On 09/07/18 11:22, 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 <kgunda@xxxxxxxxxxxxxx>
Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---
Changes from V3:
- Added Reviewed by tag.
- Addressed minor comments from Vinod
drivers/video/backlight/qcom-wled.c | 132 ++++++++++++++++++++++++++++++++++--
1 file changed, 128 insertions(+), 4 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
index 362d254..a14f1a6 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 <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/ktime.h>
#include <linux/kernel.h>
#include <linux/backlight.h>
#include <linux/module.h>
@@ -64,6 +67,16 @@
#define WLED3_SINK_REG_STR_CABC(n) (0x66 + (n * 0x10))
#define WLED3_SINK_REG_STR_CABC_MASK BIT(7)
+/* WLED4 specific 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
+
/* WLED4 specific sink registers */
#define WLED4_SINK_REG_CURR_SINK 0x46
#define WLED4_SINK_REG_CURR_SINK_MASK GENMASK(7, 4)
@@ -113,17 +126,23 @@ 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 thread irq handler */
+ ktime_t last_short_event;
u16 ctrl_addr;
u16 sink_addr;
u16 max_string_count;
u32 brightness;
u32 max_brightness;
+ u32 short_count;
+ bool disabled_by_short;
+ bool has_short_detect;
struct wled_config cfg;
int (*wled_set_brightness)(struct wled *wled, u16 brightness);
@@ -174,6 +193,9 @@ static int wled_module_enable(struct wled *wled, int val)
{
int rc;
+ if (wled->disabled_by_short)
+ return -EFAULT;
EFAULT means bad address (memory fault). Perhaps EIO or maybe even
something more exotic like ENXIO might be more appropriate?
+
rc = regmap_update_bits(wled->regmap, wled->ctrl_addr +
WLED_CTRL_REG_MOD_EN,
WLED_CTRL_REG_MOD_EN_MASK,
@@ -210,18 +232,19 @@ 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_sync_toggle(wled);
if (rc < 0) {
dev_err(wled->dev, "wled sync failed rc:%d\n", rc);
- return rc;
+ goto unlock_mutex;
}
}
@@ -229,15 +252,61 @@ 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_US USEC_PER_SEC
+
+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;
Shouldn't this reset to 1 (e.g. we have just seen a short).
Daniel.
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