1.設(shè)備號(hào)的獲取

\qquad設(shè)備號(hào)的獲取方法：自動(dòng)分配；指定設(shè)備號(hào)注冊(cè)

2.自動(dòng)分配函數(shù)

\qquad函數(shù)：int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count, const char *name)
\qquad功能：分配設(shè)備號(hào)
\qquad參數(shù)：第一個(gè)參數(shù)：dev_t類型定義的變量，取地址傳入；第二個(gè)參數(shù)：次設(shè)備號(hào)，次設(shè)備號(hào)自己指定；第三個(gè)參數(shù)：設(shè)備個(gè)數(shù)；第四個(gè)參數(shù)：名字
\qquad返回值：成功返回0；失敗返回負(fù)數(shù)錯(cuò)誤碼

int alloc_chrdev_region(dev_t *dev, unsigned baseminor, unsigned count, const char *name) {struct char_device_struct *cd;cd = __register_chrdev_region(0, baseminor, count, name);if (IS_ERR(cd))return PTR_ERR(cd);*dev = MKDEV(cd->major, cd->baseminor);return 0; }

3.指定設(shè)備號(hào)注冊(cè)

\qquad函數(shù)：int register_chrdev_region(dev_t from, unsigned count, const char *name)
\qquad功能：指定設(shè)備號(hào)注冊(cè)
\qquad參數(shù)：第一個(gè)參數(shù)：設(shè)備號(hào)（MKDEV(major,minor)）；第二個(gè)參數(shù)：設(shè)備個(gè)數(shù)；第三個(gè)參數(shù)：名字
\qquad返回值：成功返回0；失敗返回負(fù)數(shù)錯(cuò)誤碼

int register_chrdev_region(dev_t from, unsigned count, const char *name) {struct char_device_struct *cd;dev_t to = from + count;dev_t n, next;for (n = from; n < to; n = next) {next = MKDEV(MAJOR(n)+1, 0);if (next > to)next = to;cd = __register_chrdev_region(MAJOR(n), MINOR(n),next - n, name);if (IS_ERR(cd))goto fail;}return 0; fail:to = n;for (n = from; n < to; n = next) {next = MKDEV(MAJOR(n)+1, 0);kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));}return PTR_ERR(cd); }

4.注銷設(shè)備號(hào)

\qquad函數(shù)：void unregister_chrdev_region(dev_t from, unsigned count)
\qquad功能：注銷設(shè)備號(hào)
\qquad參數(shù)：第一個(gè)參數(shù)：設(shè)備號(hào)；第二個(gè)參數(shù)：設(shè)備個(gè)數(shù)
\qquad返回值：void

void unregister_chrdev_region(dev_t from, unsigned count) {dev_t to = from + count;dev_t n, next;for (n = from; n < to; n = next) {next = MKDEV(MAJOR(n)+1, 0);if (next > to)next = to;kfree(__unregister_chrdev_region(MAJOR(n), MINOR(n), next - n));} } 創(chuàng)作挑戰(zhàn)賽新人創(chuàng)作獎(jiǎng)勵(lì)來(lái)咯，堅(jiān)持創(chuàng)作打卡瓜分現(xiàn)金大獎(jiǎng)

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