linux-kernel - Re: [PATCHv4 09/13] mfd: rk8xx: add rk806 support

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Message-ID: <Y1/V3GOIPoqMgBUO@google.com>
Date:   Mon, 31 Oct 2022 14:04:12 +0000
From:   Lee Jones <lee@...nel.org>
To:     Sebastian Reichel <sebastian.reichel@...labora.com>
Cc:     Heiko Stuebner <heiko@...ech.de>, Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        linux-rockchip@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel@...labora.com
Subject: Re: [PATCHv4 09/13] mfd: rk8xx: add rk806 support

On Thu, 20 Oct 2022, Sebastian Reichel wrote:

> Add support for SPI connected rk806, which is used by the RK3588
> evaluation boards. The PMIC is advertised to support I2C and SPI,
> but the evaluation boards all use SPI. Thus only SPI support is
> added here.
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
> ---

Change log?  What happened over the previous 4 iterations?

>  drivers/mfd/Kconfig       |  14 ++
>  drivers/mfd/Makefile      |   1 +
>  drivers/mfd/rk8xx-core.c  |  67 ++++++-
>  drivers/mfd/rk8xx-spi.c   | 115 +++++++++++
>  include/linux/mfd/rk808.h | 409 ++++++++++++++++++++++++++++++++++++++
>  5 files changed, 604 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/mfd/rk8xx-spi.c

[...]

> @@ -0,0 +1,115 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Rockchip RK806 Core (SPI) driver
> + *
> + * Copyright (c) 2021 Rockchip Electronics Co., Ltd.
> + *
> + * Author: Xu Shengfei <xsf@...k-chips.com>
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/rk808.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/spi/spi.h>
> +
> +static const struct regmap_range rk806_volatile_ranges[] = {
> +	regmap_reg_range(RK806_POWER_EN0, RK806_POWER_EN5),
> +	regmap_reg_range(RK806_DVS_START_CTRL, RK806_INT_MSK1),
> +};
> +
> +static const struct regmap_access_table rk806_volatile_table = {
> +	.yes_ranges = rk806_volatile_ranges,
> +	.n_yes_ranges = ARRAY_SIZE(rk806_volatile_ranges),
> +};
> +
> +static const struct regmap_config rk806_regmap_config_spi = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.cache_type = REGCACHE_RBTREE,
> +	.volatile_table = &rk806_volatile_table,
> +};
> +
> +static int rk806_spi_bus_write(void *context, const void *vdata, size_t count)
> +{
> +	struct device *dev = context;
> +	struct spi_device *spi = to_spi_device(dev);
> +	const char *data = vdata;
> +	char buffer[4] = { 0 };
> +
> +	/* implementation currently only supports single write */
> +	if (count != 2)
> +		return -EINVAL;

Is this a H/W limitation?

> +	buffer[0] = RK806_CMD_WRITE | (count - 2);
> +	buffer[1] = data[0]; /* register address */

You can make these clearer by defining the indexes.

> +	buffer[2] = RK806_REG_H;
> +	buffer[3] = data[1]; /* register value */
> +
> +	return spi_write(spi, &buffer, sizeof(buffer));
> +}
> +
> +static int rk806_spi_bus_read(void *context, const void *vreg, size_t reg_size,
> +			      void *val, size_t val_size)
> +{
> +	struct device *dev = context;
> +	struct spi_device *spi = to_spi_device(dev);
> +	const char *reg = vreg;
> +	char txbuf[3] = { 0 };
> +
> +	if (reg_size != sizeof(char) || val_size < 1)
> +		return -EINVAL;
> +
> +	txbuf[0] = RK806_CMD_READ | (val_size - 1);
> +	txbuf[1] = *reg;
> +	txbuf[2] = RK806_REG_H;
> +
> +	return spi_write_then_read(spi, txbuf, sizeof(txbuf), val, val_size);
> +}
> +
> +static const struct regmap_bus rk806_regmap_bus_spi = {
> +	.write = rk806_spi_bus_write,
> +	.read = rk806_spi_bus_read,
> +	.reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,
> +};
> +
> +static int rk8xx_spi_probe(struct spi_device *spi)
> +{
> +	struct regmap *regmap;
> +
> +	regmap = devm_regmap_init(&spi->dev, &rk806_regmap_bus_spi,
> +				  &spi->dev, &rk806_regmap_config_spi);
> +	if (IS_ERR(regmap))
> +		return dev_err_probe(&spi->dev, PTR_ERR(regmap),
> +				     "Failed to initialize register map\n");
> +
> +	return rk8xx_probe(&spi->dev, RK806_ID, spi->irq, regmap);
> +}
> +
> +static const struct of_device_id rk8xx_spi_of_match[] = {
> +	{ .compatible = "rockchip,rk806", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, rk8xx_spi_of_match);
> +
> +static const struct spi_device_id rk8xx_spi_id_table[] = {
> +	{ "rk806", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(spi, rk8xx_spi_id_table);

Are these simple tables required for SPI?

Is there anything akin to I2C's probe_new that you could use?

> +static struct spi_driver rk8xx_spi_driver = {
> +	.driver		= {
> +		.name	= "rk8xx-spi",
> +		.of_match_table = rk8xx_spi_of_match,
> +	},
> +	.probe		= rk8xx_spi_probe,
> +	.id_table	= rk8xx_spi_id_table,
> +};
> +module_spi_driver(rk8xx_spi_driver);
> +
> +MODULE_AUTHOR("Xu Shengfei <xsf@...k-chips.com>");
> +MODULE_DESCRIPTION("RK8xx SPI PMIC driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h
> index 4183427a80fe..78e167a92483 100644
> --- a/include/linux/mfd/rk808.h
> +++ b/include/linux/mfd/rk808.h

[...]

-- 
Lee Jones [李琼斯]