diff options
Diffstat (limited to 'drivers/auxdisplay/ks0108.c')
| -rw-r--r-- | drivers/auxdisplay/ks0108.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/drivers/auxdisplay/ks0108.c b/drivers/auxdisplay/ks0108.c new file mode 100644 index 0000000000..234f9dbe6e --- /dev/null +++ b/drivers/auxdisplay/ks0108.c @@ -0,0 +1,172 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Filename: ks0108.c + * Version: 0.1.0 + * Description: ks0108 LCD Controller driver + * Depends: parport + * + * Author: Copyright (C) Miguel Ojeda <ojeda@kernel.org> + * Date: 2006-10-31 + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/delay.h> +#include <linux/parport.h> +#include <linux/ks0108.h> + +#define KS0108_NAME "ks0108" + +/* + * Module Parameters + */ + +static unsigned int ks0108_port = CONFIG_KS0108_PORT; +module_param(ks0108_port, uint, 0444); +MODULE_PARM_DESC(ks0108_port, "Parallel port where the LCD is connected"); + +static unsigned int ks0108_delay = CONFIG_KS0108_DELAY; +module_param(ks0108_delay, uint, 0444); +MODULE_PARM_DESC(ks0108_delay, "Delay between each control writing (microseconds)"); + +/* + * Device + */ + +static struct parport *ks0108_parport; +static struct pardevice *ks0108_pardevice; + +/* + * ks0108 Exported Commands (don't lock) + * + * You _should_ lock in the top driver: This functions _should not_ + * get race conditions in any way. Locking for each byte here would be + * so slow and useless. + * + * There are not bit definitions because they are not flags, + * just arbitrary combinations defined by the documentation for each + * function in the ks0108 LCD controller. If you want to know what means + * a specific combination, look at the function's name. + * + * The ks0108_writecontrol bits need to be reverted ^(0,1,3) because + * the parallel port also revert them using a "not" logic gate. + */ + +#define bit(n) (((unsigned char)1)<<(n)) + +void ks0108_writedata(unsigned char byte) +{ + parport_write_data(ks0108_parport, byte); +} + +void ks0108_writecontrol(unsigned char byte) +{ + udelay(ks0108_delay); + parport_write_control(ks0108_parport, byte ^ (bit(0) | bit(1) | bit(3))); +} + +void ks0108_displaystate(unsigned char state) +{ + ks0108_writedata((state ? bit(0) : 0) | bit(1) | bit(2) | bit(3) | bit(4) | bit(5)); +} + +void ks0108_startline(unsigned char startline) +{ + ks0108_writedata(min_t(unsigned char, startline, 63) | bit(6) | + bit(7)); +} + +void ks0108_address(unsigned char address) +{ + ks0108_writedata(min_t(unsigned char, address, 63) | bit(6)); +} + +void ks0108_page(unsigned char page) +{ + ks0108_writedata(min_t(unsigned char, page, 7) | bit(3) | bit(4) | + bit(5) | bit(7)); +} + +EXPORT_SYMBOL_GPL(ks0108_writedata); +EXPORT_SYMBOL_GPL(ks0108_writecontrol); +EXPORT_SYMBOL_GPL(ks0108_displaystate); +EXPORT_SYMBOL_GPL(ks0108_startline); +EXPORT_SYMBOL_GPL(ks0108_address); +EXPORT_SYMBOL_GPL(ks0108_page); + +/* + * Is the module inited? + */ + +static unsigned char ks0108_inited; +unsigned char ks0108_isinited(void) +{ + return ks0108_inited; +} +EXPORT_SYMBOL_GPL(ks0108_isinited); + +static void ks0108_parport_attach(struct parport *port) +{ + struct pardev_cb ks0108_cb; + + if (port->base != ks0108_port) + return; + + memset(&ks0108_cb, 0, sizeof(ks0108_cb)); + ks0108_cb.flags = PARPORT_DEV_EXCL; + ks0108_pardevice = parport_register_dev_model(port, KS0108_NAME, + &ks0108_cb, 0); + if (!ks0108_pardevice) { + pr_err("ERROR: parport didn't register new device\n"); + return; + } + if (parport_claim(ks0108_pardevice)) { + pr_err("could not claim access to parport %i. Aborting.\n", + ks0108_port); + goto err_unreg_device; + } + + ks0108_parport = port; + ks0108_inited = 1; + return; + +err_unreg_device: + parport_unregister_device(ks0108_pardevice); + ks0108_pardevice = NULL; +} + +static void ks0108_parport_detach(struct parport *port) +{ + if (port->base != ks0108_port) + return; + + if (!ks0108_pardevice) { + pr_err("%s: already unregistered.\n", KS0108_NAME); + return; + } + + parport_release(ks0108_pardevice); + parport_unregister_device(ks0108_pardevice); + ks0108_pardevice = NULL; + ks0108_parport = NULL; +} + +/* + * Module Init & Exit + */ + +static struct parport_driver ks0108_parport_driver = { + .name = "ks0108", + .match_port = ks0108_parport_attach, + .detach = ks0108_parport_detach, + .devmodel = true, +}; +module_parport_driver(ks0108_parport_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Miguel Ojeda <ojeda@kernel.org>"); +MODULE_DESCRIPTION("ks0108 LCD Controller driver"); + |