Re: [linux-sunxi] [PATCH 02/10] regulator: add support for SY8106A regulator

icenowy
2017-07-24T03:18:15Z

在 2017-07-24 11:03，Chen-Yu Tsai 写道：
> On Sun, Jul 23, 2017 at 6:27 PM, Icenowy Zheng <icenowy@aosc.io> wrote:
>> From: Ondrej Jirman <megous@megous.com>
>>
>> SY8106A is an I2C attached single output regulator made by Silergy
>> Corp,
>> which is used on several Allwinner H3/H5 SBCs to control the power
>> supply of the ARM cores.
>>
>> Add a driver for it.
>>
>> Signed-off-by: Ondrej Jirman <megous@megous.com>
>> [Icenowy: Change commit message]
>> Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
>> ---
>> drivers/regulator/Kconfig | 8 +-
>> drivers/regulator/Makefile | 2 +-
>> drivers/regulator/sy8106a-regulator.c | 163
>> ++++++++++++++++++++++++++++++++++
>> 3 files changed, 171 insertions(+), 2 deletions(-)
>> create mode 100644 drivers/regulator/sy8106a-regulator.c
>>
>> diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
>> index 99b9362331b5..1efa73e18d07 100644
>> --- a/drivers/regulator/Kconfig
>> +++ b/drivers/regulator/Kconfig
>> @@ -764,6 +764,13 @@ config REGULATOR_STW481X_VMMC
>> This driver supports the internal VMMC regulator in the
>> STw481x
>> PMIC chips.
>>
>> +config REGULATOR_SY8106A
>> + tristate "Silergy SY8106A regulator"
>> + depends on I2C && (OF || COMPILE_TEST)
>> + select REGMAP_I2C
>> + help
>> + This driver supports SY8106A single output regulator.
>> +
>> config REGULATOR_TPS51632
>> tristate "TI TPS51632 Power Regulator"
>> depends on I2C
>> @@ -938,4 +945,3 @@ config REGULATOR_WM8994
>> WM8994 CODEC.
>>
>> endif
>> -
>> diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
>> index 95b1e86ae692..f5120252f86a 100644
>> --- a/drivers/regulator/Makefile
>> +++ b/drivers/regulator/Makefile
>> @@ -95,6 +95,7 @@ obj-$(CONFIG_REGULATOR_S2MPS11) += s2mps11.o
>> obj-$(CONFIG_REGULATOR_S5M8767) += s5m8767.o
>> obj-$(CONFIG_REGULATOR_SKY81452) += sky81452-regulator.o
>> obj-$(CONFIG_REGULATOR_STW481X_VMMC) += stw481x-vmmc.o
>> +obj-$(CONFIG_REGULATOR_SY8106A) += sy8106a-regulator.o
>> obj-$(CONFIG_REGULATOR_TI_ABB) += ti-abb-regulator.o
>> obj-$(CONFIG_REGULATOR_TPS6105X) += tps6105x-regulator.o
>> obj-$(CONFIG_REGULATOR_TPS62360) += tps62360-regulator.o
>> @@ -120,5 +121,4 @@ obj-$(CONFIG_REGULATOR_WM8350) +=
>> wm8350-regulator.o
>> obj-$(CONFIG_REGULATOR_WM8400) += wm8400-regulator.o
>> obj-$(CONFIG_REGULATOR_WM8994) += wm8994-regulator.o
>>
>> -
>> ccflags-$(CONFIG_REGULATOR_DEBUG) += -DDEBUG
>> diff --git a/drivers/regulator/sy8106a-regulator.c
>> b/drivers/regulator/sy8106a-regulator.c
>> new file mode 100644
>> index 000000000000..1df889f68b3d
>> --- /dev/null
>> +++ b/drivers/regulator/sy8106a-regulator.c
>> @@ -0,0 +1,163 @@
>> +/*
>> + * sy8106a-regulator.c - Regulator device driver for SY8106A
>> + *
>> + * Copyright (C) 2016 Ondřej Jirman <megous@megous.com>
>> + *
>> + * This program is free software; you can redistribute it and/or
>> + * modify it under the terms of the GNU Library General Public
>> + * License as published by the Free Software Foundation; either
>> + * version 2 of the License, or (at your option) any later version.
>> + *
>> + * 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
>> + * Library General Public License for more details.
>> + */
>> +
>> +#include <linux/err.h>
>> +#include <linux/i2c.h>
>> +#include <linux/module.h>
>> +#include <linux/regmap.h>
>> +#include <linux/regulator/driver.h>
>> +#include <linux/regulator/of_regulator.h>
>> +
>> +#define SY8106A_REG_VOUT1_SEL 0x01
>> +#define SY8106A_REG_VOUT_COM 0x02
>> +#define SY8106A_REG_VOUT1_SEL_MASK 0x7f
>> +#define SY8106A_DISABLE_REG BIT(0)
>> +#define SY8106A_GO_BIT BIT(7)
>> +
>> +struct sy8106a {
>> + struct regulator_dev *rdev;
>> + struct regmap *regmap;
>> +};
>> +
>> +static const struct regmap_config sy8106a_regmap_config = {
>> + .reg_bits = 8,
>> + .val_bits = 8,
>> +};
>> +
>> +static int sy8106a_set_voltage_sel(struct regulator_dev *rdev,
>> unsigned int sel)
>> +{
>> + /* We use our set_voltage_sel in order to avoid unnecessary
>> I2C
>> + * chatter, because the regulator_get_voltage_sel_regmap using
>> + * apply_bit would perform 4 unnecessary transfers instead of
>> one,
>> + * increasing the chance of error.
>> + */
>> + return regmap_write(rdev->regmap, rdev->desc->vsel_reg,
>> + sel | SY8106A_GO_BIT);
>
> There should also be an explanation of what the "go bit" does.
> In this case it enables control of the voltage over I2C.
>
>> +}
>> +
>> +static const struct regulator_ops sy8106a_ops = {
>> + .is_enabled = regulator_is_enabled_regmap,
>> + .set_voltage_sel = sy8106a_set_voltage_sel,
>> + .set_voltage_time_sel = regulator_set_voltage_time_sel,
>> + .get_voltage_sel = regulator_get_voltage_sel_regmap,
>> + .list_voltage = regulator_list_voltage_linear,
>
> No enable/disable ops?
>
>> +};
>> +
>> +/* Default limits measured in millivolts and milliamps */
>> +#define SY8106A_MIN_MV 680
>> +#define SY8106A_MAX_MV 1950
>> +#define SY8106A_STEP_MV 10
>> +
>> +static const struct regulator_desc sy8106a_reg = {
>> + .name = "SY8106A",
>> + .id = 0,
>> + .ops = &sy8106a_ops,
>> + .type = REGULATOR_VOLTAGE,
>> + .n_voltages = ((SY8106A_MAX_MV - SY8106A_MIN_MV) /
>> SY8106A_STEP_MV) + 1,
>> + .min_uV = (SY8106A_MIN_MV * 1000),
>> + .uV_step = (SY8106A_STEP_MV * 1000),
>> + .vsel_reg = SY8106A_REG_VOUT1_SEL,
>> + .vsel_mask = SY8106A_REG_VOUT1_SEL_MASK,
>> + .enable_reg = SY8106A_REG_VOUT_COM,
>> + .enable_mask = SY8106A_DISABLE_REG,
>> + .disable_val = SY8106A_DISABLE_REG,
>> + .enable_is_inverted = 1,
>
> As the regulator core helpers currently are, there is no way to disable
> this regulator. regulator_disable_regmap looks like:

By reading the current code, I think removing the disable_val variable
will
just make it work -- when enabling, the enable_reg will be set to
disable_val
(as enable_is_inverted is 1), and disable_val is defaultly 0; when
disabling,
the enable_reg will be set to enable_mask (fallbacked from enable_val,
which
is also the default value 0), and the regulator successfully get
disabled.

>
> if (rdev->desc->enable_is_inverted) {
> val = rdev->desc->enable_val;
> if (!val)
> val = rdev->desc->enable_mask;
> } else {
> val = rdev->desc->disable_val;
> }
>
> return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
> rdev->desc->enable_mask, val);
>
> Note the fallback to enable_mask if enable_val is not set. The enable
> helper has a similar structure. This regulator uses an enable value
> of 0, and disable value of 1, it is impossible to get it right. As
> it is now, it doesn't really make sense to me.
>
> The code was introduced in ca5d1b3524b4 ("regulator: helpers: Modify
> helpers enabling multi-bit control"). I wonder if it was an unintended
> consequence of the change? (original author CC-ed)
>
>> + .owner = THIS_MODULE,
>> +};
>> +
>> +/*
>> + * I2C driver interface functions
>> + */
>> +static int sy8106a_i2c_probe(struct i2c_client *i2c,
>> + const struct i2c_device_id *id)
>> +{
>> + struct sy8106a *chip;
>> + struct device *dev = &i2c->dev;
>> + struct regulator_dev *rdev = NULL;
>> + struct regulator_config config = { };
>> + unsigned int selector;
>> + int error;
>> +
>> + chip = devm_kzalloc(&i2c->dev, sizeof(struct sy8106a),
>> GFP_KERNEL);
>> + if (!chip)
>> + return -ENOMEM;
>> +
>> + chip->regmap = devm_regmap_init_i2c(i2c,
>> &sy8106a_regmap_config);
>> + if (IS_ERR(chip->regmap)) {
>> + error = PTR_ERR(chip->regmap);
>> + dev_err(&i2c->dev, "Failed to allocate register map:
>> %d\n",
>> + error);
>> + return error;
>> + }
>> +
>> + config.dev = &i2c->dev;
>> + config.regmap = chip->regmap;
>> + config.driver_data = chip;
>> +
>> + config.of_node = dev->of_node;
>> + config.init_data = of_get_regulator_init_data(dev,
>> dev->of_node,
>> + &sy8106a_reg);
>> +
>> + if (!config.init_data)
>> + return -ENOMEM;
>> +
>> + /* Probe regulator */
>> + error = regmap_read(chip->regmap, SY8106A_REG_VOUT1_SEL,
>> &selector);
>> + if (error) {
>> + dev_err(&i2c->dev, "Failed to read voltage at probe
>> time: %d\n", error);
>> + return error;
>> + }
>> +
>> + rdev = devm_regulator_register(&i2c->dev, &sy8106a_reg,
>> &config);
>> + if (IS_ERR(rdev)) {
>> + error = PTR_ERR(rdev);
>> + dev_err(&i2c->dev, "Failed to register SY8106A
>> regulator: %d\n", error);
>> + return error;
>> + }
>> +
>> + chip->rdev = rdev;
>> +
>> + i2c_set_clientdata(i2c, chip);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id sy8106a_i2c_of_match[] = {
>> + { .compatible = "silergy,sy8106a" },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(of, sy8106a_i2c_of_match);
>> +
>> +static const struct i2c_device_id sy8106a_i2c_id[] = {
>> + { "sy8106a", 0 },
>> + { },
>> +};
>> +MODULE_DEVICE_TABLE(i2c, sy8106a_i2c_id);
>> +
>> +static struct i2c_driver sy8106a_regulator_driver = {
>> + .driver = {
>> + .name = "sy8106a",
>> + .of_match_table = of_match_ptr(sy8106a_i2c_of_match),
>> + },
>> + .probe = sy8106a_i2c_probe,
>> + .id_table = sy8106a_i2c_id,
>> +};
>> +
>> +module_i2c_driver(sy8106a_regulator_driver);
>> +
>> +MODULE_AUTHOR("Ondřej Jirman <megous@megous.com>");
>> +MODULE_DESCRIPTION("Regulator device driver for Silergy SY8106A");
>> +MODULE_LICENSE("GPL v2");
>
> This should be "GPL", to match what the license at the very top says.
>
> Regards
> ChenYu
>
>> --
>> 2.13.0
>>
>> --
>> You received this message because you are subscribed to the Google
>> Groups "linux-sunxi" group.
>> To unsubscribe from this group and stop receiving emails from it, send
>> an email to linux-sunxi+unsubscribe@googlegroups.com.
>> For more options, visit https://groups.google.com/d/optout.
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel