diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-07-22 14:50:57 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-07-22 14:50:57 -0700 |
commit | c7c8518498e82591d7784452f5674c3aeb4d079c (patch) | |
tree | 790ff7e6b6741daf32ec686b9a302b957b07c0f4 /drivers/gpio/gpio-max7301.c | |
parent | ece236ce2fad9c27a6fd2530f899289025194bce (diff) | |
parent | 591567a5ea25852f20b7ef2953f6f72020121199 (diff) |
Merge branch 'gpio/next' of git://git.secretlab.ca/git/linux-2.6
* 'gpio/next' of git://git.secretlab.ca/git/linux-2.6: (61 commits)
gpio/mxc/mxs: fix build error introduced by the irq_gc_ack() renaming
mcp23s08: add i2c support
mcp23s08: isolate spi specific parts
mcp23s08: get rid of setup/teardown callbacks
gpio/tegra: dt: add binding for gpio polarity
mcp23s08: remove unused work queue
gpio/da9052: remove a redundant assignment for gpio->da9052
gpio/mxc: add device tree probe support
ARM: mxc: use ARCH_NR_GPIOS to define gpio number
gpio/mxc: get rid of the uses of cpu_is_mx()
gpio/mxc: add missing initialization of basic_mmio_gpio shadow variables
gpio: Move mpc5200 gpio driver to drivers/gpio
GPIO: DA9052 GPIO module v3
gpio/tegra: Use engineering names in DT compatible property
of/gpio: Add new method for getting gpios under different property names
gpio/dt: Refine GPIO device tree binding
gpio/ml-ioh: fix off-by-one for displaying variable i in dev_err
gpio/pca953x: Deprecate meaningless device-tree bindings
gpio/pca953x: Remove dynamic platform data pointer
gpio/pca953x: Fix IRQ support.
...
Diffstat (limited to 'drivers/gpio/gpio-max7301.c')
-rw-r--r-- | drivers/gpio/gpio-max7301.c | 116 |
1 files changed, 116 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-max7301.c b/drivers/gpio/gpio-max7301.c new file mode 100644 index 00000000000..741acfcbe76 --- /dev/null +++ b/drivers/gpio/gpio-max7301.c @@ -0,0 +1,116 @@ +/* + * 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 __devinit 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 = kzalloc(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); + if (ret) + kfree(ts); + return ret; +} + +static int __devexit 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 = __devexit_p(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"); |