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Subject[PATCH v1 36/63] Input: atmel_mxt_ts - configure and use gpios as real gpios
Date
From: Kautuk Consul <kautuk_consul@mentor.com>

The upstream Atmel mXT driver implementation seems to handle the
T19 GPIO/PWM object as a key pad. Keys can be defined in the
device tree ("linux,gpio-keymap") and will be transported as key
events to the Linux input device if GPIO state changes.

With our hardware, the GPIO pins of the touch controller are
connected to a PWM/backlight controller and used as supervision
inputs. We like to read the status of the pins by a script or an
application in the sysfs.

Adding newer sysfs entries which shall be placed in the input
class directory eg:
/sys/class/input/input<n>/backlight_error1

Signed-off-by: Kautuk Consul <kautuk_consul@mentor.com>
Signed-off-by: Balasubramani Vivekanandan <balasubramani_vivekanandan@mentor.com>
Signed-off-by: George G. Davis <george_davis@mentor.com>
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
---
.../bindings/input/atmel,maxtouch.txt | 15 +++
drivers/input/touchscreen/atmel_mxt_ts.c | 120 ++++++++++++++++++
2 files changed, 135 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
index d7db16920083..7afe12a93202 100644
--- a/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
+++ b/Documentation/devicetree/bindings/input/atmel,maxtouch.txt
@@ -42,6 +42,9 @@ Optional properties for main touchpad device:

- atmel,input_name: Override name of input device from the default.

+- atmel,gpios: Specify the GPIO input pins whose status will be read via the
+ /sys/class/input/input<n>/backlight_error<x> sysfs entries.
+
Example:

touch@4b {
@@ -49,4 +52,16 @@ Example:
reg = <0x4b>;
interrupt-parent = <&gpio>;
interrupts = <TEGRA_GPIO(W, 3) IRQ_TYPE_LEVEL_LOW>;
+
+ atmel,gpios {
+ backlight_error1 {
+ gpio = <3 GPIO_ACTIVE_HIGH>; /* connected to
+ * the GPIO3 pin of mXT input */
+ };
+
+ backlight_error2 {
+ gpio = <5 GPIO_ACTIVE_HIGH>; /* connected to
+ * the GPIO5 pin of mXT input */
+ };
+ };
};
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index 9cdb7754599c..a8e2b927bb12 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -414,6 +414,15 @@ struct mxt_data {

/* Indicates whether device is updating configuration */
bool updating_config;
+
+ unsigned long gpio_input_pin_status;
+ struct attribute_group gpio_attrs;
+ unsigned long gpio_input_pin_status_default;
+};
+
+struct mxt_gpio_attr {
+ struct device_attribute attr;
+ int bit_index;
};

struct mxt_vb2_buffer {
@@ -1381,6 +1390,7 @@ static int mxt_proc_message(struct mxt_data *data, u8 *message)
} else if (report_id == data->T19_reportid) {
mxt_input_button(data, message);
data->update_input = true;
+ data->gpio_input_pin_status = message[1];
} else if (report_id >= data->T15_reportid_min
&& report_id <= data->T15_reportid_max) {
mxt_proc_t15_messages(data, message);
@@ -2747,6 +2757,16 @@ static int mxt_initialize_input_device(struct mxt_data *data)
goto err_free_mem;
}

+ if (data->gpio_attrs.attrs) {
+ error = sysfs_create_group(&input_dev->dev.kobj,
+ &data->gpio_attrs);
+ if (error) {
+ dev_err(dev, "Failure %d creating sysfs group\n",
+ error);
+ goto err_free_mem;
+ }
+ }
+
data->input_dev = input_dev;

return 0;
@@ -3995,10 +4015,26 @@ static void mxt_input_close(struct input_dev *dev)
dev_err(&data->client->dev, "%s failed rc=%d\n", __func__, ret);
}

+static ssize_t mxt_gpio_input_pin_read(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct mxt_data *data = dev_get_drvdata(dev);
+ struct mxt_gpio_attr *attr_p = container_of(attr, struct mxt_gpio_attr,
+ attr);
+ int pin_status = test_bit(attr_p->bit_index,
+ &data->gpio_input_pin_status);
+
+ return scnprintf(buf, PAGE_SIZE, "%d\n", pin_status);
+}
+
static int mxt_parse_device_properties(struct mxt_data *data)
{
static const char keymap_property[] = "linux,gpio-keymap";
+ static const char gpios_property[] = "atmel,gpios";
struct device *dev = &data->client->dev;
+ struct device_node *np = dev ? dev->of_node : NULL;
+ struct device_node *np_gpio;
u32 *keymap;
int n_keys;
int error;
@@ -4036,7 +4072,89 @@ static int mxt_parse_device_properties(struct mxt_data *data)

device_property_read_u32(dev, "atmel,suspend-mode", &data->suspend_mode);

+ np_gpio = of_get_child_by_name(np, gpios_property);
+ if (np_gpio) {
+ int gpio_pin;
+ struct mxt_gpio_attr *attr_p;
+ char *sysfs_gpio_file_name;
+ u8 num_gpio_pins = 0;
+
+ np_gpio = of_find_node_with_property(np_gpio, "gpio");
+ if (!np_gpio)
+ return -EINVAL;
+
+ data->gpio_attrs.attrs =
+ devm_kzalloc(dev,
+ 9 * sizeof(struct attribute *),
+ GFP_KERNEL);
+ if (!data->gpio_attrs.attrs) {
+ error = -ENOMEM;
+ goto err_gpios_property_put;
+ }
+
+ do {
+ attr_p = devm_kmalloc(dev,
+ sizeof(struct mxt_gpio_attr),
+ GFP_KERNEL);
+ if (!attr_p) {
+ error = -ENOMEM;
+ goto err_gpios_property_put;
+ }
+
+ error = of_property_read_u32_index(np_gpio, "gpio", 0,
+ &gpio_pin);
+ if (error) {
+ dev_warn(dev,
+ "Couldn't read gpio property for node : %s\n",
+ np_gpio->name);
+ error = -EINVAL;
+ goto err_gpios_property_put;
+ }
+
+ if (gpio_pin > 7) {
+ dev_warn(dev,
+ "Incorrect GPIO pin index for node %s: %u\n",
+ np_gpio->name, gpio_pin);
+ error = -EINVAL;
+ goto err_gpios_property_put;
+ }
+
+ sysfs_gpio_file_name =
+ devm_kmalloc(dev,
+ strlen(np_gpio->name) + 1,
+ GFP_KERNEL);
+ if (!sysfs_gpio_file_name) {
+ error = -ENOMEM;
+ goto err_gpios_property_put;
+ }
+
+ strcpy(sysfs_gpio_file_name, np_gpio->name);
+
+ sysfs_attr_init(&attr_p->attr.attr);
+
+ attr_p->attr.attr.name = sysfs_gpio_file_name;
+ attr_p->attr.attr.mode = 0444;
+ attr_p->attr.show = mxt_gpio_input_pin_read;
+ attr_p->attr.store = NULL;
+ attr_p->bit_index = gpio_pin;
+
+ data->gpio_input_pin_status_default |= BIT(gpio_pin);
+
+ data->gpio_attrs.attrs[num_gpio_pins++] =
+ &attr_p->attr.attr;
+ } while ((np_gpio =
+ of_find_node_with_property(np_gpio, "gpio")) &&
+ num_gpio_pins < 8);
+
+ if (np_gpio)
+ of_node_put(np_gpio);
+ }
+
return 0;
+
+err_gpios_property_put:
+ of_node_put(np_gpio);
+ return error;
}

static const struct dmi_system_id chromebook_T9_suspend_dmi[] = {
@@ -4106,6 +4224,8 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id)
if (error)
return error;

+ data->gpio_input_pin_status = data->gpio_input_pin_status_default;
+
if (data->pcfg_name)
mxt_update_file_name(&data->client->dev,
&data->cfg_name,
--
2.19.2
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