Re: [PATCH V1 4/5] backlight: qcom-wled: Add support for OVP interrupt handling
From: kgunda
Date: Tue May 08 2018 - 08:26:11 EST
On 2018-05-07 22:51, Bjorn Andersson wrote:
On Thu 03 May 02:57 PDT 2018, Kiran Gunda wrote:
WLED peripheral has over voltage protection(OVP) circuitry and the OVP
fault is notified through an interrupt. Though this fault condition
rising
is due to an incorrect hardware configuration is mitigated in the
hardware,
it still needs to be detected and handled. Add support for it.
When WLED module is enabled, keep OVP fault interrupt disabled for 10
ms to
account for soft start delay.
Signed-off-by: Kiran Gunda <kgunda@xxxxxxxxxxxxxx>
---
drivers/video/backlight/qcom-wled.c | 118
+++++++++++++++++++++++++++++++++++-
1 file changed, 116 insertions(+), 2 deletions(-)
diff --git a/drivers/video/backlight/qcom-wled.c
b/drivers/video/backlight/qcom-wled.c
index 2cfba77..80ae084 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c
@@ -23,14 +23,20 @@
/* From DT binding */
#define WLED_DEFAULT_BRIGHTNESS 2048
-
+#define WLED_SOFT_START_DLY_US 10000
#define WLED3_SINK_REG_BRIGHT_MAX 0xFFF
/* WLED3 Control registers */
#define WLED3_CTRL_REG_FAULT_STATUS 0x08
+#define WLED3_CTRL_REG_ILIM_FAULT_BIT BIT(0)
+#define WLED3_CTRL_REG_OVP_FAULT_BIT BIT(1)
+#define WLED4_CTRL_REG_SC_FAULT_BIT BIT(2)
+
+#define WLED3_CTRL_REG_INT_RT_STS 0x10
#define WLED3_CTRL_REG_MOD_EN 0x46
#define WLED3_CTRL_REG_MOD_EN_MASK BIT(7)
+#define WLED3_CTRL_REG_MOD_EN_BIT BIT(7)
"BIT(7)" is not a "bit" it's a "mask", so perhaps you could use the
define with that name...which has the same value?
Sure. I will change it in next series.
#define WLED3_CTRL_REG_FREQ 0x4c
#define WLED3_CTRL_REG_FREQ_MASK GENMASK(3, 0)
@@ -161,9 +167,12 @@ struct wled {
u32 short_count;
const int *version;
int short_irq;
+ int ovp_irq;
bool force_mod_disable;
+ bool ovp_irq_disabled;
struct wled_config cfg;
+ struct delayed_work ovp_work;
int (*wled_set_brightness)(struct wled *wled, u16 brightness);
int (*wled_sync_toggle)(struct wled *wled);
};
@@ -209,6 +218,32 @@ static int wled4_set_brightness(struct wled
*wled, u16 brightness)
return 0;
}
+static void wled_ovp_work(struct work_struct *work)
+{
+ u32 val;
+ int rc;
+
+ struct wled *wled = container_of(work,
+ struct wled, ovp_work.work);
+
+ rc = regmap_read(wled->regmap, wled->ctrl_addr +
WLED3_CTRL_REG_MOD_EN,
+ &val);
+ if (rc < 0)
+ return;
+
+ if (val & WLED3_CTRL_REG_MOD_EN_BIT) {
+ if (wled->ovp_irq > 0 && wled->ovp_irq_disabled) {
+ enable_irq(wled->ovp_irq);
+ wled->ovp_irq_disabled = false;
+ }
+ } else {
+ if (wled->ovp_irq > 0 && !wled->ovp_irq_disabled) {
+ disable_irq(wled->ovp_irq);
+ wled->ovp_irq_disabled = true;
+ }
+ }
+}
+
static int wled_module_enable(struct wled *wled, int val)
{
int rc;
@@ -220,7 +255,12 @@ static int wled_module_enable(struct wled *wled,
int val)
WLED3_CTRL_REG_MOD_EN,
WLED3_CTRL_REG_MOD_EN_MASK,
WLED3_CTRL_REG_MOD_EN_MASK);
- return rc;
+ if (rc < 0)
+ return rc;
+
+ schedule_delayed_work(&wled->ovp_work, WLED_SOFT_START_DLY_US);
Do you really want to delay the work on disable?
Wouldn't it be better to use a delay worker for the enablement and in
the disable case you cancel the work and just disable_irq() directly
here.
Sure. Will do it in the next series.
But more importantly, if this is only related to auto detection, do you
really want to enable/disable the ovp_irq after you have detected the
string configuration?
Ok. This is used for the genuine OVP detection and for the auto
detection as well.
+
+ return 0;
}
static int wled3_sync_toggle(struct wled *wled)
@@ -346,6 +386,36 @@ static irqreturn_t wled_short_irq_handler(int
irq, void *_wled)
return IRQ_HANDLED;
}
+static irqreturn_t wled_ovp_irq_handler(int irq, void *_wled)
+{
+ struct wled *wled = _wled;
+ int rc;
+ u32 int_sts, fault_sts;
+
+ rc = regmap_read(wled->regmap,
+ wled->ctrl_addr + WLED3_CTRL_REG_INT_RT_STS, &int_sts);
+ if (rc < 0) {
+ dev_err(wled->dev, "Error in reading WLED3_INT_RT_STS rc=%d\n",
+ rc);
+ return IRQ_HANDLED;
+ }
+
+ rc = regmap_read(wled->regmap, wled->ctrl_addr +
+ WLED3_CTRL_REG_FAULT_STATUS, &fault_sts);
+ if (rc < 0) {
+ dev_err(wled->dev, "Error in reading WLED_FAULT_STATUS rc=%d\n",
+ rc);
+ return IRQ_HANDLED;
+ }
+
+ if (fault_sts &
+ (WLED3_CTRL_REG_OVP_FAULT_BIT | WLED3_CTRL_REG_ILIM_FAULT_BIT))
+ dev_dbg(wled->dev, "WLED OVP fault detected, int_sts=%x fault_sts=
%x\n",
+ int_sts, fault_sts);
+
It's hard to give a good review on this, as the actual logic comes in
the next patch. And as these two patches both implement auto detection
(without a clear separation) I think you should squash them.
Ok. I will squash them in the next series.
+ return IRQ_HANDLED;
+}
+
static int wled3_setup(struct wled *wled)
{
u16 addr;
@@ -821,6 +891,44 @@ static int wled_configure_short_irq(struct wled
*wled,
return rc;
}
+static int wled_configure_ovp_irq(struct wled *wled,
+ struct platform_device *pdev)
+{
+ int rc = 0;
+ u32 val;
+
+ if (*wled->version == WLED_PM8941)
+ return 0;
+
+ wled->ovp_irq = platform_get_irq_byname(pdev, "ovp");
+ if (wled->ovp_irq < 0) {
+ dev_dbg(&pdev->dev, "ovp irq is not used\n");
+ return 0;
+ }
+
+ rc = devm_request_threaded_irq(wled->dev, wled->ovp_irq, NULL,
+ wled_ovp_irq_handler, IRQF_ONESHOT,
+ "wled_ovp_irq", wled);
+ if (rc < 0) {
+ dev_err(wled->dev, "Unable to request ovp_irq (err:%d)\n",
+ rc);
wled->ovp_irq might be > 0 here which means wled_ovp_work() will find
it
valid and call enabled_irq()/disable_irq() on it.
Ok. I will make it '0' if the "request_threaded_irq" fails.
+ return 0;
+ }
+
Regards,
Bjorn