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authorLinus Torvalds <torvalds@linux-foundation.org>2011-07-22 14:50:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-07-22 14:50:57 -0700
commitc7c8518498e82591d7784452f5674c3aeb4d079c (patch)
tree790ff7e6b6741daf32ec686b9a302b957b07c0f4 /drivers/gpio/gpio-max7301.c
parentece236ce2fad9c27a6fd2530f899289025194bce (diff)
parent591567a5ea25852f20b7ef2953f6f72020121199 (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.c116
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");