Re: [PATCH v7] extcon-axp288: Add axp288 extcon driver support

From: Chanwoo Choi
Date: Wed Apr 29 2015 - 12:36:25 EST

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Hi Ram,

I added my comment.

On Wed, Apr 29, 2015 at 11:22 AM, Ramakrishna Pallala
<ramakrishna.pallala@xxxxxxxxx> wrote:
> This patch adds the extcon support for AXP288 PMIC which
> has the BC1.2 charger detection capability. Additionally
> it also adds the USB mux switching support b/w SOC and PMIC
> based on GPIO control.
>
> Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@xxxxxxxxx>
> ---
> drivers/extcon/Kconfig | 7 +
> drivers/extcon/Makefile | 1 +
> drivers/extcon/extcon-axp288.c | 403 ++++++++++++++++++++++++++++++++++++++++
> include/linux/mfd/axp20x.h | 5 +
> 4 files changed, 416 insertions(+)
> create mode 100644 drivers/extcon/extcon-axp288.c
>
> diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
> index fdc0bf0..2305edc 100644
> --- a/drivers/extcon/Kconfig
> +++ b/drivers/extcon/Kconfig
> @@ -28,6 +28,13 @@ config EXTCON_ARIZONA
> with Wolfson Arizona devices. These are audio CODECs with
> advanced audio accessory detection support.
>
> +config EXTCON_AXP288
> + tristate "X-Power AXP288 EXTCON support"
> + depends on MFD_AXP20X && USB_PHY
> + help
> + Say Y here to enable support for USB peripheral detection
> + and USB MUX switching by X-Power AXP288 PMIC.
> +
> config EXTCON_GPIO
> tristate "GPIO extcon support"
> depends on GPIOLIB
> diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
> index 9204114..ba787d0 100644
> --- a/drivers/extcon/Makefile
> +++ b/drivers/extcon/Makefile
> @@ -5,6 +5,7 @@
> obj-$(CONFIG_EXTCON) += extcon.o
> obj-$(CONFIG_EXTCON_ADC_JACK) += extcon-adc-jack.o
> obj-$(CONFIG_EXTCON_ARIZONA) += extcon-arizona.o
> +obj-$(CONFIG_EXTCON_AXP288) += extcon-axp288.o
> obj-$(CONFIG_EXTCON_GPIO) += extcon-gpio.o
> obj-$(CONFIG_EXTCON_MAX14577) += extcon-max14577.o
> obj-$(CONFIG_EXTCON_MAX77693) += extcon-max77693.o
> diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
> new file mode 100644
> index 0000000..7d72d44
> --- /dev/null
> +++ b/drivers/extcon/extcon-axp288.c
> @@ -0,0 +1,403 @@
> +/*
> + * extcon-axp288.c - X-Power AXP288 PMIC extcon cable detection driver
> + *
> + * Copyright (C) 2014 Intel Corporation

2014 -> 2015

> + * Author: Ramakrishna Pallala <ramakrishna.pallala@xxxxxxxxx>
> + *
> + * 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/io.h>
> +#include <linux/slab.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/usb/phy.h>
> +#include <linux/notifier.h>
> +#include <linux/extcon.h>
> +#include <linux/regmap.h>
> +#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/mfd/axp20x.h>
> +
> +/* Power source status register */
> +#define PS_STAT_VBUS_TRIGGER BIT(0)
> +#define PS_STAT_BAT_CHRG_DIR BIT(2)
> +#define PS_STAT_VBUS_ABOVE_VHOLD BIT(3)
> +#define PS_STAT_VBUS_VALID BIT(4)
> +#define PS_STAT_VBUS_PRESENT BIT(5)
> +
> +/* BC module global register */
> +#define BC_GLOBAL_RUN BIT(0)
> +#define BC_GLOBAL_DET_STAT BIT(2)
> +#define BC_GLOBAL_DBP_TOUT BIT(3)
> +#define BC_GLOBAL_VLGC_COM_SEL BIT(4)
> +#define BC_GLOBAL_DCD_TOUT_MASK (BIT(6)|BIT(5))
> +#define BC_GLOBAL_DCD_TOUT_300MS 0
> +#define BC_GLOBAL_DCD_TOUT_100MS 1
> +#define BC_GLOBAL_DCD_TOUT_500MS 2
> +#define BC_GLOBAL_DCD_TOUT_900MS 3
> +#define BC_GLOBAL_DCD_DET_SEL BIT(7)
> +
> +/* BC module vbus control and status register */
> +#define VBUS_CNTL_DPDM_PD_EN BIT(4)
> +#define VBUS_CNTL_DPDM_FD_EN BIT(5)
> +#define VBUS_CNTL_FIRST_PO_STAT BIT(6)
> +
> +/* BC USB status register */
> +#define USB_STAT_BUS_STAT_MASK (BIT(3)|BIT(2)|BIT(1)|BIT(0))
> +#define USB_STAT_BUS_STAT_SHIFT 0
> +#define USB_STAT_BUS_STAT_ATHD 0
> +#define USB_STAT_BUS_STAT_CONN 1
> +#define USB_STAT_BUS_STAT_SUSP 2
> +#define USB_STAT_BUS_STAT_CONF 3
> +#define USB_STAT_USB_SS_MODE BIT(4)
> +#define USB_STAT_DEAD_BAT_DET BIT(6)
> +#define USB_STAT_DBP_UNCFG BIT(7)
> +
> +/* BC detect status register */
> +#define DET_STAT_MASK (BIT(7)|BIT(6)|BIT(5))
> +#define DET_STAT_SHIFT 5
> +#define DET_STAT_SDP 1
> +#define DET_STAT_CDP 2
> +#define DET_STAT_DCP 3
> +
> +/* IRQ enable-1 register */
> +#define PWRSRC_IRQ_CFG_MASK (BIT(4)|BIT(3)|BIT(2))
> +
> +/* IRQ enable-6 register */
> +#define BC12_IRQ_CFG_MASK BIT(1)
> +
> +#define AXP288_EXTCON_SLOW_CHARGER "SLOW-CHARGER"
> +#define AXP288_EXTCON_DOWNSTREAM_CHARGER "CHARGE-DOWNSTREAM"
> +#define AXP288_EXTCON_FAST_CHARGER "FAST-CHARGER"
> +
> +enum axp288_extcon_reg {
> + AXP288_PS_STAT_REG = 0x00,
> + AXP288_PS_BOOT_REASON_REG = 0x02,
> + AXP288_BC_GLOBAL_REG = 0x2c,
> + AXP288_BC_VBUS_CNTL_REG = 0x2d,
> + AXP288_BC_USB_STAT_REG = 0x2e,
> + AXP288_BC_DET_STAT_REG = 0x2f,
> + AXP288_PWRSRC_IRQ_CFG_REG = 0x40,
> + AXP288_BC12_IRQ_CFG_REG = 0x45,
> +};
> +
> +enum axp288_mux_select {
> + EXTCON_GPIO_MUX_SEL_PMIC = 0,
> + EXTCON_GPIO_MUX_SEL_SOC,
> +};
> +
> +enum axp288_extcon_irq {
> + VBUS_FALLING_IRQ = 0,
> + VBUS_RISING_IRQ,
> + MV_CHNG_IRQ,
> + BC_USB_CHNG_IRQ,
> + EXTCON_IRQ_END,
> +};
> +
> +static const char *axp288_extcon_cables[] = {
> + AXP288_EXTCON_SLOW_CHARGER,
> + AXP288_EXTCON_DOWNSTREAM_CHARGER,
> + AXP288_EXTCON_FAST_CHARGER,
> + NULL,
> +};
> +
> +struct axp288_extcon_info {
> + struct device *dev;
> + struct regmap *regmap;
> + struct regmap_irq_chip_data *regmap_irqc;
> + struct axp288_extcon_pdata *pdata;
> + int irq[EXTCON_IRQ_END];
> + struct extcon_dev *edev;
> + struct notifier_block extcon_nb;
> + struct usb_phy *otg;
> +};
> +
> +/* Power up/down reason string array */
> +static char *axp288_pwr_up_down_info[] = {
> + "Last wake caused by user pressing the power button",
> + "Last wake caused by a charger insertion",
> + "Last wake caused by a battery insertion",
> + "Last wake caused by SOC initiated global reset",
> + "Last wake caused by cold reset",
> + "Last shutdown caused by PMIC UVLO threshold",
> + "Last shutdown caused by SOC initiated cold off",
> + "Last shutdown caused by user pressing the power button",
> + NULL,
> +};
> +
> +/*
> + * Decode and log the given "reset source indicator" (rsi)
> + * register and then clear it.
> + */
> +static void axp288_extcon_log_rsi(struct axp288_extcon_info *info)
> +{
> + char **rsi;
> + unsigned int val, i, clear_mask = 0;
> + int ret;
> +
> + ret = regmap_read(info->regmap, AXP288_PS_BOOT_REASON_REG, &val);
> + for (i = 0, rsi = axp288_pwr_up_down_info; *rsi; rsi++, i++) {
> + if (val & BIT(i)) {
> + dev_dbg(info->dev, "%s\n", *rsi);
> + clear_mask |= BIT(i);
> + }
> + }
> +
> + /* Clear the register value for next reboot (write 1 to clear bit) */
> + regmap_write(info->regmap, AXP288_PS_BOOT_REASON_REG, clear_mask);
> +}
> +
> +static int handle_chrg_det_event(struct axp288_extcon_info *info)

Add 'axp288' prefix to function name as following:
- handle_chrg_det_event -> axp288_handle_chrg_det_event

> +{
> + static bool notify_otg, notify_charger;
> + static char *cable;
> + int ret, stat, cfg, pwr_stat;
> + u8 chrg_type;
> + bool vbus_attach = false;
> +
> + ret = regmap_read(info->regmap, AXP288_PS_STAT_REG, &pwr_stat);
> + if (ret < 0) {
> + dev_err(info->dev, "vbus status read error\n");

I recommend that you use the consistency log pattern as following:
"failed to read vbus status\n"

> + return ret;
> + }
> +
> + vbus_attach = (pwr_stat & PS_STAT_VBUS_PRESENT);
> + if (vbus_attach) {
> + dev_dbg(info->dev, "vbus present\n");
> + } else {
> + dev_dbg(info->dev, "vbus not present\n");
> + goto notify_otg;
> + }

I think that you can simplify upper if/else statement as following
without any unneeded debug log.
if (!vbus_attach) {
goto notify_otg;

> +
> + /* Check charger detection completion status */
> + ret = regmap_read(info->regmap, AXP288_BC_GLOBAL_REG, &cfg);
> + if (ret < 0)
> + goto dev_det_ret;
> + if (cfg & BC_GLOBAL_DET_STAT) {
> + dev_dbg(info->dev, "charger detection not complete!!\n");

ditto. Don't need to add '!' at the end of log message.
"charger detection not complete!!\n" -> "can't complete the charger detection\n"

> + goto dev_det_ret;
> + }
> +
> + ret = regmap_read(info->regmap, AXP288_BC_DET_STAT_REG, &stat);
> + if (ret < 0)
> + goto dev_det_ret;
> + dev_dbg(info->dev, "stat:%x, cfg:%x\n", stat, cfg);

I don't prefer to show the just register value without any log message.

> +
> + chrg_type = (stat & DET_STAT_MASK) >> DET_STAT_SHIFT;
> +
> + if (chrg_type == DET_STAT_SDP) {
> + dev_dbg(info->dev, "sdp cable connecetd\n");

"sdp cable connecetd\n"-> "sdp cable is connected\n"

> + notify_otg = true;
> + notify_charger = true;
> + cable = AXP288_EXTCON_SLOW_CHARGER;
> + } else if (chrg_type == DET_STAT_CDP) {
> + dev_dbg(info->dev, "cdp cable connecetd\n");

"cdp cable connecetd\n" -> "cdp cable is connected"

> + notify_otg = true;
> + notify_charger = true;
> + cable = AXP288_EXTCON_DOWNSTREAM_CHARGER;
> + } else if (chrg_type == DET_STAT_DCP) {
> + dev_dbg(info->dev, "dcp cable connecetd\n");

"dcp cable connecetd\n" -> "dcp cable is connecetd\n"

> + notify_charger = true;
> + cable = AXP288_EXTCON_FAST_CHARGER;
> + } else {
> + dev_warn(info->dev,
> + "disconnect or unknown or ID event\n");
> + }

How about using the 'switch' statement instead of 'if/else'?

> +
> +notify_otg:
> + if (notify_otg) {
> + /*
> + * If VBUS is absent Connect D+/D- lines to PMIC for BC
> + * detection. Else connect them to SOC for USB communication.
> + */
> + if (info->pdata->gpio_mux_cntl)
> + gpiod_set_value(info->pdata->gpio_mux_cntl,
> + vbus_attach ? EXTCON_GPIO_MUX_SEL_SOC
> + : EXTCON_GPIO_MUX_SEL_PMIC);
> +
> + atomic_notifier_call_chain(&info->otg->notifier,
> + vbus_attach ? USB_EVENT_VBUS : USB_EVENT_NONE, NULL);
> + }
> +
> + if (notify_charger)
> + extcon_set_cable_state(info->edev, cable, vbus_attach);
> +
> + /* Clear the flags on disconnect event */
> + if (!vbus_attach) {
> + notify_otg = false;
> + notify_charger = false;
> + }

You better to modify if statement as following without brace:
if (!vbus_attach)
notify_otg = notify_charger = false;

> +
> + return 0;
> +
> +dev_det_ret:
> + if (ret < 0)
> + dev_warn(info->dev, "BC Mod detection error\n");

Use the dev_err() instead of dev_warn() because log message means error state.

> +
> + return ret;
> +}
> +
> +static irqreturn_t axp288_extcon_isr(int irq, void *data)
> +{
> + struct axp288_extcon_info *info = data;
> + unsigned int i;
> + int ret;
> +
> + for (i = 0; i < EXTCON_IRQ_END; i++) {
> + if (info->irq[i] == irq)
> + break;
> + }
> +
> + if (i == EXTCON_IRQ_END) {
> + dev_warn(info->dev, "spurious interrupt!!\n");

for and if statement is not necessary because 'int irq' must be included
in 'info->irq[]' array.

> + return IRQ_NONE;
> + }
> +
> + ret = handle_chrg_det_event(info);

ditto.
- axp288_handle_chrg_det_event()

> + if (ret < 0)
> + dev_warn(info->dev, "error in PWRSRC INT handling\n");

Use the 'dev_err' instead of 'dev_warn' and modify the log message on
upper comment.
"failed to handle PWRSRC interrupt\n"

> +
> + return IRQ_HANDLED;
> +}
> +
> +static void axp288_extcon_enable_irq(struct axp288_extcon_info *info)
> +{
> + /* Unmask VBUS interrupt */
> + regmap_write(info->regmap, AXP288_PWRSRC_IRQ_CFG_REG,
> + PWRSRC_IRQ_CFG_MASK);
> + regmap_update_bits(info->regmap, AXP288_BC_GLOBAL_REG,
> + BC_GLOBAL_RUN, 0);
> + /* Unmask the BC1.2 complte interrupts */

complte? complete?

> + regmap_write(info->regmap, AXP288_BC12_IRQ_CFG_REG, BC12_IRQ_CFG_MASK);
> + /* Enable the charger detection logic */
> + regmap_update_bits(info->regmap, AXP288_BC_GLOBAL_REG,
> + BC_GLOBAL_RUN, BC_GLOBAL_RUN);
> +}
> +
> +static int axp288_extcon_probe(struct platform_device *pdev)
> +{
> + struct axp288_extcon_info *info;
> + struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
> + int ret, i, pirq, gpio;
> +
> + info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
> + if (!info)
> + return -ENOMEM;
> +
> + info->dev = &pdev->dev;
> + info->regmap = axp20x->regmap;
> + info->regmap_irqc = axp20x->regmap_irqc;
> + info->pdata = pdev->dev.platform_data;
> +
> + if (!info->pdata) {
> + /* TODO: Try ACPI provided pdata via device properties */

I prefer to remove "TODO" comment.

> + if (!device_property_present(&pdev->dev,
> + "axp288_extcon_data\n"))
> + dev_err(&pdev->dev, "no platform data\n");

ditto.
- "failed to get platform data'

> + return -ENODEV;
> + }
> + platform_set_drvdata(pdev, info);
> +
> + axp288_extcon_log_rsi(info);
> +
> + /* Initialize extcon device */
> + info->edev = devm_extcon_dev_allocate(&pdev->dev,
> + axp288_extcon_cables);
> + if (IS_ERR(info->edev)) {
> + dev_err(&pdev->dev, "failed to allocate memory for extcon\n");
> + ret = PTR_ERR(info->edev);
> + return ret;

Return 'PTR_ERR(info->edev)' directly without allocation to 'ret' variable.

> + }
> +
> + /* Register extcon device */
> + ret = devm_extcon_dev_register(&pdev->dev, info->edev);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to register extcon device\n");
> + return ret;
> + }
> +
> + /* Get otg transceiver phy */
> + info->otg = usb_get_phy(USB_PHY_TYPE_USB2);
> + if (IS_ERR(info->otg)) {
> + dev_warn(&pdev->dev, "failed to get otg transceiver\n");
> + ret = PTR_ERR(info->otg);
> + return ret;

ditto.

> + }
> +
> + /* Set up gpio control for USB Mux */
> + if (info->pdata->gpio_mux_cntl) {
> + gpio = desc_to_gpio(info->pdata->gpio_mux_cntl);
> + ret = gpio_request(gpio, "USB_MUX");
> + if (ret < 0) {
> + dev_err(&pdev->dev,
> + "failed to request the gpio=%d\n", gpio);
> + goto gpio_req_failed;
> + }
> + gpiod_direction_output(info->pdata->gpio_mux_cntl,
> + EXTCON_GPIO_MUX_SEL_PMIC);
> + }
> +
> + for (i = 0; i < EXTCON_IRQ_END; i++) {
> + pirq = platform_get_irq(pdev, i);
> + info->irq[i] = regmap_irq_get_virq(info->regmap_irqc, pirq);
> + if (info->irq[i] < 0) {
> + dev_warn(&pdev->dev,
> + "regmap_irq get virq failed for IRQ %d: %d\n",

I recommend that you use the consistency log pattern as following:
"failed to get virtual interrupt ..."

> + pirq, info->irq[i]);
> + info->irq[i] = -1;
> + goto intr_reg_failed;

Use 'gpio_req_failed' instead of 'intr_reg_failed'.

> + }
> +
> + ret = devm_request_threaded_irq(&pdev->dev, info->irq[i],
> + NULL, axp288_extcon_isr,
> + IRQF_ONESHOT | IRQF_NO_SUSPEND,
> + pdev->name, info);
> + if (ret) {
> + dev_err(&pdev->dev, "request_irq fail :%d err:%d\n",

ditto. "failed to request interrupt

> + info->irq[i], ret);
> + goto intr_reg_failed;

Use 'gpio_req_failed' instead of 'intr_reg_failed'.

> + }
> + }
> +
> + /* Enable interrupts */
> + axp288_extcon_enable_irq(info);
> +
> + return 0;
> +
> +intr_reg_failed:

'intr_reg_failed' is not necessary. I prefer to remove it.

> +gpio_req_failed:
> + usb_put_phy(info->otg);
> + return ret;
> +}
> +
> +static int axp288_extcon_remove(struct platform_device *pdev)
> +{
> + struct axp288_extcon_info *info = platform_get_drvdata(pdev);
> +
> + usb_put_phy(info->otg);
> + return 0;
> +}
> +
> +static struct platform_driver axp288_extcon_driver = {
> + .probe = axp288_extcon_probe,
> + .remove = axp288_extcon_remove,
> + .driver = {
> + .name = "axp288_extcon",
> + },
> +};
> +module_platform_driver(axp288_extcon_driver);
> +
> +MODULE_AUTHOR("Ramakrishna Pallala <ramakrishna.pallala@xxxxxxxxx>");
> +MODULE_DESCRIPTION("X-Powers AXP288 extcon driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/axp20x.h b/include/linux/mfd/axp20x.h
> index dfabd6d..4ed8071 100644
> --- a/include/linux/mfd/axp20x.h
> +++ b/include/linux/mfd/axp20x.h
> @@ -275,4 +275,9 @@ struct axp20x_fg_pdata {
> int thermistor_curve[MAX_THERM_CURVE_SIZE][2];
> };
>
> +struct axp288_extcon_pdata {
> + /* GPIO pin control to switch D+/D- lines b/w PMIC and SOC */
> + struct gpio_desc *gpio_mux_cntl;
> +};
> +
> #endif /* __LINUX_MFD_AXP20X_H */

Thanks,
Chanwoo Choi
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