Re: [PATCH v2 2/2] leds: max597x: Add support for max597x

From: Naresh Solanki
Date: Fri Mar 24 2023 - 06:54:27 EST


Hi,

On 24-03-2023 01:48 am, Christophe JAILLET wrote:
Le 23/03/2023 à 20:45, Naresh Solanki a écrit :
From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>

max597x is hot swap controller with indicator LED support.
This driver uses DT property to configure led during boot time &
also provide the LED control in sysfs.

DTS example:
     i2c {
         #address-cells = <1>;
         #size-cells = <0>;
         regulator@3a {
             compatible = "maxim,max5978";
             reg = <0x3a>;
             vss1-supply = <&p3v3>;

             regulators {
                 sw0_ref_0: sw0 {
                     shunt-resistor-micro-ohms = <12000>;
                 };
             };

             leds {
                 #address-cells = <1>;
                 #size-cells = <0>;
                 led@0 {
                     reg = <0>;
                     label = "led0";
                     default-state = "on";
                 };
                 led@1 {
                     reg = <1>;
                     label = "led1";
                     default-state = "on";
                 };
             };
         };
     };

Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
...
Changes in V2:
- Fix regmap update
- Remove devm_kfree
- Remove default-state
- Add example dts in commit message
- Fix whitespace in Kconfig
- Fix comment
---
  drivers/leds/Kconfig        |  11 ++++
  drivers/leds/Makefile       |   1 +
  drivers/leds/leds-max597x.c | 112 ++++++++++++++++++++++++++++++++++++
  3 files changed, 124 insertions(+)
  create mode 100644 drivers/leds/leds-max597x.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 9dbce09eabac..ec2b731ae545 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -590,6 +590,17 @@ config LEDS_ADP5520
        To compile this driver as a module, choose M here: the module will
        be called leds-adp5520.
+config LEDS_MAX597X
+    tristate "LED Support for Maxim 597x"
+    depends on LEDS_CLASS
+    depends on MFD_MAX597X
+    help
+      This option enables support for the Maxim 597x smart switch indication LEDs
+      via the I2C bus.
+
+      To compile this driver as a module, choose M here: the module will
+      be called max597x-led.

leds-max597x?
As per struct max597x_led_driver, driver name is max597x-led

+
  config LEDS_MC13783
      tristate "LED Support for MC13XXX PMIC"
      depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index d30395d11fd8..da1192e40268 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_LEDS_LP8501)        += leds-lp8501.o
  obj-$(CONFIG_LEDS_LP8788)        += leds-lp8788.o
  obj-$(CONFIG_LEDS_LP8860)        += leds-lp8860.o
  obj-$(CONFIG_LEDS_LT3593)        += leds-lt3593.o
+obj-$(CONFIG_LEDS_MAX597X)        += leds-max597x.o
  obj-$(CONFIG_LEDS_MAX77650)        += leds-max77650.o
  obj-$(CONFIG_LEDS_MAX8997)        += leds-max8997.o
  obj-$(CONFIG_LEDS_MC13783)        += leds-mc13783.o
diff --git a/drivers/leds/leds-max597x.c b/drivers/leds/leds-max597x.c
new file mode 100644
index 000000000000..3e1747c8693e
--- /dev/null
+++ b/drivers/leds/leds-max597x.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Device driver for leds in MAX5970 and MAX5978 IC
+ *
+ * Copyright (c) 2022 9elements GmbH
+ *
+ * Author: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
+ */
+
+#include <linux/leds.h>
+#include <linux/mfd/max597x.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#define ldev_to_maxled(c)       container_of(c, struct max597x_led, led)
+
+struct max597x_led {
+    struct regmap *regmap;
+    struct led_classdev led;
+    unsigned int index;
+};
+
+static int max597x_led_set_brightness(struct led_classdev *cdev,
+                      enum led_brightness brightness)
+{
+    struct max597x_led *led = ldev_to_maxled(cdev);
+    int ret, val = 0;
+
+    if (!led || !led->regmap)
+        return -ENODEV;
+
+    val = !brightness ? BIT(led->index) : 0;
+    ret = regmap_update_bits(led->regmap, MAX5970_REG_LED_FLASH, BIT(led->index), val);
+    if (ret < 0)
+        dev_err(cdev->dev, "failed to set brightness %d\n", ret);
+    return ret;
+}
+
+static int max597x_setup_led(struct device *dev, struct regmap *regmap, struct device_node *nc,
+                 u32 reg)
+{
+    struct max597x_led *led;
+    int ret = 0;

Nit: useless "= 0"
Ack. Will be removing ' = 0' in V3

+
+    led = devm_kzalloc(dev, sizeof(struct max597x_led),
+               GFP_KERNEL);
+    if (!led)
+        return -ENOMEM;
+
+    if (of_property_read_string(nc, "label", &led->led.name))
+        led->led.name = nc->name;
+
+    led->led.max_brightness = 1;
+    led->led.brightness_set_blocking = max597x_led_set_brightness;
+    led->led.default_trigger = "none";
+    led->index = reg;
+    led->regmap = regmap;
+    ret = led_classdev_register(dev, &led->led);

devm_led_classdev_register?
Ack. Will update in V3

+    if (ret)
+        dev_err(dev, "Error in initializing led %s", led->led.name);
+
+    return ret;
+}
+
+static int max597x_led_probe(struct platform_device *pdev)
+{
+    struct device_node *np = dev_of_node(pdev->dev.parent);
+    struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
+    struct device_node *led_node;
+    struct device_node *child;
+    int ret = 0;
+
+    if (!regmap)
+        return -EPROBE_DEFER;
+
+    led_node = of_get_child_by_name(np, "leds");
+    if (!led_node)
+        return -ENODEV;
+
+    for_each_available_child_of_node(led_node, child) {
+        u32 reg;
+
+        if (of_property_read_u32(child, "reg", &reg))
+            continue;
+
+        if (reg >= MAX597X_NUM_LEDS) {
+            dev_err(&pdev->dev, "invalid LED (%u >= %d)\n", reg,
+                MAX597X_NUM_LEDS);
+            continue;
+        }
+
+        ret = max597x_setup_led(&pdev->dev, regmap, child, reg);
+        if (ret < 0)
+            of_node_put(child);

This of_node_put() looks odd to me.
Not sure if I get this right but if led setup fails of_node_put should be called.
"return ret;" or "break;" missing ?

Didn't add a break so that it can continue initializing remaining led if any.
+    }
+
+    return ret;
+}
+
+static struct platform_driver max597x_led_driver = {
+    .driver = {
+        .name = "max597x-led",
+    },
+    .probe = max597x_led_probe,
+};
+
+module_platform_driver(max597x_led_driver);
+
+MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("MAX5970_hot-swap controller driver");
+MODULE_LICENSE("GPL");


Will push V3 based on feedback.

Regards,
Naresh