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SubjectRe: [PATCH] mfd: Add support for CPLD chip on Mikrotik RB4xx boards
From
On Mon, Apr 6, 2015 at 4:51 AM, Bert Vermeulen <bert@biot.com> wrote:
> The SPI-connected CPLD chip controls access to the main NAND flash
> chip and five LEDs.
>

Few comments below.

> Signed-off-by: Bert Vermeulen <bert@biot.com>
> ---
> arch/mips/include/asm/mach-ath79/rb4xx_cpld.h | 49 +++++
> drivers/mfd/Kconfig | 7 +
> drivers/mfd/Makefile | 1 +
> drivers/mfd/rb4xx-cpld.c | 279 ++++++++++++++++++++++++++
> 4 files changed, 336 insertions(+)
> create mode 100644 arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
> create mode 100644 drivers/mfd/rb4xx-cpld.c
>
> diff --git a/arch/mips/include/asm/mach-ath79/rb4xx_cpld.h b/arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
> new file mode 100644
> index 0000000..40c109c
> --- /dev/null
> +++ b/arch/mips/include/asm/mach-ath79/rb4xx_cpld.h
> @@ -0,0 +1,49 @@
> +/*
> + * SPI driver definitions for the CPLD chip on the Mikrotik RB4xx boards
> + *
> + * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
> + *
> + * This file was based on the patches for Linux 2.6.27.39 published by
> + * MikroTik for their RouterBoard 4xx series devices.
> + *
> + * 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.
> + */
> +
> +#define CPLD_GPIO_LED1 0
> +#define CPLD_GPIO_LED2 1
> +#define CPLD_GPIO_LED3 2
> +#define CPLD_GPIO_LED4 3
> +#define CPLD_GPIO_FAN 4
> +#define CPLD_GPIO_ALE 5
> +#define CPLD_GPIO_CLE 6
> +#define CPLD_GPIO_nCE 7
> +#define CPLD_GPIO_LED5 8
> +
> +#define CPLD_NUM_GPIOS 9
> +
> +#define CPLD_CFG_LED1 BIT(CPLD_GPIO_LED1)
> +#define CPLD_CFG_LED2 BIT(CPLD_GPIO_LED2)
> +#define CPLD_CFG_LED3 BIT(CPLD_GPIO_LED3)
> +#define CPLD_CFG_LED4 BIT(CPLD_GPIO_LED4)
> +#define CPLD_CFG_FAN BIT(CPLD_GPIO_FAN)
> +#define CPLD_CFG_ALE BIT(CPLD_GPIO_ALE)
> +#define CPLD_CFG_CLE BIT(CPLD_GPIO_CLE)
> +#define CPLD_CFG_nCE BIT(CPLD_GPIO_nCE)
> +#define CPLD_CFG_LED5 BIT(CPLD_GPIO_LED5)
> +
> +#define CPLD_CMD_WRITE_NAND 0x08 /* send cmd, n x send data, send idle */
> +#define CPLD_CMD_WRITE_CFG 0x09 /* send cmd, n x send cfg */
> +#define CPLD_CMD_READ_NAND 0x0a /* send cmd, send idle, n x read data */
> +#define CPLD_CMD_READ_FAST 0x0b /* send cmd, 4 x idle, n x read data */
> +#define CPLD_CMD_LED5_ON 0x0c /* send cmd */
> +#define CPLD_CMD_LED5_OFF 0x0d /* send cmd */
> +
> +struct rb4xx_cpld_platform_data {
> + unsigned gpio_base;
> +};
> +
> +extern int rb4xx_cpld_read(struct spi_device *spi, unsigned char *rx_buf,
> + unsigned len);
> +extern int rb4xx_cpld_write(struct spi_device *spi, const u8 *buf, int len);
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 38356e3..c4a6a4e 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -631,6 +631,13 @@ config MFD_SPMI_PMIC
> Say M here if you want to include support for the SPMI PMIC
> series as a module. The module will be called "qcom-spmi-pmic".
>
> +config MFD_RB4XX_CPLD
> + tristate "MikroTik RB4XX CPLD driver"
> + depends on ATH79 && SPI_RB4XX
> + help
> + Driver for the CPLD chip present on MikroTik RB4xx boards.
> + It controls CPU access to NAND flash and user LEDs.
> +
> config MFD_RDC321X
> tristate "RDC R-321x southbridge"
> select MFD_CORE
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 19f3d74..6cc9fe3 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -155,6 +155,7 @@ obj-$(CONFIG_MFD_OMAP_USB_HOST) += omap-usb-host.o omap-usb-tll.o
> obj-$(CONFIG_MFD_PM8921_CORE) += pm8921-core.o ssbi.o
> obj-$(CONFIG_MFD_QCOM_RPM) += qcom_rpm.o
> obj-$(CONFIG_MFD_SPMI_PMIC) += qcom-spmi-pmic.o
> +obj-$(CONFIG_MFD_RB4XX_CPLD) += rb4xx-cpld.o
> obj-$(CONFIG_TPS65911_COMPARATOR) += tps65911-comparator.o
> obj-$(CONFIG_MFD_TPS65090) += tps65090.o
> obj-$(CONFIG_MFD_AAT2870_CORE) += aat2870-core.o
> diff --git a/drivers/mfd/rb4xx-cpld.c b/drivers/mfd/rb4xx-cpld.c
> new file mode 100644
> index 0000000..0f8de62
> --- /dev/null
> +++ b/drivers/mfd/rb4xx-cpld.c
> @@ -0,0 +1,279 @@
> +/*
> + * SPI driver for the CPLD chip on the Mikrotik RB4xx boards
> + *
> + * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
> + *
> + * This file was based on the patches for Linux 2.6.27.39 published by
> + * MikroTik for their RouterBoard 4xx series devices.
> + *
> + * 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/types.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/device.h>
> +#include <linux/bitops.h>
> +#include <linux/spi/spi.h>
> +#include <linux/gpio.h>
> +#include <linux/slab.h>
> +
> +#include <asm/mach-ath79/rb4xx_cpld.h>
> +
> +struct rb4xx_cpld {
> + struct spi_device *spi;
> + struct mutex lock;
> + struct gpio_chip chip;
> + unsigned int config;
> +};
> +
> +static inline struct rb4xx_cpld *gpio_to_cpld(struct gpio_chip *chip)
> +{
> + return container_of(chip, struct rb4xx_cpld, chip);
> +}
> +
> +static int rb4xx_cpld_write_cmd(struct rb4xx_cpld *cpld, unsigned char cmd)
> +{
> + struct spi_transfer t[1];

Just t. And modify below accordingly.

> + struct spi_message m;
> + unsigned char tx_buf[1];
> + int err;
> +
> + spi_message_init(&m);
> + memset(&t, 0, sizeof(t));
> +
> + t[0].tx_buf = tx_buf;
> + t[0].len = sizeof(tx_buf);
> + spi_message_add_tail(&t[0], &m);

> +
> + tx_buf[0] = cmd;
> +
> + err = spi_sync(cpld->spi, &m);
> + return err;

There is no point for two lines and err variable.

> +}
> +
> +static int rb4xx_cpld_write_cfg(struct rb4xx_cpld *cpld, unsigned char config)
> +{
> + struct spi_transfer t[1];

Same as for previous.


> + struct spi_message m;
> + unsigned char cmd[2];

Can you keep similar name as in previous function? Either cmd or tx_buf.

> + int err;
> +
> + spi_message_init(&m);
> + memset(&t, 0, sizeof(t));
> +
> + t[0].tx_buf = cmd;
> + t[0].len = sizeof(cmd);
> + spi_message_add_tail(&t[0], &m);
> +
> + cmd[0] = CPLD_CMD_WRITE_CFG;
> + cmd[1] = config;
> +
> + err = spi_sync(cpld->spi, &m);
> + return err;

Same as for previous.

> +}
> +
> +static int rb4xx_cpld_change_cfg(struct rb4xx_cpld *cpld, u32 mask, u32 value)
> +{
> + unsigned int config;
> + int err;
> +
> + config = cpld->config & ~mask;
> + config |= value;
> +
> + if ((cpld->config ^ config) & 0xff) {
> + err = rb4xx_cpld_write_cfg(cpld, config);
> + if (err)
> + return err;
> + }
> +
> + if ((cpld->config ^ config) & CPLD_CFG_LED5) {
> + err = rb4xx_cpld_write_cmd(cpld, (value) ? CPLD_CMD_LED5_ON :
> + CPLD_CMD_LED5_OFF);
> + if (err)
> + return err;
> + }
> +
> + cpld->config = config;
> + return 0;
> +}
> +
> +int rb4xx_cpld_read(struct spi_device *spi, unsigned char *rx_buf, unsigned len)
> +{
> + struct spi_message m;
> + static const unsigned char cmd[2] = { CPLD_CMD_READ_NAND, 0 };

Why different style of assignment across functions?

> + struct spi_transfer t[2] = {
> + {
> + .tx_buf = &cmd,
> + .len = 2,
> + }, {
> + .rx_buf = rx_buf,
> + .len = len,
> + },
> + };
> +
> + spi_message_init(&m);
> + spi_message_add_tail(&t[0], &m);
> + spi_message_add_tail(&t[1], &m);
> + return spi_sync(spi, &m);
> +}
> +EXPORT_SYMBOL_GPL(rb4xx_cpld_read);
> +
> +/* The cs_change flag indicates to the spi-rb4xx driver to use "fast mode". */
> +int rb4xx_cpld_write(struct spi_device *spi, const u8 *buf, int len)
> +{
> + struct spi_message m;
> + static const unsigned char cmd = CPLD_CMD_WRITE_NAND;
> + static const unsigned char dummy = 0x00;
> + struct spi_transfer t[3] = {
> + {
> + .tx_buf = &cmd,

Ditto.

> + .len = 1,
> + }, {
> + .tx_buf = buf,
> + .len = len,
> + .cs_change = 1,
> + }, {
> + .tx_buf = &dummy,
> + .len = 1,
> + .cs_change = 1,
> + },
> + };
> +
> + spi_message_init(&m);
> + spi_message_add_tail(&t[0], &m);
> + spi_message_add_tail(&t[1], &m);
> + spi_message_add_tail(&t[2], &m);
> + return spi_sync(spi, &m);
> +}
> +EXPORT_SYMBOL_GPL(rb4xx_cpld_write);
> +
> +static int rb4xx_cpld_gpio_get(struct gpio_chip *chip, unsigned offset)
> +{
> + struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
> + int ret;
> +
> + mutex_lock(&cpld->lock);
> + ret = (cpld->config >> offset) & 1;
> + mutex_unlock(&cpld->lock);
> +
> + return ret;
> +}
> +
> +static void rb4xx_cpld_gpio_set(struct gpio_chip *chip,
> + unsigned offset, int value)
> +{
> + struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
> +
> + mutex_lock(&cpld->lock);
> + rb4xx_cpld_change_cfg(cpld, (1 << offset), !!value << offset);
> + mutex_unlock(&cpld->lock);
> +}
> +
> +static int rb4xx_cpld_gpio_direction_input(struct gpio_chip *chip,
> + unsigned offset)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +static int rb4xx_cpld_gpio_direction_output(struct gpio_chip *chip,
> + unsigned offset, int value)
> +{
> + struct rb4xx_cpld *cpld = gpio_to_cpld(chip);
> + int ret;
> +
> + mutex_lock(&cpld->lock);
> + ret = rb4xx_cpld_change_cfg(cpld, (1 << offset), !!value << offset);
> + mutex_unlock(&cpld->lock);
> +
> + return ret;
> +}
> +
> +static int rb4xx_cpld_gpio_init(struct rb4xx_cpld *cpld, unsigned int base)
> +{
> + int err;

In some it is err in other ret. Choose one for all.

> +
> + cpld->chip.label = "rb4xx-cpld";
> + cpld->chip.base = base;
> + cpld->chip.ngpio = CPLD_NUM_GPIOS;
> + cpld->chip.can_sleep = 1;
> + cpld->chip.dev = &cpld->spi->dev;

> + cpld->chip.owner = THIS_MODULE;

Do we really need this?

> + cpld->chip.get = rb4xx_cpld_gpio_get;
> + cpld->chip.set = rb4xx_cpld_gpio_set;
> + cpld->chip.direction_input = rb4xx_cpld_gpio_direction_input;
> + cpld->chip.direction_output = rb4xx_cpld_gpio_direction_output;
> +
> + err = gpiochip_add(&cpld->chip);
> + if (err)
> + dev_err(&cpld->spi->dev, "adding GPIO chip failed, error %d\n",
> + err);
> +
> + return err;
> +}
> +
> +static int rb4xx_cpld_probe(struct spi_device *spi)
> +{
> + struct rb4xx_cpld *cpld;
> + struct rb4xx_cpld_platform_data *pdata;
> + int err;
> +
> + pdata = spi->dev.platform_data;

Shouldn't be standard getter for this?

> + if (!pdata) {
> + dev_dbg(&spi->dev, "no platform data\n");

It's an error condition for the driver, so, following might help as
well as dev_err() here.

> + return -EINVAL;

I think -ENODATA suits better.

> + }
> +
> + cpld = devm_kzalloc(&spi->dev, sizeof(*cpld), GFP_KERNEL);
> + if (!cpld)
> + return -ENOMEM;
> +
> + mutex_init(&cpld->lock);
> + cpld->spi = spi_dev_get(spi);
> + dev_set_drvdata(&spi->dev, cpld);
> +
> + spi->mode = SPI_MODE_0;
> + err = spi_setup(spi);
> + if (err) {
> + dev_err(&spi->dev, "SPI setup failed, error %d\n", err);
> + return err;
> + }
> +
> + err = rb4xx_cpld_gpio_init(cpld, pdata->gpio_base);
> + if (err)
> + return err;
> +
> + return 0;

Too many lines:
return rb4xx_cpld_gpio_init();

> +}
> +
> +static int rb4xx_cpld_remove(struct spi_device *spi)
> +{
> + struct rb4xx_cpld_platform_data *pdata;
> + struct rb4xx_cpld *cpld;
> +
> + pdata = spi->dev.platform_data;

Same question as for probe.

> + cpld = dev_get_drvdata(&spi->dev);
> + mutex_destroy(&cpld->lock);
> +
> + return 0;
> +}
> +
> +static struct spi_driver rb4xx_cpld_driver = {
> + .probe = rb4xx_cpld_probe,
> + .remove = rb4xx_cpld_remove,
> + .driver = {
> + .name = "rb4xx-cpld",
> + .bus = &spi_bus_type,
> + .owner = THIS_MODULE,

Do we really need this line?

> + },
> +};
> +
> +module_spi_driver(rb4xx_cpld_driver);
> +
> +MODULE_DESCRIPTION("RB4xx CPLD driver");
> +MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
> +MODULE_LICENSE("GPL v2");
> --
> 1.9.1
>
> --
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--
With Best Regards,
Andy Shevchenko


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