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Subject[PATCH V1 2/4] qcom: spmi-wled: Add support for short circuit handling
Date
Handle the short circuit(SC) interrupt and check if the SC interrupt
is valid. Re-enable the module to check if it goes away. Disable the
module altogether if the SC event persists.

Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
---
.../bindings/leds/backlight/qcom-spmi-wled.txt | 22 ++++
drivers/video/backlight/qcom-spmi-wled.c | 126 ++++++++++++++++++++-
2 files changed, 142 insertions(+), 6 deletions(-)

diff --git a/Documentation/devicetree/bindings/leds/backlight/qcom-spmi-wled.txt b/Documentation/devicetree/bindings/leds/backlight/qcom-spmi-wled.txt
index f1ea25b..768608c 100644
--- a/Documentation/devicetree/bindings/leds/backlight/qcom-spmi-wled.txt
+++ b/Documentation/devicetree/bindings/leds/backlight/qcom-spmi-wled.txt
@@ -74,6 +74,26 @@ The PMIC is connected to the host processor via SPMI bus.
Definition: Specify if cabc (content adaptive backlight control) is
needed.

+- qcom,ext-pfet-sc-pro-en
+ Usage: optional
+ Value type: <bool>
+ Definition: Specify if external PFET control for short circuit
+ protection is needed.
+
+- interrupts
+ Usage: optional
+ Value type: <prop encoded array>
+ Definition: Interrupts associated with WLED. Interrupts can be
+ specified as per the encoding listed under
+ Documentation/devicetree/bindings/spmi/
+ qcom,spmi-pmic-arb.txt.
+
+- interrupt-names
+ Usage: optional
+ Value type: <string>
+ Definition: Interrupt names associated with the interrupts.
+ Must be "sc-irq".
+
Example:

qcom-wled@d800 {
@@ -82,6 +102,8 @@ qcom-wled@d800 {
reg-names = "qcom-wled-ctrl-base", "qcom-wled-sink-base";
label = "backlight";

+ interrupts = <0x3 0xd8 0x2 IRQ_TYPE_EDGE_RISING>;
+ interrupt-names = "sc-irq";
qcom,fs-current-limit = <25000>;
qcom,current-boost-limit = <970>;
qcom,switching-freq = <800>;
diff --git a/drivers/video/backlight/qcom-spmi-wled.c b/drivers/video/backlight/qcom-spmi-wled.c
index 14c3adc..7dbaaa7 100644
--- a/drivers/video/backlight/qcom-spmi-wled.c
+++ b/drivers/video/backlight/qcom-spmi-wled.c
@@ -11,6 +11,9 @@
* 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>
@@ -23,7 +26,13 @@
#define QCOM_WLED_DEFAULT_BRIGHTNESS 2048
#define QCOM_WLED_MAX_BRIGHTNESS 4095

+#define QCOM_WLED_SC_DLY_MS 20
+#define QCOM_WLED_SC_CNT_MAX 5
+#define QCOM_WLED_SC_RESET_CNT_DLY_US 1000000
+
/* WLED control registers */
+#define QCOM_WLED_CTRL_FAULT_STATUS 0x08
+
#define QCOM_WLED_CTRL_MOD_ENABLE 0x46
#define QCOM_WLED_CTRL_MOD_EN_MASK BIT(7)
#define QCOM_WLED_CTRL_MODULE_EN_SHIFT 7
@@ -37,6 +46,15 @@
#define QCOM_WLED_CTRL_ILIM 0x4e
#define QCOM_WLED_CTRL_ILIM_MASK GENMASK(2, 0)

+#define QCOM_WLED_CTRL_SHORT_PROTECT 0x5e
+#define QCOM_WLED_CTRL_SHORT_EN_MASK BIT(7)
+
+#define QCOM_WLED_CTRL_SEC_ACCESS 0xd0
+#define QCOM_WLED_CTRL_SEC_UNLOCK 0xa5
+
+#define QCOM_WLED_CTRL_TEST1 0xe2
+#define QCOM_WLED_EXT_FET_DTEST2 0x09
+
/* WLED sink registers */
#define QCOM_WLED_SINK_CURR_SINK_EN 0x46
#define QCOM_WLED_SINK_CURR_SINK_MASK GENMASK(7, 4)
@@ -71,19 +89,23 @@ struct qcom_wled_config {
u32 switch_freq;
u32 fs_current;
u32 string_cfg;
+ int sc_irq;
bool en_cabc;
+ bool ext_pfet_sc_pro_en;
};

struct qcom_wled {
const char *name;
struct platform_device *pdev;
struct regmap *regmap;
+ struct mutex lock;
+ struct qcom_wled_config cfg;
+ ktime_t last_sc_event_time;
u16 sink_addr;
u16 ctrl_addr;
u32 brightness;
+ u32 sc_count;
bool prev_state;
-
- struct qcom_wled_config cfg;
};

static int qcom_wled_module_enable(struct qcom_wled *wled, int val)
@@ -157,25 +179,26 @@ static int qcom_wled_update_status(struct backlight_device *bl)
bl->props.state & BL_CORE_FBBLANK)
brightness = 0;

+ mutex_lock(&wled->lock);
if (brightness) {
rc = qcom_wled_set_brightness(wled, brightness);
if (rc < 0) {
pr_err("wled failed to set brightness rc:%d\n", rc);
- return rc;
+ goto unlock_mutex;
}

if (!!brightness != wled->prev_state) {
rc = qcom_wled_module_enable(wled, !!brightness);
if (rc < 0) {
pr_err("wled enable failed rc:%d\n", rc);
- return rc;
+ goto unlock_mutex;
}
}
} else {
rc = qcom_wled_module_enable(wled, brightness);
if (rc < 0) {
pr_err("wled disable failed rc:%d\n", rc);
- return rc;
+ goto unlock_mutex;
}
}

@@ -184,19 +207,69 @@ static int qcom_wled_update_status(struct backlight_device *bl)
rc = qcom_wled_sync_toggle(wled);
if (rc < 0) {
pr_err("wled sync failed rc:%d\n", rc);
- return rc;
+ goto unlock_mutex;
}

wled->brightness = brightness;

+unlock_mutex:
+ mutex_unlock(&wled->lock);
return rc;
}

+static irqreturn_t qcom_wled_sc_irq_handler(int irq, void *_wled)
+{
+ struct qcom_wled *wled = _wled;
+ int rc;
+ u32 val;
+ s64 elapsed_time;
+
+ rc = regmap_read(wled->regmap,
+ wled->ctrl_addr + QCOM_WLED_CTRL_FAULT_STATUS, &val);
+ if (rc < 0) {
+ pr_err("Error in reading WLED_FAULT_STATUS rc=%d\n", rc);
+ return IRQ_HANDLED;
+ }
+
+ wled->sc_count++;
+ pr_err("WLED short circuit detected %d times fault_status=%x\n",
+ wled->sc_count, val);
+ mutex_lock(&wled->lock);
+ rc = qcom_wled_module_enable(wled, false);
+ if (rc < 0) {
+ pr_err("wled disable failed rc:%d\n", rc);
+ goto unlock_mutex;
+ }
+
+ elapsed_time = ktime_us_delta(ktime_get(),
+ wled->last_sc_event_time);
+ if (elapsed_time > QCOM_WLED_SC_RESET_CNT_DLY_US) {
+ wled->sc_count = 0;
+ } else if (wled->sc_count > QCOM_WLED_SC_CNT_MAX) {
+ pr_err("SC trigged %d times, disabling WLED forever!\n",
+ wled->sc_count);
+ goto unlock_mutex;
+ }
+
+ wled->last_sc_event_time = ktime_get();
+
+ msleep(QCOM_WLED_SC_DLY_MS);
+ rc = qcom_wled_module_enable(wled, true);
+ if (rc < 0)
+ pr_err("wled enable failed rc:%d\n", rc);
+
+unlock_mutex:
+ mutex_unlock(&wled->lock);
+
+ return IRQ_HANDLED;
+}
+
static int qcom_wled_setup(struct qcom_wled *wled)
{
int rc, temp, i;
u8 sink_en = 0;
u8 string_cfg = wled->cfg.string_cfg;
+ int sc_irq = wled->cfg.sc_irq;

rc = regmap_update_bits(wled->regmap,
wled->ctrl_addr + QCOM_WLED_CTRL_OVP,
@@ -261,6 +334,39 @@ static int qcom_wled_setup(struct qcom_wled *wled)
return rc;
}

+ if (sc_irq >= 0) {
+ rc = devm_request_threaded_irq(&wled->pdev->dev, sc_irq,
+ NULL, qcom_wled_sc_irq_handler, IRQF_ONESHOT,
+ "qcom_wled_sc_irq", wled);
+ if (rc < 0) {
+ pr_err("Unable to request sc(%d) IRQ(err:%d)\n",
+ sc_irq, rc);
+ return rc;
+ }
+
+ rc = regmap_update_bits(wled->regmap,
+ wled->ctrl_addr + QCOM_WLED_CTRL_SHORT_PROTECT,
+ QCOM_WLED_CTRL_SHORT_EN_MASK,
+ QCOM_WLED_CTRL_SHORT_EN_MASK);
+ if (rc < 0)
+ return rc;
+
+ if (wled->cfg.ext_pfet_sc_pro_en) {
+ /* unlock the secure access regisetr */
+ rc = regmap_write(wled->regmap, wled->ctrl_addr +
+ QCOM_WLED_CTRL_SEC_ACCESS,
+ QCOM_WLED_CTRL_SEC_UNLOCK);
+ if (rc < 0)
+ return rc;
+
+ rc = regmap_write(wled->regmap,
+ wled->ctrl_addr + QCOM_WLED_CTRL_TEST1,
+ QCOM_WLED_EXT_FET_DTEST2);
+ if (rc < 0)
+ return rc;
+ }
+ }
+
return 0;
}

@@ -271,6 +377,7 @@ static int qcom_wled_setup(struct qcom_wled *wled)
.switch_freq = 11,
.string_cfg = 0xf,
.en_cabc = 0,
+ .ext_pfet_sc_pro_en = 1,
};

struct qcom_wled_var_cfg {
@@ -376,6 +483,7 @@ static int qcom_wled_configure(struct qcom_wled *wled, struct device *dev)
bool *val_ptr;
} bool_opts[] = {
{ "qcom,en-cabc", &cfg->en_cabc, },
+ { "qcom,ext-pfet-sc-pro", &cfg->ext_pfet_sc_pro_en, },
};

prop_addr = of_get_address(dev->of_node, 0, NULL, NULL);
@@ -427,6 +535,10 @@ static int qcom_wled_configure(struct qcom_wled *wled, struct device *dev)
*bool_opts[i].val_ptr = true;
}

+ wled->cfg.sc_irq = platform_get_irq_byname(wled->pdev, "sc-irq");
+ if (wled->cfg.sc_irq < 0)
+ dev_dbg(&wled->pdev->dev, "sc irq is not used\n");
+
return 0;
}

@@ -469,6 +581,8 @@ static int qcom_wled_probe(struct platform_device *pdev)
return rc;
}

+ mutex_init(&wled->lock);
+
val = QCOM_WLED_DEFAULT_BRIGHTNESS;
of_property_read_u32(pdev->dev.of_node, "default-brightness", &val);
wled->brightness = val;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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