Add the MAX7300-I2C variant to the MAX7301-SPI version. They share most parts
of the driver (i.e. the logic) and the read/write-register functions get
encapsulated. It is thus possible to use both variants simultaneously. (This
is the outcome of an experiment how to combine I2C and SPI into one driver.)
Signed-off-by: Wolfram Sang <w.sang@xxxxxxxxxxxxxx>
Cc: Juergen Beisert <j.beisert@xxxxxxxxxxxxxx>
Cc: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Cc: Jean Delvare <khali@xxxxxxxxxxxx>
Cc: Anton Vorontsov <avorontsov@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Changes since V2:
* improve Kconfig logic. Main part depends now on I2C or SPI (Thanks again, Anton!).
Seperate busses are now 'default y' if a bus is present, so old defconfigs will
update automatically (it is also more convenient).
* use already present #defines instead of hardcoded values
* add some empty lines to make code more readable
Changes since V1:
* Use id_table for spi, too (Thanks to Anton for the hint!)
* removed some whitespace issues
* in driver init, remove first driver if registering the second fails
drivers/gpio/Kconfig | 27 ++++-
drivers/gpio/max7301.c | 307 ++++++++++++++++++++++++++++++++----------------
2 files changed, 225 insertions(+), 109 deletions(-)
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 2ad0128..3ba21c7 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -65,6 +65,27 @@ config GPIO_SYSFS
# put expanders in the right section, in alphabetical order
+comment "GPIO expanders for multiple busses"
+
+config GPIO_MAX7301
+ tristate "Maxim MAX730x GPIO expander"
+ depends on I2C || SPI_MASTER
+ help
+ GPIO driver for Maxim MAX7300/7301 GPIO expanders.
+ Also select which bus you want to use.
+
+if GPIO_MAX7301
+config GPIO_MAX7301_I2C
+ bool "I2C support (for MAX7300)"
+ depends on I2C
+ default y
+
+config GPIO_MAX7301_SPI
+ bool "SPI support (for MAX7301)"
+ depends on SPI_MASTER
+ default y
+endif
+
comment "Memory mapped GPIO expanders:"
config GPIO_PL061
@@ -198,12 +219,6 @@ config GPIO_LANGWELL
comment "SPI GPIO expanders:"
-config GPIO_MAX7301
- tristate "Maxim MAX7301 GPIO expander"
- depends on SPI_MASTER
- help
- gpio driver for Maxim MAX7301 SPI GPIO expander.
-
config GPIO_MCP23S08
tristate "Microchip MCP23S08 I/O expander"
depends on SPI_MASTER
diff --git a/drivers/gpio/max7301.c b/drivers/gpio/max7301.c
index 480956f..8a4233f 100644
--- a/drivers/gpio/max7301.c
+++ b/drivers/gpio/max7301.c
@@ -3,6 +3,7 @@
*
* 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
@@ -34,12 +35,11 @@
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
+#include <linux/i2c.h>
#include <linux/spi/spi.h>
#include <linux/spi/max7301.h>
#include <linux/gpio.h>
-#define DRIVER_NAME "max7301"
-
/*
* Pin configurations, see MAX7301 datasheet page 6
*/
@@ -50,7 +50,6 @@
#define PIN_NUMBER 28
-
/*
* Some registers must be read back to modify.
* To save time we cache them here in memory
@@ -60,62 +59,21 @@ struct max7301 {
u8 port_config[8]; /* field 0 is unused */
u32 out_level; /* cached output levels */
struct gpio_chip chip;
- struct spi_device *spi;
+ struct device *dev;
+ int (*write)(struct device *dev, unsigned int reg, unsigned int val);
+ int (*read)(struct device *dev, unsigned int reg);
};
-/**
- * max7301_write - Write a new register content
- * @spi: The SPI device
- * @reg: Register offset
- * @val: Value to write
- *
- * A write to the MAX7301 means one message with one transfer
- *
- * Returns 0 if successful or a negative value on error
- */
-static int max7301_write(struct spi_device *spi, unsigned int reg, unsigned int val)
-{
- u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);
- return spi_write(spi, (const u8 *)&word, sizeof(word));
-}
-
-/**
- * max7301_read - Read back register content
- * @spi: The SPI device
- * @reg: Register offset
- *
- * A read from the MAX7301 means two transfers; here, one message each
- *
- * Returns positive 8 bit value from device if successful or a
- * negative value on error
- */
-static int max7301_read(struct spi_device *spi, unsigned int reg)
-{
- int ret;
- u16 word;
-
- 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_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct max7301 *ts = container_of(chip, struct max7301, chip);
u8 *config;
+ u8 offset_bits;
int ret;
/* First 4 pins are unused in the controller */
offset += 4;
+ offset_bits = (offset & 3) << 1;
config = &ts->port_config[offset >> 2];
@@ -123,9 +81,10 @@ static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
/* Standard GPIO API doesn't support pull-ups, has to be extended.
* Hard-coding no pollup for now. */
- *config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3));
+ *config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
+ | (PIN_CONFIG_IN_WO_PULLUP << offset_bits);
- ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config);
+ ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
mutex_unlock(&ts->lock);
@@ -136,10 +95,10 @@ static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
{
if (value) {
ts->out_level |= 1 << offset;
- return max7301_write(ts->spi, 0x20 + offset, 0x01);
+ return ts->write(ts->dev, 0x20 + offset, 0x01);
} else {
ts->out_level &= ~(1 << offset);
- return max7301_write(ts->spi, 0x20 + offset, 0x00);
+ return ts->write(ts->dev, 0x20 + offset, 0x00);
}
}
@@ -148,21 +107,24 @@ static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
{
struct max7301 *ts = container_of(chip, struct max7301, chip);
u8 *config;
+ u8 offset_bits;
int ret;
/* First 4 pins are unused in the controller */
offset += 4;
+ offset_bits = (offset & 3) << 1;
config = &ts->port_config[offset >> 2];
mutex_lock(&ts->lock);
- *config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3));
+ *config = (*config & ~(PIN_CONFIG_MASK << offset_bits))
+ | (PIN_CONFIG_OUT << offset_bits);
ret = __max7301_set(ts, offset, value);
if (!ret)
- ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config);
+ ret = ts->write(ts->dev, 0x08 + (offset >> 2), *config);
mutex_unlock(&ts->lock);
@@ -179,17 +141,18 @@ static int max7301_get(struct gpio_chip *chip, unsigned offset)
mutex_lock(&ts->lock);
- config = (ts->port_config[offset >> 2] >> ((offset & 3) * 2)) & 3;
+ config = (ts->port_config[offset >> 2] >> ((offset & 3) << 1))
+ & PIN_CONFIG_MASK;
switch (config) {
- case 1:
+ case PIN_CONFIG_OUT:
/* Output: return cached level */
level = !!(ts->out_level & (1 << offset));
break;
- case 2:
- case 3:
+ case PIN_CONFIG_IN_WO_PULLUP:
+ case PIN_CONFIG_IN_PULLUP:
/* Input: read out */
- level = max7301_read(ts->spi, 0x20 + offset) & 0x01;
+ level = ts->read(ts->dev, 0x20 + offset) & 0x01;
}
mutex_unlock(&ts->lock);
@@ -210,41 +173,25 @@ static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
mutex_unlock(&ts->lock);
}
-static int __devinit max7301_probe(struct spi_device *spi)
+static int __devinit __max7301_probe(struct max7301 *ts)
{
- struct max7301 *ts;
+ struct device *dev = ts->dev;
struct max7301_platform_data *pdata;
int i, ret;
- pdata = spi->dev.platform_data;
+ pdata = dev->platform_data;
if (!pdata || !pdata->base) {
- dev_dbg(&spi->dev, "incorrect or missing platform data\n");
+ dev_err(dev, "incorrect or missing platform data\n");
return -EINVAL;
}
- /*
- * 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;
-
mutex_init(&ts->lock);
-
- dev_set_drvdata(&spi->dev, ts);
+ dev_set_drvdata(dev, ts);
/* Power up the chip and disable IRQ output */
- max7301_write(spi, 0x04, 0x01);
-
- ts->spi = spi;
+ ts->write(dev, 0x04, 0x01);
- ts->chip.label = DRIVER_NAME,
+ ts->chip.label = dev->driver->name;
ts->chip.direction_input = max7301_direction_input;
ts->chip.get = max7301_get;
@@ -254,7 +201,7 @@ static int __devinit max7301_probe(struct spi_device *spi)
ts->chip.base = pdata->base;
ts->chip.ngpio = PIN_NUMBER;
ts->chip.can_sleep = 1;
- ts->chip.dev = &spi->dev;
+ ts->chip.dev = dev;
ts->chip.owner = THIS_MODULE;
/*
@@ -264,7 +211,7 @@ static int __devinit max7301_probe(struct spi_device *spi)
for (i = 1; i < 8; i++) {
int j;
/* 0xAA means input with internal pullup disabled */
- max7301_write(spi, 0x08 + i, 0xAA);
+ ts->write(dev, 0x08 + i, 0xAA);
ts->port_config[i] = 0xAA;
for (j = 0; j < 4; j++) {
int offset = (i - 1) * 4 + j;
@@ -281,49 +228,203 @@ static int __devinit max7301_probe(struct spi_device *spi)
return ret;
exit_destroy:
- dev_set_drvdata(&spi->dev, NULL);
+ dev_set_drvdata(dev, NULL);
mutex_destroy(&ts->lock);
- kfree(ts);
return ret;
}
-static int __devexit max7301_remove(struct spi_device *spi)
+static int __devexit __max7301_remove(struct device *dev)
{
- struct max7301 *ts;
+ struct max7301 *ts = dev_get_drvdata(dev);
int ret;
- ts = dev_get_drvdata(&spi->dev);
if (ts == NULL)
return -ENODEV;
- dev_set_drvdata(&spi->dev, NULL);
+ dev_set_drvdata(dev, NULL);
/* Power down the chip and disable IRQ output */
- max7301_write(spi, 0x04, 0x00);
+ ts->write(dev, 0x04, 0x00);
ret = gpiochip_remove(&ts->chip);
if (!ret) {
mutex_destroy(&ts->lock);
kfree(ts);
} else
- dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
- ret);
+ dev_err(dev, "Failed to remove GPIO controller: %d\n", ret);
+
+ return ret;
+}
+
+#ifdef CONFIG_GPIO_MAX7301_SPI
+
+/* 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 = __max7301_probe(ts);
+ if (ret)
+ kfree(ts);
return ret;
}
+static int __devexit max7301_remove(struct spi_device *spi)
+{
+ return __max7301_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 = DRIVER_NAME,
- .owner = THIS_MODULE,
+ .name = "max7301",
+ .owner = THIS_MODULE,
},
- .probe = max7301_probe,
- .remove = __devexit_p(max7301_remove),
+ .probe = max7301_probe,
+ .remove = __devexit_p(max7301_remove),
+ .id_table = max7301_id,
};
+#define max7301_add_driver(drv) spi_register_driver(drv)
+#define max7301_del_driver(drv) spi_unregister_driver(drv)
+#else
+#define max7301_add_driver(drv) (0)
+#define max7301_del_driver(drv) do { } while (0)
+#endif /* CONFIG_GPIO_MAX7301_SPI */
+
+#ifdef CONFIG_GPIO_MAX7301_I2C
+
+static int max7301_i2c_write(struct device *dev, unsigned int reg,
+ unsigned int val)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+
+ return i2c_smbus_write_byte_data(client, reg, val);
+}
+
+static int max7301_i2c_read(struct device *dev, unsigned int reg)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+
+ return i2c_smbus_read_byte_data(client, reg);
+}
+
+static int __devinit max7300_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct max7301 *ts;
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_BYTE_DATA))
+ return -EIO;
+
+ ts = kzalloc(sizeof(struct max7301), GFP_KERNEL);
+ if (!ts)
+ return -ENOMEM;
+
+ ts->read = max7301_i2c_read;
+ ts->write = max7301_i2c_write;
+ ts->dev = &client->dev;
+
+ ret = __max7301_probe(ts);
+ if (ret)
+ kfree(ts);
+ return ret;
+}
+
+static int __devexit max7300_remove(struct i2c_client *client)
+{
+ return __max7301_remove(&client->dev);
+}
+
+static const struct i2c_device_id max7300_id[] = {
+ { "max7300", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, max7300_id);
+
+static struct i2c_driver max7300_driver = {
+ .driver = {
+ .name = "max7300",
+ .owner = THIS_MODULE,
+ },
+ .probe = max7300_probe,
+ .remove = __devexit_p(max7300_remove),
+ .id_table = max7300_id,
+};
+
+#define max7300_add_driver(drv) i2c_add_driver(drv)
+#define max7300_del_driver(drv) i2c_del_driver(drv)
+#else
+#define max7300_add_driver(drv) (0)
+#define max7300_del_driver(drv) do { } while (0)
+#endif /* CONFIG_GPIO_MAX7301_I2C */
+
static int __init max7301_init(void)
{
- return spi_register_driver(&max7301_driver);
+ int ret;
+
+ ret = max7300_add_driver(&max7300_driver);
+ if (ret)
+ return ret;
+
+ ret = max7301_add_driver(&max7301_driver);
+ if (ret)
+ max7300_del_driver(&max7300_driver);
+
+ return ret;
}
/* register after spi postcore initcall and before
* subsys initcalls that may rely on these GPIOs
@@ -332,11 +433,11 @@ subsys_initcall(max7301_init);
static void __exit max7301_exit(void)
{
- spi_unregister_driver(&max7301_driver);
+ max7300_del_driver(&max7300_driver);
+ max7301_del_driver(&max7301_driver);
}
module_exit(max7301_exit);
-MODULE_AUTHOR("Juergen Beisert");
+MODULE_AUTHOR("Juergen Beisert, Wolfram Sang");
MODULE_LICENSE("GPL v2");
-MODULE_DESCRIPTION("MAX7301 SPI based GPIO-Expander");
-MODULE_ALIAS("spi:" DRIVER_NAME);
+MODULE_DESCRIPTION("MAX7300/1 based GPIO-Expander");
--
1.6.3.3
--
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