From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Expose the two TWL4030 LED signals as output-only GPIOs. Boards
need to explicitly ask that this be done, to help avoid conflicts
on boards using these same pins to hook up to a vibrator motor.
Note that these are high drive open drain signals; LEDA is rated
for up to 160 mA (!), LEDB up to 60 mA. Boards using one of these
signals to drive a bank of LCD backlight LEDs would probably want
to access the dedicated PWMs for brightness control, too; easy to
add such support later.
Example: Beagle has one real LED here (PWM not necessary), and
one GPIO controlling VBUS output over EHCI (PWM not wanted).
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/gpio/twl4030-gpio.c | 129 ++++++++++++++++++++++++++++++++++++++++--
include/linux/i2c/twl4030.h | 3
2 files changed, 126 insertions(+), 6 deletions(-)
--- a/drivers/gpio/twl4030-gpio.c
+++ b/drivers/gpio/twl4030-gpio.c
@@ -85,6 +85,32 @@ static inline int gpio_twl4030_write(u8
return twl4030_i2c_write_u8(TWL4030_MODULE_GPIO, data, address);
}
+/*----------------------------------------------------------------------*/
+
+/*
+ * LED register offsets (use TWL4030_MODULE_{LED,PWMA,PWMB}))
+ * PWMs A and B are dedicated to LEDs A and B, respectively.
+ */
+
+#define TWL4030_LED_LEDEN 0x0
+
+/* LEDEN bits */
+#define LEDEN_LEDAON BIT(0)
+#define LEDEN_LEDBON BIT(1)
+#define LEDEN_LEDAEXT BIT(2)
+#define LEDEN_LEDBEXT BIT(3)
+#define LEDEN_LEDAPWM BIT(4)
+#define LEDEN_LEDBPWM BIT(5)
+#define LEDEN_PWM_LENGTHA BIT(6)
+#define LEDEN_PWM_LENGTHB BIT(7)
+
+#define TWL4030_PWMx_PWMxON 0x0
+#define TWL4030_PWMx_PWMxOFF 0x1
+
+#define PWMxON_LENGTH BIT(7)
+
+/*----------------------------------------------------------------------*/
+
/*
* To read a TWL4030 GPIO module register
*/
@@ -97,6 +123,32 @@ static inline int gpio_twl4030_read(u8 a
return (ret < 0) ? ret : data;
}
+/*----------------------------------------------------------------------*/
+
+static u8 cached_leden; /* protected by gpio_lock */
+
+/* The LED lines are open drain outputs ... a FET pulls to GND, so an
+ * external pullup is needed. We could also expose the integrated PWM
+ * as a LED brightness control; we initialize it as "always on".
+ */
+static void twl4030_led_set_value(int led, int value)
+{
+ u8 mask = LEDEN_LEDAON | LEDEN_LEDAPWM;
+ int status;
+
+ if (led)
+ mask <<= 1;
+
+ mutex_lock(&gpio_lock);
+ if (value)
+ cached_leden &= ~mask;
+ else
+ cached_leden |= mask;
+ status = twl4030_i2c_write_u8(TWL4030_MODULE_LED, cached_leden,
+ TWL4030_LED_LEDEN);
+ mutex_unlock(&gpio_lock);
+}
+
static int twl4030_set_gpio_direction(int gpio, int is_input)
{
u8 d_bnk = gpio >> 3;
@@ -226,6 +278,44 @@ static int twl_request(struct gpio_chip
mutex_lock(&gpio_lock);
+ /* Support the two LED outputs as output-only GPIOs. */
+ if (offset >= TWL4030_GPIO_MAX) {
+ u8 ledclr_mask = LEDEN_LEDAON | LEDEN_LEDAEXT
+ | LEDEN_LEDAPWM | LEDEN_PWM_LENGTHA;
+ u8 module = TWL4030_MODULE_PWMA;
+
+ offset -= TWL4030_GPIO_MAX;
+ if (offset) {
+ ledclr_mask <<= 1;
+ module = TWL4030_MODULE_PWMB;
+ }
+
+ /* initialize PWM to always-drive */
+ status = twl4030_i2c_write_u8(module, 0x7f,
+ TWL4030_PWMx_PWMxOFF);
+ if (status < 0)
+ goto done;
+ status = twl4030_i2c_write_u8(module, 0x7f,
+ TWL4030_PWMx_PWMxON);
+ if (status < 0)
+ goto done;
+
+ /* init LED to not-driven (high) */
+ module = TWL4030_MODULE_LED;
+ status = twl4030_i2c_read_u8(module, &cached_leden,
+ TWL4030_LED_LEDEN);
+ if (status < 0)
+ goto done;
+ cached_leden &= ~ledclr_mask;
+ status = twl4030_i2c_write_u8(module, cached_leden,
+ TWL4030_LED_LEDEN);
+ if (status < 0)
+ goto done;
+
+ status = 0;
+ goto done;
+ }
+
/* on first use, turn GPIO module "on" */
if (!gpio_usage_count)
status = gpio_twl4030_write(REG_GPIO_CTRL,
@@ -241,6 +331,11 @@ done:
static void twl_free(struct gpio_chip *chip, unsigned offset)
{
+ if (offset >= TWL4030_GPIO_MAX) {
+ twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1);
+ return;
+ }
+
mutex_lock(&gpio_lock);
gpio_usage_count &= ~BIT(offset);
@@ -254,30 +349,46 @@ static void twl_free(struct gpio_chip *c
static int twl_direction_in(struct gpio_chip *chip, unsigned offset)
{
- return twl4030_set_gpio_direction(offset, 1);
+ return (offset < TWL4030_GPIO_MAX)
+ ? twl4030_set_gpio_direction(offset, 1)
+ : -EINVAL;
}
static int twl_get(struct gpio_chip *chip, unsigned offset)
{
- int status = twl4030_get_gpio_datain(offset);
+ int status = 0;
+ if (offset < TWL4030_GPIO_MAX)
+ status = twl4030_get_gpio_datain(offset);
+ else if (offset == TWL4030_GPIO_MAX)
+ status = cached_leden & LEDEN_LEDAON;
+ else
+ status = cached_leden & LEDEN_LEDBON;
return (status < 0) ? 0 : status;
}
static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value)
{
- twl4030_set_gpio_dataout(offset, value);
- return twl4030_set_gpio_direction(offset, 0);
+ if (offset < TWL4030_GPIO_MAX) {
+ twl4030_set_gpio_dataout(offset, value);
+ return twl4030_set_gpio_direction(offset, 0);
+ } else {
+ twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value);
+ return 0;
+ }
}
static void twl_set(struct gpio_chip *chip, unsigned offset, int value)
{
- twl4030_set_gpio_dataout(offset, value);
+ if (offset < TWL4030_GPIO_MAX)
+ twl4030_set_gpio_dataout(offset, value);
+ else
+ twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value);
}
static int twl_to_irq(struct gpio_chip *chip, unsigned offset)
{
- return twl4030_gpio_irq_base
+ return (twl4030_gpio_irq_base && (offset < TWL4030_GPIO_MAX))
? (twl4030_gpio_irq_base + offset)
: -EINVAL;
}
@@ -360,6 +471,12 @@ no_irqs:
twl_gpiochip.ngpio = TWL4030_GPIO_MAX;
twl_gpiochip.dev = &pdev->dev;
+ /* NOTE: we assume VIBRA_CTL.VIBRA_EN, in MODULE_AUDIO_VOICE,
+ * is (still) clear if use_leds is set.
+ */
+ if (pdata->use_leds)
+ twl_gpiochip.ngpio += 2;
+
ret = gpiochip_add(&twl_gpiochip);
if (ret < 0) {
dev_err(&pdev->dev,
--- a/include/linux/i2c/twl4030.h
+++ b/include/linux/i2c/twl4030.h
@@ -228,6 +228,9 @@ struct twl4030_gpio_platform_data {
int gpio_base;
unsigned irq_base, irq_end;
+ /* package the two LED signals as output-only GPIOs? */
+ bool use_leds;
+
/* For gpio-N, bit (1 << N) in "pullups" is set if that pullup
* should be enabled. Else, if that bit is set in "pulldowns",
* that pulldown is enabled. Don't waste power by letting any
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