO, radio_nr)==-1) {							printk("radio-maestro: can't register device!");							return 0;						}						printk(KERN_INFO "radio-maestro: version "						       DRIVER_VERSION 						       " time " 						       __TIME__ "  "						       __DATE__						       "\n");						printk(KERN_INFO "radio-maestro: radio chip initialized\n");						return 1;					} else						return 0;   				}											

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