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Message-ID: <fbe8314e-8e52-4a6d-06e9-9e400a847545@ti.com>
Date: Wed, 15 Nov 2017 07:11:12 -0600
From: Dan Murphy <dmurphy@...com>
To: <robh+dt@...nel.org>, <mark.rutland@....com>, <rpurdie@...ys.net>,
<jacek.anaszewski@...il.com>, <pavel@....cz>
CC: <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-leds@...r.kernel.org>
Subject: Re: [PATCH 2/2] leds: lm3692x: Introduce LM3692x dual string driver
On 11/13/2017 02:50 PM, Dan Murphy wrote:
> Introducing the LM3692x Dual-String white LED driver.
>
> Data sheet is located
> http://www.ti.com/lit/ds/snvsa29/snvsa29.pdf
>
> Signed-off-by: Dan Murphy <dmurphy@...com>
> ---
> drivers/leds/leds-lm3692x.c | 380 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 380 insertions(+)
> create mode 100644 drivers/leds/leds-lm3692x.c
>
> diff --git a/drivers/leds/leds-lm3692x.c b/drivers/leds/leds-lm3692x.c
> new file mode 100644
> index 000000000000..beb753abc7b0
> --- /dev/null
> +++ b/drivers/leds/leds-lm3692x.c
> @@ -0,0 +1,380 @@
> +/*
> + * TI lm3692x LED Driver
> + *
> + * Copyright (C) 2017 Texas Instruments
> + *
> + * Author: Dan Murphy <dmurphy@...com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * version 2 as published by the Free Software Foundation.
> + *
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/leds.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/slab.h>
> +
> +#define LM3692X_LED_NAME "lm3692x_led"
> +
> +#define LM3692X_REV 0x0
> +#define LM3692X_RESET 0x1
> +#define LM3692X_EN 0x10
> +#define LM3692X_BRT_CTRL 0x11
> +#define LM3692X_PWM_CTRL 0x12
> +#define LM3692X_BOOST_CTRL 0x13
> +#define LM3692X_AUTO_FREQ_HI 0x15
> +#define LM3692X_AUTO_FREQ_LO 0x16
> +#define LM3692X_BL_ADJ_THRESH 0x17
> +#define LM3692X_BRT_LSB 0x18
> +#define LM3692X_BRT_MSB 0x19
> +#define LM3692X_FAULT_CTRL 0x1e
> +#define LM3692X_FAULT_FLAGS 0x1f
> +
> +#define LM3692X_SW_RESET BIT(0)
> +#define LM3692X_DEVICE_EN BIT(0)
> +#define LM3692X_LED1_EN BIT(1)
> +#define LM3692X_LED2_EN BIT(2)
> +
> +/* Brightness Control Bits */
> +#define LM3692X_BL_ADJ_POL BIT(0)
> +#define LM3692X_RAMP_RATE_125us 0x00
> +#define LM3692X_RAMP_RATE_250us BIT(1)
> +#define LM3692X_RAMP_RATE_500us BIT(2)
> +#define LM3692X_RAMP_RATE_1ms (BIT(1) | BIT(2))
> +#define LM3692X_RAMP_RATE_2ms BIT(3)
> +#define LM3692X_RAMP_RATE_4ms (BIT(3) | BIT(1))
> +#define LM3692X_RAMP_RATE_8ms (BIT(2) | BIT(3))
> +#define LM3692X_RAMP_RATE_16ms (BIT(1) | BIT(2) | BIT(3))
> +#define LM3692X_RAMP_EN BIT(4)
> +#define LM3692X_BRHT_MODE_REG 0x00
> +#define LM3692X_BRHT_MODE_PWM BIT(5)
> +#define LM3692X_BRHT_MODE_MULTI_RAMP BIT(6)
> +#define LM3692X_BRHT_MODE_RAMP_MULTI (BIT(5) | BIT(6))
> +#define LM3692X_MAP_MODE_EXP BIT(7)
> +
> +/* PWM Register Bits */
> +#define LM3692X_PWM_FILTER_100 BIT(0)
> +#define LM3692X_PWM_FILTER_150 BIT(1)
> +#define LM3692X_PWM_FILTER_200 (BIT(0) | BIT(1))
> +#define LM3692X_PWM_HYSTER_1LSB BIT(2)
> +#define LM3692X_PWM_HYSTER_2LSB BIT(3)
> +#define LM3692X_PWM_HYSTER_3LSB (BIT(3) | BIT(2))
> +#define LM3692X_PWM_HYSTER_4LSB BIT(4)
> +#define LM3692X_PWM_HYSTER_5LSB (BIT(4) | BIT(2))
> +#define LM3692X_PWM_HYSTER_6LSB (BIT(4) | BIT(3))
> +#define LM3692X_PWM_POLARITY BIT(5)
> +#define LM3692X_PWM_SAMP_4MHZ BIT(6)
> +#define LM3692X_PWM_SAMP_24MHZ BIT(7)
> +
> +/* Boost Control Bits */
> +#define LM3692X_OCP_PROT_1A BIT(0)
> +#define LM3692X_OCP_PROT_1_25A BIT(1)
> +#define LM3692X_OCP_PROT_1_5A (BIT(0) | BIT(1))
> +#define LM3692X_OVP_21V BIT(2)
> +#define LM3692X_OVP_25V BIT(3)
> +#define LM3692X_OVP_29V (BIT(2) | BIT(3))
> +#define LM3692X_MIN_IND_22UH BIT(4)
> +#define LM3692X_BOOST_SW_1MHZ BIT(5)
> +#define LM3692X_BOOST_SW_NO_SHIFT BIT(6)
> +
> +/* Fault Control Bits */
> +#define LM3692X_FAULT_CTRL_OVP BIT(0)
> +#define LM3692X_FAULT_CTRL_OCP BIT(1)
> +#define LM3692X_FAULT_CTRL_TSD BIT(2)
> +#define LM3692X_FAULT_CTRL_OPEN BIT(3)
> +
> +/* Fault Flag Bits */
> +#define LM3692X_FAULT_FLAG_OVP BIT(0)
> +#define LM3692X_FAULT_FLAG_OCP BIT(1)
> +#define LM3692X_FAULT_FLAG_TSD BIT(2)
> +#define LM3692X_FAULT_FLAG_SHRT BIT(3)
> +#define LM3692X_FAULT_FLAG_OPEN BIT(4)
> +
> +/**
> + * struct lm3692x_led -
> + * @lock - Lock for reading/writing the device
> + * @client - Pointer to the I2C client
> + * @led_dev - led class device pointer
> + * @regmap - Devices register map
> + * @enable_gpio - VDDIO/EN gpio to enable communication interface
> + * @regulator - LED supply regulator pointer
> + * @label - LED label
> + **/
> +struct lm3692x_led {
> + struct mutex lock;
> + struct i2c_client *client;
> + struct led_classdev led_dev;
> + struct regmap *regmap;
> + struct gpio_desc *enable_gpio;
> + struct regulator *regulator;
> + const char *label;
> +};
> +
> +static const struct reg_default lm3692x_reg_defs[] = {
> + {LM3692X_EN, 0xf},
> + {LM3692X_BRT_CTRL, 0x61},
> + {LM3692X_PWM_CTRL, 0x73},
> + {LM3692X_BOOST_CTRL, 0x6f},
> + {LM3692X_AUTO_FREQ_HI, 0x0},
> + {LM3692X_AUTO_FREQ_LO, 0x0},
> + {LM3692X_BL_ADJ_THRESH, 0x0},
> + {LM3692X_BRT_LSB, 0x7},
> + {LM3692X_BRT_MSB, 0xff},
> + {LM3692X_FAULT_CTRL, 0x7},
> +};
> +
> +static const struct regmap_config lm3692x_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> +
> + .max_register = LM3692X_FAULT_FLAGS,
> + .reg_defaults = lm3692x_reg_defs,
> + .num_reg_defaults = ARRAY_SIZE(lm3692x_reg_defs),
> + .cache_type = REGCACHE_RBTREE,
> +};
> +
> +static int lm3692x_fault_check(struct lm3692x_led *led)
> +{
> + int ret, fault;
> + unsigned int read_buf;
> +
> + ret = regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
> + if (ret)
> + goto out;
> +
> + fault = read_buf;
> +
> + if (fault)
> + dev_err(&led->client->dev, "Detected a fault 0x%X\n",
> + fault);
> +out:
> + return ret;
> +}
> +
> +static int lm3692x_brightness_set(struct led_classdev *led_cdev,
> + enum led_brightness brt_val)
> +{
> + struct lm3692x_led *led =
> + container_of(led_cdev, struct lm3692x_led, led_dev);
> + int led_brightness = (brt_val << 4) + 7;
After a peer review with the hardware team it was determined that the brightness value
calculation always sets the LSB to a value of 7. Therefore this will be changed in patch
v2 so that the MSB will contain the brt_val and the LSB will contain the 3 MSB bits of the
brt_val.
So the values will look something like this:
Code 0x00 thru code 0x1f --> LSB = 0
Code 0x20 thru code 0x3f --> LSB = 1, 0x101 up to 0x1f9
Code 0x40 thru code 0x5f --> LSB = 2, 0x202 up to 0x2fa
Code 0x60 thru code 0x7f --> LSB = 3, 0x303 thru 0x3fb
Code 0x80 thru code 0x9f --> LSB = 4, 0x404 thru 0x4fc
.
.
Code 0xe0 thru code 0xff --> LSB = 7, 0x707 thru 0x7ff
> + int ret;
> +
> + if (brt_val == LED_OFF)
> + led_brightness = 0;
> +
> + mutex_lock(&led->lock);
> +
> + ret = lm3692x_fault_check(led);
> + if (ret) {
> + dev_err(&led->client->dev, "Cannot read/clear faults\n");
> + goto out;
> + }
> +
> + ret = regmap_write(led->regmap, LM3692X_BRT_MSB,
> + (led_brightness & 0xff0) >> 4);
> + if (ret) {
> + dev_err(&led->client->dev, "Cannot write MSB\n");
> + goto out;
> + }
> +
> + ret = regmap_write(led->regmap, LM3692X_BRT_LSB,
> + led_brightness & 0x07);
> + if (ret) {
> + dev_err(&led->client->dev, "Cannot write LSB\n");
> + goto out;
> + }
> +out:
> + mutex_unlock(&led->lock);
> + return ret;
> +}
> +
> +static int lm3692x_init(struct lm3692x_led *led)
> +{
> + int ret;
> +
> + if (led->regulator) {
> + ret = regulator_enable(led->regulator);
> + if (ret)
> + dev_err(&led->client->dev,
> + "Failed to enable regulator\n");
> + }
> +
> + if (led->enable_gpio)
> + gpiod_direction_output(led->enable_gpio, 1);
> +
> + ret = lm3692x_fault_check(led);
> + if (ret) {
> + dev_err(&led->client->dev, "Cannot read/clear faults\n");
> + goto out;
> + }
> +
> + ret = regmap_write(led->regmap, LM3692X_BRT_CTRL, 0x00);
> + if (ret)
> + dev_err(&led->client->dev, "Fail writing BRT CTRL\n");
> + /*
> + * For glitch free operation, the following data should
> + * only be written while device enable bit is 0
> + * Per Section 7.5.14 of the data sheet
> + */
> + ret = regmap_write(led->regmap, LM3692X_PWM_CTRL,
> + LM3692X_PWM_FILTER_100 | LM3692X_PWM_SAMP_24MHZ);
> + if (ret)
> + dev_err(&led->client->dev, "Failed programming PWM CTRL\n");
> +
> + ret = regmap_write(led->regmap, LM3692X_BOOST_CTRL,
> + LM3692X_BRHT_MODE_RAMP_MULTI |
> + LM3692X_BL_ADJ_POL |
> + LM3692X_RAMP_RATE_250us);
> + if (ret)
> + dev_err(&led->client->dev, "Failed programming BOOST CTRL\n");
> +
> + ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_HI, 0x00);
> + if (ret)
> + dev_err(&led->client->dev, "Failed programming AUTO HI FREQ\n");
> +
> + ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_LO, 0x00);
> + if (ret)
> + dev_err(&led->client->dev, "Failed programming AUTO LO FREQ\n");
> +
> +
> + ret = regmap_write(led->regmap, LM3692X_BL_ADJ_THRESH, 0x00);
> + if (ret)
> + dev_err(&led->client->dev, "Failed programming BL Threshold\n");
> +
> + ret = regmap_write(led->regmap, LM3692X_BRT_CTRL,
> + LM3692X_BL_ADJ_POL | LM3692X_PWM_HYSTER_4LSB);
> + if (ret)
> + dev_err(&led->client->dev, "Failed programming BRT CTRL\n");
> +
> + return ret;
> +out:
> +
> + if (led->enable_gpio)
> + gpiod_direction_output(led->enable_gpio, 0);
> +
> + if (led->regulator) {
> + ret = regulator_disable(led->regulator);
> + if (ret)
> + dev_err(&led->client->dev,
> + "Failed to disable regulator\n");
> + }
> +
> + return ret;
> +}
> +
> +static int lm3692x_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + int ret;
> + struct lm3692x_led *led;
> + struct device_node *np = client->dev.of_node;
> +
> + led = devm_kzalloc(&client->dev, sizeof(*led), GFP_KERNEL);
> + if (!led)
> + return -ENOMEM;
> +
> + if (client->dev.of_node) {
> + ret = of_property_read_string(np, "label", &led->label);
> + if (ret)
> + led->label = LM3692X_LED_NAME;
> + }
> +
> + led->enable_gpio = devm_gpiod_get_optional(&client->dev,
> + "enable", GPIOD_OUT_LOW);
> + if (IS_ERR(led->enable_gpio)) {
> + ret = PTR_ERR(led->enable_gpio);
> + dev_err(&client->dev, "Failed to get enable gpio: %d\n", ret);
> + return ret;
> + }
> +
> + led->regulator = devm_regulator_get(&client->dev, "vled");
> + if (IS_ERR(led->regulator))
> + led->regulator = NULL;
> +
> + led->client = client;
> + led->led_dev.name = led->label;
> + led->led_dev.max_brightness = LED_FULL;
> + led->led_dev.brightness_set_blocking = lm3692x_brightness_set;
> +
> + mutex_init(&led->lock);
> +
> + i2c_set_clientdata(client, led);
> +
> + led->regmap = devm_regmap_init_i2c(client, &lm3692x_regmap_config);
> + if (IS_ERR(led->regmap)) {
> + ret = PTR_ERR(led->regmap);
> + dev_err(&client->dev, "Failed to allocate register map: %d\n",
> + ret);
> + return ret;
> + }
> +
> + ret = lm3692x_init(led);
> + if (ret)
> + return ret;
> +
> + ret = led_classdev_register(&client->dev, &led->led_dev);
> + if (ret) {
> + dev_err(&client->dev, "led register err: %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int lm3692x_remove(struct i2c_client *client)
> +{
> + struct lm3692x_led *led = i2c_get_clientdata(client);
> + int ret;
> +
> + led_classdev_unregister(&led->led_dev);
> +
> + if (led->enable_gpio)
> + gpiod_direction_output(led->enable_gpio, 0);
> +
> + if (led->regulator) {
> + ret = regulator_disable(led->regulator);
> + if (ret)
> + dev_err(&led->client->dev,
> + "Failed to disable regulator\n");
> + }
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id lm3692x_id[] = {
> + { "lm3692x", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, lm3692x_id);
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id of_lm3692x_leds_match[] = {
> + { .compatible = "ti,lm3692x", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, of_lm3692x_leds_match);
> +#endif
> +
> +static struct i2c_driver lm3692x_driver = {
> + .driver = {
> + .name = "lm3692x",
> + .of_match_table = of_match_ptr(of_lm3692x_leds_match),
> + },
> + .probe = lm3692x_probe,
> + .remove = lm3692x_remove,
> + .id_table = lm3692x_id,
> +};
> +module_i2c_driver(lm3692x_driver);
> +
> +MODULE_DESCRIPTION("Texas Instruments LM3692X LED driver");
> +MODULE_AUTHOR("Dan Murphy <dmurphy@...com>");
> +MODULE_LICENSE("GPL");
>
--
------------------
Dan Murphy
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