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leds: turris-omnia: Add support for enabling/disabling HW gamma corre…
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If the MCU on Turris Omnia is running newer firmware versions, the LED
controller supports RGB gamma correction (and enables it by default for
newer boards).

Determine whether the gamma correction setting feature is supported and
add the ability to set it via sysfs attribute file.

Signed-off-by: Marek Behún <kabel@kernel.org>
Link: https://lore.kernel.org/r/20230918161104.20860-5-kabel@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
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Marek Behún authored and Lee Jones committed Nov 1, 2023
1 parent cbd6954 commit 43e9082
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14 changes: 14 additions & 0 deletions Documentation/ABI/testing/sysfs-class-led-driver-turris-omnia
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Original file line number Diff line number Diff line change
Expand Up @@ -12,3 +12,17 @@ Description: (RW) On the front panel of the Turris Omnia router there is also
able to change this setting from software.

Format: %i

What: /sys/class/leds/<led>/device/gamma_correction
Date: August 2023
KernelVersion: 6.6
Contact: Marek Behún <kabel@kernel.org>
Description: (RW) Newer versions of the microcontroller firmware of the
Turris Omnia router support gamma correction for the RGB LEDs.
This feature can be enabled/disabled by writing to this file.

If the feature is not supported because the MCU firmware is too
old, the file always reads as 0, and writing to the file results
in the EOPNOTSUPP error.

Format: %i
137 changes: 120 additions & 17 deletions drivers/leds/leds-turris-omnia.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,17 +15,30 @@
#define OMNIA_BOARD_LEDS 12
#define OMNIA_LED_NUM_CHANNELS 3

#define CMD_LED_MODE 3
#define CMD_LED_MODE_LED(l) ((l) & 0x0f)
#define CMD_LED_MODE_USER 0x10
/* MCU controller commands at I2C address 0x2a */
#define OMNIA_MCU_I2C_ADDR 0x2a

#define CMD_LED_STATE 4
#define CMD_LED_STATE_LED(l) ((l) & 0x0f)
#define CMD_LED_STATE_ON 0x10
#define CMD_GET_STATUS_WORD 0x01
#define STS_FEATURES_SUPPORTED BIT(2)

#define CMD_LED_COLOR 5
#define CMD_LED_SET_BRIGHTNESS 7
#define CMD_LED_GET_BRIGHTNESS 8
#define CMD_GET_FEATURES 0x10
#define FEAT_LED_GAMMA_CORRECTION BIT(5)

/* LED controller commands at I2C address 0x2b */
#define CMD_LED_MODE 0x03
#define CMD_LED_MODE_LED(l) ((l) & 0x0f)
#define CMD_LED_MODE_USER 0x10

#define CMD_LED_STATE 0x04
#define CMD_LED_STATE_LED(l) ((l) & 0x0f)
#define CMD_LED_STATE_ON 0x10

#define CMD_LED_COLOR 0x05
#define CMD_LED_SET_BRIGHTNESS 0x07
#define CMD_LED_GET_BRIGHTNESS 0x08

#define CMD_SET_GAMMA_CORRECTION 0x30
#define CMD_GET_GAMMA_CORRECTION 0x31

struct omnia_led {
struct led_classdev_mc mc_cdev;
Expand All @@ -40,6 +53,7 @@ struct omnia_led {
struct omnia_leds {
struct i2c_client *client;
struct mutex lock;
bool has_gamma_correction;
struct omnia_led leds[];
};

Expand All @@ -50,30 +64,42 @@ static int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd, u8 val)
return i2c_master_send(client, buf, sizeof(buf));
}

static int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
static int omnia_cmd_read_raw(struct i2c_adapter *adapter, u8 addr, u8 cmd,
void *reply, size_t len)
{
struct i2c_msg msgs[2];
u8 reply;
int ret;

msgs[0].addr = client->addr;
msgs[0].addr = addr;
msgs[0].flags = 0;
msgs[0].len = 1;
msgs[0].buf = &cmd;
msgs[1].addr = client->addr;
msgs[1].addr = addr;
msgs[1].flags = I2C_M_RD;
msgs[1].len = 1;
msgs[1].buf = &reply;
msgs[1].len = len;
msgs[1].buf = reply;

ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs));
if (likely(ret == ARRAY_SIZE(msgs)))
return reply;
return len;
else if (ret < 0)
return ret;
else
return -EIO;
}

static int omnia_cmd_read_u8(const struct i2c_client *client, u8 cmd)
{
u8 reply;
int ret;

ret = omnia_cmd_read_raw(client->adapter, client->addr, cmd, &reply, 1);
if (ret < 0)
return ret;

return reply;
}

static int omnia_led_send_color_cmd(const struct i2c_client *client,
struct omnia_led *led)
{
Expand Down Expand Up @@ -352,12 +378,74 @@ static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
}
static DEVICE_ATTR_RW(brightness);

static ssize_t gamma_correction_show(struct device *dev,
struct device_attribute *a, char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
struct omnia_leds *leds = i2c_get_clientdata(client);
int ret;

if (leds->has_gamma_correction) {
ret = omnia_cmd_read_u8(client, CMD_GET_GAMMA_CORRECTION);
if (ret < 0)
return ret;
} else {
ret = 0;
}

return sysfs_emit(buf, "%d\n", !!ret);
}

static ssize_t gamma_correction_store(struct device *dev,
struct device_attribute *a,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
struct omnia_leds *leds = i2c_get_clientdata(client);
bool val;
int ret;

if (!leds->has_gamma_correction)
return -EOPNOTSUPP;

if (kstrtobool(buf, &val) < 0)
return -EINVAL;

ret = omnia_cmd_write_u8(client, CMD_SET_GAMMA_CORRECTION, val);

return ret < 0 ? ret : count;
}
static DEVICE_ATTR_RW(gamma_correction);

static struct attribute *omnia_led_controller_attrs[] = {
&dev_attr_brightness.attr,
&dev_attr_gamma_correction.attr,
NULL,
};
ATTRIBUTE_GROUPS(omnia_led_controller);

static int omnia_mcu_get_features(const struct i2c_client *client)
{
u16 reply;
int err;

err = omnia_cmd_read_raw(client->adapter, OMNIA_MCU_I2C_ADDR,
CMD_GET_STATUS_WORD, &reply, sizeof(reply));
if (err < 0)
return err;

/* Check whether MCU firmware supports the CMD_GET_FEAUTRES command */
if (!(le16_to_cpu(reply) & STS_FEATURES_SUPPORTED))
return 0;

err = omnia_cmd_read_raw(client->adapter, OMNIA_MCU_I2C_ADDR,
CMD_GET_FEATURES, &reply, sizeof(reply));
if (err < 0)
return err;

return le16_to_cpu(reply);
}

static int omnia_leds_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
Expand All @@ -382,6 +470,21 @@ static int omnia_leds_probe(struct i2c_client *client)
leds->client = client;
i2c_set_clientdata(client, leds);

ret = omnia_mcu_get_features(client);
if (ret < 0) {
dev_err(dev, "Cannot determine MCU supported features: %d\n",
ret);
return ret;
}

leds->has_gamma_correction = ret & FEAT_LED_GAMMA_CORRECTION;
if (!leds->has_gamma_correction) {
dev_info(dev,
"Your board's MCU firmware does not support the LED gamma correction feature.\n");
dev_info(dev,
"Consider upgrading MCU firmware with the omnia-mcutool utility.\n");
}

mutex_init(&leds->lock);

ret = devm_led_trigger_register(dev, &omnia_hw_trigger);
Expand Down

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