On 2018-05-08 16:05, Daniel Thompson wrote:
Yes. We wait for the short to report 5 times with in this time. If the short still persists, we go and disable the WLED module to avoid the damage. This isOn Thu, May 03, 2018 at 03:42:30PM +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@xxxxxxxxxxxxxx> ---drivers/video/backlight/qcom-wled.c | 134 ++++++++++++++++++++++++++++++++++--1 file changed, 130 insertions(+), 4 deletions(-)diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.cindex be8b8d3..2cfba77 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> @@ -23,7 +26,9 @@ #define WLED3_SINK_REG_BRIGHT_MAX 0xFFF -/* Control registers */ +/* WLED3 Control registers */ +#define WLED3_CTRL_REG_FAULT_STATUS 0x08 + #define WLED3_CTRL_REG_MOD_EN 0x46 #define WLED3_CTRL_REG_MOD_EN_MASK BIT(7) @@ -36,7 +41,17 @@ #define WLED3_CTRL_REG_ILIMIT 0x4e #define WLED3_CTRL_REG_ILIMIT_MASK GENMASK(2, 0) -/* sink registers */ +/* WLED4 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 + +/* WLED3 sink registers */ #define WLED3_SINK_REG_SYNC 0x47 #define WLED3_SINK_REG_SYNC_MASK GENMASK(2, 0) #define WLED4_SINK_REG_SYNC_MASK GENMASK(3, 0) @@ -130,17 +145,23 @@ 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 ISR */ + ktime_t last_short_event; u16 ctrl_addr; u16 sink_addr; u32 brightness; u32 max_brightness; + u32 short_count; const int *version; + int short_irq; + bool force_mod_disable; struct wled_config cfg; int (*wled_set_brightness)(struct wled *wled, u16 brightness);@@ -192,6 +213,9 @@ static int wled_module_enable(struct wled *wled, int val){ int rc; + if (wled->force_mod_disable) + return 0; + rc = regmap_update_bits(wled->regmap, wled->ctrl_addr + WLED3_CTRL_REG_MOD_EN, WLED3_CTRL_REG_MOD_EN_MASK,@@ -248,12 +272,13 @@ 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->wled_sync_toggle(wled);@@ -267,15 +292,60 @@ 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 HZSo we think a short report every quarter second is harmless?
suggested by the HW team.
+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; + + if (wled->short_count > WLED_SHORT_CNT_MAX) {+ dev_err(wled->dev, "Short trigged %d times, disabling WLED forever!\n",+ wled->short_count); + wled->force_mod_disable = 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; @@ -435,6 +505,21 @@ static int wled4_setup(struct wled *wled) 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; + } + return 0; } @@ -446,6 +531,7 @@ static int wled4_setup(struct wled *wled) .switch_freq = 11, .enabled_strings = 0xf, .cabc = false, + .external_pfet = true, }; static const u32 wled3_boost_i_limit_values[] = { @@ -628,6 +714,7 @@ static int wled_configure(struct wled *wled) { "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); @@ -701,6 +788,39 @@ static int wled_configure(struct wled *wled) return 0; } +static int wled_configure_short_irq(struct wled *wled, + struct platform_device *pdev) +{ + int rc = 0; + + /* PM8941 doesn't have the short detection support */ + if (*wled->version == WLED_PM8941) + 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; + + wled->short_irq = platform_get_irq_byname(pdev, "short"); + if (wled->short_irq < 0) { + dev_dbg(&pdev->dev, "short irq is not used\n"); + return 0; + } + + rc = devm_request_threaded_irq(wled->dev, wled->short_irq, + NULL, wled_short_irq_handler,NULL? There's no register we can check to make sure the interrupt handler did not enter spuriously?
There is FAULT_STATUS register. I will address it in the next series.
+ 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, };@@ -733,6 +853,8 @@ static int wled_probe(struct platform_device *pdev)return -ENODEV; } + mutex_init(&wled->lock); + rc = wled_configure(wled); if (rc) return rc;@@ -752,6 +874,10 @@ static int wled_probe(struct platform_device *pdev)} } + 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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