Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753073Ab3H0IBZ (ORCPT ); Tue, 27 Aug 2013 04:01:25 -0400 Received: from perceval.ideasonboard.com ([95.142.166.194]:38366 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752349Ab3H0IBX (ORCPT ); Tue, 27 Aug 2013 04:01:23 -0400 From: Laurent Pinchart To: linux-gpio@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Linus Walleij , Archit Taneja , Tomasz Figa , Sylwester Nawrocki Subject: [PATCH v5] gpio: pcf857x: Add OF support Date: Tue, 27 Aug 2013 10:02:39 +0200 Message-Id: <1377590559-14279-1-git-send-email-laurent.pinchart+renesas@ideasonboard.com> X-Mailer: git-send-email 1.8.1.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7486 Lines: 200 Add DT bindings for the pcf857x-compatible chips and parse the device tree node in the driver. Signed-off-by: Laurent Pinchart --- .../devicetree/bindings/gpio/gpio-pcf857x.txt | 71 ++++++++++++++++++++++ drivers/gpio/gpio-pcf857x.c | 44 +++++++++++--- 2 files changed, 107 insertions(+), 8 deletions(-) create mode 100644 Documentation/devicetree/bindings/gpio/gpio-pcf857x.txt Changes since v4: - Don't try to get ngpio from of_device_id data, we already get it from i2c_device_id Changes since v3: - Get rid of the #ifdef CONFIG_OF in the probe function - Give DT node priority over platform data 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..d261391 --- /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 . 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..864dd8c 100644 --- a/drivers/gpio/gpio-pcf857x.c +++ b/drivers/gpio/gpio-pcf857x.c @@ -26,6 +26,8 @@ #include #include #include +#include +#include #include #include #include @@ -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" }, + { .compatible = "nxp,pcf8574a" }, + { .compatible = "nxp,pca8574" }, + { .compatible = "nxp,pca9670" }, + { .compatible = "nxp,pca9672" }, + { .compatible = "nxp,pca9674" }, + { .compatible = "nxp,pcf8575" }, + { .compatible = "nxp,pca8575" }, + { .compatible = "nxp,pca9671" }, + { .compatible = "nxp,pca9673" }, + { .compatible = "nxp,pca9675" }, + { .compatible = "maxim,max7328" }, + { .compatible = "maxim,max7329" }, + { .compatible = "ti,tca9554" }, + { } +}; +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 +280,18 @@ 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; int status; - pdata = dev_get_platdata(&client->dev); - if (!pdata) { + if (IS_ENABLED(CONFIG_OF) && np) + of_property_read_u32(np, "pins-initial-state", &n_latch); + else if (pdata) + n_latch = pdata->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); @@ -357,11 +384,11 @@ 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 +450,7 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/