Add DT bindings for the pcf857x-compatible chips and parse the device tree node in the driver.
Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com> --- .../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 diff --git a/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt b/Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt new file mode 100644 index 0000000..df94462 --- /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 interrupts support is desired 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 070e81f..50a90f1 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 = client->dev.platform_data; + struct device_node *np = client->dev.of_node; struct pcf857x *gpio; + unsigned int n_latch = 0; + unsigned int ngpio; int status; - pdata = client->dev.platform_data; - 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, -- 1.8.1.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/