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Message-ID: <db3411e9fea2deda73ed1bb829349eef@codeaurora.org>
Date: Wed, 09 May 2018 10:47:31 +0530
From: kgunda@...eaurora.org
To: Daniel Thompson <daniel.thompson@...aro.org>
Cc: bjorn.andersson@...aro.org, Lee Jones <lee.jones@...aro.org>,
Jingoo Han <jingoohan1@...il.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
linux-leds@...r.kernel.org
Subject: Re: [PATCH V2 4/5] backlight: qcom-wled: Add support for OVP
interrupt handling
On 2018-05-08 16:09, Daniel Thompson wrote:
> On Thu, May 03, 2018 at 03:42:31PM +0530, 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.
>
> Why detect and handle it? The interrupt handler doesn't appear to do
> anything other than clear the interrupt... and it appears that the
> interrupt can be masked.
>
>
Planing to squash this patch with the auto-string-detection patch in the
next series,
where the OVP is used for the right string detection.
>> 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@...eaurora.org>
>> ---
>> 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)
>>
>> #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);
>> +
>> + 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);
>> +
>> + 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);
>> + return 0;
>> + }
>> +
>> + rc = regmap_read(wled->regmap, wled->ctrl_addr +
>> + WLED3_CTRL_REG_MOD_EN, &val);
>> + if (rc < 0)
>> + return rc;
>> +
>> + /* Keep OVP irq disabled until module is enabled */
>> + if (!rc && !(val & WLED3_CTRL_REG_MOD_EN_MASK)) {
>> + disable_irq(wled->ovp_irq);
>> + wled->ovp_irq_disabled = true;
>> + }
>> +
>> + return rc;
>> +}
>> +
>> static const struct backlight_ops wled_ops = {
>> .update_status = wled_update_status,
>> };
>> @@ -874,10 +982,16 @@ static int wled_probe(struct platform_device
>> *pdev)
>> }
>> }
>>
>> + INIT_DELAYED_WORK(&wled->ovp_work, wled_ovp_work);
>> +
>> rc = wled_configure_short_irq(wled, pdev);
>> if (rc < 0)
>> return rc;
>>
>> + rc = wled_configure_ovp_irq(wled, pdev);
>> + if (rc < 0)
>> + return rc;
>> +
>> val = WLED_DEFAULT_BRIGHTNESS;
>> of_property_read_u32(pdev->dev.of_node, "default-brightness", &val);
>>
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>> Forum,
>> a Linux Foundation Collaborative Project
>>
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