控制GPIO电平前面一定要做 GPIO的请求如gpio_request(84,"red_led"); //red led
gpio_request(85,"green_led"); //green led ，然后才能输入输出控制 gpio_direction_output(84, 1);// red led
gpio_direction_output(85, 0);//green led 通知CPU这个GPIO
WARNING: at drivers/gpio/gpiolib.c:160 gpio_ensure_requested+0x4c/0xb4()
[ 0.778457] autorequest GPIO-69
[ 0.778472] Modules linked in:
[ 0.778498] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 3.10.0 #2
[ 0.778539] [<c0013e44>] (unwind_backtrace+0x0/0xe0) from [<c001175c>] (show_stack+0x10/0x14)
[ 0.778578] [<c001175c>] (show_stack+0x10/0x14) from [<c0036278>] (warn_slowpath_common+0x4c/0x68)
[ 0.778617] [<c0036278>] (warn_slowpath_common+0x4c/0x68) from [<c0036314>] (warn_slowpath_fmt+0x2c/0x3c)
[ 0.778657] [<c0036314>] (warn_slowpath_fmt+0x2c/0x3c) from [<c0298428>] (gpio_ensure_requested+0x4c/0xb4)
[ 0.778696] [<c0298428>] (gpio_ensure_requested+0x4c/0xb4) from [<c02996b0>] (gpiod_direction_output+0x80/0x2b0)
[ 0.778738] [<c02996b0>] (gpiod_direction_output+0x80/0x2b0) from [<c0320098>] (rk818_parse_dt+0x1c4/0x20c)
[ 0.778782] [<c0320098>] (rk818_parse_dt+0x1c4/0x20c) from [<c03213ac>] (rk818_i2c_probe+0xf8/0x344)
[ 0.778822] [<c03213ac>] (rk818_i2c_probe+0xf8/0x344) from [<c051511c>] (i2c_device_probe+0xa8/0xd4)
[ 0.778860] [<c051511c>] (i2c_device_probe+0xa8/0xd4) from [<c02fe0dc>] (really_probe+0xa8/0x20c)
[ 0.778898] [<c02fe0dc>] (really_probe+0xa8/0x20c) from [<c02fe338>] (driver_probe_device+0x30/0x48)
[ 0.778936] [<c02fe338>] (driver_probe_device+0x30/0x48) from [<c02fe3b0>] (__driver_attach+0x60/0x84)
[ 0.778975] [<c02fe3b0>] (__driver_attach+0x60/0x84) from [<c02fcb8c>] (bus_for_each_dev+0x50/0x90)
[ 0.779012] [<c02fcb8c>] (bus_for_each_dev+0x50/0x90) from [<c02fd93c>] (bus_add_driver+0xac/0x20c)
[ 0.779050] [<c02fd93c>] (bus_add_driver+0xac/0x20c) from [<c02fe88c>] (driver_register+0x9c/0x138)
[ 0.779089] [<c02fe88c>] (driver_register+0x9c/0x138) from [<c0516c30>] (i2c_register_driver+0x40/0xac)
[ 0.779128] [<c0516c30>] (i2c_register_driver+0x40/0xac) from [<c0bc15e8>] (rk818_module_init+0x10/0x34)
[ 0.779167] [<c0bc15e8>] (rk818_module_init+0x10/0x34) from [<c00086a4>] (do_one_initcall+0x34/0xc8)
[ 0.779207] [<c00086a4>] (do_one_initcall+0x34/0xc8) from [<c0b99b28>] (do_initcalls+0x70/0xa0)
[ 0.779249] [<c0b99b28>] (do_initcalls+0x70/0xa0) from [<c0b99be8>] (kernel_init_freeable+0x90/0x130)
[ 0.779290] [<c0b99be8>] (kernel_init_freeable+0x90/0x130) from [<c08252fc>] (kernel_init+0x8/0xe4)
[ 0.779331] [<c08252fc>] (kernel_init+0x8/0xe4) from [<c000da98>] (ret_from_fork+0x14/0x3c)
[ 0.779356] ---[ end trace c5f9e7e849c370b0 ]---
