[PATCH v2] gpio: mcp23s08: convert driver to DT
Lars Poeschel
larsi at wh2.tu-dresden.de
Mon Feb 11 22:52:42 EST 2013
From: Lars Poeschel <poeschel at lemonage.de>
This converts the mcp23s08 driver to be able to be used with device
tree.
Explicitly allow -1 as a legal value for the
mcp23s08_platform_data->base. This is the special value lets the
kernel choose a valid global gpio base number.
There is a "mcp,chips" device tree property, that correspond to the
chips member of the struct mcp23s08_platform_data. It can be used for
multiple mcp23s08/mc23s17 on the same spi chipselect.
Signed-off-by: Lars Poeschel <poeschel at lemonage.de>
---
v2:
- squashed booth patches together
- fixed build warning, when CONFIG_OF is not defined
- use of_match_ptr macro for of_match_table
.../devicetree/bindings/gpio/gpio-mcp23s08.txt | 36 ++++++++
drivers/gpio/gpio-mcp23s08.c | 95 ++++++++++++++++++--
include/linux/spi/mcp23s08.h | 1 +
3 files changed, 126 insertions(+), 6 deletions(-)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
diff --git a/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt b/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
new file mode 100644
index 0000000..17eb669
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
@@ -0,0 +1,36 @@
+Microchip MCP2308/MCP23S08/MCP23017/MCP23S17 driver for
+8-/16-bit I/O expander with serial interface (I2C/SPI)
+
+Required properties:
+- compatible : Should be
+ - "mcp,mcp23s08" for 8 GPIO SPI version
+ - "mcp,mcp23s17" for 16 GPIO SPI version
+ - "mcp,mcp23008" for 8 GPIO I2C version or
+ - "mcp,mcp23017" for 16 GPIO I2C version of the chip
+- #gpio-cells : Should be two.
+ - first cell is the pin number
+ - second cell is used to specify optional parameters (currently unused)
+- gpio-controller : Marks the device node as a GPIO controller.
+- reg : For an address on its bus
+
+Optional device specific properties:
+- mcp,chips : This is a table with 2 columns and up to 8 entries. The first column
+ is a is_present flag, that makes only sense for SPI chips. Multiple
+ chips can share the same chipselect. This flag can be 0 or 1 depending
+ if there is a chip at this address or not.
+ The second column is written to the GPPU register, selecting a 100k
+ pullup resistor or not. Setting a 1 is activating the pullup.
+ For I2C chips only the first line in this table is used. Further chips
+ are registered at different addresses at the I2C bus.
+
+Example:
+gpiom1: gpio at 20 {
+ compatible = "mcp,mcp23017";
+ gpio-controller;
+ #gpio-cells = <2>;
+ reg = <0x20>;
+ chips = <
+ /* is_present pullups */
+ 1 0x07 /* chip address 0 */
+ >;
+};
diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c
index 3cea0ea..ad08a5a 100644
--- a/drivers/gpio/gpio-mcp23s08.c
+++ b/drivers/gpio/gpio-mcp23s08.c
@@ -12,6 +12,8 @@
#include <linux/spi/mcp23s08.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
/**
* MCP types supported by driver
@@ -473,17 +475,88 @@ fail:
/*----------------------------------------------------------------------*/
+#ifdef CONFIG_OF
+static struct of_device_id mcp23s08_of_match[] = {
+#ifdef CONFIG_SPI_MASTER
+ {
+ .compatible = "mcp,mcp23s08",
+ },
+ {
+ .compatible = "mcp,mcp23s17",
+ },
+#endif
+#if IS_ENABLED(CONFIG_I2C)
+ {
+ .compatible = "mcp,mcp23008",
+ },
+ {
+ .compatible = "mcp,mcp23017",
+ },
+#endif
+ { },
+};
+MODULE_DEVICE_TABLE(of, mcp23s08_of_match);
+
+static struct mcp23s08_platform_data *
+ of_get_mcp23s08_pdata(struct device *dev)
+{
+ struct mcp23s08_platform_data *pdata;
+ struct device_node *np = dev->of_node;
+ u32 chips[sizeof(pdata->chip)];
+ int ret, i, j;
+
+ pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return NULL;
+
+ pdata->base = -1;
+
+ for (i = ARRAY_SIZE(pdata->chip) * MCP23S08_CHIP_INFO_MEMBERS;
+ i > 0; i -= MCP23S08_CHIP_INFO_MEMBERS) {
+ ret = of_property_read_u32_array(np, "mcp,chips", chips, i);
+ if (ret == -EOVERFLOW)
+ continue;
+ break;
+ }
+ if (!ret) {
+ for (j = 0; j < i / MCP23S08_CHIP_INFO_MEMBERS ; j++) {
+ pdata->chip[j].is_present =
+ chips[j * MCP23S08_CHIP_INFO_MEMBERS];
+ pdata->chip[j].pullups =
+ chips[j * MCP23S08_CHIP_INFO_MEMBERS + 1];
+ }
+ }
+
+ return pdata;
+}
+#else
+static struct mcp23s08_platform_data *
+ of_get_mcp23s08_pdata(struct device *dev)
+{
+ return NULL;
+}
+#endif /* CONFIG_OF */
+
+
#if IS_ENABLED(CONFIG_I2C)
static int mcp230xx_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
- struct mcp23s08_platform_data *pdata;
+ struct mcp23s08_platform_data *pdata = NULL;
struct mcp23s08 *mcp;
int status;
+ const struct of_device_id *match;
- pdata = client->dev.platform_data;
- if (!pdata || !gpio_is_valid(pdata->base)) {
+ match = of_match_device(of_match_ptr(mcp23s08_of_match), &client->dev);
+ if (match)
+ pdata = of_get_mcp23s08_pdata(&client->dev);
+
+ /* if there was no pdata in DT, take it the legacy way */
+ if (!pdata)
+ pdata = client->dev.platform_data;
+
+ if ((!pdata || !gpio_is_valid(pdata->base)) && pdata->base != -1) {
dev_dbg(&client->dev, "invalid or missing platform data\n");
return -EINVAL;
}
@@ -531,6 +604,7 @@ static struct i2c_driver mcp230xx_driver = {
.driver = {
.name = "mcp230xx",
.owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(mcp23s08_of_match),
},
.probe = mcp230xx_probe,
.remove = mcp230xx_remove,
@@ -560,17 +634,25 @@ static void mcp23s08_i2c_exit(void) { }
static int mcp23s08_probe(struct spi_device *spi)
{
- struct mcp23s08_platform_data *pdata;
+ struct mcp23s08_platform_data *pdata = NULL;
unsigned addr;
unsigned chips = 0;
struct mcp23s08_driver_data *data;
int status, type;
unsigned base;
+ const struct of_device_id *match;
type = spi_get_device_id(spi)->driver_data;
- pdata = spi->dev.platform_data;
- if (!pdata || !gpio_is_valid(pdata->base)) {
+ match = of_match_device(of_match_ptr(mcp23s08_of_match), &spi->dev);
+ if (match)
+ pdata = of_get_mcp23s08_pdata(&spi->dev);
+
+ /* if there was no pdata in DT, take it the legacy way */
+ if (!pdata)
+ pdata = spi->dev.platform_data;
+
+ if ((!pdata || !gpio_is_valid(pdata->base)) && pdata->base != -1) {
dev_dbg(&spi->dev, "invalid or missing platform data\n");
return -EINVAL;
}
@@ -668,6 +750,7 @@ static struct spi_driver mcp23s08_driver = {
.driver = {
.name = "mcp23s08",
.owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(mcp23s08_of_match),
},
};
diff --git a/include/linux/spi/mcp23s08.h b/include/linux/spi/mcp23s08.h
index 2d676d5..3969e12 100644
--- a/include/linux/spi/mcp23s08.h
+++ b/include/linux/spi/mcp23s08.h
@@ -1,3 +1,4 @@
+#define MCP23S08_CHIP_INFO_MEMBERS 2
/* FIXME driver should be able to handle IRQs... */
--
1.7.10.4
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