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Date:   Tue, 10 Mar 2020 15:45:12 +0000
From:   Daniel Thompson <daniel.thompson@linaro.org>
To:     Kiran Gunda <kgunda@codeaurora.org>
Cc:     bjorn.andersson@linaro.org, jingoohan1@gmail.com,
        lee.jones@linaro.org, b.zolnierkie@samsung.com,
        dri-devel@lists.freedesktop.org, jacek.anaszewski@gmail.com,
        pavel@ucw.cz, robh+dt@kernel.org, mark.rutland@arm.com,
        linux-leds@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Dan Murphy <dmurphy@ti.com>,
        Andy Gross <agross@kernel.org>, linux-arm-msm@vger.kernel.org,
        linux-fbdev@vger.kernel.org
Subject: Re: [PATCH V3 3/4] backlight: qcom-wled: Add support for WLED5
 peripheral in PM8150L
Message-ID: <20200310154512.wvnx5k44mhrsxifv@holly.lan>
References: <1583760362-26978-1-git-send-email-kgunda@codeaurora.org>
 <1583760362-26978-4-git-send-email-kgunda@codeaurora.org>
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On Mon, Mar 09, 2020 at 06:56:01PM +0530, Kiran Gunda wrote:
> Add support for WLED5 peripheral that is present on PM8150L PMICs.
> 
> PM8150L WLED supports the following:
>     - Two modulators and each sink can use any of the modulator
>     - Multiple CABC selection options
>     - Multiple brightness width selection (12 bits to 15 bits)
> 
> Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>

Mostly just style comments below...


> ---
>  .../bindings/leds/backlight/qcom-wled.yaml         |  39 +++
>  drivers/video/backlight/qcom-wled.c                | 336 ++++++++++++++++++++-

Shouldn't the bindings and driver be separate?


>  2 files changed, 374 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/leds/backlight/qcom-wled.yaml b/Documentation/devicetree/bindings/leds/backlight/qcom-wled.yaml
> index d334f81..e0dadc4 100644
> --- a/Documentation/devicetree/bindings/leds/backlight/qcom-wled.yaml
> +++ b/Documentation/devicetree/bindings/leds/backlight/qcom-wled.yaml
> @@ -20,6 +20,7 @@ properties:
>         - qcom,pm8941-wled
>         - qcom,pmi8998-wled
>         - qcom,pm660l-wled
> +       - qcom,pm8150l-wled
>  
>    reg:
>      maxItems: 1
> @@ -28,10 +29,23 @@ properties:
>      maxItems: 1
>      description:
>        brightness value on boot, value from 0-4095.
> +      For pm8150l this value vary from 0-4095 or 0-32767
> +      depending on the brightness control mode. If CABC is
> +      enabled 0-4095 range is used.

Is this a pm8150l restriction or a WLED5 restriction (will other WLED5
have different ranges)?


>      allOf:
>        - $ref: /schemas/types.yaml#/definitions/uint32
>          default: 2048
>  
> +  max-brightness:
> +    maxItems: 1
> +    description:
> +      Maximum brightness level. Allowed values are,
> +      for pmi8998 it is  0-4095.
> +      For pm8150l, this can be either 4095 or 32767.

Ditto.


> +      If CABC is enabled, this is capped to 4095.
> +    allOf:
> +      - $ref: /schemas/types.yaml#/definitions/uint32
> +
>    label:
>      maxItems: 1
>      description:
> @@ -124,6 +138,31 @@ properties:
>        value for PM8941 from 1 to 3. Default 2
>        For PMI8998 from 1 to 4.
>  
> +  qcom,modulator-sel:
> +    maxItems: 1
> +    allOf:
> +      - $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Selects the modulator used for brightness modulation.
> +      Allowed values are,
> +               0 - Modulator A
> +               1 - Modulator B
> +      If not specified, then modulator A will be used by default.
> +      This property is applicable only to WLED5 peripheral.
> +
> +  qcom,cabc-sel:
> +    maxItems: 1
> +    allOf:
> +      - $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Selects the CABC pin signal used for brightness modulation.
> +      Allowed values are,
> +              0 - CABC disabled
> +              1 - CABC 1
> +              2 - CABC 2
> +              3 - External signal (e.g. LPG) is used for dimming
> +      This property is applicable only to WLED5 peripheral.
> +
>    interrupts:
>      maxItems: 2
>      description:
> diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
> index b73f273..edbbcb2 100644
> --- a/drivers/video/backlight/qcom-wled.c
> +++ b/drivers/video/backlight/qcom-wled.c
> @@ -19,6 +19,8 @@
>  #define WLED_DEFAULT_BRIGHTNESS				2048
>  #define WLED_SOFT_START_DLY_US				10000
>  #define WLED3_SINK_REG_BRIGHT_MAX			0xFFF
> +#define WLED5_SINK_REG_BRIGHT_MAX_12B			0xFFF
> +#define WLED5_SINK_REG_BRIGHT_MAX_15B			0x7FFF
>  
>  /* WLED3/WLED4 control registers */
>  #define WLED3_CTRL_REG_FAULT_STATUS			0x08
> @@ -40,6 +42,7 @@
>  
>  #define WLED3_CTRL_REG_OVP				0x4d
>  #define  WLED3_CTRL_REG_OVP_MASK			GENMASK(1, 0)
> +#define  WLED5_CTRL_REG_OVP_MASK			GENMASK(3, 0)
>  
>  #define WLED3_CTRL_REG_ILIMIT				0x4e
>  #define  WLED3_CTRL_REG_ILIMIT_MASK			GENMASK(2, 0)
> @@ -101,6 +104,40 @@
>  
>  #define WLED4_SINK_REG_BRIGHT(n)			(0x57 + (n * 0x10))
>  
> +/* WLED5 specific sink registers */
> +#define WLED5_SINK_REG_MOD_A_EN				0x50
> +#define WLED5_SINK_REG_MOD_B_EN				0x60
> +#define  WLED5_SINK_REG_MOD_EN_MASK			BIT(7)
> +
> +#define WLED5_SINK_REG_MOD_A_SRC_SEL			0x51
> +#define WLED5_SINK_REG_MOD_B_SRC_SEL			0x61
> +#define  WLED5_SINK_REG_MOD_SRC_SEL_HIGH		0
> +#define  WLED5_SINK_REG_MOD_SRC_SEL_EXT			0x03
> +#define  WLED5_SINK_REG_MOD_SRC_SEL_MASK		GENMASK(1, 0)
> +
> +#define WLED5_SINK_REG_MOD_A_BRIGHTNESS_WIDTH_SEL	0x52
> +#define WLED5_SINK_REG_MOD_B_BRIGHTNESS_WIDTH_SEL	0x62
> +#define  WLED5_SINK_REG_BRIGHTNESS_WIDTH_12B		0
> +#define  WLED5_SINK_REG_BRIGHTNESS_WIDTH_15B		1
> +
> +#define WLED5_SINK_REG_MOD_A_BRIGHTNESS_LSB		0x53
> +#define WLED5_SINK_REG_MOD_A_BRIGHTNESS_MSB		0x54
> +#define WLED5_SINK_REG_MOD_B_BRIGHTNESS_LSB		0x63
> +#define WLED5_SINK_REG_MOD_B_BRIGHTNESS_MSB		0x64
> +
> +#define WLED5_SINK_REG_MOD_SYNC_BIT			0x65
> +#define  WLED5_SINK_REG_SYNC_MOD_A_BIT			BIT(0)
> +#define  WLED5_SINK_REG_SYNC_MOD_B_BIT			BIT(1)
> +#define  WLED5_SINK_REG_SYNC_MASK			GENMASK(1, 0)
> +
> +/* WLED5 specific per-'string' registers below */
> +#define WLED5_SINK_REG_STR_FULL_SCALE_CURR(n)		(0x72 + (n * 0x10))
> +
> +#define WLED5_SINK_REG_STR_SRC_SEL(n)			(0x73 + (n * 0x10))
> +#define  WLED5_SINK_REG_SRC_SEL_MOD_A			0
> +#define  WLED5_SINK_REG_SRC_SEL_MOD_B			1
> +#define  WLED5_SINK_REG_SRC_SEL_MASK			GENMASK(1, 0)
> +
>  struct wled_var_cfg {
>  	const u32 *values;
>  	u32 (*fn)(u32);
> @@ -125,6 +162,8 @@ struct wled_config {
>  	u32 num_strings;
>  	u32 string_i_limit;
>  	u32 enabled_strings[WLED_MAX_STRINGS];

> +	u32 mod_sel;
> +	u32 cabc_sel;

Please explain cabc_sel (wled5) versus cabc_en (wled4).

>  	bool cs_out_en;
>  	bool ext_gen;
>  	bool cabc;
> @@ -164,6 +203,27 @@ struct wled {
>  	int (*wled_ovp_delay)(struct wled *wled);
>  };
>  
> +enum wled5_mod_sel {
> +	MOD_A,
> +	MOD_B,
> +	MOD_MAX,
> +};
> +
> +static const u8 wled5_brightness_reg[MOD_MAX] = {
> +	[MOD_A] = WLED5_SINK_REG_MOD_A_BRIGHTNESS_LSB,
> +	[MOD_B] = WLED5_SINK_REG_MOD_B_BRIGHTNESS_LSB,
> +};
> +
> +static const u8 wled5_src_sel_reg[MOD_MAX] = {
> +	[MOD_A] = WLED5_SINK_REG_MOD_A_SRC_SEL,
> +	[MOD_B] = WLED5_SINK_REG_MOD_B_SRC_SEL,
> +};
> +
> +static const u8 wled5_brt_wid_sel_reg[MOD_MAX] = {
> +	[MOD_A] = WLED5_SINK_REG_MOD_A_BRIGHTNESS_WIDTH_SEL,
> +	[MOD_B] = WLED5_SINK_REG_MOD_B_BRIGHTNESS_WIDTH_SEL,
> +};
> +
>  static int wled3_set_brightness(struct wled *wled, u16 brightness)
>  {
>  	int rc, i;
> @@ -182,6 +242,25 @@ static int wled3_set_brightness(struct wled *wled, u16 brightness)
>  	return 0;
>  }
>  
> +static int wled5_set_brightness(struct wled *wled, u16 brightness)
> +{
> +	int rc, offset;
> +	u16 low_limit = wled->max_brightness * 1 / 1000;
> +	u8 v[2];
> +
> +	/* WLED5's lower limit is 0.1% */
> +	if (brightness < low_limit)
> +		brightness = low_limit;
> +
> +	v[0] = brightness & 0xff;
> +	v[1] = (brightness >> 8) & 0x7f;
> +
> +	offset = wled5_brightness_reg[wled->cfg.mod_sel];
> +	rc = regmap_bulk_write(wled->regmap, wled->sink_addr + offset,
> +			       v, 2);
> +	return rc;
> +}
> +

Can we keep the same ordering throughout the file (wled3, wled4, wled5)?
Most of the wled5 callbacks seem to have been inserted above wled4.


Daniel.