diff options
author | 2015-08-04 12:17:53 -0700 | |
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committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/gpio/gpio-max7301.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/gpio/gpio-max7301.c')
-rw-r--r-- | kernel/drivers/gpio/gpio-max7301.c | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/kernel/drivers/gpio/gpio-max7301.c b/kernel/drivers/gpio/gpio-max7301.c new file mode 100644 index 000000000..6e1c984a7 --- /dev/null +++ b/kernel/drivers/gpio/gpio-max7301.c @@ -0,0 +1,114 @@ +/* + * Copyright (C) 2006 Juergen Beisert, Pengutronix + * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix + * Copyright (C) 2009 Wolfram Sang, Pengutronix + * + * 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. + * + * Check max730x.c for further details. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/spi/spi.h> +#include <linux/spi/max7301.h> + +/* A write to the MAX7301 means one message with one transfer */ +static int max7301_spi_write(struct device *dev, unsigned int reg, + unsigned int val) +{ + struct spi_device *spi = to_spi_device(dev); + u16 word = ((reg & 0x7F) << 8) | (val & 0xFF); + + return spi_write(spi, (const u8 *)&word, sizeof(word)); +} + +/* A read from the MAX7301 means two transfers; here, one message each */ + +static int max7301_spi_read(struct device *dev, unsigned int reg) +{ + int ret; + u16 word; + struct spi_device *spi = to_spi_device(dev); + + word = 0x8000 | (reg << 8); + ret = spi_write(spi, (const u8 *)&word, sizeof(word)); + if (ret) + return ret; + /* + * This relies on the fact, that a transfer with NULL tx_buf shifts out + * zero bytes (=NOOP for MAX7301) + */ + ret = spi_read(spi, (u8 *)&word, sizeof(word)); + if (ret) + return ret; + return word & 0xff; +} + +static int max7301_probe(struct spi_device *spi) +{ + struct max7301 *ts; + int ret; + + /* bits_per_word cannot be configured in platform data */ + spi->bits_per_word = 16; + ret = spi_setup(spi); + if (ret < 0) + return ret; + + ts = devm_kzalloc(&spi->dev, sizeof(struct max7301), GFP_KERNEL); + if (!ts) + return -ENOMEM; + + ts->read = max7301_spi_read; + ts->write = max7301_spi_write; + ts->dev = &spi->dev; + + ret = __max730x_probe(ts); + return ret; +} + +static int max7301_remove(struct spi_device *spi) +{ + return __max730x_remove(&spi->dev); +} + +static const struct spi_device_id max7301_id[] = { + { "max7301", 0 }, + { } +}; +MODULE_DEVICE_TABLE(spi, max7301_id); + +static struct spi_driver max7301_driver = { + .driver = { + .name = "max7301", + .owner = THIS_MODULE, + }, + .probe = max7301_probe, + .remove = max7301_remove, + .id_table = max7301_id, +}; + +static int __init max7301_init(void) +{ + return spi_register_driver(&max7301_driver); +} +/* register after spi postcore initcall and before + * subsys initcalls that may rely on these GPIOs + */ +subsys_initcall(max7301_init); + +static void __exit max7301_exit(void) +{ + spi_unregister_driver(&max7301_driver); +} +module_exit(max7301_exit); + +MODULE_AUTHOR("Juergen Beisert, Wolfram Sang"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("MAX7301 GPIO-Expander"); |