Add DT bindings for the pcf857x-compatible chips and parse the device
tree node in the driver.
Signed-off-by: Laurent Pinchart <[email protected]>
---
.../devicetree/bindings/gpio/gpio-pcf857x.txt | 71 ++++++++++++++++++++++
drivers/gpio/gpio-pcf857x.c | 57 ++++++++++++++---
2 files changed, 119 insertions(+), 9 deletions(-)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
Changes since v2
- Replace mention about interrupts software configuration in DT bindings
documentation with an explanation of the hardware configuration.
diff --git a/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt b/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
new file mode 100644
index 0000000..d0a3af4
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
@@ -0,0 +1,71 @@
+* PCF857x-compatible I/O expanders
+
+The PCF857x-compatible chips have "quasi-bidirectional" I/O pins that can be
+driven high by a pull-up current source or driven low to ground. This combines
+the direction and output level into a single bit per pin, which can't be read
+back. We can't actually know at initialization time whether a pin is configured
+(a) as output and driving the signal low/high, or (b) as input and reporting a
+low/high value, without knowing the last value written since the chip came out
+of reset (if any). The only reliable solution for setting up pin direction is
+thus to do it explicitly.
+
+Required Properties:
+
+ - compatible: should be one of the following.
+ - "maxim,max7328": For the Maxim MAX7378
+ - "maxim,max7329": For the Maxim MAX7329
+ - "nxp,pca8574": For the NXP PCA8574
+ - "nxp,pca8575": For the NXP PCA8575
+ - "nxp,pca9670": For the NXP PCA9670
+ - "nxp,pca9671": For the NXP PCA9671
+ - "nxp,pca9672": For the NXP PCA9672
+ - "nxp,pca9673": For the NXP PCA9673
+ - "nxp,pca9674": For the NXP PCA9674
+ - "nxp,pca9675": For the NXP PCA9675
+ - "nxp,pcf8574": For the NXP PCF8574
+ - "nxp,pcf8574a": For the NXP PCF8574A
+ - "nxp,pcf8575": For the NXP PCF8575
+ - "ti,tca9554": For the TI TCA9554
+
+ - reg: I2C slave address.
+
+ - gpio-controller: Marks the device node as a gpio controller.
+ - #gpio-cells: Should be 2. The first cell is the GPIO number and the second
+ cell specifies GPIO flags, as defined in <dt-bindings/gpio/gpio.h>. Only the
+ GPIO_ACTIVE_HIGH and GPIO_ACTIVE_LOW flags are supported.
+
+Optional Properties:
+
+ - pins-initial-state: Bitmask that specifies the initial state of each pin.
+ When a bit is set to zero, the corresponding pin will be initialized to the
+ input (pulled-up) state. When the bit is set to one, the pin will be
+ initialized the the low-level output state. If the property is not specified
+ all pins will be initialized to the input state.
+
+ The I/O expander can detect input state changes, and thus optionally act as
+ an interrupt controller. When the expander interrupt pin is connected all the
+ following properties must be set. For more information please see the
+ interrupt controller device tree bindings documentation available at
+ Documentation/devicetree/bindings/interrupt-controller/interrupts.txt.
+
+ - interrupt-controller: Identifies the node as an interrupt controller.
+ - #interrupt-cells: Number of cells to encode an interrupt source, shall be 2.
+ - interrupt-parent: phandle of the parent interrupt controller.
+ - interrupts: Interrupt specifier for the controllers interrupt.
+
+
+Please refer to gpio.txt in this directory for details of the common GPIO
+bindings used by client devices.
+
+Example: PCF8575 I/O expander node
+
+ pcf8575: gpio@20 {
+ compatible = "nxp,pcf8575";
+ reg = <0x20>;
+ interrupt-parent = <&irqpin2>;
+ interrupts = <3 0>;
+ gpio-controller;
+ #gpio-cells = <2>;
+ interrupt-controller;
+ #interrupt-cells = <2>;
+ };
diff --git a/drivers/gpio/gpio-pcf857x.c b/drivers/gpio/gpio-pcf857x.c
index 9e61bb0..474f8ce 100644
--- a/drivers/gpio/gpio-pcf857x.c
+++ b/drivers/gpio/gpio-pcf857x.c
@@ -26,6 +26,8 @@
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
@@ -50,6 +52,27 @@ static const struct i2c_device_id pcf857x_id[] = {
};
MODULE_DEVICE_TABLE(i2c, pcf857x_id);
+#ifdef CONFIG_OF
+static const struct of_device_id pcf857x_of_table[] = {
+ { .compatible = "nxp,pcf8574", .data = (void *)8 },
+ { .compatible = "nxp,pcf8574a", .data = (void *)8 },
+ { .compatible = "nxp,pca8574", .data = (void *)8 },
+ { .compatible = "nxp,pca9670", .data = (void *)8 },
+ { .compatible = "nxp,pca9672", .data = (void *)8 },
+ { .compatible = "nxp,pca9674", .data = (void *)8 },
+ { .compatible = "nxp,pcf8575", .data = (void *)16 },
+ { .compatible = "nxp,pca8575", .data = (void *)16 },
+ { .compatible = "nxp,pca9671", .data = (void *)16 },
+ { .compatible = "nxp,pca9673", .data = (void *)16 },
+ { .compatible = "nxp,pca9675", .data = (void *)16 },
+ { .compatible = "maxim,max7328", .data = (void *)8 },
+ { .compatible = "maxim,max7329", .data = (void *)8 },
+ { .compatible = "ti,tca9554", .data = (void *)8 },
+ { }
+};
+MODULE_DEVICE_TABLE(of, pcf857x_of_table);
+#endif
+
/*
* The pcf857x, pca857x, and pca967x chips only expose one read and one
* write register. Writing a "one" bit (to match the reset state) lets
@@ -257,14 +280,29 @@ fail:
static int pcf857x_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
- struct pcf857x_platform_data *pdata;
+ struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
+ struct device_node *np = client->dev.of_node;
struct pcf857x *gpio;
+ unsigned int n_latch = 0;
+ unsigned int ngpio;
int status;
- pdata = dev_get_platdata(&client->dev);
- if (!pdata) {
+#ifdef CONFIG_OF
+ if (np) {
+ const struct of_device_id *of_id;
+
+ of_id = of_match_device(pcf857x_of_table, &client->dev);
+ ngpio = (unsigned int)of_id->data;
+ } else
+#endif
+ ngpio = id->driver_data;
+
+ if (pdata)
+ n_latch = pdata->n_latch;
+ else if (IS_ENABLED(CONFIG_OF) && np)
+ of_property_read_u32(np, "pins-initial-state", &n_latch);
+ else
dev_dbg(&client->dev, "no platform data\n");
- }
/* Allocate, initialize, and register this gpio_chip. */
gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
@@ -282,7 +320,7 @@ static int pcf857x_probe(struct i2c_client *client,
gpio->chip.set = pcf857x_set;
gpio->chip.direction_input = pcf857x_input;
gpio->chip.direction_output = pcf857x_output;
- gpio->chip.ngpio = id->driver_data;
+ gpio->chip.ngpio = ngpio;
/* enable gpio_to_irq() if platform has settings */
if (client->irq) {
@@ -357,11 +395,11 @@ static int pcf857x_probe(struct i2c_client *client,
* may cause transient glitching since it can't know the last value
* written (some pins may need to be driven low).
*
- * Using pdata->n_latch avoids that trouble. When left initialized
- * to zero, our software copy of the "latch" then matches the chip's
- * all-ones reset state. Otherwise it flags pins to be driven low.
+ * Using n_latch avoids that trouble. When left initialized to zero,
+ * our software copy of the "latch" then matches the chip's all-ones
+ * reset state. Otherwise it flags pins to be driven low.
*/
- gpio->out = pdata ? ~pdata->n_latch : ~0;
+ gpio->out = ~n_latch;
gpio->status = gpio->out;
status = gpiochip_add(&gpio->chip);
@@ -423,6 +461,7 @@ static struct i2c_driver pcf857x_driver = {
.driver = {
.name = "pcf857x",
.owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(pcf857x_of_table),
},
.probe = pcf857x_probe,
.remove = pcf857x_remove,
--
Regards,
Laurent Pinchart
On 08/25/2013 02:26 AM, Laurent Pinchart wrote:
> Add DT bindings for the pcf857x-compatible chips and parse the device
> tree node in the driver.
>
> Signed-off-by: Laurent Pinchart<[email protected]>
> ---
> .../devicetree/bindings/gpio/gpio-pcf857x.txt | 71 ++++++++++++++++++++++
> drivers/gpio/gpio-pcf857x.c | 57 ++++++++++++++---
> 2 files changed, 119 insertions(+), 9 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
>
> Changes since v2
>
> - Replace mention about interrupts software configuration in DT bindings
> documentation with an explanation of the hardware configuration.
[...]
> @@ -257,14 +280,29 @@ fail:
> static int pcf857x_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> - struct pcf857x_platform_data *pdata;
> + struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
> + struct device_node *np = client->dev.of_node;
> struct pcf857x *gpio;
> + unsigned int n_latch = 0;
> + unsigned int ngpio;
> int status;
>
> - pdata = dev_get_platdata(&client->dev);
> - if (!pdata) {
> +#ifdef CONFIG_OF
> + if (np) {
> + const struct of_device_id *of_id;
> +
> + of_id = of_match_device(pcf857x_of_table,&client->dev);
> + ngpio = (unsigned int)of_id->data;
It is potentially unsafe, since of_match_device() can return NULL.
> + } else
> +#endif
> + ngpio = id->driver_data;
CodingStyle: braces are missing for the second part of the if statement.
How about something along the lines of:
const struct of_device_id *of_id;
of_id = of_match_device(of_match_ptr(pcf857x_of_table), &client->dev);
if (of_id)
ngpio = (unsigned int)of_id->data;
else
ngpio = id->driver_data;
to get rid of the #ifdef ?
But still DT has priority over platform data here.
> +
> + if (pdata)
> + n_latch = pdata->n_latch;
> + else if (IS_ENABLED(CONFIG_OF)&& np)
> + of_property_read_u32(np, "pins-initial-state",&n_latch);
And here platform data has priority over DT.
> + else
> dev_dbg(&client->dev, "no platform data\n");
> - }
>
> /* Allocate, initialize, and register this gpio_chip. */
> gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
--
Regards,
Sylwester
Hi Sylwester,
On Sunday 25 August 2013 10:16:40 Sylwester Nawrocki wrote:
> On 08/25/2013 02:26 AM, Laurent Pinchart wrote:
> > Add DT bindings for the pcf857x-compatible chips and parse the device
> > tree node in the driver.
> >
> > Signed-off-by: Laurent Pinchart<[email protected]>
> > ---
> >
> > .../devicetree/bindings/gpio/gpio-pcf857x.txt | 71 ++++++++++++++++
> > drivers/gpio/gpio-pcf857x.c | 57 +++++++++++++---
> > 2 files changed, 119 insertions(+), 9 deletions(-)
> > create mode 100644
> > Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt
> >
> > Changes since v2
> >
> > - Replace mention about interrupts software configuration in DT bindings
> > documentation with an explanation of the hardware configuration.
>
> [...]
>
> > @@ -257,14 +280,29 @@ fail:
> > static int pcf857x_probe(struct i2c_client *client,
> > const struct i2c_device_id *id)
> > {
> > - struct pcf857x_platform_data *pdata;
> > + struct pcf857x_platform_data *pdata = dev_get_platdata(&client-
> > >dev);
> > + struct device_node *np = client->dev.of_node;
> > struct pcf857x *gpio;
> > + unsigned int n_latch = 0;
> > + unsigned int ngpio;
> > int status;
> >
> > - pdata = dev_get_platdata(&client->dev);
> > - if (!pdata) {
> > +#ifdef CONFIG_OF
> > + if (np) {
> > + const struct of_device_id *of_id;
> > +
> > + of_id = of_match_device(pcf857x_of_table,&client->dev);
> > + ngpio = (unsigned int)of_id->data;
>
> It is potentially unsafe, since of_match_device() can return NULL.
But if np isn't NULL the probe function will only get called if there's a
match in the OF table, so of_match_device() won't return NULL.
> > + } else
> > +#endif
> > + ngpio = id->driver_data;
>
> CodingStyle: braces are missing for the second part of the if statement.
>
>
> How about something along the lines of:
>
> const struct of_device_id *of_id;
>
> of_id = of_match_device(of_match_ptr(pcf857x_of_table), &client->dev);
> if (of_id)
> ngpio = (unsigned int)of_id->data;
> else
> ngpio = id->driver_data;
>
> to get rid of the #ifdef ?
Looks good to me, I'll post v4.
> But still DT has priority over platform data here.
>
> > +
> > + if (pdata)
> > + n_latch = pdata->n_latch;
> > + else if (IS_ENABLED(CONFIG_OF)&& np)
> > + of_property_read_u32(np, "pins-initial-state",&n_latch);
>
> And here platform data has priority over DT.
We can't have both platform data and DT, but I'll change the order anyway.
> > + else
> > dev_dbg(&client->dev, "no platform data\n");
> > - }
> > /* Allocate, initialize, and register this gpio_chip. */
> > gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
--
Regards,
Laurent Pinchart