Re: [PATCH v4 5/5] leds: Add support for RTL8231 LED scan matrix

[Andy Shevchenko <andy.shevchenko@gmail.com>]

On Thu, Jun 3, 2021 at 1:01 PM Sander Vanheule <sander@svanheule.net> wrote:
>
> Both single and bi-color scanning modes are supported. The driver will
> verify that the addresses are valid for the current mode, before
> registering the LEDs. LEDs can be turned on, off, or toggled at one of
> six predefined rates from 40ms to 1280ms.
>
> Implements a platform device for use as a child device with RTL8231 MFD,
> and uses the parent regmap to access the required registers.

FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

> Signed-off-by: Sander Vanheule <sander@svanheule.net>
>
> ---
> v4:
> - Rename variable addr_count -> err
> - Use -EINVAL instead of -ENODEV
>
> v3:
> - Rename 'interval' to 'interval_ms'
>
> v2:
> - Use fwnode-calls instead of OF-calls
> ---
>  drivers/leds/Kconfig        |  10 ++
>  drivers/leds/Makefile       |   1 +
>  drivers/leds/leds-rtl8231.c | 291 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 302 insertions(+)
>  create mode 100644 drivers/leds/leds-rtl8231.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 49d99cb084db..8cb869e8cd09 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -593,6 +593,16 @@ config LEDS_REGULATOR
>         help
>           This option enables support for regulator driven LEDs.
>
> +config LEDS_RTL8231
> +       tristate "RTL8231 LED matrix support"
> +       depends on LEDS_CLASS
> +       depends on MFD_RTL8231
> +       default MFD_RTL8231
> +       help
> +         This option enables support for using the LED scanning matrix output
> +         of the RTL8231 GPIO and LED expander chip.
> +         When built as a module, this module will be named leds-rtl8231.
> +
>  config LEDS_BD2802
>         tristate "LED driver for BD2802 RGB LED"
>         depends on LEDS_CLASS
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index 7e604d3028c8..ce0f44a87dee 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -80,6 +80,7 @@ obj-$(CONFIG_LEDS_PM8058)             += leds-pm8058.o
>  obj-$(CONFIG_LEDS_POWERNV)             += leds-powernv.o
>  obj-$(CONFIG_LEDS_PWM)                 += leds-pwm.o
>  obj-$(CONFIG_LEDS_REGULATOR)           += leds-regulator.o
> +obj-$(CONFIG_LEDS_RTL8231)             += leds-rtl8231.o
>  obj-$(CONFIG_LEDS_S3C24XX)             += leds-s3c24xx.o
>  obj-$(CONFIG_LEDS_SC27XX_BLTC)         += leds-sc27xx-bltc.o
>  obj-$(CONFIG_LEDS_SGM3140)             += leds-sgm3140.o
> diff --git a/drivers/leds/leds-rtl8231.c b/drivers/leds/leds-rtl8231.c
> new file mode 100644
> index 000000000000..fb2b1ca419c9
> --- /dev/null
> +++ b/drivers/leds/leds-rtl8231.c
> @@ -0,0 +1,291 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +#include <linux/device.h>
> +#include <linux/leds.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +
> +#include <linux/mfd/rtl8231.h>
> +
> +/**
> + * struct led_toggle_rate - description of an LED blinking mode
> + * @interval_ms:       LED toggle rate in milliseconds
> + * @mode:              Register field value used to activate this mode
> + *
> + * For LED hardware accelerated blinking, with equal on and off delay.
> + * Both delays are given by @interval, so the interval at which the LED blinks
> + * (i.e. turn on and off once) is double this value.
> + */
> +struct led_toggle_rate {
> +       u16 interval_ms;
> +       u8 mode;
> +};
> +
> +/**
> + * struct led_modes - description of all LED modes
> + * @toggle_rates:      Array of led_toggle_rate values, sorted by ascending interval
> + * @num_toggle_rates:  Number of elements in @led_toggle_rate
> + * @off:               Register field value to turn LED off
> + * @on:                        Register field value to turn LED on
> + */
> +struct led_modes {
> +       const struct led_toggle_rate *toggle_rates;
> +       unsigned int num_toggle_rates;
> +       u8 off;
> +       u8 on;
> +};
> +
> +struct rtl8231_led {
> +       struct led_classdev led;
> +       const struct led_modes *modes;
> +       struct regmap_field *reg_field;
> +};
> +#define to_rtl8231_led(_cdev) container_of(_cdev, struct rtl8231_led, led)
> +
> +#define RTL8231_NUM_LEDS       3
> +#define RTL8231_LED_PER_REG    5
> +#define RTL8231_BITS_PER_LED   3
> +
> +static const unsigned int rtl8231_led_port_counts_single[RTL8231_NUM_LEDS] = {32, 32, 24};
> +static const unsigned int rtl8231_led_port_counts_bicolor[RTL8231_NUM_LEDS] = {24, 24, 24};
> +
> +static const unsigned int rtl8231_led_base[RTL8231_NUM_LEDS] = {
> +       RTL8231_REG_LED0_BASE,
> +       RTL8231_REG_LED1_BASE,
> +       RTL8231_REG_LED2_BASE,
> +};
> +
> +#define RTL8231_DEFAULT_TOGGLE_INTERVAL_MS     500
> +
> +static const struct led_toggle_rate rtl8231_toggle_rates[] = {
> +       {  40, 1},
> +       {  80, 2},
> +       { 160, 3},
> +       { 320, 4},
> +       { 640, 5},
> +       {1280, 6},
> +};
> +
> +static const struct led_modes rtl8231_led_modes = {
> +       .off = 0,
> +       .on = 7,
> +       .num_toggle_rates = ARRAY_SIZE(rtl8231_toggle_rates),
> +       .toggle_rates = rtl8231_toggle_rates,
> +};
> +
> +static void rtl8231_led_brightness_set(struct led_classdev *led_cdev,
> +       enum led_brightness brightness)
> +{
> +       struct rtl8231_led *pled = to_rtl8231_led(led_cdev);
> +
> +       if (brightness)
> +               regmap_field_write(pled->reg_field, pled->modes->on);
> +       else
> +               regmap_field_write(pled->reg_field, pled->modes->off);
> +}
> +
> +static enum led_brightness rtl8231_led_brightness_get(struct led_classdev *led_cdev)
> +{
> +       struct rtl8231_led *pled = to_rtl8231_led(led_cdev);
> +       u32 current_mode = pled->modes->off;
> +
> +       regmap_field_read(pled->reg_field, &current_mode);
> +
> +       if (current_mode == pled->modes->off)
> +               return LED_OFF;
> +       else
> +               return LED_ON;
> +}
> +
> +static unsigned int rtl8231_led_current_interval(struct rtl8231_led *pled)
> +{
> +       unsigned int mode;
> +       unsigned int i;
> +
> +       if (regmap_field_read(pled->reg_field, &mode))
> +               return 0;
> +
> +       for (i = 0; i < pled->modes->num_toggle_rates; i++)
> +               if (mode == pled->modes->toggle_rates[i].mode)
> +                       return pled->modes->toggle_rates[i].interval_ms;
> +
> +       return 0;
> +}
> +
> +static int rtl8231_led_blink_set(struct led_classdev *led_cdev, unsigned long *delay_on,
> +       unsigned long *delay_off)
> +{
> +       struct rtl8231_led *pled = to_rtl8231_led(led_cdev);
> +       const struct led_toggle_rate *rates = pled->modes->toggle_rates;
> +       unsigned int num_rates = pled->modes->num_toggle_rates;
> +       unsigned int interval_ms;
> +       unsigned int i;
> +       int err;
> +
> +       if (*delay_on == 0 && *delay_off == 0) {
> +               interval_ms = RTL8231_DEFAULT_TOGGLE_INTERVAL_MS;
> +       } else {
> +               /*
> +                * If the current mode is blinking, choose the delay that (likely) changed.
> +                * Otherwise, choose the interval that would have the same total delay.
> +                */
> +               interval_ms = rtl8231_led_current_interval(pled);
> +               if (interval_ms > 0 && interval_ms == *delay_off)
> +                       interval_ms = *delay_on;
> +               else if (interval_ms > 0 && interval_ms == *delay_on)
> +                       interval_ms = *delay_off;
> +               else
> +                       interval_ms = (*delay_on + *delay_off) / 2;
> +       }
> +
> +       /* Find clamped toggle interval */
> +       for (i = 0; i < (num_rates - 1); i++)
> +               if (interval_ms > rates[i].interval_ms)
> +                       break;
> +
> +       interval_ms = rates[i].interval_ms;
> +
> +       err = regmap_field_write(pled->reg_field, rates[i].mode);
> +       if (err)
> +               return err;
> +
> +       *delay_on = interval_ms;
> +       *delay_off = interval_ms;
> +
> +       return 0;
> +}
> +
> +static int rtl8231_led_read_address(struct fwnode_handle *fwnode, unsigned int *addr_port,
> +       unsigned int *addr_led)
> +{
> +       u32 addr[2];
> +       int err;
> +
> +       err = fwnode_property_count_u32(fwnode, "reg");
> +       if (err < 0)
> +               return err;
> +       if (err != ARRAY_SIZE(addr))
> +               return -EINVAL;
> +
> +       err = fwnode_property_read_u32_array(fwnode, "reg", addr, ARRAY_SIZE(addr));
> +       if (err)
> +               return err;
> +
> +       *addr_port = addr[0];
> +       *addr_led = addr[1];
> +
> +       return 0;
> +}
> +
> +static struct reg_field rtl8231_led_get_field(unsigned int port_index, unsigned int led_index)
> +{
> +       unsigned int offset, shift;
> +       struct reg_field field;
> +
> +       offset = port_index / RTL8231_LED_PER_REG;
> +       shift = (port_index % RTL8231_LED_PER_REG) * RTL8231_BITS_PER_LED;
> +
> +       field.reg = rtl8231_led_base[led_index] + offset;
> +       field.lsb = shift;
> +       field.msb = shift + RTL8231_BITS_PER_LED - 1;
> +
> +       return field;
> +}
> +
> +static int rtl8231_led_probe_single(struct device *dev, struct regmap *map,
> +       const unsigned int *port_counts, struct fwnode_handle *fwnode)
> +{
> +       struct led_init_data init_data = {};
> +       struct rtl8231_led *pled;
> +       unsigned int port_index;
> +       unsigned int led_index;
> +       struct reg_field field;
> +       int err;
> +
> +       pled = devm_kzalloc(dev, sizeof(*pled), GFP_KERNEL);
> +       if (!pled)
> +               return -ENOMEM;
> +
> +       err = rtl8231_led_read_address(fwnode, &port_index, &led_index);
> +       if (err) {
> +               dev_err(dev, "LED address invalid\n");
> +               return err;
> +       }
> +
> +       if (led_index >= RTL8231_NUM_LEDS || port_index >= port_counts[led_index]) {
> +               dev_err(dev, "LED address (%d.%d) invalid\n", port_index, led_index);
> +               return -EINVAL;
> +       }
> +
> +       field = rtl8231_led_get_field(port_index, led_index);
> +       pled->reg_field = devm_regmap_field_alloc(dev, map, field);
> +       if (IS_ERR(pled->reg_field))
> +               return PTR_ERR(pled->reg_field);
> +
> +       pled->modes = &rtl8231_led_modes;
> +
> +       pled->led.max_brightness = 1;
> +       pled->led.brightness_get = rtl8231_led_brightness_get;
> +       pled->led.brightness_set = rtl8231_led_brightness_set;
> +       pled->led.blink_set = rtl8231_led_blink_set;
> +
> +       init_data.fwnode = fwnode;
> +
> +       return devm_led_classdev_register_ext(dev, &pled->led, &init_data);
> +}
> +
> +static int rtl8231_led_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       const unsigned int *port_counts;
> +       struct fwnode_handle *child;
> +       struct regmap *map;
> +       int err;
> +
> +       map = dev_get_regmap(dev->parent, NULL);
> +       if (!map)
> +               return -ENODEV;
> +
> +       if (device_property_match_string(dev, "realtek,led-scan-mode", "single-color") >= 0) {
> +               port_counts = rtl8231_led_port_counts_single;
> +               regmap_update_bits(map, RTL8231_REG_FUNC0,
> +                       RTL8231_FUNC0_SCAN_MODE, RTL8231_FUNC0_SCAN_SINGLE);
> +       } else if (device_property_match_string(dev, "realtek,led-scan-mode", "bi-color") >= 0) {
> +               port_counts = rtl8231_led_port_counts_bicolor;
> +               regmap_update_bits(map, RTL8231_REG_FUNC0,
> +                       RTL8231_FUNC0_SCAN_MODE, RTL8231_FUNC0_SCAN_BICOLOR);
> +       } else {
> +               dev_err(dev, "scan mode missing or invalid\n");
> +               return -EINVAL;
> +       }
> +
> +       fwnode_for_each_available_child_node(dev->fwnode, child) {
> +               err = rtl8231_led_probe_single(dev, map, port_counts, child);
> +               if (err)
> +                       dev_warn(dev, "failed to register LED %pfwP\n", child);
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id of_rtl8231_led_match[] = {
> +       { .compatible = "realtek,rtl8231-leds" },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(of, of_rtl8231_led_match);
> +
> +static struct platform_driver rtl8231_led_driver = {
> +       .driver = {
> +               .name = "rtl8231-leds",
> +               .of_match_table = of_rtl8231_led_match,
> +       },
> +       .probe = rtl8231_led_probe,
> +};
> +module_platform_driver(rtl8231_led_driver);
> +
> +MODULE_AUTHOR("Sander Vanheule <sander@svanheule.net>");
> +MODULE_DESCRIPTION("Realtek RTL8231 LED support");
> +MODULE_LICENSE("GPL v2");
> --
> 2.31.1
>


-- 
With Best Regards,
Andy Shevchenko