Re: [PATCH v9 09/10] leds: flash: mt6370: Add MediaTek MT6370 flashlight support

AngeloGioacchino Del Regno
2022-08-30T08:49:54Z

Il 30/08/22 05:40, ChiaEn Wu ha scritto:
> From: Alice Chen <alice_chen@richtek.com>
>
> The MediaTek MT6370 is a highly-integrated smart power management IC,
> which includes a single cell Li-Ion/Li-Polymer switching battery
> charger, a USB Type-C & Power Delivery (PD) controller, dual Flash
> LED current sources, a RGB LED driver, a backlight WLED driver,
> a display bias driver and a general LDO for portable devices.
>
> Add support for the MT6370 Flash LED driver. Flash LED in MT6370
> has 2 channels and support torch/strobe mode.
>
> Signed-off-by: Alice Chen <alice_chen@richtek.com>
> Signed-off-by: ChiaEn Wu <chiaen_wu@richtek.com>
> ---
>
> v9
> - Revise the format of the comments.
> ---
> drivers/leds/flash/Kconfig | 14 +
> drivers/leds/flash/Makefile | 1 +
> drivers/leds/flash/leds-mt6370-flash.c | 632 +++++++++++++++++++++++++++++++++
> 3 files changed, 647 insertions(+)
> create mode 100644 drivers/leds/flash/leds-mt6370-flash.c
>
> diff --git a/drivers/leds/flash/Kconfig b/drivers/leds/flash/Kconfig
> index d3eb689..405bd16 100644
> --- a/drivers/leds/flash/Kconfig
> +++ b/drivers/leds/flash/Kconfig
> @@ -61,6 +61,20 @@ config LEDS_MT6360
> Independent current sources supply for each flash LED support torch
> and strobe mode.
>
> +config LEDS_MT6370_FLASH
> + tristate "Flash LED Support for MediaTek MT6370 PMIC"
> + depends on LEDS_CLASS && OF
> + depends on LEDS_CLASS_FLASH || !LEDS_CLASS_FLASH
> + depends on V4L2_FLASH_LED_CLASS || !V4L2_FLASH_LED_CLASS
> + depends on MFD_MT6370
> + help
> + Support 2 channels and torch/strobe mode.
> + Say Y here to enable support for
> + MT6370_FLASH_LED device.
> +
> + This driver can also be built as a module. If so, the module
> + will be called "leds-mt6370-flash".
> +
> config LEDS_RT4505
> tristate "LED support for RT4505 flashlight controller"
> depends on I2C && OF
> diff --git a/drivers/leds/flash/Makefile b/drivers/leds/flash/Makefile
> index 0acbddc..0c1f3c5 100644
> --- a/drivers/leds/flash/Makefile
> +++ b/drivers/leds/flash/Makefile
> @@ -9,3 +9,4 @@ obj-$(CONFIG_LEDS_MAX77693) += leds-max77693.o
> obj-$(CONFIG_LEDS_RT4505) += leds-rt4505.o
> obj-$(CONFIG_LEDS_RT8515) += leds-rt8515.o
> obj-$(CONFIG_LEDS_SGM3140) += leds-sgm3140.o
> +obj-$(CONFIG_LEDS_MT6370_FLASH) += leds-mt6370-flash.o
> diff --git a/drivers/leds/flash/leds-mt6370-flash.c b/drivers/leds/flash/leds-mt6370-flash.c
> new file mode 100644
> index 0000000..a8ec7e1
> --- /dev/null
> +++ b/drivers/leds/flash/leds-mt6370-flash.c
> @@ -0,0 +1,632 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2022 Richtek Technology Corp.
> + *
> + * Author: Alice Chen <alice_chen@richtek.com>
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/led-class-flash.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +
> +#include <media/v4l2-flash-led-class.h>
> +
> +enum {
> + MT6370_LED_FLASH1,
> + MT6370_LED_FLASH2,
> + MT6370_MAX_LEDS
> +};
> +
> +/* Virtual definition for multicolor */
> +
> +#define MT6370_REG_FLEDEN 0x17E
> +#define MT6370_REG_STRBTO 0x173
> +#define MT6370_REG_CHGSTAT2 0x1D1
> +#define MT6370_REG_FLEDSTAT1 0x1D9
> +#define MT6370_REG_FLEDISTRB(_id) (0x174 + 4 * (_id))
> +#define MT6370_REG_FLEDITOR(_id) (0x175 + 4 * (_id))
> +#define MT6370_ITORCH_MASK GENMASK(4, 0)
> +#define MT6370_ISTROBE_MASK GENMASK(6, 0)
> +#define MT6370_STRBTO_MASK GENMASK(6, 0)
> +#define MT6370_TORCHEN_MASK BIT(3)
> +#define MT6370_STROBEN_MASK BIT(2)
> +#define MT6370_FLCSEN_MASK(_id) BIT(MT6370_LED_FLASH2 - (_id))
> +#define MT6370_FLCSEN_MASK_ALL GENMASK(1, 0)
> +#define MT6370_FLEDCHGVINOVP_MASK BIT(3)
> +#define MT6370_FLED1STRBTO_MASK BIT(11)
> +#define MT6370_FLED2STRBTO_MASK BIT(10)
> +#define MT6370_FLED1STRB_MASK BIT(9)
> +#define MT6370_FLED2STRB_MASK BIT(8)
> +#define MT6370_FLED1SHORT_MASK BIT(7)
> +#define MT6370_FLED2SHORT_MASK BIT(6)
> +#define MT6370_FLEDLVF_MASK BIT(3)
> +
> +#define MT6370_LED_JOINT 2
> +#define MT6370_RANGE_FLED_REG 4
> +#define MT6370_ITORCH_MIN_uA 25000
> +#define MT6370_ITORCH_STEP_uA 12500
> +#define MT6370_ITORCH_MAX_uA 400000
> +#define MT6370_ITORCH_DOUBLE_MAX_uA 800000
> +#define MT6370_ISTRB_MIN_uA 50000
> +#define MT6370_ISTRB_STEP_uA 12500
> +#define MT6370_ISTRB_MAX_uA 1500000
> +#define MT6370_ISTRB_DOUBLE_MAX_uA 3000000
> +#define MT6370_STRBTO_MIN_US 64000
> +#define MT6370_STRBTO_STEP_US 32000
> +#define MT6370_STRBTO_MAX_US 2432000
> +
> +#define STATE_OFF 0
> +#define STATE_KEEP 1
> +#define STATE_ON 2
> +
> +#define to_mt6370_led(ptr, member) container_of(ptr, struct mt6370_led, member)
> +
> +struct mt6370_led {
> + struct led_classdev_flash flash;
> + struct v4l2_flash *v4l2_flash;
> + struct mt6370_priv *priv;
> + u32 led_no;

The maximum value that we will ever see for `led_no` is 2: this means
that we don't need 32 full bits here.

u8 led_no;

> + u32 default_state;

This should be...

enum led_default_state default_state;

...but then, you're never using this variable as far as I can see, apart from
initializing it in mt6370_init_common_properties, for which, there's a comment
below.

In any case, please either fix the initialization and actually make use of
this variable, or remove it entirely.

> +};
> +
> +struct mt6370_priv {
> + struct device *dev;
> + struct regmap *regmap;
> + struct mutex lock;
> + unsigned int fled_strobe_used;
> + unsigned int fled_torch_used;
> + unsigned int leds_active;
> + unsigned int leds_count;
> + struct mt6370_led leds[];
> +};
> +
> +static int mt6370_torch_brightness_set(struct led_classdev *lcdev,
> + enum led_brightness level)
> +{
> + struct mt6370_led *led = to_mt6370_led(lcdev, flash.led_cdev);
> + struct mt6370_priv *priv = led->priv;
> + u32 led_enable_mask = (led->led_no == MT6370_LED_JOINT) ?
> + MT6370_FLCSEN_MASK_ALL :
> + MT6370_FLCSEN_MASK(led->led_no);
> + u32 enable_mask = MT6370_TORCHEN_MASK | led_enable_mask;
> + u32 val = level ? led_enable_mask : 0;
> + u32 curr;
> + int ret, i;
> +
> + mutex_lock(&priv->lock);
> +
> + /*
> + * There is only one set of flash control logic, and this
> + * flag is used to check if 'strobe' is currently being used.
> + */
> + if (priv->fled_strobe_used) {
> + dev_warn(lcdev->dev, "Please disable strobe first [%d]\n",
> + priv->fled_strobe_used);
> + ret = -EBUSY;
> + goto unlock;
> + }
> +
> + if (level)
> + curr = priv->fled_torch_used | BIT(led->led_no);
> + else
> + curr = priv->fled_torch_used & ~BIT(led->led_no);
> +
> + if (curr)
> + val |= MT6370_TORCHEN_MASK;
> +
> + if (level) {
> + level -= 1;
> + if (led->led_no == MT6370_LED_JOINT) {
> + int flevel[MT6370_MAX_LEDS];
> +
> + flevel[0] = level / 2;
> + flevel[1] = level - flevel[0];
> + for (i = 0; i < MT6370_MAX_LEDS; i++) {
> + ret = regmap_update_bits(priv->regmap,
> + MT6370_REG_FLEDITOR(i),
> + MT6370_ITORCH_MASK, flevel[i]);
> + if (ret)
> + goto unlock;
> + }
> + } else {
> + ret = regmap_update_bits(priv->regmap,
> + MT6370_REG_FLEDITOR(led->led_no),
> + MT6370_ITORCH_MASK, level);
> + if (ret)
> + goto unlock;
> + }
> + }
> +
> + ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDEN,
> + enable_mask, val);
> + if (ret)
> + goto unlock;
> +
> + priv->fled_torch_used = curr;
> +
> +unlock:
> + mutex_unlock(&priv->lock);
> + return ret;
> +}
> +
> +static int mt6370_flash_brightness_set(struct led_classdev_flash *fl_cdev,
> + u32 brightness)
> +{
> + /*
> + * Because of the current spikes when turning on the flash,
> + * the brightness should be kept by the LED framework. This
> + * empty function is used to prevent checking failure when
> + * led_classdev_flash registers ops.
> + */
> + return 0;
> +}
> +
> +static int _mt6370_flash_brightness_set(struct led_classdev_flash *fl_cdev,
> + u32 brightness)
> +{
> + struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
> + struct mt6370_priv *priv = led->priv;
> + struct led_flash_setting *s = &fl_cdev->brightness;
> + u32 val = (brightness - s->min) / s->step;
> + int ret, i;
> +
> + if (led->led_no == MT6370_LED_JOINT) {
> + int flevel[MT6370_MAX_LEDS];

Since you're writing this value to registers, please use fixed size variables.
If this is really supposed to be a signed value, it would be:

s32 flevel[MT6370_MAX_LEDS];

> +
> + flevel[0] = val / 2;
> + flevel[1] = val - flevel[0];
> + for (i = 0; i < MT6370_MAX_LEDS; i++) {
> + ret = regmap_update_bits(priv->regmap,
> + MT6370_REG_FLEDISTRB(i),
> + MT6370_ISTROBE_MASK, flevel[i]);
> + if (ret)
> + return ret;
> + }
> + } else {
> + return regmap_update_bits(priv->regmap,
> + MT6370_REG_FLEDISTRB(led->led_no),
> + MT6370_ISTROBE_MASK, val);
> + }
> +
> + return 0;

If we reach this point, this means that led_no is out of range (which is never
supposed to happen - I know).
Since that condition is something unexpected and unhandled, you should return
an error here.

> +}
> +
> +static int mt6370_strobe_set(struct led_classdev_flash *fl_cdev, bool state)
> +{
> + struct mt6370_led *led = to_mt6370_led(fl_cdev, flash);
> + struct mt6370_priv *priv = led->priv;
> + struct led_classdev *lcdev = &fl_cdev->led_cdev;
> + struct led_flash_setting *s = &fl_cdev->brightness;
> + u32 led_enable_mask = (led->led_no == MT6370_LED_JOINT) ?
> + MT6370_FLCSEN_MASK_ALL :
> + MT6370_FLCSEN_MASK(led->led_no);
> + u32 enable_mask = MT6370_STROBEN_MASK | led_enable_mask;
> + u32 val = state ? led_enable_mask : 0;
> + u32 curr;
> + int ret;
> +
> + mutex_lock(&priv->lock);
> +
> + /*
> + * There is only one set of flash control logic, and this
> + * flag is used to check if 'torch' is currently being used.
> + */
> + if (priv->fled_torch_used) {
> + dev_warn(lcdev->dev, "Please disable torch first [0x%x]\n",
> + priv->fled_torch_used);
> + ret = -EBUSY;
> + goto unlock;
> + }
> +
> + if (state)
> + curr = priv->fled_strobe_used | BIT(led->led_no);
> + else
> + curr = priv->fled_strobe_used & ~BIT(led->led_no);
> +
> + if (curr)
> + val |= MT6370_STROBEN_MASK;
> +
> + ret = regmap_update_bits(priv->regmap, MT6370_REG_FLEDEN, enable_mask,
> + val);
> + if (ret) {
> + dev_err(lcdev->dev, "[%d] control current source %d fail\n",
> + led->led_no, state);
> + goto unlock;
> + }
> +
> + /*
> + * If the flash needs to turn on, configure the flash current to
> + * ramp up to the setting value. Otherwise, always revert to the
> + * minimum one.
> + */
> + ret = _mt6370_flash_brightness_set(fl_cdev, state ? s->val : s->min);
> + if (ret)
> + goto unlock;

If this fails, I think that we should revert the previous changes to FLEDEN
before returning.

> +
> + /*
> + * For the flash to turn on/off, we must wait for HW ramping
> + * up/down time 5ms/500us to prevent the unexpected problem.
> + */
> + if (!priv->fled_strobe_used && curr)
> + usleep_range(5000, 6000);
> + else if (priv->fled_strobe_used && !curr)
> + usleep_range(500, 600);
> +
> + priv->fled_strobe_used = curr;
> +
> +unlock:
> + mutex_unlock(&priv->lock);
> + return ret;
> +}
> +

..snip..

> +
> +static int mt6370_init_common_properties(struct mt6370_led *led,
> + struct led_init_data *init_data)
> +{
> + const char * const states[] = { "off", "keep", "on" };
> + const char *str = states[STATE_OFF];
> + int ret;
> +
> + fwnode_property_read_string(init_data->fwnode, "default-state", &str);
> + ret = match_string(states, ARRAY_SIZE(states), str);
> + if (ret >= 0)
> + led->default_state = ret;
> +
> + return 0;
> +}
> +
> +static int mt6370_led_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct mt6370_priv *priv;
> + struct fwnode_handle *child;
> + size_t count;
> + int i = 0, ret;
> +
> + count = device_get_child_node_count(dev);
> + if (!count || count > MT6370_MAX_LEDS)
> + return dev_err_probe(dev, -EINVAL,
> + "No child node or node count over max led number %zu\n", count);
> +
> + priv = devm_kzalloc(dev, struct_size(priv, leds, count), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->leds_count = count;
> + priv->dev = dev;
> + mutex_init(&priv->lock);
> +
> + priv->regmap = dev_get_regmap(dev->parent, NULL);
> + if (!priv->regmap)
> + return dev_err_probe(dev, -ENODEV, "Failed to get parent regmap\n");
> +
> + device_for_each_child_node(dev, child) {
> + struct mt6370_led *led = priv->leds + i;
> + struct led_init_data init_data = { .fwnode = child, };
> +
> + led->priv = priv;
> + ret = mt6370_init_common_properties(led, &init_data);

This is only initializing the default state, for which you do have a helper.

Please use led_init_default_state_get(fwnode).

> + if (ret)
> + return ret;
> +
> + ret = mt6370_init_flash_properties(led, &init_data);
> + if (ret)
> + return ret;
> +
> + ret = mt6370_led_register(dev, led, &init_data);
> + if (ret)
> + return ret;
> +
> + i++;
> + }
> +
> + return 0;
> +}
> +

Regards,
Angelo