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Date: Thu, 6 Sep 2018 22:16:05 +0200
From: Jacek Anaszewski <jacek.anaszewski@...il.com>
To: Baolin Wang <baolin.wang@...aro.org>, pavel@....cz
Cc: rteysseyre@...il.com, bjorn.andersson@...aro.org,
broonie@...nel.org, linus.walleij@...aro.org,
linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v10 2/2] leds: sc27xx: Add pattern_set/clear interfaces
for LED controller
Hi Baolin,
Thank you for the patch. I really appreciate your effort.
I see one more thing I forgot to mention in the previous
review. Please take a look at my comment to pattern_set().
On 09/06/2018 04:37 AM, Baolin Wang wrote:
> This patch implements the 'pattern_set'and 'pattern_clear'
> interfaces to support SC27XX LED breathing mode.
>
> Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
> ---
> Changes from v9:
> - Optimize the ABI documentation file.
> - Update the brightness value in hardware pattern mode.
>
> Changes from v8:
> - Optimize the ABI documentation file.
>
> Changes from v7:
> - Add its own ABI documentation file.
>
> Changes from v6:
> - None.
>
> Changes from v5:
> - None.
>
> Changes from v4:
> - None.
>
> Changes from v3:
> - None.
>
> Changes from v2:
> - None.
>
> Changes from v1:
> - Remove pattern_get interface.
> ---
> .../ABI/testing/sysfs-class-led-driver-sc27xx | 22 +++++
> drivers/leds/leds-sc27xx-bltc.c | 103 ++++++++++++++++++++
> 2 files changed, 125 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
>
> diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
> new file mode 100644
> index 0000000..d8056d5
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-led-driver-sc27xx
> @@ -0,0 +1,22 @@
> +What: /sys/class/leds/<led>/hw_pattern
> +Date: September 2018
> +KernelVersion: 4.20
> +Description:
> + Specify a hardware pattern for the SC27XX LED. For the SC27XX
> + LED controller, it only supports 4 stages to make a single
> + hardware pattern, which is used to configure the rise time,
> + high time, fall time and low time for the breathing mode.
> +
> + For the breathing mode, the SC27XX LED only expects one brightness
> + for the high stage. To be compatible with the hardware pattern
> + format, we should set brightness as 0 for rise stage, fall
> + stage and low stage.
> +
> + Min stage duration: 125 ms
> + Max stage duration: 31875 ms
> +
> + Since the stage duration step is 125 ms, the duration must be
> + a multiplier of 125, like 125ms, 250ms, 375ms, 500ms ... 31875ms.
> +
> + Thus the format of the hardware pattern values should be:
> + "0 rise_duration brightness high_duration 0 fall_duration 0 low_duration".
> diff --git a/drivers/leds/leds-sc27xx-bltc.c b/drivers/leds/leds-sc27xx-bltc.c
> index 9d9b7aa..558a325 100644
> --- a/drivers/leds/leds-sc27xx-bltc.c
> +++ b/drivers/leds/leds-sc27xx-bltc.c
> @@ -32,8 +32,15 @@
> #define SC27XX_DUTY_MASK GENMASK(15, 0)
> #define SC27XX_MOD_MASK GENMASK(7, 0)
>
> +#define SC27XX_CURVE_SHIFT 8
> +#define SC27XX_CURVE_L_MASK GENMASK(7, 0)
> +#define SC27XX_CURVE_H_MASK GENMASK(15, 8)
> +
> #define SC27XX_LEDS_OFFSET 0x10
> #define SC27XX_LEDS_MAX 3
> +#define SC27XX_LEDS_PATTERN_CNT 4
> +/* Stage duration step, in milliseconds */
> +#define SC27XX_LEDS_STEP 125
>
> struct sc27xx_led {
> char name[LED_MAX_NAME_SIZE];
> @@ -122,6 +129,98 @@ static int sc27xx_led_set(struct led_classdev *ldev, enum led_brightness value)
> return err;
> }
>
> +static int sc27xx_led_pattern_clear(struct led_classdev *ldev)
> +{
> + struct sc27xx_led *leds = to_sc27xx_led(ldev);
> + struct regmap *regmap = leds->priv->regmap;
> + u32 base = sc27xx_led_get_offset(leds);
> + u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
> + u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
> + int err;
> +
> + mutex_lock(&leds->priv->lock);
> +
> + /* Reset the rise, high, fall and low time to zero. */
> + regmap_write(regmap, base + SC27XX_LEDS_CURVE0, 0);
> + regmap_write(regmap, base + SC27XX_LEDS_CURVE1, 0);
> +
> + err = regmap_update_bits(regmap, ctrl_base,
> + (SC27XX_LED_RUN | SC27XX_LED_TYPE) << ctrl_shift, 0);
> +
> + ldev->brightness = LED_OFF;
> +
> + mutex_unlock(&leds->priv->lock);
> +
> + return err;
> +}
> +
> +static int sc27xx_led_pattern_set(struct led_classdev *ldev,
> + struct led_pattern *pattern,
> + int len, u32 repeat)
> +{
> + struct sc27xx_led *leds = to_sc27xx_led(ldev);
> + u32 base = sc27xx_led_get_offset(leds);
> + u32 ctrl_base = leds->priv->base + SC27XX_LEDS_CTRL;
> + u8 ctrl_shift = SC27XX_CTRL_SHIFT * leds->line;
> + struct regmap *regmap = leds->priv->regmap;
> + int err;
> +
> + /*
> + * Must contain 4 tuples to configure the rise time, high time, fall
> + * time and low time to enable the breathing mode.
> + */
> + if (len != SC27XX_LEDS_PATTERN_CNT)
> + return -EINVAL;
> +
> + mutex_lock(&leds->priv->lock);
Please add below macros at the top of the file and the function
shown. It will allow to nicely align the value provided by
the user to the nearest delta_t step. We have similar thing
in led_class_flash.c (led_clamp_align()), that was adopted from
v4l2-ctrls.c.
#define SC27XX_DELTA_T_MIN SC27XX_LEDS_STEP
#define SC27XX_DELTA_T_MAX (SC27XX_LEDS_STEP * 255)
static void sc27xx_led_clamp_align_delta_t(u32 *delta_t)
{
u32 v, offset, t = *delta_t;
v = t + SC27XX_LEDS_STEP / 2;
v = clamp(v, SC27XX_DELTA_T_MIN, SC27XX_DELTA_T_MAX);
offset = v - SC27XX_DELTA_T_MIN;
offset = SC27XX_LEDS_STEP * (offset / SC27XX_LEDS_STEP);
*delta_t = SC27XX_DELTA_T_MIN + offset;
}
Then call the function for each delta_t before writing it to the device:
sc27xx_led_clamp_align_delta_t(&pattern[0].delta_t);
sc27xx_led_clamp_align_delta_t(&pattern[1].delta_t);
sc27xx_led_clamp_align_delta_t(&pattern[2].delta_t);
sc27xx_led_clamp_align_delta_t(&pattern[3].delta_t);
Also, regarding PATCH v8 1/2, please change the types of properties
in struct led_pattern as follows:
+struct led_pattern {
+ u32 delta_t;
+ enum led_brightness brightness;
+};
+
Best regards,
Jacek Anaszewski
> +
> + err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
> + SC27XX_CURVE_L_MASK,
> + pattern[0].delta_t / SC27XX_LEDS_STEP);
> + if (err)
> + goto out;
> +
> + err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
> + SC27XX_CURVE_L_MASK,
> + pattern[1].delta_t / SC27XX_LEDS_STEP);
> + if (err)
> + goto out;
> +
> + err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE0,
> + SC27XX_CURVE_H_MASK,
> + (pattern[2].delta_t / SC27XX_LEDS_STEP) <<
> + SC27XX_CURVE_SHIFT);
> + if (err)
> + goto out;
> +
> +
> + err = regmap_update_bits(regmap, base + SC27XX_LEDS_CURVE1,
> + SC27XX_CURVE_H_MASK,
> + (pattern[3].delta_t / SC27XX_LEDS_STEP) <<
> + SC27XX_CURVE_SHIFT);
> + if (err)
> + goto out;
> +
> + err = regmap_update_bits(regmap, base + SC27XX_LEDS_DUTY,
> + SC27XX_DUTY_MASK,
> + (pattern[1].brightness << SC27XX_DUTY_SHIFT) |
> + SC27XX_MOD_MASK);
> + if (err)
> + goto out;
> +
> + /* Enable the LED breathing mode */
> + err = regmap_update_bits(regmap, ctrl_base,
> + SC27XX_LED_RUN << ctrl_shift,
> + SC27XX_LED_RUN << ctrl_shift);
> + if (!err)
> + ldev->brightness = pattern[1].brightness;
> +
> +out:
> + mutex_unlock(&leds->priv->lock);
> +
> + return err;
> +}
> +
> static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv *priv)
> {
> int i, err;
> @@ -140,6 +239,9 @@ static int sc27xx_led_register(struct device *dev, struct sc27xx_led_priv *priv)
> led->priv = priv;
> led->ldev.name = led->name;
> led->ldev.brightness_set_blocking = sc27xx_led_set;
> + led->ldev.pattern_set = sc27xx_led_pattern_set;
> + led->ldev.pattern_clear = sc27xx_led_pattern_clear;
> + led->ldev.default_trigger = "pattern";
>
> err = devm_led_classdev_register(dev, &led->ldev);
> if (err)
> @@ -241,4 +343,5 @@ static int sc27xx_led_remove(struct platform_device *pdev)
>
> MODULE_DESCRIPTION("Spreadtrum SC27xx breathing light controller driver");
> MODULE_AUTHOR("Xiaotong Lu <xiaotong.lu@...eadtrum.com>");
> +MODULE_AUTHOR("Baolin Wang <baolin.wang@...aro.org>");
> MODULE_LICENSE("GPL v2");
>
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