The PCA955x family of chips are I2C LED blinkers whose pins not used
to control LEDs can be used as general purpose I/Os (GPIOs).
The following adds such a support by defining different operation
modes for the pins (See bindings documentation for more details). The
pca955x driver is then extended with a gpio_chip when some of pins are
operating as GPIOs. The default operating mode is to behave as a LED.
The GPIO support is conditioned by CONFIG_LEDS_PCA955X_GPIO.
Signed-off-by: Cédric Le Goater <clg@xxxxxxxx>
---
drivers/leds/Kconfig | 11 +++
drivers/leds/leds-pca955x.c | 158 +++++++++++++++++++++++++++-----
include/dt-bindings/leds/leds-pca955x.h | 16 ++++
3 files changed, 162 insertions(+), 23 deletions(-)
create mode 100644 include/dt-bindings/leds/leds-pca955x.h
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 594b24d410c3..3013cd35c65e 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -377,6 +377,17 @@ config LEDS_PCA955X
LED driver chips accessed via the I2C bus. Supported
devices include PCA9550, PCA9551, PCA9552, and PCA9553.
+config LEDS_PCA955X_GPIO
+ bool "Enable GPIO support for PCA955X"
+ depends on LEDS_PCA955X
+ depends on GPIOLIB
+ help
+ Allow unused pins on PCA955X to be used as gpio.
+
+ To use a pin as gpio the pin type should be set to
+ PCA955X_TYPE_GPIO in the device tree.
+
+
config LEDS_PCA963X
tristate "LED support for PCA963x I2C chip"
depends on LEDS_CLASS
diff --git a/drivers/leds/leds-pca955x.c b/drivers/leds/leds-pca955x.c
index a8918ff0a7e9..ac0f726ff1af 100644
--- a/drivers/leds/leds-pca955x.c
+++ b/drivers/leds/leds-pca955x.c
@@ -53,6 +53,8 @@
#include <linux/slab.h>
#include <linux/string.h>
+#include <dt-bindings/leds/leds-pca955x.h>
+
/* LED select registers determine the source that drives LED outputs */
#define PCA955X_LS_LED_ON 0x0 /* Output LOW */
#define PCA955X_LS_LED_OFF 0x1 /* Output HI-Z */
@@ -118,6 +120,9 @@ struct pca955x {
struct pca955x_led *leds;
struct pca955x_chipdef *chipdef;
struct i2c_client *client;
+#ifdef CONFIG_LEDS_PCA955X_GPIO
+ struct gpio_chip gpio;
+#endif
};
struct pca955x_led {
@@ -125,6 +130,7 @@ struct pca955x_led {
struct led_classdev led_cdev;
int led_num; /* 0 .. 15 potentially */
char name[32];
+ u32 type;
const char *default_trigger;
};
@@ -259,6 +265,65 @@ static int pca955x_led_set(struct led_classdev *led_cdev,
return 0;
}
+#ifdef CONFIG_LEDS_PCA955X_GPIO
+/*
+ * Read the INPUT register, which contains the state of LEDs.
+ */
+static u8 pca955x_read_input(struct i2c_client *client, int n)
+{
+ return (u8)i2c_smbus_read_byte_data(client, n);
+}
+
+static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
+{
+ struct pca955x *pca955x = gpiochip_get_data(gc);
+ struct pca955x_led *led = &pca955x->leds[offset];
+
+ if (led->type == PCA955X_TYPE_GPIO)
+ return 0;
+
+ return -EBUSY;
+}
+
+static void pca955x_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
+ int val)
+{
+ struct pca955x *pca955x = gpiochip_get_data(gc);
+ struct pca955x_led *led = &pca955x->leds[offset];
+
+ if (val)
+ pca955x_led_set(&led->led_cdev, LED_FULL);
+ else
+ pca955x_led_set(&led->led_cdev, LED_OFF);
+}
+
+static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
+{
+ struct pca955x *pca955x = gpiochip_get_data(gc);
+ struct pca955x_led *led = &pca955x->leds[offset];
+ u8 reg = pca955x_read_input(pca955x->client, led->led_num / 8);
+
+ return !!(reg & (1 << (led->led_num % 8)));
+}
+
+static int pca955x_gpio_direction_input(struct gpio_chip *gc,
+ unsigned int offset)
+{
+ /* To use as input ensure pin is not driven */
+ pca955x_gpio_set_value(gc, offset, 0);
+
+ return 0;
+}
+
+static int pca955x_gpio_direction_output(struct gpio_chip *gc,
+ unsigned int offset, int val)
+{
+ pca955x_gpio_set_value(gc, offset, val);
+
+ return 0;
+}
+#endif /* CONFIG_LEDS_PCA955X_GPIO */
+
#if IS_ENABLED(CONFIG_OF)
static struct pca955x_platform_data *
pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
@@ -297,6 +362,8 @@ pca955x_pdata_of_init(struct i2c_client *client, struct pca955x_chipdef *chip)
snprintf(pdata->leds[reg].name, sizeof(pdata->leds[reg].name),
"%s", name);
+ pdata->leds[reg].type = PCA955X_TYPE_LED;
+ of_property_read_u32(child, "type", &pdata->leds[reg].type);
of_property_read_string(child, "linux,default-trigger",
&pdata->leds[reg].default_trigger);
}
@@ -332,6 +399,7 @@ static int pca955x_probe(struct i2c_client *client,
struct i2c_adapter *adapter;
int i, err;
struct pca955x_platform_data *pdata;
+ int ngpios = 0;
if (id) {
chip = &pca955x_chipdefs[id->driver_data];
@@ -391,36 +459,52 @@ static int pca955x_probe(struct i2c_client *client,
pca955x->chipdef = chip;
for (i = 0; i < chip->bits; i++) {
+ struct pca955x_led *pdata_led = &pdata->leds[i];
+
pca955x_led = &pca955x->leds[i];
pca955x_led->led_num = i;
pca955x_led->pca955x = pca955x;
-
- /* Platform data can specify LED names and default triggers */
- if (pdata) {
- if (pdata->leds[i].name)
+ pca955x_led->type = pdata_led->type;
+
+ switch (pca955x_led->type) {
+ case PCA955X_TYPE_NONE:
+ break;
+ case PCA955X_TYPE_GPIO:
+ ngpios++;
+ break;
+ case PCA955X_TYPE_LED:
+ /*
+ * Platform data can specify LED names and
+ * default triggers
+ */
+ if (pdata) {
+ if (pdata->leds[i].name)
+ snprintf(pca955x_led->name,
+ sizeof(pca955x_led->name),
+ "pca955x:%s",
+ pdata->leds[i].name);
+ if (pdata->leds[i].default_trigger)
+ pca955x_led->led_cdev.default_trigger =
+ pdata->leds[i].default_trigger;
+ } else {
snprintf(pca955x_led->name,
- sizeof(pca955x_led->name), "pca955x:%s",
- pdata->leds[i].name);
- if (pdata->leds[i].default_trigger)
- pca955x_led->led_cdev.default_trigger =
- pdata->leds[i].default_trigger;
- } else {
- snprintf(pca955x_led->name, sizeof(pca955x_led->name),
- "pca955x:%d", i);
- }
+ sizeof(pca955x_led->name),
+ "pca955x:%d", i);
+ }
- pca955x_led->led_cdev.name = pca955x_led->name;
- pca955x_led->led_cdev.brightness_set_blocking = pca955x_led_set;
+ pca955x_led->led_cdev.name = pca955x_led->name;
+ pca955x_led->led_cdev.brightness_set_blocking =
+ pca955x_led_set;
- err = devm_led_classdev_register(&client->dev,
- &pca955x_led->led_cdev);
- if (err)
- return err;
- }
+ err = devm_led_classdev_register(&client->dev,
+ &pca955x_led->led_cdev);
+ if (err)
+ return err;
- /* Turn off LEDs */
- for (i = 0; i < pca95xx_num_led_regs(chip->bits); i++)
- pca955x_write_ls(client, i, 0x55);
+ /* Turn off LED */
+ pca955x_led_set(&pca955x_led->led_cdev, LED_OFF);
+ }
+ }
/* PWM0 is used for half brightness or 50% duty cycle */
pca955x_write_pwm(client, 0, 255-LED_HALF);
@@ -432,6 +516,34 @@ static int pca955x_probe(struct i2c_client *client,
pca955x_write_psc(client, 0, 0);
pca955x_write_psc(client, 1, 0);
+#ifdef CONFIG_LEDS_PCA955X_GPIO
+ if (ngpios) {
+ pca955x->gpio.label = "gpio-pca955x";
+ pca955x->gpio.direction_input = pca955x_gpio_direction_input;
+ pca955x->gpio.direction_output = pca955x_gpio_direction_output;
+ pca955x->gpio.set = pca955x_gpio_set_value;
+ pca955x->gpio.get = pca955x_gpio_get_value;
+ pca955x->gpio.request = pca955x_gpio_request_pin;
+ pca955x->gpio.can_sleep = 1;
+ pca955x->gpio.base = -1;
+ pca955x->gpio.ngpio = ngpios;
+ pca955x->gpio.parent = &client->dev;
+ pca955x->gpio.owner = THIS_MODULE;
+
+ err = devm_gpiochip_add_data(&client->dev, &pca955x->gpio,
+ pca955x);
+ if (err) {
+ /* Use data->gpio.dev as a flag for freeing gpiochip */
+ pca955x->gpio.parent = NULL;
+ dev_warn(&client->dev, "could not add gpiochip\n");
+ return err;
+ }
+ dev_info(&client->dev, "gpios %i...%i\n",
+ pca955x->gpio.base, pca955x->gpio.base +
+ pca955x->gpio.ngpio - 1);
+ }
+#endif
+
return 0;
}
diff --git a/include/dt-bindings/leds/leds-pca955x.h b/include/dt-bindings/leds/leds-pca955x.h
new file mode 100644
index 000000000000..78cb7e979de7
--- /dev/null
+++ b/include/dt-bindings/leds/leds-pca955x.h
@@ -0,0 +1,16 @@
+/*
+ * This header provides constants for pca955x LED bindings.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef _DT_BINDINGS_LEDS_PCA955X_H
+#define _DT_BINDINGS_LEDS_PCA955X_H
+
+#define PCA955X_TYPE_NONE 0
+#define PCA955X_TYPE_LED 1
+#define PCA955X_TYPE_GPIO 2
+
+#endif /* _DT_BINDINGS_LEDS_PCA955X_H */
--
2.7.5
--
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