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Message-ID: <697597b2-088d-9ffb-54bd-e50b3ca8c012@st.com>
Date: Wed, 8 May 2019 14:44:10 +0000
From: Amelie DELAUNAY <amelie.delaunay@...com>
To: Lee Jones <lee.jones@...aro.org>
CC: Linus Walleij <linus.walleij@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexandre TORGUE <alexandre.torgue@...com>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-stm32@...md-mailman.stormreply.com"
<linux-stm32@...md-mailman.stormreply.com>
Subject: Re: [PATCH v5 2/9] mfd: Add ST Multi-Function eXpander (STMFX) core
driver
On 5/8/19 10:36 AM, Lee Jones wrote:
> On Tue, 09 Apr 2019, Amelie Delaunay wrote:
>
>> STMicroelectronics Multi-Function eXpander (STMFX) is a slave controller
>> using I2C for communication with the main MCU. Main features are:
>> - 16 fast GPIOs individually configurable in input/output
>> - 8 alternate GPIOs individually configurable in input/output when other
>> STMFX functions are not used
>> - Main MCU IDD measurement
>> - Resistive touchscreen controller
>>
>> Signed-off-by: Amelie Delaunay <amelie.delaunay@...com>
>> ---
>> drivers/mfd/Kconfig | 13 ++
>> drivers/mfd/Makefile | 2 +-
>> drivers/mfd/stmfx.c | 566 ++++++++++++++++++++++++++++++++++++++++++++++
>> include/linux/mfd/stmfx.h | 123 ++++++++++
>> 4 files changed, 703 insertions(+), 1 deletion(-)
>> create mode 100644 drivers/mfd/stmfx.c
>> create mode 100644 include/linux/mfd/stmfx.h
>>
>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index 3443f1a..9783e18 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -1907,6 +1907,19 @@ config MFD_STPMIC1
>> To compile this driver as a module, choose M here: the
>> module will be called stpmic1.
>>
>> +config MFD_STMFX
>> + tristate "Support for STMicroelectronics Multi-Function eXpander (STMFX)"
>> + depends on I2C
>> + depends on OF || COMPILE_TEST
>> + select MFD_CORE
>> + select REGMAP_I2C
>> + help
>> + Support for the STMicroelectronics Multi-Function eXpander.
>> +
>> + This driver provides common support for accessing the device,
>> + additional drivers must be enabled in order to use the functionality
>> + of the device.
>> +
>> menu "Multimedia Capabilities Port drivers"
>> depends on ARCH_SA1100
>>
>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>> index b4569ed7..614eea8 100644
>> --- a/drivers/mfd/Makefile
>> +++ b/drivers/mfd/Makefile
>> @@ -246,4 +246,4 @@ obj-$(CONFIG_MFD_MXS_LRADC) += mxs-lradc.o
>> obj-$(CONFIG_MFD_SC27XX_PMIC) += sprd-sc27xx-spi.o
>> obj-$(CONFIG_RAVE_SP_CORE) += rave-sp.o
>> obj-$(CONFIG_MFD_ROHM_BD718XX) += rohm-bd718x7.o
>> -
>> +obj-$(CONFIG_MFD_STMFX) += stmfx.o
>> diff --git a/drivers/mfd/stmfx.c b/drivers/mfd/stmfx.c
>> new file mode 100644
>> index 0000000..59f0a03
>> --- /dev/null
>> +++ b/drivers/mfd/stmfx.c
>> @@ -0,0 +1,566 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Driver for STMicroelectronics Multi-Function eXpander (STMFX) core
>> + *
>> + * Copyright (C) 2019 STMicroelectronics
>> + * Author(s): Amelie Delaunay <amelie.delaunay@...com>.
>> + */
>> +#include <linux/bitfield.h>
>> +#include <linux/i2c.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/irq.h>
>> +#include <linux/mfd/core.h>
>> +#include <linux/mfd/stmfx.h>
>> +#include <linux/module.h>
>> +#include <linux/regulator/consumer.h>
>
> [...]
>
>> +static int stmfx_chip_init(struct i2c_client *client)
>> +{
>> + struct stmfx *stmfx = i2c_get_clientdata(client);
>> + u32 id;
>> + u8 version[2];
>> + int ret;
>> +
>> + stmfx->vdd = devm_regulator_get_optional(&client->dev, "vdd");
>> + if (IS_ERR(stmfx->vdd)) {
>> + ret = PTR_ERR(stmfx->vdd);
>> + if (ret != -ENODEV) {
>> + if (ret != -EPROBE_DEFER)
>> + dev_err(&client->dev,
>> + "Can't get VDD regulator:%d\n", ret);
>> + return ret;
>> + }
>
> Any reason you've decided to stick with this 3-layer nested if instead
> of going with my suggestion?
>
Sorry, I didn't see your suggestion. I'll go with it in v6.
>> + } else {
>> + ret = regulator_enable(stmfx->vdd);
>> + if (ret) {
>> + dev_err(&client->dev, "VDD enable failed: %d\n", ret);
>> + return ret;
>> + }
>> + }
>
> [...]
>
>> +#ifdef CONFIG_PM_SLEEP
>> +static int stmfx_backup_regs(struct stmfx *stmfx)
>> +{
>> + int ret;
>> +
>> + ret = regmap_raw_read(stmfx->map, STMFX_REG_SYS_CTRL,
>> + &stmfx->bkp_sysctrl, sizeof(stmfx->bkp_sysctrl));
>> + if (ret)
>> + return ret;
>> +
>> + ret = regmap_raw_read(stmfx->map, STMFX_REG_IRQ_OUT_PIN,
>> + &stmfx->bkp_irqoutpin,
>> + sizeof(stmfx->bkp_irqoutpin));
>> + if (ret)
>> + return ret;
>> +
>> + return 0;
>> +}
>> +
>> +static int stmfx_restore_regs(struct stmfx *stmfx)
>> +{
>> + int ret;
>> +
>> + ret = regmap_raw_write(stmfx->map, STMFX_REG_SYS_CTRL,
>> + &stmfx->bkp_sysctrl, sizeof(stmfx->bkp_sysctrl));
>> + if (ret)
>> + return ret;
>> +
>> + ret = regmap_raw_write(stmfx->map, STMFX_REG_IRQ_OUT_PIN,
>> + &stmfx->bkp_irqoutpin,
>> + sizeof(stmfx->bkp_irqoutpin));
>> + if (ret)
>> + return ret;
>> +
>> + ret = regmap_raw_write(stmfx->map, STMFX_REG_IRQ_SRC_EN,
>> + &stmfx->irq_src, sizeof(stmfx->irq_src));
>> + if (ret)
>> + return ret;
>> +
>> + return 0;
>> +}
>> +
>> +static int stmfx_suspend(struct device *dev)
>> +{
>> + struct stmfx *stmfx = dev_get_drvdata(dev);
>> + int ret;
>> +
>> + ret = stmfx_backup_regs(stmfx);
>> + if (ret) {
>> + dev_err(stmfx->dev, "Registers backup failure\n");
>> + return ret;
>> + }
>
> This doesn't need to be an extra function. You're just adding more
> lines of code for no real gain in reusability/readability.
>
I used a separate function to have only one dev_err in case of
backup/restore failure.
But anyway, I'll drop backup/restore functions and put the code in
suspend/resume.
>> + if (!IS_ERR(stmfx->vdd)) {
>> + ret = regulator_disable(stmfx->vdd);
>> + if (ret)
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int stmfx_resume(struct device *dev)
>> +{
>> + struct stmfx *stmfx = dev_get_drvdata(dev);
>> + int ret;
>> +
>> + if (!IS_ERR(stmfx->vdd)) {
>> + ret = regulator_enable(stmfx->vdd);
>> + if (ret) {
>> + dev_err(stmfx->dev,
>> + "VDD enable failed: %d\n", ret);
>> + return ret;
>> + }
>> + }
>> +
>> + ret = stmfx_restore_regs(stmfx);
>> + if (ret) {
>> + dev_err(stmfx->dev, "Registers restoration failure\n");
>> + return ret;
>> + }
>
> This doesn't need to be an extra function. You're just adding more
> lines of code for no real gain in reusability/readability.
>
>> + return 0;
>> +}
>> +#endif
>
> [...]
>
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