[PATCH v2 2/2] leds: add Qualcomm PM8941 WLED driver

Bjorn Andersson
2015-01-24T00:54:27Z

From: Courtney Cavin <courtney.cavin@sonymobile.com>

This adds support for the WLED ('White' LED) block on Qualcomm's
PM8941 PMICs.

Signed-off-by: Courtney Cavin <courtney.cavin@sonymobile.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
---
drivers/leds/Kconfig | 8 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-pm8941-wled.c | 459 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 468 insertions(+)
create mode 100644 drivers/leds/leds-pm8941-wled.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index a6c3d2f..901b21a 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -516,6 +516,14 @@ config LEDS_VERSATILE
This option enabled support for the LEDs on the ARM Versatile
and RealView boards. Say Y to enabled these.

+config LEDS_PM8941_WLED
+ tristate "LED support for the Qualcomm PM8941 WLED block"
+ depends on LEDS_CLASS
+ select REGMAP
+ help
+ This option enables support for the 'White' LED block
+ on Qualcomm PM8941 PMICs.
+
comment "LED Triggers"
source "drivers/leds/trigger/Kconfig"

diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 1c65a19..4325e49 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_LEDS_BLINKM) += leds-blinkm.o
obj-$(CONFIG_LEDS_SYSCON) += leds-syscon.o
obj-$(CONFIG_LEDS_VERSATILE) += leds-versatile.o
obj-$(CONFIG_LEDS_MENF21BMC) += leds-menf21bmc.o
+obj-$(CONFIG_LEDS_PM8941_WLED) += leds-pm8941-wled.o

# LED SPI Drivers
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
diff --git a/drivers/leds/leds-pm8941-wled.c b/drivers/leds/leds-pm8941-wled.c
new file mode 100644
index 0000000..beaa7de
--- /dev/null
+++ b/drivers/leds/leds-pm8941-wled.c
@@ -0,0 +1,459 @@
+/* Copyright (c) 2015, Sony Mobile Communications, AB.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/regmap.h>
+
+#define PM8941_WLED_REG_VAL_BASE 0x40
+#define PM8941_WLED_REG_VAL_MAX 0xFFF
+
+#define PM8941_WLED_REG_MOD_EN 0x46
+#define PM8941_WLED_REG_MOD_EN_BIT BIT(7)
+#define PM8941_WLED_REG_MOD_EN_MASK BIT(7)
+
+#define PM8941_WLED_REG_SYNC 0x47
+#define PM8941_WLED_REG_SYNC_MASK 0x07
+#define PM8941_WLED_REG_SYNC_LED1 BIT(0)
+#define PM8941_WLED_REG_SYNC_LED2 BIT(1)
+#define PM8941_WLED_REG_SYNC_LED3 BIT(2)
+#define PM8941_WLED_REG_SYNC_ALL 0x07
+#define PM8941_WLED_REG_SYNC_CLEAR 0x00
+
+#define PM8941_WLED_REG_FREQ 0x4c
+#define PM8941_WLED_REG_FREQ_MASK 0x0f
+
+#define PM8941_WLED_REG_OVP 0x4d
+#define PM8941_WLED_REG_OVP_MASK 0x03
+
+#define PM8941_WLED_REG_BOOST 0x4e
+#define PM8941_WLED_REG_BOOST_MASK 0x07
+
+#define PM8941_WLED_REG_SINK 0x4f
+#define PM8941_WLED_REG_SINK_MASK 0xe0
+#define PM8941_WLED_REG_SINK_SHFT 0x05
+
+/* Per-'string' registers below */
+#define PM8941_WLED_REG_STR_OFFSET 0x10
+
+#define PM8941_WLED_REG_STR_MOD_EN_BASE 0x60
+#define PM8941_WLED_REG_STR_MOD_MASK BIT(7)
+#define PM8941_WLED_REG_STR_MOD_EN BIT(7)
+
+#define PM8941_WLED_REG_STR_SCALE_BASE 0x62
+#define PM8941_WLED_REG_STR_SCALE_MASK 0x1f
+
+#define PM8941_WLED_REG_STR_MOD_SRC_BASE 0x63
+#define PM8941_WLED_REG_STR_MOD_SRC_MASK 0x01
+#define PM8941_WLED_REG_STR_MOD_SRC_INT 0x00
+#define PM8941_WLED_REG_STR_MOD_SRC_EXT 0x01
+
+#define PM8941_WLED_REG_STR_CABC_BASE 0x66
+#define PM8941_WLED_REG_STR_CABC_MASK BIT(7)
+#define PM8941_WLED_REG_STR_CABC_EN BIT(7)
+
+struct pm8941_wled_config {
+ u32 i_boost_limit;
+ u32 ovp;
+ u32 switch_freq;
+ u32 num_strings;
+ u32 i_limit;
+ bool cs_out_en;
+ bool ext_gen;
+ bool cabc_en;
+};
+
+struct pm8941_wled {
+ struct regmap *regmap;
+ u16 addr;
+
+ struct led_classdev cdev;
+
+ struct pm8941_wled_config cfg;
+};
+
+static int pm8941_wled_set(struct led_classdev *cdev,
+ enum led_brightness value)
+{
+ struct pm8941_wled *wled;
+ u8 ctrl = 0;
+ u16 val;
+ int rc;
+ int i;
+
+ wled = container_of(cdev, struct pm8941_wled, cdev);
+
+ if (value != 0)
+ ctrl = PM8941_WLED_REG_MOD_EN_BIT;
+
+ val = value * PM8941_WLED_REG_VAL_MAX / LED_FULL;
+
+ rc = regmap_update_bits(wled->regmap,
+ wled->addr + PM8941_WLED_REG_MOD_EN,
+ PM8941_WLED_REG_MOD_EN_MASK, ctrl);
+ if (rc)
+ return rc;
+
+ for (i = 0; i < wled->cfg.num_strings; ++i) {
+ u8 v[2] = { val & 0xff, (val >> 8) & 0xf };
+
+ rc = regmap_bulk_write(wled->regmap,
+ wled->addr + PM8941_WLED_REG_VAL_BASE + 2 * i,
+ v, 2);
+ if (rc)
+ return rc;
+ }
+
+ rc = regmap_update_bits(wled->regmap,
+ wled->addr + PM8941_WLED_REG_SYNC,
+ PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_ALL);
+ if (rc)
+ return rc;
+
+ rc = regmap_update_bits(wled->regmap,
+ wled->addr + PM8941_WLED_REG_SYNC,
+ PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_CLEAR);
+ return rc;
+}
+
+static void pm8941_wled_set_brightness(struct led_classdev *cdev,
+ enum led_brightness value)
+{
+ if (pm8941_wled_set(cdev, value)) {
+ dev_err(cdev->dev, "Unable to set brightness\n");
+ return;
+ }
+ cdev->brightness = value;
+}
+
+static int pm8941_wled_setup(struct pm8941_wled *wled)
+{
+ int rc;
+ int i;
+
+ rc = regmap_update_bits(wled->regmap,
+ wled->addr + PM8941_WLED_REG_OVP,
+ PM8941_WLED_REG_OVP_MASK, wled->cfg.ovp);
+ if (rc)
+ return rc;
+
+ rc = regmap_update_bits(wled->regmap,
+ wled->addr + PM8941_WLED_REG_BOOST,
+ PM8941_WLED_REG_BOOST_MASK, wled->cfg.i_boost_limit);
+ if (rc)
+ return rc;
+
+ rc = regmap_update_bits(wled->regmap,
+ wled->addr + PM8941_WLED_REG_FREQ,
+ PM8941_WLED_REG_FREQ_MASK, wled->cfg.switch_freq);
+ if (rc)
+ return rc;
+
+ if (wled->cfg.cs_out_en) {
+ u8 all = (BIT(wled->cfg.num_strings) - 1)
+ << PM8941_WLED_REG_SINK_SHFT;
+
+ rc = regmap_update_bits(wled->regmap,
+ wled->addr + PM8941_WLED_REG_SINK,
+ PM8941_WLED_REG_SINK_MASK, all);
+ if (rc)
+ return rc;
+ }
+
+ for (i = 0; i < wled->cfg.num_strings; ++i) {
+ u16 addr = wled->addr + PM8941_WLED_REG_STR_OFFSET * i;
+
+ rc = regmap_update_bits(wled->regmap,
+ addr + PM8941_WLED_REG_STR_MOD_EN_BASE,
+ PM8941_WLED_REG_STR_MOD_MASK,
+ PM8941_WLED_REG_STR_MOD_EN);
+ if (rc)
+ return rc;
+
+ if (wled->cfg.ext_gen) {
+ rc = regmap_update_bits(wled->regmap,
+ addr + PM8941_WLED_REG_STR_MOD_SRC_BASE,
+ PM8941_WLED_REG_STR_MOD_SRC_MASK,
+ PM8941_WLED_REG_STR_MOD_SRC_EXT);
+ if (rc)
+ return rc;
+ }
+
+ rc = regmap_update_bits(wled->regmap,
+ addr + PM8941_WLED_REG_STR_SCALE_BASE,
+ PM8941_WLED_REG_STR_SCALE_MASK,
+ wled->cfg.i_limit);
+ if (rc)
+ return rc;
+
+ rc = regmap_update_bits(wled->regmap,
+ addr + PM8941_WLED_REG_STR_CABC_BASE,
+ PM8941_WLED_REG_STR_CABC_MASK,
+ wled->cfg.cabc_en ?
+ PM8941_WLED_REG_STR_CABC_EN : 0);
+ if (rc)
+ return rc;
+ }
+
+ return 0;
+}
+
+static const struct pm8941_wled_config pm8941_wled_config_defaults = {
+ .i_boost_limit = 3,
+ .i_limit = 20,
+ .ovp = 2,
+ .switch_freq = 5,
+ .num_strings = 0,
+ .cs_out_en = false,
+ .ext_gen = false,
+ .cabc_en = false,
+};
+
+struct pm8941_wled_var_cfg {
+ const u32 *values;
+ u32 (*fn)(u32);
+ int size;
+};
+
+static const u32 pm8941_wled_i_boost_limit_values[] = {
+ 105, 385, 525, 805, 980, 1260, 1400, 1680,
+};
+
+static const struct pm8941_wled_var_cfg pm8941_wled_i_boost_limit_cfg = {
+ .values = pm8941_wled_i_boost_limit_values,
+ .size = ARRAY_SIZE(pm8941_wled_i_boost_limit_values),
+};
+
+static const u32 pm8941_wled_ovp_values[] = {
+ 35, 32, 29, 27,
+};
+
+static const struct pm8941_wled_var_cfg pm8941_wled_ovp_cfg = {
+ .values = pm8941_wled_ovp_values,
+ .size = ARRAY_SIZE(pm8941_wled_ovp_values),
+};
+
+static u32 pm8941_wled_num_strings_values_fn(u32 idx)
+{
+ return idx + 1;
+}
+
+static const struct pm8941_wled_var_cfg pm8941_wled_num_strings_cfg = {
+ .fn = pm8941_wled_num_strings_values_fn,
+ .size = 3,
+};
+
+static u32 pm8941_wled_switch_freq_values_fn(u32 idx)
+{
+ return 19200 / (2 * (1 + idx));
+}
+
+static const struct pm8941_wled_var_cfg pm8941_wled_switch_freq_cfg = {
+ .fn = pm8941_wled_switch_freq_values_fn,
+ .size = 16,
+};
+
+static const struct pm8941_wled_var_cfg pm8941_wled_i_limit_cfg = {
+ .size = 26,
+};
+
+static u32 pm8941_wled_values(const struct pm8941_wled_var_cfg *cfg, u32 idx)
+{
+ if (idx >= cfg->size)
+ return UINT_MAX;
+ if (cfg->fn)
+ return cfg->fn(idx);
+ if (cfg->values)
+ return cfg->values[idx];
+ return idx;
+}
+
+static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
+{
+ struct pm8941_wled_config *cfg = &wled->cfg;
+ u32 val;
+ int rc;
+ int i;
+
+ const struct {
+ const char *name;
+ u32 *val_ptr;
+ const struct pm8941_wled_var_cfg *cfg;
+ } u32_opts[] = {
+ {
+ "qcom,current-boost-limit",
+ &cfg->i_boost_limit,
+ .cfg = &pm8941_wled_i_boost_limit_cfg,
+ },
+ {
+ "qcom,current-limit",
+ &cfg->i_limit,
+ .cfg = &pm8941_wled_i_limit_cfg,
+ },
+ {
+ "qcom,ovp",
+ &cfg->ovp,
+ .cfg = &pm8941_wled_ovp_cfg,
+ },
+ {
+ "qcom,switching-freq",
+ &cfg->switch_freq,
+ .cfg = &pm8941_wled_switch_freq_cfg,
+ },
+ {
+ "qcom,num-strings",
+ &cfg->num_strings,
+ .cfg = &pm8941_wled_num_strings_cfg,
+ },
+ };
+ const struct {
+ const char *name;
+ bool *val_ptr;
+ } bool_opts[] = {
+ { "qcom,cs-out", &cfg->cs_out_en, },
+ { "qcom,ext-gen", &cfg->ext_gen, },
+ { "qcom,cabc", &cfg->cabc_en, },
+ };
+
+ rc = of_property_read_u32(dev->of_node, "reg", &val);
+ if (rc || val > 0xffff) {
+ dev_err(dev, "invalid IO resources\n");
+ return rc ? rc : -EINVAL;
+ }
+ wled->addr = val;
+
+ rc = of_property_read_string(dev->of_node, "label", &wled->cdev.name);
+ if (rc)
+ wled->cdev.name = dev->of_node->name;
+
+ wled->cdev.default_trigger = of_get_property(dev->of_node,
+ "linux,default-trigger", NULL);
+
+ *cfg = pm8941_wled_config_defaults;
+ for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
+ u32 sel, c;
+ int j, rj;
+
+ rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
+ if (rc) {
+ if (rc != -EINVAL) {
+ dev_err(dev, "error reading '%s'\n",
+ u32_opts[i].name);
+ return rc;
+ }
+ continue;
+ }
+
+ sel = UINT_MAX;
+ rj = -1;
+ c = pm8941_wled_values(u32_opts[i].cfg, 0);
+ for (j = 0; c != UINT_MAX; ++j) {
+ if (c <= val && (sel == UINT_MAX || c >= sel)) {
+ sel = c;
+ rj = j;
+ }
+ c = pm8941_wled_values(u32_opts[i].cfg, j + 1);
+ }
+ if (sel == UINT_MAX) {
+ dev_err(dev, "invalid value for '%s'\n",
+ u32_opts[i].name);
+ return rc;
+ }
+ if (sel != val) {
+ dev_warn(dev, "rounding '%s' down to %u\n",
+ u32_opts[i].name, sel);
+ }
+ dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, sel);
+ *u32_opts[i].val_ptr = rj;
+ };
+
+ for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
+ if (of_property_read_bool(dev->of_node, bool_opts[i].name))
+ *bool_opts[i].val_ptr = true;
+ }
+
+ cfg->num_strings = cfg->num_strings + 1;
+
+ return 0;
+}
+
+static int pm8941_wled_probe(struct platform_device *pdev)
+{
+ struct pm8941_wled *wled;
+ struct regmap *regmap;
+ int rc;
+
+ regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ if (!regmap) {
+ dev_err(&pdev->dev, "Unable to get regmap\n");
+ return -EINVAL;
+ }
+
+ wled = devm_kzalloc(&pdev->dev, sizeof(*wled), GFP_KERNEL);
+ if (!wled)
+ return -ENOMEM;
+
+ wled->regmap = regmap;
+
+ rc = pm8941_wled_configure(wled, &pdev->dev);
+ if (rc)
+ return rc;
+
+ rc = pm8941_wled_setup(wled);
+ if (rc)
+ return rc;
+
+ wled->cdev.brightness_set = pm8941_wled_set_brightness;
+
+ rc = led_classdev_register(&pdev->dev, &wled->cdev);
+ if (rc)
+ return rc;
+
+ platform_set_drvdata(pdev, wled);
+
+ return 0;
+};
+
+static int pm8941_wled_remove(struct platform_device *pdev)
+{
+ struct pm8941_wled *wled;
+
+ wled = platform_get_drvdata(pdev);
+ led_classdev_unregister(&wled->cdev);
+
+ return 0;
+}
+
+static const struct of_device_id pm8941_wled_match_table[] = {
+ { .compatible = "qcom,pm8941-wled" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, pm8941_wled_match_table);
+
+static struct platform_driver pm8941_wled_driver = {
+ .probe = pm8941_wled_probe,
+ .remove = pm8941_wled_remove,
+ .driver = {
+ .name = "pm8941-wled",
+ .owner = THIS_MODULE,
+ .of_match_table = pm8941_wled_match_table,
+ },
+};
+
+module_platform_driver(pm8941_wled_driver);
+
+MODULE_DESCRIPTION("pm8941 wled driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:pm8941-wled");
--
1.9.1