Re: [PATCH V2 3/5] backlight: qcom-wled: Add support for short circuit handling
On 2018-05-08 16:05, Daniel Thompson wrote:
On Thu, May 03, 2018 at 03:42:30PM +0530, Kiran Gunda wrote:
Handle the short circuit interrupt and check if the short circuit
interrupt is valid. Re-enable the module to check if it goes
away. Disable the module altogether if the short circuit event
persists.
Signed-off-by: Kiran Gunda
---
drivers/video/backlight/qcom-wled.c | 134
++--
1 file changed, 130 insertions(+), 4 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c
b/drivers/video/backlight/qcom-wled.c
index be8b8d3..2cfba77 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c
@@ -10,6 +10,9 @@
* GNU General Public License for more details.
*/
+#include
+#include
+#include
#include
#include
#include
@@ -23,7 +26,9 @@
#define WLED3_SINK_REG_BRIGHT_MAX 0xFFF
-/* Control registers */
+/* WLED3 Control registers */
+#define WLED3_CTRL_REG_FAULT_STATUS0x08
+
#define WLED3_CTRL_REG_MOD_EN 0x46
#define WLED3_CTRL_REG_MOD_EN_MASKBIT(7)
@@ -36,7 +41,17 @@
#define WLED3_CTRL_REG_ILIMIT 0x4e
#define WLED3_CTRL_REG_ILIMIT_MASKGENMASK(2, 0)
-/* sink registers */
+/* WLED4 control registers */
+#define WLED4_CTRL_REG_SHORT_PROTECT 0x5e
+#define WLED4_CTRL_REG_SHORT_EN_MASK BIT(7)
+
+#define WLED4_CTRL_REG_SEC_ACCESS 0xd0
+#define WLED4_CTRL_REG_SEC_UNLOCK 0xa5
+
+#define WLED4_CTRL_REG_TEST1 0xe2
+#define WLED4_CTRL_REG_TEST1_EXT_FET_DTEST2 0x09
+
+/* WLED3 sink registers */
#define WLED3_SINK_REG_SYNC0x47
#define WLED3_SINK_REG_SYNC_MASK GENMASK(2, 0)
#define WLED4_SINK_REG_SYNC_MASK GENMASK(3, 0)
@@ -130,17 +145,23 @@ struct wled_config {
bool cs_out_en;
bool ext_gen;
bool cabc;
+ bool external_pfet;
};
struct wled {
const char *name;
struct device *dev;
struct regmap *regmap;
+ struct mutex lock; /* Lock to avoid race from ISR */
+ ktime_t last_short_event;
u16 ctrl_addr;
u16 sink_addr;
u32 brightness;
u32 max_brightness;
+ u32 short_count;
const int *version;
+ int short_irq;
+ bool force_mod_disable;
struct wled_config cfg;
int (*wled_set_brightness)(struct wled *wled, u16 brightness);
@@ -192,6 +213,9 @@ static int wled_module_enable(struct wled *wled,
int val)
{
int rc;
+ if (wled->force_mod_disable)
+ return 0;
+
rc = regmap_update_bits(wled->regmap, wled->ctrl_addr +
WLED3_CTRL_REG_MOD_EN,
WLED3_CTRL_REG_MOD_EN_MASK,
@@ -248,12 +272,13 @@ static int wled_update_status(struct
backlight_device *bl)
bl->props.state & BL_CORE_FBBLANK)
brightness = 0;
+ mutex_lock(&wled->lock);
if (brightness) {
rc = wled->wled_set_brightness(wled, brightness);
if (rc < 0) {
dev_err(wled->dev, "wled failed to set brightness
rc:%d\n",
rc);
- return rc;
+ goto unlock_mutex;
}
rc = wled->wled_sync_toggle(wled);
@@ -267,15 +292,60 @@ static int wled_update_status(struct
backlight_device *bl)
rc = wled_module_enable(wled, !!brightness);
if (rc < 0) {
dev_err(wled->dev, "wled enable failed rc:%d\n", rc);
- return rc;
+ goto unlock_mutex;
}
}
wled->brightness = brightness;
+unlock_mutex:
+ mutex_unlock(&wled->lock);
+
return rc;
}
+#define WLED_SHORT_DLY_MS 20
+#define WLED_SHORT_CNT_MAX 5
+#define WLED_SHORT_RESET_CNT_DLY_USHZ
So we think a short report every quarter second is harmless?
Yes. We wait for the short to report 5 times with in this time. If the
short
still persists, we go and disable the WLED module to avoid the damage.
This is
suggested by the HW team.
+static irqreturn_t wled_short_irq_handler(int irq, void *_wled)
+{
+ struct wled *wled = _wled;
+ int rc;
+ s64 elapsed_time;
+
+ wled->short_count++;
+ mutex_lock(&wled->lock);
+ rc = wled_module_enable(wled, false);
+ if (rc < 0) {
+ dev_err(wled->dev, "wled disable failed rc:%d\n", rc);
+ goto unlock_mutex;
+ }
+
+ elapsed_time = ktime_us_delta(ktime_get(),
+ wled->last_short_event);
+ if (elapsed_time > WLED_SHORT_RESET_CNT_DLY_US)
+ wled->short_cou
Re: [PATCH V2 3/5] backlight: qcom-wled: Add support for short circuit handling
On Thu, May 03, 2018 at 03:42:30PM +0530, Kiran Gunda wrote:
> Handle the short circuit interrupt and check if the short circuit
> interrupt is valid. Re-enable the module to check if it goes
> away. Disable the module altogether if the short circuit event
> persists.
>
> Signed-off-by: Kiran Gunda
> ---
> drivers/video/backlight/qcom-wled.c | 134
> ++--
> 1 file changed, 130 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/video/backlight/qcom-wled.c
> b/drivers/video/backlight/qcom-wled.c
> index be8b8d3..2cfba77 100644
> --- a/drivers/video/backlight/qcom-wled.c
> +++ b/drivers/video/backlight/qcom-wled.c
> @@ -10,6 +10,9 @@
> * GNU General Public License for more details.
> */
>
> +#include
> +#include
> +#include
> #include
> #include
> #include
> @@ -23,7 +26,9 @@
>
> #define WLED3_SINK_REG_BRIGHT_MAX0xFFF
>
> -/* Control registers */
> +/* WLED3 Control registers */
> +#define WLED3_CTRL_REG_FAULT_STATUS 0x08
> +
> #define WLED3_CTRL_REG_MOD_EN0x46
> #define WLED3_CTRL_REG_MOD_EN_MASK BIT(7)
>
> @@ -36,7 +41,17 @@
> #define WLED3_CTRL_REG_ILIMIT0x4e
> #define WLED3_CTRL_REG_ILIMIT_MASK GENMASK(2, 0)
>
> -/* sink registers */
> +/* WLED4 control registers */
> +#define WLED4_CTRL_REG_SHORT_PROTECT 0x5e
> +#define WLED4_CTRL_REG_SHORT_EN_MASKBIT(7)
> +
> +#define WLED4_CTRL_REG_SEC_ACCESS0xd0
> +#define WLED4_CTRL_REG_SEC_UNLOCK 0xa5
> +
> +#define WLED4_CTRL_REG_TEST1 0xe2
> +#define WLED4_CTRL_REG_TEST1_EXT_FET_DTEST2 0x09
> +
> +/* WLED3 sink registers */
> #define WLED3_SINK_REG_SYNC 0x47
> #define WLED3_SINK_REG_SYNC_MASKGENMASK(2, 0)
> #define WLED4_SINK_REG_SYNC_MASKGENMASK(3, 0)
> @@ -130,17 +145,23 @@ struct wled_config {
> bool cs_out_en;
> bool ext_gen;
> bool cabc;
> + bool external_pfet;
> };
>
> struct wled {
> const char *name;
> struct device *dev;
> struct regmap *regmap;
> + struct mutex lock; /* Lock to avoid race from ISR */
> + ktime_t last_short_event;
> u16 ctrl_addr;
> u16 sink_addr;
> u32 brightness;
> u32 max_brightness;
> + u32 short_count;
> const int *version;
> + int short_irq;
> + bool force_mod_disable;
>
> struct wled_config cfg;
> int (*wled_set_brightness)(struct wled *wled, u16 brightness);
> @@ -192,6 +213,9 @@ static int wled_module_enable(struct wled *wled, int val)
> {
> int rc;
>
> + if (wled->force_mod_disable)
> + return 0;
> +
> rc = regmap_update_bits(wled->regmap, wled->ctrl_addr +
> WLED3_CTRL_REG_MOD_EN,
> WLED3_CTRL_REG_MOD_EN_MASK,
> @@ -248,12 +272,13 @@ static int wled_update_status(struct backlight_device
> *bl)
> bl->props.state & BL_CORE_FBBLANK)
> brightness = 0;
>
> + mutex_lock(&wled->lock);
> if (brightness) {
> rc = wled->wled_set_brightness(wled, brightness);
> if (rc < 0) {
> dev_err(wled->dev, "wled failed to set brightness
> rc:%d\n",
> rc);
> - return rc;
> + goto unlock_mutex;
> }
>
> rc = wled->wled_sync_toggle(wled);
> @@ -267,15 +292,60 @@ static int wled_update_status(struct backlight_device
> *bl)
> rc = wled_module_enable(wled, !!brightness);
> if (rc < 0) {
> dev_err(wled->dev, "wled enable failed rc:%d\n", rc);
> - return rc;
> + goto unlock_mutex;
> }
> }
>
> wled->brightness = brightness;
>
> +unlock_mutex:
> + mutex_unlock(&wled->lock);
> +
> return rc;
> }
>
> +#define WLED_SHORT_DLY_MS20
> +#define WLED_SHORT_CNT_MAX 5
> +#define WLED_SHORT_RESET_CNT_DLY_US HZ
So we think a short report every quarter second is harmless?
> +static irqreturn_t wled_short_irq_handler(int irq, void *_wled)
> +{
> + struct wled *wled = _wled;
> + int rc;
> + s64 elapsed_time;
> +
> + wled->short_count++;
> + mutex_lock(&wled->lock);
> + rc = wled_module_enable(wled, false);
> + if (rc < 0) {
> + dev_err(wled->dev, "wled disable failed rc:%d\n", rc);
> + goto unlock_mutex;
> + }
> +
> + elapsed_time = ktime_us_delta(ktime_get(),
> + wled->last_short_event);
> + if (elapsed_time > WLED_SHORT_RESET_CNT_DLY_US)
> + wled->short_count = 0;
> +
> + if (wled->short_count > WLED_SHORT_CNT_MAX) {
> +
