Re: [PATCH V3 3/4] backlight: qcom-wled: Add support for WLED5 peripheral in PM8150L

From: kgunda
Date: Wed Mar 11 2020 - 03:00:19 EST

On 2020-03-10 21:15, Daniel Thompson wrote:
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@xxxxxxxxxxxxxx>

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?


Ok. I will split it out in to a separate patch in next post.
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)?

It is a WLED5 restriction which is used in pm8150l PMIC.

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.

It is a WLED5 restriction which is used in pm8150l PMIC.

+ 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).

Ok. WLED5 has 2 CABC modules, from which one can be selected/enabled.
wled4 has only one CABC module and it is just enabled based on the user input.
I will add a comment in next post.

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.

Sure. Will do it in next post.

Daniel.