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Date: Thu, 17 Oct 2019 13:26:53 +0100
From: Lee Jones <lee.jones@...aro.org>
To: Kiran Gunda <kgunda@...eaurora.org>
Cc: bjorn.andersson@...aro.org, jingoohan1@...il.com,
b.zolnierkie@...sung.com, dri-devel@...ts.freedesktop.org,
daniel.thompson@...aro.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 6/6] backlight: qcom-wled: Add auto string detection
logic
On Wed, 16 Oct 2019, Kiran Gunda wrote:
> The auto string detection algorithm checks if the current WLED
> sink configuration is valid. It tries enabling every sink and
> checks if the OVP fault is observed. Based on this information
> it detects and enables the valid sink configuration.
> Auto calibration will be triggered when the OVP fault interrupts
> are seen frequently thereby it tries to fix the sink configuration.
>
> The auto-detection also kicks in when the connected LED string
> of the display-backlight malfunctions (because of damage) and
> requires the damaged string to be turned off to prevent the
> complete panel and/or board from being damaged.
>
> Signed-off-by: Kiran Gunda <kgunda@...eaurora.org>
> ---
> drivers/video/backlight/qcom-wled.c | 410 +++++++++++++++++++++++++++++++++++-
> 1 file changed, 404 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
> index b5b125c..ff7c409 100644
> --- a/drivers/video/backlight/qcom-wled.c
> +++ b/drivers/video/backlight/qcom-wled.c
[...]
> + /* iterate through the strings one by one */
Please use proper English in comments (less a full stop).
In this case, just s/iterate/Iterate/.
> + for (i = 0; i < wled->cfg.num_strings; i++) {
> + sink_test = BIT((WLED4_SINK_REG_CURR_SINK_SHFT + i));
> +
> + /* Enable feedback control */
> + rc = regmap_write(wled->regmap, wled->ctrl_addr +
> + WLED3_CTRL_REG_FEEDBACK_CONTROL, i + 1);
> + if (rc < 0) {
> + dev_err(wled->dev, "Failed to enable feedback for SINK %d rc = %d\n",
> + i + 1, rc);
> + goto failed_detect;
> + }
> +
> + /* enable the sink */
Here too. And everywhere else.
> + rc = regmap_write(wled->regmap, wled->sink_addr +
> + WLED4_SINK_REG_CURR_SINK, sink_test);
> + if (rc < 0) {
> + dev_err(wled->dev, "Failed to configure SINK %d rc=%d\n",
> + i + 1, rc);
> + goto failed_detect;
> + }
> +
> + /* Enable the module */
> + rc = regmap_update_bits(wled->regmap, wled->ctrl_addr +
> + WLED3_CTRL_REG_MOD_EN,
> + WLED3_CTRL_REG_MOD_EN_MASK,
> + WLED3_CTRL_REG_MOD_EN_MASK);
> + if (rc < 0) {
> + dev_err(wled->dev, "Failed to enable WLED module rc=%d\n",
> + rc);
> + goto failed_detect;
> + }
> +
> + usleep_range(WLED_SOFT_START_DLY_US,
> + WLED_SOFT_START_DLY_US + 1000);
> +
> + 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_CTRL_INT_RT_STS rc=%d\n",
> + rc);
> + goto failed_detect;
> + }
> +
> + if (int_sts & WLED3_CTRL_REG_OVP_FAULT_STATUS)
> + dev_dbg(wled->dev, "WLED OVP fault detected with SINK %d\n",
> + i + 1);
I haven't reviewed the whole patch, but this caught my eye.
I think this should be upgraded to dev_warn().
> + else
> + sink_valid |= sink_test;
> +
> + /* Disable the module */
> + rc = regmap_update_bits(wled->regmap,
> + wled->ctrl_addr + WLED3_CTRL_REG_MOD_EN,
> + WLED3_CTRL_REG_MOD_EN_MASK, 0);
> + if (rc < 0) {
> + dev_err(wled->dev, "Failed to disable WLED module rc=%d\n",
> + rc);
> + goto failed_detect;
> + }
> + }
> +
> + if (!sink_valid) {
> + dev_err(wled->dev, "No valid WLED sinks found\n");
> + wled->disabled_by_short = true;
> + goto failed_detect;
> + }
> +
> + if (sink_valid == sink_config) {
> + dev_dbg(wled->dev, "WLED auto-detection complete, sink-config=%x OK!\n",
> + sink_config);
Does this really need to be placed in the kernel log?
> + } else {
> + dev_warn(wled->dev, "New WLED string configuration found %x\n",
> + sink_valid);
Why would the user care about this? Is it not normal?
> + sink_config = sink_valid;
> + }
[...]
> +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))
Break the line at the '|'.
> + dev_dbg(wled->dev, "WLED OVP fault detected, int_sts=%x fault_sts= %x\n",
> + int_sts, fault_sts);
dev_warn().
> + if (fault_sts & WLED3_CTRL_REG_OVP_FAULT_BIT) {
> + mutex_lock(&wled->lock);
> + disable_irq_nosync(wled->ovp_irq);
> +
> + if (wled_auto_detection_required(wled))
> + wled_auto_string_detection(wled);
> +
> + enable_irq(wled->ovp_irq);
> +
> + mutex_unlock(&wled->lock);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> static int wled3_setup(struct wled *wled)
> {
> u16 addr;
> @@ -435,8 +775,10 @@ static int wled4_setup(struct wled *wled)
> sink_en |= 1 << temp;
> }
>
> - if (sink_cfg == sink_en)
> - return 0;
> + if (sink_cfg == sink_en) {
> + rc = wled_auto_detection_at_init(wled);
> + return rc;
> + }
>
> rc = regmap_update_bits(wled->regmap,
> wled->sink_addr + WLED4_SINK_REG_CURR_SINK,
> @@ -499,7 +841,9 @@ static int wled4_setup(struct wled *wled)
> return rc;
> }
>
> - return 0;
> + rc = wled_auto_detection_at_init(wled);
> +
> + return rc;
> }
>
> static const struct wled_config wled4_config_defaults = {
> @@ -510,6 +854,7 @@ static int wled4_setup(struct wled *wled)
> .switch_freq = 11,
> .cabc = false,
> .external_pfet = false,
> + .auto_detection_enabled = false,
> };
>
> static const u32 wled3_boost_i_limit_values[] = {
> @@ -676,6 +1021,7 @@ static int wled_configure(struct wled *wled, int version)
> { "qcom,ext-gen", &cfg->ext_gen, },
> { "qcom,cabc", &cfg->cabc, },
> { "qcom,external-pfet", &cfg->external_pfet, },
> + { "qcom,auto-string-detection", &cfg->auto_detection_enabled, },
> };
>
> prop_addr = of_get_address(dev->of_node, 0, NULL, NULL);
> @@ -796,6 +1142,40 @@ 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;
> + u32 val;
> +
> + wled->ovp_irq = platform_get_irq_byname(pdev, "ovp");
> + if (wled->ovp_irq < 0) {
> + dev_dbg(&pdev->dev, "ovp irq is not used\n");
I assume this is optional. What happens if no IRQ is provided?
If, for instance, polling mode is enabled, maybe something like this
would be better?
dev_warn(&pdev->dev, "No IRQ found, falling back to polling mode\n");
--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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