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Message-ID: <4218f677260d90ee763fe0cf02b3ba5d@codeaurora.org>
Date: Thu, 17 Oct 2019 18:00:01 +0530
From: kgunda@...eaurora.org
To: Daniel Thompson <daniel.thompson@...aro.org>
Cc: bjorn.andersson@...aro.org, jingoohan1@...il.com,
lee.jones@...aro.org, b.zolnierkie@...sung.com,
dri-devel@...ts.freedesktop.org, jacek.anaszewski@...il.com,
pavel@....cz, robh+dt@...nel.org, mark.rutland@....com,
linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, Andy Gross <agross@...nel.org>,
linux-arm-msm@...r.kernel.org, linux-fbdev@...r.kernel.org
Subject: Re: [PATCH V7 5/6] backlight: qcom-wled: add support for short
circuit handling.
On 2019-10-17 16:39, Daniel Thompson wrote:
> On Wed, Oct 16, 2019 at 03:43:45PM +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 <kgunda@...eaurora.org>
>> Reviewed-by: Bjorn Andersson <bjorn.andersson@...aro.org>
>
> Reviewed-by: Daniel Thompson <daniel.thompson@...aro.org>
>
Thanks for that !
>> ---
>> 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 2807b4b..b5b125c 100644
>> --- a/drivers/video/backlight/qcom-wled.c
>> +++ b/drivers/video/backlight/qcom-wled.c
>> @@ -2,6 +2,9 @@
>> /* Copyright (c) 2015, Sony Mobile Communications, AB.
>> */
>>
>> +#include <linux/delay.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/ktime.h>
>> #include <linux/kernel.h>
>> #include <linux/backlight.h>
>> #include <linux/module.h>
>> @@ -56,6 +59,16 @@
>> #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)
>> @@ -105,17 +118,23 @@ 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);
>> @@ -166,6 +185,9 @@ static int wled_module_enable(struct wled *wled,
>> int val)
>> {
>> int rc;
>>
>> + if (wled->disabled_by_short)
>> + return -ENXIO;
>> +
>> rc = regmap_update_bits(wled->regmap, wled->ctrl_addr +
>> WLED3_CTRL_REG_MOD_EN,
>> WLED3_CTRL_REG_MOD_EN_MASK,
>> @@ -202,18 +224,19 @@ 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;
>> }
>> }
>>
>> @@ -221,15 +244,61 @@ 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 = 1;
>> +
>> + if (wled->short_count > WLED_SHORT_CNT_MAX) {
>> + dev_err(wled->dev, "Short trigged %d times, disabling WLED
>> forever!\n",
>> + wled->short_count);
>> + wled->disabled_by_short = true;
>> + goto unlock_mutex;
>> + }
>> +
>> + wled->last_short_event = ktime_get();
>> +
>> + msleep(WLED_SHORT_DLY_MS);
>> + rc = wled_module_enable(wled, true);
>> + if (rc < 0)
>> + dev_err(wled->dev, "wled enable failed rc:%d\n", rc);
>> +
>> +unlock_mutex:
>> + mutex_unlock(&wled->lock);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> static int wled3_setup(struct wled *wled)
>> {
>> u16 addr;
>> @@ -318,7 +387,7 @@ static int wled4_setup(struct wled *wled)
>> int rc, temp, i, j;
>> u16 addr;
>> u8 sink_en = 0;
>> - u32 sink_cfg = 0;
>> + u32 sink_cfg;
>>
>> rc = regmap_update_bits(wled->regmap,
>> wled->ctrl_addr + WLED3_CTRL_REG_OVP,
>> @@ -340,6 +409,21 @@ static int wled4_setup(struct wled *wled)
>> if (rc < 0)
>> return rc;
>>
>> + if (wled->cfg.external_pfet) {
>> + /* Unlock the secure register access */
>> + rc = regmap_write(wled->regmap, wled->ctrl_addr +
>> + WLED4_CTRL_REG_SEC_ACCESS,
>> + WLED4_CTRL_REG_SEC_UNLOCK);
>> + if (rc < 0)
>> + return rc;
>> +
>> + rc = regmap_write(wled->regmap,
>> + wled->ctrl_addr + WLED4_CTRL_REG_TEST1,
>> + WLED4_CTRL_REG_TEST1_EXT_FET_DTEST2);
>> + if (rc < 0)
>> + return rc;
>> + }
>> +
>> rc = regmap_read(wled->regmap, wled->sink_addr +
>> WLED4_SINK_REG_CURR_SINK, &sink_cfg);
>> if (rc < 0)
>> @@ -425,6 +509,7 @@ static int wled4_setup(struct wled *wled)
>> .num_strings = 4,
>> .switch_freq = 11,
>> .cabc = false,
>> + .external_pfet = false,
>> };
>>
>> static const u32 wled3_boost_i_limit_values[] = {
>> @@ -590,6 +675,7 @@ static int wled_configure(struct wled *wled, int
>> version)
>> { "qcom,cs-out", &cfg->cs_out_en, },
>> { "qcom,ext-gen", &cfg->ext_gen, },
>> { "qcom,cabc", &cfg->cabc, },
>> + { "qcom,external-pfet", &cfg->external_pfet, },
>> };
>>
>> prop_addr = of_get_address(dev->of_node, 0, NULL, NULL);
>> @@ -678,6 +764,38 @@ static int wled_configure(struct wled *wled, int
>> version)
>> return 0;
>> }
>>
>> +static int wled_configure_short_irq(struct wled *wled,
>> + struct platform_device *pdev)
>> +{
>> + int rc, short_irq;
>> +
>> + if (!wled->has_short_detect)
>> + return 0;
>> +
>> + rc = regmap_update_bits(wled->regmap, wled->ctrl_addr +
>> + WLED4_CTRL_REG_SHORT_PROTECT,
>> + WLED4_CTRL_REG_SHORT_EN_MASK,
>> + WLED4_CTRL_REG_SHORT_EN_MASK);
>> + if (rc < 0)
>> + return rc;
>> +
>> + short_irq = platform_get_irq_byname(pdev, "short");
>> + if (short_irq < 0) {
>> + dev_dbg(&pdev->dev, "short irq is not used\n");
>> + return 0;
>> + }
>> +
>> + rc = devm_request_threaded_irq(wled->dev, short_irq,
>> + NULL, wled_short_irq_handler,
>> + IRQF_ONESHOT,
>> + "wled_short_irq", wled);
>> + if (rc < 0)
>> + dev_err(wled->dev, "Unable to request short_irq (err:%d)\n",
>> + rc);
>> +
>> + return rc;
>> +}
>> +
>> static const struct backlight_ops wled_ops = {
>> .update_status = wled_update_status,
>> };
>> @@ -711,6 +829,7 @@ static int wled_probe(struct platform_device
>> *pdev)
>> return -ENODEV;
>> }
>>
>> + mutex_init(&wled->lock);
>> rc = wled_configure(wled, version);
>> if (rc)
>> return rc;
>> @@ -725,6 +844,7 @@ static int wled_probe(struct platform_device
>> *pdev)
>> break;
>>
>> case 4:
>> + wled->has_short_detect = true;
>> rc = wled4_setup(wled);
>> if (rc) {
>> dev_err(&pdev->dev, "wled4_setup failed\n");
>> @@ -737,6 +857,10 @@ static int wled_probe(struct platform_device
>> *pdev)
>> break;
>> }
>>
>> + rc = wled_configure_short_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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