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Subject[PATCHv2 3/3] mcp23s08: add i2c support
Date
Add i2c bindings for the mcp230xx devices. This is quite a lot simpler
than the spi one as there's no funky sub addressing done (one struct
i2c_client per struct gpio_chip).

The mcp23s08_platform_data structure is reused for i2c, even though
only a single mcp23s08_chip_info structure is needed.

To use, simply fill out a platform_data structure and pass it in
i2c_board_info, E.G.:

static const struct mcp23s08_platform_data mcp23017_data = {
.chip[0] = {
.pullups = 0x00ff,
},
.base = 240,
};

static struct i2c_board_info __initdata i2c_devs[] = {
{ I2C_BOARD_INFO("mcp23017", 0x20),
.platform_data = &smartview_mcp23017_data, },
...
};

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
---
Changes since v1:
- Adjust according to Grants feedback
- Add mcp23s08_i2c_{init,exit} wrappers. Unwind on registration failures

drivers/gpio/Kconfig | 7 +-
drivers/gpio/gpio-mcp23s08.c | 192 ++++++++++++++++++++++++++++++++++++++++-
2 files changed, 191 insertions(+), 8 deletions(-)

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 111321c..6778f56 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -418,10 +418,11 @@ config GPIO_MAX7301
GPIO driver for Maxim MAX7301 SPI-based GPIO expander.

config GPIO_MCP23S08
- tristate "Microchip MCP23Sxx I/O expander"
- depends on SPI_MASTER
+ tristate "Microchip MCP23xxx I/O expander"
+ depends on SPI_MASTER || I2C
help
- SPI driver for Microchip MCP23S08/MPC23S17 I/O expanders.
+ SPI/I2C driver for Microchip MCP23S08/MCP23S17/MCP23008/MCP23017
+ I/O expanders.
This provides a GPIO interface supporting inputs and outputs.

config GPIO_MC33880
diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c
index 7b78f94..1ef46e6 100644
--- a/drivers/gpio/gpio-mcp23s08.c
+++ b/drivers/gpio/gpio-mcp23s08.c
@@ -1,11 +1,12 @@
/*
- * MCP23S08 SPI gpio expander driver
+ * MCP23S08 SPI/GPIO gpio expander driver
*/

#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/gpio.h>
+#include <linux/i2c.h>
#include <linux/spi/spi.h>
#include <linux/spi/mcp23s08.h>
#include <linux/slab.h>
@@ -16,13 +17,13 @@
*/
#define MCP_TYPE_S08 0
#define MCP_TYPE_S17 1
+#define MCP_TYPE_008 2
+#define MCP_TYPE_017 3

/* Registers are all 8 bits wide.
*
* The mcp23s17 has twice as many bits, and can be configured to work
* with either 16 bit registers or with two adjacent 8 bit banks.
- *
- * Also, there are I2C versions of both chips.
*/
#define MCP_IODIR 0x00 /* init/reset: all ones */
#define MCP_IPOL 0x01
@@ -73,6 +74,72 @@ struct mcp23s08_driver_data {
struct mcp23s08 chip[];
};

+/*----------------------------------------------------------------------*/
+
+#ifdef CONFIG_I2C
+
+static int mcp23008_read(struct mcp23s08 *mcp, unsigned reg)
+{
+ return i2c_smbus_read_byte_data(mcp->data, reg);
+}
+
+static int mcp23008_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
+{
+ return i2c_smbus_write_byte_data(mcp->data, reg, val);
+}
+
+static int
+mcp23008_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
+{
+ while (n--) {
+ int ret = mcp23008_read(mcp, reg++);
+ if (ret < 0)
+ return ret;
+ *vals++ = ret;
+ }
+
+ return 0;
+}
+
+static int mcp23017_read(struct mcp23s08 *mcp, unsigned reg)
+{
+ return i2c_smbus_read_word_data(mcp->data, reg << 1);
+}
+
+static int mcp23017_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
+{
+ return i2c_smbus_write_word_data(mcp->data, reg << 1, val);
+}
+
+static int
+mcp23017_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
+{
+ while (n--) {
+ int ret = mcp23017_read(mcp, reg++);
+ if (ret < 0)
+ return ret;
+ *vals++ = ret;
+ }
+
+ return 0;
+}
+
+static const struct mcp23s08_ops mcp23008_ops = {
+ .read = mcp23008_read,
+ .write = mcp23008_write,
+ .read_regs = mcp23008_read_regs,
+};
+
+static const struct mcp23s08_ops mcp23017_ops = {
+ .read = mcp23017_read,
+ .write = mcp23017_write,
+ .read_regs = mcp23017_read_regs,
+};
+
+#endif /* CONFIG_I2C */
+
+/*----------------------------------------------------------------------*/
+
#ifdef CONFIG_SPI_MASTER

static int mcp23s08_read(struct mcp23s08 *mcp, unsigned reg)
@@ -331,6 +398,20 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
break;
#endif /* CONFIG_SPI_MASTER */

+#ifdef CONFIG_I2C
+ case MCP_TYPE_008:
+ mcp->ops = &mcp23008_ops;
+ mcp->chip.ngpio = 8;
+ mcp->chip.label = "mcp23008";
+ break;
+
+ case MCP_TYPE_017:
+ mcp->ops = &mcp23017_ops;
+ mcp->chip.ngpio = 16;
+ mcp->chip.label = "mcp23017";
+ break;
+#endif /* CONFIG_I2C */
+
default:
dev_err(dev, "invalid device type (%d)\n", type);
return -EINVAL;
@@ -389,6 +470,91 @@ fail:
return status;
}

+/*----------------------------------------------------------------------*/
+
+#ifdef CONFIG_I2C
+
+static int __devinit mcp230xx_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct mcp23s08_platform_data *pdata;
+ struct mcp23s08 *mcp;
+ int status;
+
+ pdata = client->dev.platform_data;
+ if (!pdata || !gpio_is_valid(pdata->base)) {
+ dev_dbg(&client->dev, "invalid or missing platform data\n");
+ return -EINVAL;
+ }
+
+ mcp = kzalloc(sizeof *mcp, GFP_KERNEL);
+ if (!mcp)
+ return -ENOMEM;
+
+ status = mcp23s08_probe_one(mcp, &client->dev, client, client->addr,
+ id->driver_data, pdata->base,
+ pdata->chip[0].pullups);
+ if (status)
+ goto fail;
+
+ i2c_set_clientdata(client, mcp);
+
+ return 0;
+
+fail:
+ kfree(mcp);
+
+ return status;
+}
+
+static int __devexit mcp230xx_remove(struct i2c_client *client)
+{
+ struct mcp23s08 *mcp = i2c_get_clientdata(client);
+ int status;
+
+ status = gpiochip_remove(&mcp->chip);
+ if (status == 0)
+ kfree(mcp);
+
+ return status;
+}
+
+static const struct i2c_device_id mcp230xx_id[] = {
+ { "mcp23008", MCP_TYPE_008 },
+ { "mcp23017", MCP_TYPE_017 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, mcp230xx_id);
+
+static struct i2c_driver mcp230xx_driver = {
+ .driver = {
+ .name = "mcp230xx",
+ .owner = THIS_MODULE,
+ },
+ .probe = mcp230xx_probe,
+ .remove = __devexit_p(mcp230xx_remove),
+ .id_table = mcp230xx_id,
+};
+
+static int __init mcp23s08_i2c_init(void)
+{
+ return i2c_add_driver(&mcp230xx_driver);
+}
+
+static void mcp23s08_i2c_exit(void)
+{
+ i2c_del_driver(&mcp230xx_driver);
+}
+
+#else
+
+static int __init mcp23s08_i2c_init(void) { return 0; }
+static void mcp23s08_i2c_exit(void) { }
+
+#endif /* CONFIG_I2C */
+
+/*----------------------------------------------------------------------*/
+
#ifdef CONFIG_SPI_MASTER

static int mcp23s08_probe(struct spi_device *spi)
@@ -525,9 +691,24 @@ static void mcp23s08_spi_exit(void) { }

static int __init mcp23s08_init(void)
{
- return mcp23s08_spi_init();
+ int ret;
+
+ ret = mcp23s08_spi_init();
+ if (ret)
+ goto spi_fail;
+
+ ret = mcp23s08_i2c_init();
+ if (ret)
+ goto i2c_fail;
+
+ return 0;
+
+ i2c_fail:
+ mcp23s08_spi_exit();
+ spi_fail:
+ return ret;
}
-/* register after spi postcore initcall and before
+/* register after spi/i2c postcore initcall and before
* subsys initcalls that may rely on these GPIOs
*/
subsys_initcall(mcp23s08_init);
@@ -535,6 +716,7 @@ subsys_initcall(mcp23s08_init);
static void __exit mcp23s08_exit(void)
{
mcp23s08_spi_exit();
+ mcp23s08_i2c_exit();
}
module_exit(mcp23s08_exit);

--
1.7.5.4


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