Add code to parse the GPIO expander Device Tree node and extract platform data
out of it, and populate the struct 'pcf857x_platform_data' maintained by the
driver. This enables devices to reference the gpio expander from Device Tree.
Add DT binding info in Documentation.
Signed-off-by: Archit Taneja <archit@xxxxxx>
---
- v2 posted after quite a while, sorry for the delay!
Changes in v2:
- second gpeio-cell description corrected in Documentation
- interrupt controller description removed for now, will be added in a follow
up patch
- n_latch description updated
.../devicetree/bindings/gpio/gpio-pcf857x.txt | 41 ++++++++++++++++
drivers/gpio/gpio-pcf857x.c | 57 ++++++++++++++++++++--
2 files changed, 94 insertions(+), 4 deletions(-)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
diff --git a/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt b/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
new file mode 100644
index 0000000..504d114
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
@@ -0,0 +1,41 @@
+PCF857x I2C based GPIO controller bindings
+
+Required properties:
+- compatible:
+ - "nxp,pca9670" for NXP PCA9670 8 bit I/O expander
+ - "nxp,pca9672" for NXP PCA9672 8 bit I/O expander with interrupt
+ - "nxp,pca9674" for NXP PCA9672 8 bit I/O expander with interrupt
+ - "nxp,pca8574" for NXP PCA8574 8 bit I/O expander with interrupt
+ - "nxp,pca8575" for NXP PCA8575 16 bit I/O expander with interrupt
+ - "nxp,pca9671" for NXP PCA9671 16 bit I/O expander
+ - "nxp,pca9673" for NXP PCA9673 16 bit I/O expander with interrupt
+ - "nxp,pca9675" for NXP PCA9675 16 bit I/O expander with interrupt
+ - "ti,pcf8574" for TI PCF8574 8 bit I/O expander with interrupt
+ - "ti,pcf8574a" for TI PCF8574A 8 bit I/O expander with interrupt
+ - "ti,pcf8575" for TI PCF8575 16 bit I/O expander with interrupt
+ - "ti,tca9554" for TI TCA9554 8 bit I/O expander with interrupt
+ - "maxim,max7328" for MAXIM MAX7328 8 bit I/O expander with interrupt
+ - "maxim,max7329" for MAXIM MAX7329 8 bit I/O expander with interrupt
+- gpio-controller : Marks the device node as a GPIO controller.
+- #gpio-cells : Should be two.
+ - first cell is the pin number.
+ - second cell is used to specify optional parameters (currently unused, but
+ needed by gpiolib).
+- reg: I2C address of the chip.
+
+Device speific properties:
+- n_latch: optional bit-inverse of initial register value; if
+ you leave this initialized to zero the driver will act
+ like the chip was just reset. If it is a non-zero
+ value, the driver will program the inverted value of
+ n_latch as the initial state of the gpios.
+
+Example:
+
+pcf8575: pcf8575 {
+ compatible = "ti,pcf8575";
+ gpio-controller;
+ #gpio-cells = <2>;
+ reg = <0x20>;
+ n_latch = <0x0>;
+};
diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
index e8faf53..3435790 100644
--- a/drivers/gpio/gpio-pcf857x.c
+++ b/drivers/gpio/gpio-pcf857x.c
@@ -21,6 +21,7 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/gpio.h>
+#include <linux/of.h>
#include <linux/i2c.h>
#include <linux/i2c/pcf857x.h>
#include <linux/interrupt.h>
@@ -255,17 +256,42 @@ fail:
/*-------------------------------------------------------------------------*/
+static struct pcf857x_platform_data *of_gpio_pcf857x(struct device *dev)
+{
+ struct pcf857x_platform_data *pdata;
+ int r;
+
+ pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return NULL;
+
+ pdata->gpio_base = -1;
+
+ r = of_property_read_u32(dev->of_node, "n_latch", &pdata->n_latch);
+ if (r) {
+ dev_dbg(dev, "couldn't find n-latch, use default\n");
+ pdata->n_latch = 0;
+ }
+
+ return pdata;
+}
+
static int pcf857x_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pcf857x_platform_data *pdata;
+ struct device_node *node;
struct pcf857x *gpio;
int status;
pdata = client->dev.platform_data;
- if (!pdata) {
+ node = client->dev.of_node;
+
+ if (!pdata && node)
+ pdata = of_gpio_pcf857x(&client->dev);
+
+ if (!pdata)
dev_dbg(&client->dev, "no platform data\n");
- }
/* Allocate, initialize, and register this gpio_chip. */
gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
@@ -420,10 +446,33 @@ static int pcf857x_remove(struct i2c_client *client)
return status;
}
+static const struct of_device_id pcf857x_dt_ids[] = {
+ { .compatible = "nxp,pca9670", },
+ { .compatible = "nxp,pca9672", },
+ { .compatible = "nxp,pca9674", },
+ { .compatible = "nxp,pca8574", },
+ { .compatible = "nxp,pca8575", },
+ { .compatible = "nxp,pca9671", },
+ { .compatible = "nxp,pca9673", },
+ { .compatible = "nxp,pca9675", },
+
+ { .compatible = "ti,pcf8574", },
+ { .compatible = "ti,pcf8574a", },
+ { .compatible = "ti,pcf8575", },
+ { .compatible = "ti,tca9554", },
+
+ { .compatible = "maxim,max7328", },
+ { .compatible = "maxim,max7329", },
+ { }
+};
+
+MODULE_DEVICE_TABLE(of, pcf857x_dt_ids);
+
static struct i2c_driver pcf857x_driver = {
.driver = {
- .name = "pcf857x",
- .owner = THIS_MODULE,
+ .name = "pcf857x",
+ .owner = THIS_MODULE,
+ .of_match_table = pcf857x_dt_ids,
},
.probe = pcf857x_probe,
.remove = pcf857x_remove,
--
1.8.1.2
--
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