From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jacek Anaszewski Subject: Re: [PATCH 2/2] leds: Add driver for NCP5623 3-channel I2C LED driver Date: Tue, 21 Jun 2016 17:29:09 +0200 Message-ID: <57695D45.60107@samsung.com> References: <1466494154-3786-1-git-send-email-florian.vaussard@heig-vd.ch> <1466494154-3786-3-git-send-email-florian.vaussard@heig-vd.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mailout3.w1.samsung.com ([210.118.77.13]:50104 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751704AbcFUPkU (ORCPT ); Tue, 21 Jun 2016 11:40:20 -0400 In-reply-to: <1466494154-3786-3-git-send-email-florian.vaussard@heig-vd.ch> Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org To: Florian Vaussard Cc: devicetree@vger.kernel.org, Richard Purdie , Rob Herring , Mark Rutland , linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org, Florian Vaussard Hi Florian, Thanks for the patch. Please refer to my comments in the code. On 06/21/2016 09:29 AM, Florian Vaussard wrote: > The NCP5623 is a 3-channel LED driver from On Semiconductor controlled > through I2C. The PWM of each channel can be independently set with 32 > distinct levels. In addition, the intensity of the current source can be > globally set using an external bias resistor fixing the reference > current (Iref) and a dedicated register (ILED), following the > relationship: > > I = 2400*Iref/(31-ILED) > > with Iref = Vref/Rbias, and Vref = 0.6V. > > Signed-off-by: Florian Vaussard > --- > drivers/leds/Kconfig | 11 ++ > drivers/leds/Makefile | 1 + > drivers/leds/leds-ncp5623.c | 265 ++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 277 insertions(+) > create mode 100644 drivers/leds/leds-ncp5623.c > > diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig > index 5ae2834..6d3e44d 100644 > --- a/drivers/leds/Kconfig > +++ b/drivers/leds/Kconfig > @@ -588,6 +588,17 @@ config LEDS_BLINKM > This option enables support for the BlinkM RGB LED connected > through I2C. Say Y to enable support for the BlinkM LED. > > +config LEDS_NCP5623 > + tristate "LED Support for NCP5623 I2C chip" > + depends on LEDS_CLASS > + depends on I2C > + help > + This option enables support for LEDs connected to NCP5623 > + LED driver chips accessed via the I2C bus. > + Driver supports brightness control. > + > + Say Y to enable this driver. > + > config LEDS_POWERNV > tristate "LED support for PowerNV Platform" > depends on LEDS_CLASS > diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile > index cb2013d..a2f0e10 100644 > --- a/drivers/leds/Makefile > +++ b/drivers/leds/Makefile > @@ -67,6 +67,7 @@ obj-$(CONFIG_LEDS_KTD2692) += leds-ktd2692.o > obj-$(CONFIG_LEDS_POWERNV) += leds-powernv.o > obj-$(CONFIG_LEDS_SEAD3) += leds-sead3.o > obj-$(CONFIG_LEDS_IS31FL32XX) += leds-is31fl32xx.o > +obj-$(CONFIG_LEDS_NCP5623) += leds-ncp5623.o > > # LED SPI Drivers > obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o > diff --git a/drivers/leds/leds-ncp5623.c b/drivers/leds/leds-ncp5623.c > new file mode 100644 > index 0000000..a341e4a > --- /dev/null > +++ b/drivers/leds/leds-ncp5623.c > @@ -0,0 +1,265 @@ > +/* > + * Copyright 2016 Florian Vaussard > + * > + * Based on leds-tlc591xx.c > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; version 2 of the License. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define NCP5623_MAX_LEDS 3 > +#define NCP5623_MAX_STEPS 32 > +#define NCP5623_MAX_CURRENT 31 > +#define NCP5623_MAX_CURRENT_UA 30000 > + > +#define NCP5623_CMD_SHIFT 5 > +#define CMD_SHUTDOWN (0x00 << NCP5623_CMD_SHIFT) > +#define CMD_ILED (0x01 << NCP5623_CMD_SHIFT) > +#define CMD_PWM1 (0x02 << NCP5623_CMD_SHIFT) > +#define CMD_PWM2 (0x03 << NCP5623_CMD_SHIFT) > +#define CMD_PWM3 (0x04 << NCP5623_CMD_SHIFT) > +#define CMD_UPWARD_DIM (0x05 << NCP5623_CMD_SHIFT) > +#define CMD_DOWNWARD_DIM (0x06 << NCP5623_CMD_SHIFT) > +#define CMD_DIM_STEP (0x07 << NCP5623_CMD_SHIFT) > + > +#define NCP5623_DATA_MASK GENMASK(NCP5623_CMD_SHIFT - 1, 0) > + > +#define NCP5623_CMD(cmd, data) (cmd | (data & NCP5623_DATA_MASK)) > + > +struct ncp5623_led { > + bool active; > + unsigned int led_no; > + struct led_classdev ldev; > + struct work_struct work; > + struct ncp5623_priv *priv; > +}; > + > +struct ncp5623_priv { > + struct ncp5623_led leds[NCP5623_MAX_LEDS]; Please allocate memory dynamically, depending on the number of LEDs defined in a Device Tree. > + u32 led_iref; > + u32 led_max_current; > + struct i2c_client *client; > +}; > + > +static struct ncp5623_led *ldev_to_led(struct led_classdev *ldev) > +{ > + return container_of(ldev, struct ncp5623_led, ldev); > +} > + > +static struct ncp5623_led *work_to_led(struct work_struct *work) > +{ > + return container_of(work, struct ncp5623_led, work); > +} If you registered brightness_set_blocking op instead of brightness_set, then the workqueue wouldn't be required in the driver. > +static int ncp5623_send_cmd(struct ncp5623_priv *priv, u8 cmd, u8 data) > +{ > + char cmd_data[1] = { NCP5623_CMD(cmd, data) }; > + int err; > + > + err = i2c_master_send(priv->client, cmd_data, ARRAY_SIZE(cmd_data)); Please add empty line here. > + return (err < 0 ? err : 0); > +} > + > +static int ncp5623_set_pwm(struct ncp5623_led *led, u8 brightness) > +{ > + struct ncp5623_priv *priv = led->priv; > + u8 cmd; > + > + switch (led->led_no) { > + case 0: > + cmd = CMD_PWM1; > + break; > + case 1: > + cmd = CMD_PWM2; > + break; > + case 2: > + cmd = CMD_PWM3; > + break; > + default: > + return -EINVAL; > + } Macro for calculating cmd basing on led->led_no would allow for getting rid of the switch statement. > + > + return ncp5623_send_cmd(priv, cmd, brightness); > +} > + > +static void ncp5623_led_work(struct work_struct *work) > +{ > + struct ncp5623_led *led = work_to_led(work); > + enum led_brightness brightness = led->ldev.brightness; > + int err; > + > + err = ncp5623_set_pwm(led, brightness); > + > + if (err < 0) > + dev_err(led->ldev.dev, "failed setting brightness\n"); > +} > + > +static void ncp5623_brightness_set(struct led_classdev *led_cdev, > + enum led_brightness brightness) > +{ > + struct ncp5623_led *led = ldev_to_led(led_cdev); > + > + led->ldev.brightness = brightness; This is secured by LED core. > + schedule_work(&led->work); > +} > + > +static void ncp5623_destroy_devices(struct ncp5623_priv *priv) > +{ > + struct ncp5623_led *led; > + int i; > + > + for (i = 0; i < NCP5623_MAX_LEDS; i++) { > + led = &priv->leds[i]; > + if (led->active) { > + led_classdev_unregister(&led->ldev); > + cancel_work_sync(&led->work); > + } > + } > +} > + > +static int ncp5623_configure(struct device *dev, > + struct ncp5623_priv *priv) > +{ > + unsigned int i; > + unsigned int n; > + struct ncp5623_led *led; > + int err; > + > + /* Compute the value of ILED register to honor led_max_current */ > + n = 2400 * priv->led_iref / priv->led_max_current + 1; > + if (n > NCP5623_MAX_CURRENT) > + n = NCP5623_MAX_CURRENT; > + n = NCP5623_MAX_CURRENT - n; > + > + dev_dbg(dev, "setting maximum current to %u uA\n", > + 2400 * priv->led_iref / (NCP5623_MAX_CURRENT - n)); > + > + err = ncp5623_send_cmd(priv, CMD_ILED, n); > + if (err < 0) { > + dev_err(dev, "cannot set the current\n"); > + return err; > + } > + > + /* Setup each individual LED */ > + for (i = 0; i < NCP5623_MAX_LEDS; i++) { > + led = &priv->leds[i]; > + > + if (!led->active) > + continue; > + > + led->priv = priv; > + led->led_no = i; > + led->ldev.brightness_set = ncp5623_brightness_set; > + led->ldev.max_brightness = NCP5623_MAX_STEPS - 1; max_brightness should be asserted according to led-max-microamp property. > + INIT_WORK(&led->work, ncp5623_led_work); Please remove it and use brightness_set_blocking op. > + err = led_classdev_register(dev, &led->ldev); Use devm prefixed version. > + if (err < 0) { > + dev_err(dev, "couldn't register LED %s\n", > + led->ldev.name); > + goto exit; > + } > + } > + > + return 0; > + > +exit: > + ncp5623_destroy_devices(priv); > + return err; > +} > + > +static const struct of_device_id ncp5623_of_match[] = { > + { .compatible = "onnn,ncp5623" }, > + { /* sentinel */ }, > +}; > +MODULE_DEVICE_TABLE(of, ncp5623_of_match); > + > +static int ncp5623_probe(struct i2c_client *client, > + const struct i2c_device_id *id) > +{ > + struct device *dev = &client->dev; > + struct device_node *np = dev->of_node, *child; > + struct ncp5623_priv *priv; > + struct ncp5623_led *led; > + u32 reg; > + int err, count; > + > + count = of_get_child_count(np); > + if (!count || count > NCP5623_MAX_LEDS) > + return -EINVAL; Please separate DT parsing from LED class device registration. You could add ncp5623_parse_dt(). This is kind of standard. > + > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + priv->client = client; > + > + i2c_set_clientdata(client, priv); > + > + err = of_property_read_u32(np, "onnn,led-iref-microamp", > + &priv->led_iref); > + if (err) > + return -EINVAL; > + err = of_property_read_u32(np, "led-max-microamp", > + &priv->led_max_current); > + if (err || priv->led_max_current > NCP5623_MAX_CURRENT_UA) > + return -EINVAL; > + > + for_each_child_of_node(np, child) { > + err = of_property_read_u32(child, "reg", ®); > + if (err) > + return err; > + if (reg < 0 || reg >= NCP5623_MAX_LEDS) > + return -EINVAL; You need to call of_node_put if breaking this loop. Please refer to the other LED class drivers. > + led = &priv->leds[reg]; > + if (led->active) > + return -EINVAL; > + led->active = true; > + led->ldev.name = > + of_get_property(child, "label", NULL) ? : child->name; > + led->ldev.default_trigger = > + of_get_property(child, "linux,default-trigger", NULL); Please mention also default-trigger property in the DT documenation. > + } > + return ncp5623_configure(dev, priv); > +} > + > +static int ncp5623_remove(struct i2c_client *client) > +{ > + struct ncp5623_priv *priv = i2c_get_clientdata(client); > + > + ncp5623_destroy_devices(priv); > + > + return 0; > +} > + > +static const struct i2c_device_id ncp5623_id[] = { > + { "ncp5623" }, > + {}, > +}; > +MODULE_DEVICE_TABLE(i2c, ncp5623_id); > + > +static struct i2c_driver ncp5623_driver = { > + .driver = { > + .name = "ncp5623", > + .of_match_table = of_match_ptr(ncp5623_of_match), > + }, > + .probe = ncp5623_probe, > + .remove = ncp5623_remove, > + .id_table = ncp5623_id, > +}; > + > +module_i2c_driver(ncp5623_driver); > + > +MODULE_AUTHOR("Florian Vaussard "); > +MODULE_LICENSE("GPL"); You mentioned GPL v2 at the top. > +MODULE_DESCRIPTION("NCP5623 LED driver"); > -- Best regards, Jacek Anaszewski