linux/drivers/leds/leds-turris-omnia.c
Marek Behún 78cbcfd8b1 leds: turris-omnia: Fix brightness setting and trigger activating
I have improperly refactored commits
  4d5ed2621c24 ("leds: turris-omnia: Make set_brightness() more efficient")
and
  aaf38273cf76 ("leds: turris-omnia: Support HW controlled mode via private trigger")
after Lee requested a change in API semantics of the new functions I
introduced in commit
  28350bc0ac77 ("leds: turris-omnia: Do not use SMBUS calls").

Before the change, the function omnia_cmd_write_u8() returned 0 on
success, and afterwards it returned a positive value (number of bytes
written). The latter version was applied, but the following commits did
not properly account for this change.

This results in non-functional LED's .brightness_set_blocking() and
trigger's .activate() methods.

The main reasoning behind the semantics change was that read/write
methods should return the number of read/written bytes on success.
It was pointed to me [1] that this is not always true (for example the
regmap API does not do so), and since the driver never uses this number
of read/written bytes information, I decided to fix this issue by
changing the functions to the original semantics (return 0 on success).

[1] https://lore.kernel.org/linux-gpio/ZQnn+Gi0xVlsGCYA@smile.fi.intel.com/

Fixes: 28350bc0ac77 ("leds: turris-omnia: Do not use SMBUS calls")
Signed-off-by: Marek Behún <kabel@kernel.org>
Link: https://lore.kernel.org/r/20231016141538.30037-1-kabel@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
2023-11-01 11:29:16 +00:00

558 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* CZ.NIC's Turris Omnia LEDs driver
*
* 2020, 2023 by Marek Behún <kabel@kernel.org>
*/
#include <linux/i2c.h>
#include <linux/led-class-multicolor.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include "leds.h"
#define OMNIA_BOARD_LEDS 12
#define OMNIA_LED_NUM_CHANNELS 3
/* MCU controller commands at I2C address 0x2a */
#define OMNIA_MCU_I2C_ADDR 0x2a
#define CMD_GET_STATUS_WORD 0x01
#define STS_FEATURES_SUPPORTED BIT(2)
#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;
struct mc_subled subled_info[OMNIA_LED_NUM_CHANNELS];
u8 cached_channels[OMNIA_LED_NUM_CHANNELS];
bool on, hwtrig;
int reg;
};
#define to_omnia_led(l) container_of(l, struct omnia_led, mc_cdev)
struct omnia_leds {
struct i2c_client *client;
struct mutex lock;
bool has_gamma_correction;
struct omnia_led leds[];
};
static int omnia_cmd_write_u8(const struct i2c_client *client, u8 cmd, u8 val)
{
u8 buf[2] = { cmd, val };
int ret;
ret = i2c_master_send(client, buf, sizeof(buf));
return ret < 0 ? ret : 0;
}
static int omnia_cmd_read_raw(struct i2c_adapter *adapter, u8 addr, u8 cmd,
void *reply, size_t len)
{
struct i2c_msg msgs[2];
int ret;
msgs[0].addr = addr;
msgs[0].flags = 0;
msgs[0].len = 1;
msgs[0].buf = &cmd;
msgs[1].addr = addr;
msgs[1].flags = I2C_M_RD;
msgs[1].len = len;
msgs[1].buf = reply;
ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs));
if (likely(ret == ARRAY_SIZE(msgs)))
return 0;
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 err;
err = omnia_cmd_read_raw(client->adapter, client->addr, cmd, &reply, 1);
if (err)
return err;
return reply;
}
static int omnia_led_send_color_cmd(const struct i2c_client *client,
struct omnia_led *led)
{
char cmd[5];
int ret;
cmd[0] = CMD_LED_COLOR;
cmd[1] = led->reg;
cmd[2] = led->subled_info[0].brightness;
cmd[3] = led->subled_info[1].brightness;
cmd[4] = led->subled_info[2].brightness;
/* Send the color change command */
ret = i2c_master_send(client, cmd, 5);
if (ret < 0)
return ret;
/* Cache the RGB channel brightnesses */
for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
led->cached_channels[i] = led->subled_info[i].brightness;
return 0;
}
/* Determine if the computed RGB channels are different from the cached ones */
static bool omnia_led_channels_changed(struct omnia_led *led)
{
for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i)
if (led->subled_info[i].brightness != led->cached_channels[i])
return true;
return false;
}
static int omnia_led_brightness_set_blocking(struct led_classdev *cdev,
enum led_brightness brightness)
{
struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
struct omnia_led *led = to_omnia_led(mc_cdev);
int err = 0;
mutex_lock(&leds->lock);
/*
* Only recalculate RGB brightnesses from intensities if brightness is
* non-zero (if it is zero and the LED is in HW blinking mode, we use
* max_brightness as brightness). Otherwise we won't be using them and
* we can save ourselves some software divisions (Omnia's CPU does not
* implement the division instruction).
*/
if (brightness || led->hwtrig) {
led_mc_calc_color_components(mc_cdev, brightness ?:
cdev->max_brightness);
/*
* Send color command only if brightness is non-zero and the RGB
* channel brightnesses changed.
*/
if (omnia_led_channels_changed(led))
err = omnia_led_send_color_cmd(leds->client, led);
}
/*
* Send on/off state change only if (bool)brightness changed and the LED
* is not being blinked by HW.
*/
if (!err && !led->hwtrig && !brightness != !led->on) {
u8 state = CMD_LED_STATE_LED(led->reg);
if (brightness)
state |= CMD_LED_STATE_ON;
err = omnia_cmd_write_u8(leds->client, CMD_LED_STATE, state);
if (!err)
led->on = !!brightness;
}
mutex_unlock(&leds->lock);
return err;
}
static struct led_hw_trigger_type omnia_hw_trigger_type;
static int omnia_hwtrig_activate(struct led_classdev *cdev)
{
struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
struct omnia_led *led = to_omnia_led(mc_cdev);
int err = 0;
mutex_lock(&leds->lock);
if (!led->on) {
/*
* If the LED is off (brightness was set to 0), the last
* configured color was not necessarily sent to the MCU.
* Recompute with max_brightness and send if needed.
*/
led_mc_calc_color_components(mc_cdev, cdev->max_brightness);
if (omnia_led_channels_changed(led))
err = omnia_led_send_color_cmd(leds->client, led);
}
if (!err) {
/* Put the LED into MCU controlled mode */
err = omnia_cmd_write_u8(leds->client, CMD_LED_MODE,
CMD_LED_MODE_LED(led->reg));
if (!err)
led->hwtrig = true;
}
mutex_unlock(&leds->lock);
return err;
}
static void omnia_hwtrig_deactivate(struct led_classdev *cdev)
{
struct omnia_leds *leds = dev_get_drvdata(cdev->dev->parent);
struct omnia_led *led = to_omnia_led(lcdev_to_mccdev(cdev));
int err;
mutex_lock(&leds->lock);
led->hwtrig = false;
/* Put the LED into software mode */
err = omnia_cmd_write_u8(leds->client, CMD_LED_MODE,
CMD_LED_MODE_LED(led->reg) |
CMD_LED_MODE_USER);
mutex_unlock(&leds->lock);
if (err)
dev_err(cdev->dev, "Cannot put LED to software mode: %i\n",
err);
}
static struct led_trigger omnia_hw_trigger = {
.name = "omnia-mcu",
.activate = omnia_hwtrig_activate,
.deactivate = omnia_hwtrig_deactivate,
.trigger_type = &omnia_hw_trigger_type,
};
static int omnia_led_register(struct i2c_client *client, struct omnia_led *led,
struct device_node *np)
{
struct led_init_data init_data = {};
struct device *dev = &client->dev;
struct led_classdev *cdev;
int ret, color;
ret = of_property_read_u32(np, "reg", &led->reg);
if (ret || led->reg >= OMNIA_BOARD_LEDS) {
dev_warn(dev,
"Node %pOF: must contain 'reg' property with values between 0 and %i\n",
np, OMNIA_BOARD_LEDS - 1);
return 0;
}
ret = of_property_read_u32(np, "color", &color);
if (ret || color != LED_COLOR_ID_RGB) {
dev_warn(dev,
"Node %pOF: must contain 'color' property with value LED_COLOR_ID_RGB\n",
np);
return 0;
}
led->subled_info[0].color_index = LED_COLOR_ID_RED;
led->subled_info[1].color_index = LED_COLOR_ID_GREEN;
led->subled_info[2].color_index = LED_COLOR_ID_BLUE;
/* Initial color is white */
for (int i = 0; i < OMNIA_LED_NUM_CHANNELS; ++i) {
led->subled_info[i].intensity = 255;
led->subled_info[i].brightness = 255;
led->subled_info[i].channel = i;
}
led->mc_cdev.subled_info = led->subled_info;
led->mc_cdev.num_colors = OMNIA_LED_NUM_CHANNELS;
init_data.fwnode = &np->fwnode;
cdev = &led->mc_cdev.led_cdev;
cdev->max_brightness = 255;
cdev->brightness_set_blocking = omnia_led_brightness_set_blocking;
cdev->trigger_type = &omnia_hw_trigger_type;
/*
* Use the omnia-mcu trigger as the default trigger. It may be rewritten
* by LED class from the linux,default-trigger property.
*/
cdev->default_trigger = omnia_hw_trigger.name;
/* put the LED into software mode */
ret = omnia_cmd_write_u8(client, CMD_LED_MODE,
CMD_LED_MODE_LED(led->reg) |
CMD_LED_MODE_USER);
if (ret) {
dev_err(dev, "Cannot set LED %pOF to software mode: %i\n", np,
ret);
return ret;
}
/* disable the LED */
ret = omnia_cmd_write_u8(client, CMD_LED_STATE,
CMD_LED_STATE_LED(led->reg));
if (ret) {
dev_err(dev, "Cannot set LED %pOF brightness: %i\n", np, ret);
return ret;
}
/* Set initial color and cache it */
ret = omnia_led_send_color_cmd(client, led);
if (ret < 0) {
dev_err(dev, "Cannot set LED %pOF initial color: %i\n", np,
ret);
return ret;
}
ret = devm_led_classdev_multicolor_register_ext(dev, &led->mc_cdev,
&init_data);
if (ret < 0) {
dev_err(dev, "Cannot register LED %pOF: %i\n", np, ret);
return ret;
}
return 1;
}
/*
* On the front panel of the Turris Omnia router there is also a button which
* can be used to control the intensity of all the LEDs at once, so that if they
* are too bright, user can dim them.
* The microcontroller cycles between 8 levels of this global brightness (from
* 100% to 0%), but this setting can have any integer value between 0 and 100.
* It is therefore convenient to be able to change this setting from software.
* We expose this setting via a sysfs attribute file called "brightness". This
* file lives in the device directory of the LED controller, not an individual
* LED, so it should not confuse users.
*/
static ssize_t brightness_show(struct device *dev, struct device_attribute *a,
char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
int ret;
ret = omnia_cmd_read_u8(client, CMD_LED_GET_BRIGHTNESS);
if (ret < 0)
return ret;
return sysfs_emit(buf, "%d\n", ret);
}
static ssize_t brightness_store(struct device *dev, struct device_attribute *a,
const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
unsigned long brightness;
int err;
if (kstrtoul(buf, 10, &brightness))
return -EINVAL;
if (brightness > 100)
return -EINVAL;
err = omnia_cmd_write_u8(client, CMD_LED_SET_BRIGHTNESS, brightness);
return err ?: count;
}
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 err;
if (!leds->has_gamma_correction)
return -EOPNOTSUPP;
if (kstrtobool(buf, &val) < 0)
return -EINVAL;
err = omnia_cmd_write_u8(client, CMD_SET_GAMMA_CORRECTION, val);
return err ?: 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)
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)
return err;
return le16_to_cpu(reply);
}
static int omnia_leds_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct device_node *np = dev_of_node(dev), *child;
struct omnia_leds *leds;
struct omnia_led *led;
int ret, count;
count = of_get_available_child_count(np);
if (!count) {
dev_err(dev, "LEDs are not defined in device tree!\n");
return -ENODEV;
} else if (count > OMNIA_BOARD_LEDS) {
dev_err(dev, "Too many LEDs defined in device tree!\n");
return -EINVAL;
}
leds = devm_kzalloc(dev, struct_size(leds, leds, count), GFP_KERNEL);
if (!leds)
return -ENOMEM;
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);
if (ret < 0) {
dev_err(dev, "Cannot register private LED trigger: %d\n", ret);
return ret;
}
led = &leds->leds[0];
for_each_available_child_of_node(np, child) {
ret = omnia_led_register(client, led, child);
if (ret < 0) {
of_node_put(child);
return ret;
}
led += ret;
}
return 0;
}
static void omnia_leds_remove(struct i2c_client *client)
{
u8 buf[5];
/* put all LEDs into default (HW triggered) mode */
omnia_cmd_write_u8(client, CMD_LED_MODE,
CMD_LED_MODE_LED(OMNIA_BOARD_LEDS));
/* set all LEDs color to [255, 255, 255] */
buf[0] = CMD_LED_COLOR;
buf[1] = OMNIA_BOARD_LEDS;
buf[2] = 255;
buf[3] = 255;
buf[4] = 255;
i2c_master_send(client, buf, 5);
}
static const struct of_device_id of_omnia_leds_match[] = {
{ .compatible = "cznic,turris-omnia-leds", },
{},
};
static const struct i2c_device_id omnia_id[] = {
{ "omnia", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, omnia_id);
static struct i2c_driver omnia_leds_driver = {
.probe = omnia_leds_probe,
.remove = omnia_leds_remove,
.id_table = omnia_id,
.driver = {
.name = "leds-turris-omnia",
.of_match_table = of_omnia_leds_match,
.dev_groups = omnia_led_controller_groups,
},
};
module_i2c_driver(omnia_leds_driver);
MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");
MODULE_DESCRIPTION("CZ.NIC's Turris Omnia LEDs");
MODULE_LICENSE("GPL v2");