diff options
Diffstat (limited to 'kernel/arch/arm/mach-sa1100/jornada720_ssp.c')
| -rw-r--r-- | kernel/arch/arm/mach-sa1100/jornada720_ssp.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/kernel/arch/arm/mach-sa1100/jornada720_ssp.c b/kernel/arch/arm/mach-sa1100/jornada720_ssp.c new file mode 100644 index 000000000..b143c4659 --- /dev/null +++ b/kernel/arch/arm/mach-sa1100/jornada720_ssp.c @@ -0,0 +1,203 @@ +/** + * arch/arm/mac-sa1100/jornada720_ssp.c + * + * Copyright (C) 2006/2007 Kristoffer Ericson <Kristoffer.Ericson@gmail.com> + * Copyright (C) 2006 Filip Zyzniewski <filip.zyzniewski@tefnet.pl> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * SSP driver for the HP Jornada 710/720/728 + */ + +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/sched.h> +#include <linux/io.h> + +#include <mach/hardware.h> +#include <mach/jornada720.h> +#include <asm/hardware/ssp.h> + +static DEFINE_SPINLOCK(jornada_ssp_lock); +static unsigned long jornada_ssp_flags; + +/** + * jornada_ssp_reverse - reverses input byte + * + * we need to reverse all data we receive from the mcu due to its physical location + * returns : 01110111 -> 11101110 + */ +u8 inline jornada_ssp_reverse(u8 byte) +{ + return + ((0x80 & byte) >> 7) | + ((0x40 & byte) >> 5) | + ((0x20 & byte) >> 3) | + ((0x10 & byte) >> 1) | + ((0x08 & byte) << 1) | + ((0x04 & byte) << 3) | + ((0x02 & byte) << 5) | + ((0x01 & byte) << 7); +}; +EXPORT_SYMBOL(jornada_ssp_reverse); + +/** + * jornada_ssp_byte - waits for ready ssp bus and sends byte + * + * waits for fifo buffer to clear and then transmits, if it doesn't then we will + * timeout after <timeout> rounds. Needs mcu running before its called. + * + * returns : %mcu output on success + * : %-ETIMEDOUT on timeout + */ +int jornada_ssp_byte(u8 byte) +{ + int timeout = 400000; + u16 ret; + + while ((GPLR & GPIO_GPIO10)) { + if (!--timeout) { + printk(KERN_WARNING "SSP: timeout while waiting for transmit\n"); + return -ETIMEDOUT; + } + cpu_relax(); + } + + ret = jornada_ssp_reverse(byte) << 8; + + ssp_write_word(ret); + ssp_read_word(&ret); + + return jornada_ssp_reverse(ret); +}; +EXPORT_SYMBOL(jornada_ssp_byte); + +/** + * jornada_ssp_inout - decide if input is command or trading byte + * + * returns : (jornada_ssp_byte(byte)) on success + * : %-ETIMEDOUT on timeout failure + */ +int jornada_ssp_inout(u8 byte) +{ + int ret, i; + + /* true means command byte */ + if (byte != TXDUMMY) { + ret = jornada_ssp_byte(byte); + /* Proper return to commands is TxDummy */ + if (ret != TXDUMMY) { + for (i = 0; i < 256; i++)/* flushing bus */ + if (jornada_ssp_byte(TXDUMMY) == -1) + break; + return -ETIMEDOUT; + } + } else /* Exchange TxDummy for data */ + ret = jornada_ssp_byte(TXDUMMY); + + return ret; +}; +EXPORT_SYMBOL(jornada_ssp_inout); + +/** + * jornada_ssp_start - enable mcu + * + */ +void jornada_ssp_start(void) +{ + spin_lock_irqsave(&jornada_ssp_lock, jornada_ssp_flags); + GPCR = GPIO_GPIO25; + udelay(50); + return; +}; +EXPORT_SYMBOL(jornada_ssp_start); + +/** + * jornada_ssp_end - disable mcu and turn off lock + * + */ +void jornada_ssp_end(void) +{ + GPSR = GPIO_GPIO25; + spin_unlock_irqrestore(&jornada_ssp_lock, jornada_ssp_flags); + return; +}; +EXPORT_SYMBOL(jornada_ssp_end); + +static int jornada_ssp_probe(struct platform_device *dev) +{ + int ret; + + GPSR = GPIO_GPIO25; + + ret = ssp_init(); + + /* worked fine, lets not bother with anything else */ + if (!ret) { + printk(KERN_INFO "SSP: device initialized with irq\n"); + return ret; + } + + printk(KERN_WARNING "SSP: initialization failed, trying non-irq solution \n"); + + /* init of Serial 4 port */ + Ser4MCCR0 = 0; + Ser4SSCR0 = 0x0387; + Ser4SSCR1 = 0x18; + + /* clear out any left over data */ + ssp_flush(); + + /* enable MCU */ + jornada_ssp_start(); + + /* see if return value makes sense */ + ret = jornada_ssp_inout(GETBRIGHTNESS); + + /* seems like it worked, just feed it with TxDummy to get rid of data */ + if (ret == TXDUMMY) + jornada_ssp_inout(TXDUMMY); + + jornada_ssp_end(); + + /* failed, lets just kill everything */ + if (ret == -ETIMEDOUT) { + printk(KERN_WARNING "SSP: attempts failed, bailing\n"); + ssp_exit(); + return -ENODEV; + } + + /* all fine */ + printk(KERN_INFO "SSP: device initialized\n"); + return 0; +}; + +static int jornada_ssp_remove(struct platform_device *dev) +{ + /* Note that this doesn't actually remove the driver, since theres nothing to remove + * It just makes sure everything is turned off */ + GPSR = GPIO_GPIO25; + ssp_exit(); + return 0; +}; + +struct platform_driver jornadassp_driver = { + .probe = jornada_ssp_probe, + .remove = jornada_ssp_remove, + .driver = { + .name = "jornada_ssp", + }, +}; + +static int __init jornada_ssp_init(void) +{ + return platform_driver_register(&jornadassp_driver); +} + +module_init(jornada_ssp_init); |