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Date: Fri, 20 Nov 2015 09:41:43 -0600
From: Rob Herring <robh@...nel.org>
To: Irina Tirdea <irina.tirdea@...el.com>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Bastien Nocera <hadess@...ess.net>,
Aleksei Mamlin <mamlinav@...il.com>,
Karsten Merker <merker@...ian.org>,
linux-input@...r.kernel.org, Mark Rutland <mark.rutland@....com>,
Octavian Purdila <octavian.purdila@...el.com>,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v11 2/8] Input: goodix - reset device at init
On Thu, Nov 19, 2015 at 02:26:35PM +0200, Irina Tirdea wrote:
> After power on, it is recommended that the driver resets the device.
> The reset procedure timing is described in the datasheet and is used
> at device init (before writing device configuration) and
> for power management. It is a sequence of setting the interrupt
> and reset pins high/low at specific timing intervals. This procedure
> also includes setting the slave address to the one specified in the
> ACPI/device tree.
>
> This is based on Goodix datasheets for GT911 and GT9271 and on Goodix
> driver gt9xx.c for Android (publicly available in Android kernel
> trees for various devices).
>
> For reset the driver needs to control the interrupt and
> reset gpio pins (configured through ACPI/device tree). For devices
> that do not have the gpio pins properly declared, the functionality
> depending on these pins will not be available, but the device can still
> be used with basic functionality.
>
> For both device tree and ACPI, the interrupt gpio pin configuration is
> read from the "irq-gpios" property and the reset pin configuration is
> read from the "reset-gpios" property. For ACPI 5.1, named properties
> can be specified using the _DSD section. This functionality will not be
> available for devices that use indexed gpio pins declared in the _CRS
> section (we need to provide backward compatibility with devices
> that do not support using the interrupt gpio pin as output).
>
> For ACPI, the pins can be specified using ACPI 5.1:
> Device (STAC)
> {
> Name (_HID, "GDIX1001")
> ...
>
> Method (_CRS, 0, Serialized)
> {
> Name (RBUF, ResourceTemplate ()
> {
> I2cSerialBus (0x0014, ControllerInitiated, 0x00061A80,
> AddressingMode7Bit, "\\I2C0",
> 0x00, ResourceConsumer, ,
> )
>
> GpioInt (Edge, ActiveHigh, Exclusive, PullNone, 0x0000,
> "\\I2C0", 0x00, ResourceConsumer, ,
> )
> { // Pin list
> 0
> }
>
> GpioIo (Exclusive, PullDown, 0x0000, 0x0000,
> IoRestrictionOutputOnly, "\\I2C0", 0x00,
> ResourceConsumer, ,
> )
> {
> 1
> }
> })
> Return (RBUF)
> }
>
> Name (_DSD, Package ()
> {
> ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
> Package ()
> {
> Package (2) {"irq-gpios", Package() {^STAC, 0, 0, 0 }},
> Package (2) {"reset-gpios", Package() {^STAC, 1, 0, 0 }},
> ...
> }
> }
>
> Signed-off-by: Octavian Purdila <octavian.purdila@...el.com>
> Signed-off-by: Irina Tirdea <irina.tirdea@...el.com>
> ---
> .../bindings/input/touchscreen/goodix.txt | 9 ++
For the binding:
Acked-by: Rob Herring <robh@...nel.org>
> drivers/input/touchscreen/Kconfig | 1 +
> drivers/input/touchscreen/goodix.c | 101 +++++++++++++++++++++
> 3 files changed, 111 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> index 8ba98ee..c42d2ce 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> @@ -13,6 +13,12 @@ Required properties:
> - interrupt-parent : Interrupt controller to which the chip is connected
> - interrupts : Interrupt to which the chip is connected
>
> +Optional properties:
> +
> + - irq-gpios : GPIO pin used for IRQ. The driver uses the
> + interrupt gpio pin as output to reset the device.
> + - reset-gpios : GPIO pin used for reset
> +
> Example:
>
> i2c@...00000 {
> @@ -23,6 +29,9 @@ Example:
> reg = <0x5d>;
> interrupt-parent = <&gpio>;
> interrupts = <0 0>;
> +
> + irq-gpios = <&gpio1 0 0>;
> + reset-gpios = <&gpio1 1 0>;
> };
>
> /* ... */
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 2ccc522..121a0ac 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -324,6 +324,7 @@ config TOUCHSCREEN_FUJITSU
> config TOUCHSCREEN_GOODIX
> tristate "Goodix I2C touchscreen"
> depends on I2C
> + depends on GPIOLIB
> help
> Say Y here if you have the Goodix touchscreen (such as one
> installed in Onda v975w tablets) connected to your
> diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> index 56d0330..4744032 100644
> --- a/drivers/input/touchscreen/goodix.c
> +++ b/drivers/input/touchscreen/goodix.c
> @@ -16,6 +16,7 @@
>
> #include <linux/kernel.h>
> #include <linux/dmi.h>
> +#include <linux/gpio.h>
> #include <linux/i2c.h>
> #include <linux/input.h>
> #include <linux/input/mt.h>
> @@ -37,8 +38,13 @@ struct goodix_ts_data {
> unsigned int int_trigger_type;
> bool rotated_screen;
> int cfg_len;
> + struct gpio_desc *gpiod_int;
> + struct gpio_desc *gpiod_rst;
> };
>
> +#define GOODIX_GPIO_INT_NAME "irq"
> +#define GOODIX_GPIO_RST_NAME "reset"
> +
> #define GOODIX_MAX_HEIGHT 4096
> #define GOODIX_MAX_WIDTH 4096
> #define GOODIX_INT_TRIGGER 1
> @@ -237,6 +243,88 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> +static int goodix_int_sync(struct goodix_ts_data *ts)
> +{
> + int error;
> +
> + error = gpiod_direction_output(ts->gpiod_int, 0);
> + if (error)
> + return error;
> + msleep(50); /* T5: 50ms */
> +
> + return gpiod_direction_input(ts->gpiod_int);
> +}
> +
> +/**
> + * goodix_reset - Reset device during power on
> + *
> + * @ts: goodix_ts_data pointer
> + */
> +static int goodix_reset(struct goodix_ts_data *ts)
> +{
> + int error;
> +
> + /* begin select I2C slave addr */
> + error = gpiod_direction_output(ts->gpiod_rst, 0);
> + if (error)
> + return error;
> + msleep(20); /* T2: > 10ms */
> + /* HIGH: 0x28/0x29, LOW: 0xBA/0xBB */
> + error = gpiod_direction_output(ts->gpiod_int, ts->client->addr == 0x14);
> + if (error)
> + return error;
> + usleep_range(100, 2000); /* T3: > 100us */
> + error = gpiod_direction_output(ts->gpiod_rst, 1);
> + if (error)
> + return error;
> + usleep_range(6000, 10000); /* T4: > 5ms */
> + /* end select I2C slave addr */
> + error = gpiod_direction_input(ts->gpiod_rst);
> + if (error)
> + return error;
> + return goodix_int_sync(ts);
> +}
> +
> +/**
> + * goodix_get_gpio_config - Get GPIO config from ACPI/DT
> + *
> + * @ts: goodix_ts_data pointer
> + */
> +static int goodix_get_gpio_config(struct goodix_ts_data *ts)
> +{
> + int error;
> + struct device *dev;
> + struct gpio_desc *gpiod;
> +
> + if (!ts->client)
> + return -EINVAL;
> + dev = &ts->client->dev;
> +
> + /* Get the interrupt GPIO pin number */
> + gpiod = devm_gpiod_get_optional(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);
> + if (IS_ERR(gpiod)) {
> + error = PTR_ERR(gpiod);
> + if (error != -EPROBE_DEFER)
> + dev_dbg(dev, "Failed to get %s GPIO: %d\n",
> + GOODIX_GPIO_INT_NAME, error);
> + return error;
> + }
> + ts->gpiod_int = gpiod;
> +
> + /* Get the reset line GPIO pin number */
> + gpiod = devm_gpiod_get_optional(dev, GOODIX_GPIO_RST_NAME, GPIOD_IN);
> + if (IS_ERR(gpiod)) {
> + error = PTR_ERR(gpiod);
> + if (error != -EPROBE_DEFER)
> + dev_dbg(dev, "Failed to get %s GPIO: %d\n",
> + GOODIX_GPIO_RST_NAME, error);
> + return error;
> + }
> + ts->gpiod_rst = gpiod;
> +
> + return 0;
> +}
> +
> /**
> * goodix_read_config - Read the embedded configuration of the panel
> *
> @@ -405,6 +493,19 @@ static int goodix_ts_probe(struct i2c_client *client,
> ts->client = client;
> i2c_set_clientdata(client, ts);
>
> + error = goodix_get_gpio_config(ts);
> + if (error)
> + return error;
> +
> + if (ts->gpiod_int && ts->gpiod_rst) {
> + /* reset the controller */
> + error = goodix_reset(ts);
> + if (error) {
> + dev_err(&client->dev, "Controller reset failed.\n");
> + return error;
> + }
> + }
> +
> error = goodix_i2c_test(client);
> if (error) {
> dev_err(&client->dev, "I2C communication failure: %d\n", error);
> --
> 1.9.1
>
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