[PATCH v3 4/7] leds: rgb: leds-qcom-lpg: Add support for PPG through single SDAM

From: Anjelique Melendez
Date: Mon Aug 14 2023 - 20:02:22 EST

In some PMICs like pmi632, the LUT pattern and LPG configuration can be
stored in a single SDAM module instead of LUT peripheral. This feature is
called PPG.

Add support for configuring and using LUT pattern from SDAM.

Signed-off-by: Anjelique Melendez <quic_amelende@xxxxxxxxxxx>
---
drivers/leds/rgb/leds-qcom-lpg.c | 309 ++++++++++++++++++++++++++++---
1 file changed, 283 insertions(+), 26 deletions(-)

diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c
index 59581b3e25ca..6fdf736d3632 100644
--- a/drivers/leds/rgb/leds-qcom-lpg.c
+++ b/drivers/leds/rgb/leds-qcom-lpg.c
@@ -8,12 +8,14 @@
#include <linux/bitfield.h>
#include <linux/led-class-multicolor.h>
#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/regmap.h>
#include <linux/slab.h>
+#include <linux/soc/qcom/qcom-pbs.h>

#define LPG_SUBTYPE_REG 0x05
#define LPG_SUBTYPE_LPG 0x2
@@ -49,9 +51,25 @@

#define LPG_RESOLUTION_9BIT BIT(9)
#define LPG_RESOLUTION_15BIT BIT(15)
+#define PPG_MAX_LED_BRIGHTNESS 255
+
#define LPG_MAX_M 7
#define LPG_MAX_PREDIV 6

+#define DEFAULT_TICK_DURATION_US 7800
+#define RAMP_STEP_DURATION(x) (((x) * 1000 / DEFAULT_TICK_DURATION_US) & 0xff)
+
+/* LPG common config settings for PPG */
+#define SDAM_REG_RAMP_STEP_DURATION 0x47
+#define SDAM_LUT_COUNT_MAX 64
+
+/* LPG per channel config settings for PPG */
+#define SDAM_LUT_EN_OFFSET 0x0
+#define SDAM_PATTERN_CONFIG_OFFSET 0x1
+#define SDAM_END_INDEX_OFFSET 0x3
+#define SDAM_START_INDEX_OFFSET 0x4
+#define SDAM_PBS_SCRATCH_LUT_COUNTER_OFFSET 0x6
+
struct lpg_channel;
struct lpg_data;

@@ -65,7 +83,12 @@ struct lpg_data;
* @lut_base: base address of the LUT block (optional)
* @lut_size: number of entries in the LUT block
* @lut_bitmap: allocation bitmap for LUT entries
- * @triled_base: base address of the TRILED block (optional)
+ * @pbs_dev: PBS device
+ * @lpg_chan_nvmem: LPG nvmem peripheral device
+ * @pbs_en_bitmap: bitmap for tracking PBS triggers
+ * @lut_sdam_base: offset where LUT pattern begins in nvmem
+ * @ppg_en: Flag indicating whether PPG is enabled/used
+ * @triled_base: base address of the TRILED block (optional)
* @triled_src: power-source for the TRILED
* @triled_has_atc_ctl: true if there is TRI_LED_ATC_CTL register
* @triled_has_src_sel: true if there is TRI_LED_SRC_SEL register
@@ -86,6 +109,12 @@ struct lpg {
u32 lut_size;
unsigned long *lut_bitmap;

+ struct pbs_dev *pbs_dev;
+ struct nvmem_device *lpg_chan_nvmem;
+ unsigned long pbs_en_bitmap;
+ u32 lut_sdam_base;
+ bool ppg_en;
+
u32 triled_base;
u32 triled_src;
bool triled_has_atc_ctl;
@@ -102,6 +131,8 @@ struct lpg {
* @triled_mask: mask in TRILED to enable this channel
* @lut_mask: mask in LUT to start pattern generator for this channel
* @subtype: PMIC hardware block subtype
+ * @sdam_offset: Channel offset in LPG nvmem
+ * @lpg_idx: index of the channel
* @in_use: channel is exposed to LED framework
* @color: color of the LED attached to this channel
* @dtest_line: DTEST line for output, or 0 if disabled
@@ -113,6 +144,7 @@ struct lpg {
* @pre_div_sel: divider selector of the reference clock
* @pre_div_exp: exponential divider of the reference clock
* @pwm_resolution_sel: pwm resolution selector
+ * @pattern_set: true when setting pattern
* @ramp_enabled: duty cycle is driven by iterating over lookup table
* @ramp_ping_pong: reverse through pattern, rather than wrapping to start
* @ramp_oneshot: perform only a single pass over the pattern
@@ -130,6 +162,8 @@ struct lpg_channel {
unsigned int triled_mask;
unsigned int lut_mask;
unsigned int subtype;
+ u32 sdam_offset;
+ u32 lpg_idx;

bool in_use;

@@ -147,6 +181,7 @@ struct lpg_channel {
unsigned int pre_div_exp;
unsigned int pwm_resolution_sel;

+ bool pattern_set;
bool ramp_enabled;
bool ramp_ping_pong;
bool ramp_oneshot;
@@ -181,10 +216,12 @@ struct lpg_led {
* struct lpg_channel_data - per channel initialization data
* @base: base address for PWM channel registers
* @triled_mask: bitmask for controlling this channel in TRILED
+ * @sdam_offset: Channel offset in LPG nvmem
*/
struct lpg_channel_data {
unsigned int base;
u8 triled_mask;
+ unsigned int sdam_offset;
};

/**
@@ -192,21 +229,87 @@ struct lpg_channel_data {
* @lut_base: base address of LUT block
* @lut_size: number of entries in LUT
* @triled_base: base address of TRILED
+ * @lut_sdam_base: base address where LUT pattern begins in nvmem device
* @triled_has_atc_ctl: true if there is TRI_LED_ATC_CTL register
* @triled_has_src_sel: true if there is TRI_LED_SRC_SEL register
* @num_channels: number of channels in LPG
+ * @nvmem_count: number of nvmems used for LUT and PPG config
* @channels: list of channel initialization data
*/
struct lpg_data {
unsigned int lut_base;
unsigned int lut_size;
unsigned int triled_base;
+ unsigned int lut_sdam_base;
bool triled_has_atc_ctl;
bool triled_has_src_sel;
int num_channels;
+ int nvmem_count;
const struct lpg_channel_data *channels;
};

+static int lpg_sdam_write(struct lpg *lpg, u16 addr, u8 val)
+{
+ int rc;
+
+ rc = nvmem_device_write(lpg->lpg_chan_nvmem, addr, 1, &val);
+ if (rc < 0)
+ dev_err(lpg->dev, "writing %u to SDAM addr %#x failed, rc=%d\n",
+ val, addr, rc);
+
+ return rc > 0 ? 0 : rc;
+}
+
+#define SDAM_REG_PBS_SEQ_EN 0x42
+#define PBS_SW_TRIG_BIT BIT(0)
+
+static int lpg_clear_pbs_trigger(struct lpg_channel *chan)
+{
+ int rc;
+
+ clear_bit(chan->lpg_idx, &chan->lpg->pbs_en_bitmap);
+ if (!chan->lpg->pbs_en_bitmap) {
+ rc = lpg_sdam_write(chan->lpg, SDAM_REG_PBS_SEQ_EN, 0);
+ if (rc < 0)
+ return rc;
+ }
+
+ return 0;
+}
+
+static int lpg_set_pbs_trigger(struct lpg_channel *chan)
+{
+ int rc;
+
+ if (!chan->lpg->pbs_en_bitmap) {
+ rc = lpg_sdam_write(chan->lpg, SDAM_REG_PBS_SEQ_EN, PBS_SW_TRIG_BIT);
+ if (rc < 0)
+ return rc;
+
+ rc = qcom_pbs_trigger_event(chan->lpg->pbs_dev, PBS_SW_TRIG_BIT);
+ if (rc < 0)
+ return rc;
+ }
+ set_bit(chan->lpg_idx, &chan->lpg->pbs_en_bitmap);
+
+ return 0;
+}
+
+static void lpg_sdam_configure_triggers(struct lpg_channel *chan)
+{
+ if (!chan->lpg->ppg_en)
+ return;
+
+ if (chan->enabled && chan->pattern_set) {
+ lpg_sdam_write(chan->lpg, SDAM_LUT_EN_OFFSET + chan->sdam_offset, 1);
+ lpg_set_pbs_trigger(chan);
+ chan->pattern_set = false;
+ } else {
+ lpg_sdam_write(chan->lpg, SDAM_LUT_EN_OFFSET + chan->sdam_offset, 0);
+ lpg_clear_pbs_trigger(chan);
+ }
+}
+
static int triled_set(struct lpg *lpg, unsigned int mask, unsigned int enable)
{
/* Skip if we don't have a triled block */
@@ -217,6 +320,41 @@ static int triled_set(struct lpg *lpg, unsigned int mask, unsigned int enable)
mask, enable);
}

+static int lpg_lut_store_sdam(struct lpg *lpg, struct led_pattern *pattern,
+ size_t len, unsigned int *lo_idx, unsigned int *hi_idx)
+{
+ u8 brightness;
+ u16 addr;
+ unsigned int idx;
+ int i, rc;
+
+ if (len > SDAM_LUT_COUNT_MAX) {
+ dev_err(lpg->dev, "Pattern length (%zu) exceeds maximum pattern length (%d)\n",
+ len, SDAM_LUT_COUNT_MAX);
+ return -EINVAL;
+ }
+
+ idx = bitmap_find_next_zero_area(lpg->lut_bitmap, lpg->lut_size,
+ 0, len, 0);
+ if (idx >= lpg->lut_size)
+ return -ENOSPC;
+
+ for (i = 0; i < len; i++) {
+ brightness = pattern[i].brightness;
+ addr = lpg->lut_sdam_base + i + idx;
+ rc = lpg_sdam_write(lpg, addr, brightness);
+ if (rc < 0)
+ return rc;
+ }
+
+ bitmap_set(lpg->lut_bitmap, idx, len);
+
+ *lo_idx = idx;
+ *hi_idx = idx + len - 1;
+
+ return 0;
+}
+
static int lpg_lut_store(struct lpg *lpg, struct led_pattern *pattern,
size_t len, unsigned int *lo_idx, unsigned int *hi_idx)
{
@@ -463,6 +601,26 @@ static void lpg_apply_pwm_value(struct lpg_channel *chan)
#define LPG_PATTERN_CONFIG_PAUSE_HI BIT(1)
#define LPG_PATTERN_CONFIG_PAUSE_LO BIT(0)

+static void lpg_sdam_apply_lut_control(struct lpg_channel *chan)
+{
+ u8 val, conf = 0;
+ struct lpg *lpg = chan->lpg;
+
+ if (!chan->ramp_oneshot)
+ conf |= LPG_PATTERN_CONFIG_REPEAT;
+
+ lpg_sdam_write(lpg, SDAM_PBS_SCRATCH_LUT_COUNTER_OFFSET + chan->sdam_offset, 0);
+ lpg_sdam_write(lpg, SDAM_PATTERN_CONFIG_OFFSET + chan->sdam_offset, conf);
+
+ lpg_sdam_write(lpg, SDAM_END_INDEX_OFFSET + chan->sdam_offset, chan->pattern_hi_idx);
+ lpg_sdam_write(lpg, SDAM_START_INDEX_OFFSET + chan->sdam_offset, chan->pattern_lo_idx);
+
+ val = RAMP_STEP_DURATION(chan->ramp_tick_ms);
+ if (val > 0)
+ val--;
+ lpg_sdam_write(lpg, SDAM_REG_RAMP_STEP_DURATION, val);
+}
+
static void lpg_apply_lut_control(struct lpg_channel *chan)
{
struct lpg *lpg = chan->lpg;
@@ -476,6 +634,9 @@ static void lpg_apply_lut_control(struct lpg_channel *chan)
if (!chan->ramp_enabled || chan->pattern_lo_idx == chan->pattern_hi_idx)
return;

+ if (lpg->ppg_en)
+ return lpg_sdam_apply_lut_control(chan);
+
hi_pause = DIV_ROUND_UP(chan->ramp_hi_pause_ms, step);
lo_pause = DIV_ROUND_UP(chan->ramp_lo_pause_ms, step);

@@ -632,7 +793,7 @@ static void lpg_brightness_set(struct lpg_led *led, struct led_classdev *cdev,
} else {
lpg_calc_freq(chan, NSEC_PER_MSEC);

- duty = div_u64(brightness * chan->period, cdev->max_brightness);
+ duty = div_u64(brightness * chan->period, LPG_RESOLUTION_9BIT);
lpg_calc_duty(chan, duty);
chan->enabled = true;
chan->ramp_enabled = false;
@@ -643,6 +804,7 @@ static void lpg_brightness_set(struct lpg_led *led, struct led_classdev *cdev,
triled_mask |= chan->triled_mask;

lpg_apply(chan);
+ lpg_sdam_configure_triggers(chan);
}

/* Toggle triled lines */
@@ -775,7 +937,7 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
unsigned int lo_idx;
unsigned int hi_idx;
unsigned int i;
- bool ping_pong = true;
+ bool ping_pong = false;
int ret = -EINVAL;

/* Hardware only support oneshot or indefinite loops */
@@ -824,7 +986,7 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
* used to stretch the first delay of the pattern and a "high pause"
* the last one.
*
- * In order to save space the pattern can be played in "ping pong"
+ * In order to save space for the pattern can be played in "ping pong"
* mode, in which the pattern is first played forward, then "high
* pause" is applied, then the pattern is played backwards and finally
* the "low pause" is applied.
@@ -837,16 +999,22 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
* If the specified pattern is a palindrome the ping pong mode is
* enabled. In this scenario the delta_t of the middle entry (i.e. the
* last in the programmed pattern) determines the "high pause".
+ *
+ * NVMEM devices supporting LUT do not support "low pause", "high pause"
+ * or "ping pong"
*/

/* Detect palindromes and use "ping pong" to reduce LUT usage */
- for (i = 0; i < len / 2; i++) {
- brightness_a = pattern[i].brightness;
- brightness_b = pattern[len - i - 1].brightness;
-
- if (brightness_a != brightness_b) {
- ping_pong = false;
- break;
+ if (lpg->lut_base) {
+ ping_pong = true;
+ for (i = 0; i < len / 2; i++) {
+ brightness_a = pattern[i].brightness;
+ brightness_b = pattern[len - i - 1].brightness;
+
+ if (brightness_a != brightness_b) {
+ ping_pong = false;
+ break;
+ }
}
}

@@ -860,14 +1028,21 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
* Validate that all delta_t in the pattern are the same, with the
* exception of the middle element in case of ping_pong.
*/
- delta_t = pattern[1].delta_t;
- for (i = 2; i < len; i++) {
+ if (lpg->ppg_en) {
+ i = 1;
+ delta_t = pattern[0].delta_t;
+ } else {
+ i = 2;
+ delta_t = pattern[1].delta_t;
+ }
+
+ for (; i < len; i++) {
if (pattern[i].delta_t != delta_t) {
/*
* Allow last entry in the full or shortened pattern to
* specify hi pause. Reject other variations.
*/
- if (i != actual_len - 1)
+ if (i != actual_len - 1 || lpg->ppg_en)
goto out_free_pattern;
}
}
@@ -876,12 +1051,19 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,
if (delta_t >= BIT(9))
goto out_free_pattern;

- /* Find "low pause" and "high pause" in the pattern */
- lo_pause = pattern[0].delta_t;
- hi_pause = pattern[actual_len - 1].delta_t;
+ /* Find "low pause" and "high pause" in the pattern if not an NVMEM device*/
+ if (!lpg->ppg_en) {
+ lo_pause = pattern[0].delta_t;
+ hi_pause = pattern[actual_len - 1].delta_t;
+ }

mutex_lock(&lpg->lock);
- ret = lpg_lut_store(lpg, pattern, actual_len, &lo_idx, &hi_idx);
+
+ if (lpg->ppg_en)
+ ret = lpg_lut_store_sdam(lpg, pattern, actual_len, &lo_idx, &hi_idx);
+ else
+ ret = lpg_lut_store(lpg, pattern, actual_len, &lo_idx, &hi_idx);
+
if (ret < 0)
goto out_unlock;

@@ -897,6 +1079,8 @@ static int lpg_pattern_set(struct lpg_led *led, struct led_pattern *led_pattern,

chan->pattern_lo_idx = lo_idx;
chan->pattern_hi_idx = hi_idx;
+
+ chan->pattern_set = lpg->ppg_en;
}

out_unlock:
@@ -1190,8 +1374,8 @@ static int lpg_add_led(struct lpg *lpg, struct device_node *np)
cdev->brightness_set_blocking = lpg_brightness_mc_set;
cdev->blink_set = lpg_blink_mc_set;

- /* Register pattern accessors only if we have a LUT block */
- if (lpg->lut_base) {
+ /* Register pattern accessors if we have a LUT block or when using PPG */
+ if (lpg->lut_base || lpg->ppg_en) {
cdev->pattern_set = lpg_pattern_mc_set;
cdev->pattern_clear = lpg_pattern_mc_clear;
}
@@ -1204,15 +1388,19 @@ static int lpg_add_led(struct lpg *lpg, struct device_node *np)
cdev->brightness_set_blocking = lpg_brightness_single_set;
cdev->blink_set = lpg_blink_single_set;

- /* Register pattern accessors only if we have a LUT block */
- if (lpg->lut_base) {
+ /* Register pattern accessors if we have a LUT block or when using PPG */
+ if (lpg->lut_base || lpg->ppg_en) {
cdev->pattern_set = lpg_pattern_single_set;
cdev->pattern_clear = lpg_pattern_single_clear;
}
}

cdev->default_trigger = of_get_property(np, "linux,default-trigger", NULL);
- cdev->max_brightness = LPG_RESOLUTION_9BIT - 1;
+
+ if (lpg->ppg_en)
+ cdev->max_brightness = PPG_MAX_LED_BRIGHTNESS;
+ else
+ cdev->max_brightness = LPG_RESOLUTION_9BIT - 1;

if (!of_property_read_string(np, "default-state", &state) &&
!strcmp(state, "on"))
@@ -1253,6 +1441,8 @@ static int lpg_init_channels(struct lpg *lpg)
chan->base = data->channels[i].base;
chan->triled_mask = data->channels[i].triled_mask;
chan->lut_mask = BIT(i);
+ chan->sdam_offset = data->channels[i].sdam_offset;
+ chan->lpg_idx = i;

regmap_read(lpg->map, chan->base + LPG_SUBTYPE_REG, &chan->subtype);
}
@@ -1299,10 +1489,13 @@ static int lpg_init_lut(struct lpg *lpg)
{
const struct lpg_data *data = lpg->data;

- if (!data->lut_base)
+ if (data->lut_base)
+ lpg->lut_base = data->lut_base;
+ else if (lpg->ppg_en)
+ lpg->lut_sdam_base = data->lut_sdam_base;
+ else
return 0;

- lpg->lut_base = data->lut_base;
lpg->lut_size = data->lut_size;

lpg->lut_bitmap = devm_bitmap_zalloc(lpg->dev, lpg->lut_size, GFP_KERNEL);
@@ -1312,6 +1505,60 @@ static int lpg_init_lut(struct lpg *lpg)
return 0;
}

+static int lpg_parse_sdam(struct lpg *lpg)
+{
+ int rc = 0;
+
+ if (lpg->data->nvmem_count == 0)
+ return 0;
+
+ /* get the nvmem device for LPG/LUT config */
+ lpg->lpg_chan_nvmem = devm_nvmem_device_get(lpg->dev, "lpg_chan_sdam");
+ if (IS_ERR(lpg->lpg_chan_nvmem)) {
+ rc = PTR_ERR(lpg->lpg_chan_nvmem);
+ if (rc != -EPROBE_DEFER)
+ dev_err(lpg->dev, "Failed to get nvmem device, rc=%d\n", rc);
+ return rc;
+ }
+
+ lpg->pbs_dev = get_pbs_client_device(lpg->dev);
+ if (IS_ERR(lpg->pbs_dev)) {
+ rc = PTR_ERR(lpg->pbs_dev);
+ if (rc != -EPROBE_DEFER)
+ dev_err(lpg->dev, "Failed to get PBS client device, rc=%d\n", rc);
+ return rc;
+ }
+
+ lpg->ppg_en = true;
+
+ return rc;
+}
+
+static int lpg_init_sdam(struct lpg *lpg)
+{
+ struct lpg_channel *chan;
+ int i, rc;
+
+ if (!lpg->ppg_en)
+ return 0;
+
+ for (i = 0; i < lpg->num_channels; i++) {
+ chan = &lpg->channels[i];
+ if (chan->sdam_offset) {
+ rc = lpg_sdam_write(lpg, SDAM_LUT_EN_OFFSET + chan->sdam_offset, 0);
+ if (rc < 0)
+ break;
+
+ rc = lpg_sdam_write(lpg,
+ SDAM_PBS_SCRATCH_LUT_COUNTER_OFFSET + chan->sdam_offset, 0);
+ if (rc < 0)
+ break;
+ }
+ }
+
+ return rc;
+}
+
static int lpg_probe(struct platform_device *pdev)
{
struct device_node *np;
@@ -1348,6 +1595,14 @@ static int lpg_probe(struct platform_device *pdev)
if (ret < 0)
return ret;

+ ret = lpg_parse_sdam(lpg);
+ if (ret < 0)
+ return ret;
+
+ ret = lpg_init_sdam(lpg);
+ if (ret < 0)
+ return ret;
+
ret = lpg_init_lut(lpg);
if (ret < 0)
return ret;
@@ -1363,7 +1618,9 @@ static int lpg_probe(struct platform_device *pdev)
for (i = 0; i < lpg->num_channels; i++)
lpg_apply_dtest(&lpg->channels[i]);

- return lpg_add_pwm(lpg);
+ ret = lpg_add_pwm(lpg);
+
+ return ret;
}

static int lpg_remove(struct platform_device *pdev)
--
2.41.0