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Message-ID: <9e4733910807022026r98f565brc84da873747a5631@mail.gmail.com>
Date: Wed, 2 Jul 2008 23:26:07 -0400
From: "Jon Smirl" <jonsmirl@...il.com>
To: "Anton Vorontsov" <avorontsov@...mvista.com>
Cc: "Pierre Ossman" <drzeus-mmc@...eus.cx>,
"David Brownell" <dbrownell@...rs.sourceforge.net>,
"Grant Likely" <grant.likely@...retlab.ca>,
"Jochen Friedrich" <jochen@...am.de>,
"Segher Boessenkool" <segher@...nel.crashing.org>,
"Gary Jennejohn" <garyj@...x.de>,
"Guennadi Liakhovetski" <g.liakhovetski@....de>,
linuxppc-dev@...abs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [RFC v3] OF: OpenFirmware bindings for the mmc_spi driver
On 6/5/08, Anton Vorontsov <avorontsov@...mvista.com> wrote:
> Here is v3. I'm out of ideas if you won't like it. :-)
>
> v3:
> - Now these bindings are using bus notifiers chain, thus we adhere to the
> spi bus.
>
> By the way, this scheme (IMO) looks good for I2C devices which needs
> platform_data extracted from the device tree too (Cc'ing Jochen).
>
> - Plus changed the OF bindings themselves, implemented voltage-range
> property. (Pierre, please take a look at vddrange_to_ocrmask(). I
> wonder if you would like this in the MMC core instead, with a kernel
> doc, of course.)
>
> v2:
> - Bindings were adhered to the MMC_SPI driver. Withdrawn by Pierre Ossman.
>
> v1:
> - Bindings were adhered to the OF SPI core. Withdrawn by OF people.
>
> Signed-off-by: Anton Vorontsov <avorontsov@...mvista.com>
> ---
> Documentation/powerpc/booting-without-of.txt | 21 +++
> drivers/of/Kconfig | 8 +
> drivers/of/Makefile | 1 +
> drivers/of/of_mmc_spi.c | 210 ++++++++++++++++++++++++++
> 4 files changed, 240 insertions(+), 0 deletions(-)
> create mode 100644 drivers/of/of_mmc_spi.c
>
> diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
> index 6e1711c..6c55f3f 100644
> --- a/Documentation/powerpc/booting-without-of.txt
> +++ b/Documentation/powerpc/booting-without-of.txt
> @@ -3143,7 +3143,28 @@ platforms are moved over to use the flattened-device-tree model.
> };
> };
>
> + ...) MMC-over-SPI
>
> + Required properties:
> + - compatible : should be "mmc-spi".
> + - reg : should specify SPI address (chip-select number).
> + - max-speed : (optional) maximum frequency for this device (Hz).
> + - voltage-range : two cells are required, first cell specifies minimum
> + slot voltage (mV), second cell specifies maximum slot voltage (mV).
> + - gpios : (optional) may specify GPIOs in this order: Write-Protect GPIO,
> + Card-Detect GPIO.
> +
> + Example:
> +
> + mmc-slot@0 {
> + compatible = "mmc-spi";
> + reg = <0>;
> + max-speed = <50000000>;
> + /* Unregulated slot. */
> + voltage-range = <3300 3300>;
> + gpios = <&sdcsr_pio 1 0 /* WP */
> + &sdcsr_pio 0 1>; /* nCD */
> + };
>
> VII - Marvell Discovery mv64[345]6x System Controller chips
> ===========================================================
> diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
> index 3a7a11a..aadbfb3 100644
> --- a/drivers/of/Kconfig
> +++ b/drivers/of/Kconfig
> @@ -13,3 +13,11 @@ config OF_I2C
> depends on PPC_OF && I2C
> help
> OpenFirmware I2C accessors
> +
> +config OF_MMC_SPI
> + bool "OpenFirmware bindings for MMC/SD over SPI"
> + depends on PPC_OF && SPI
> + default y if MMC_SPI
> + help
> + Say Y here to enable OpenFirmware bindings for the MMC/SD over SPI
> + driver.
> diff --git a/drivers/of/Makefile b/drivers/of/Makefile
> index 548772e..a7c44fc 100644
> --- a/drivers/of/Makefile
> +++ b/drivers/of/Makefile
> @@ -2,3 +2,4 @@ obj-y = base.o
> obj-$(CONFIG_OF_DEVICE) += device.o platform.o
> obj-$(CONFIG_OF_GPIO) += gpio.o
> obj-$(CONFIG_OF_I2C) += of_i2c.o
> +obj-$(CONFIG_OF_MMC_SPI) += of_mmc_spi.o
> diff --git a/drivers/of/of_mmc_spi.c b/drivers/of/of_mmc_spi.c
> new file mode 100644
> index 0000000..aa4e017
> --- /dev/null
> +++ b/drivers/of/of_mmc_spi.c
> @@ -0,0 +1,210 @@
> +/*
> + * OpenFirmware bindings for the MMC-over-SPI driver
> + *
> + * Copyright (c) MontaVista Software, Inc. 2008.
> + *
> + * Author: Anton Vorontsov <avorontsov@...mvista.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or (at your
> + * option) any later version.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/device.h>
> +#include <linux/notifier.h>
> +#include <linux/gpio.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_platform.h>
> +#include <linux/spi/spi.h>
> +#include <linux/spi/mmc_spi.h>
> +#include <linux/mmc/host.h>
> +
> +/*
> + * XXX: Place it somewhere in the generic MMC code?
> + */
> +static int vdd_to_bitnum(int vdd)
> +{
> + int bit;
> + const int max_bit = ilog2(MMC_VDD_35_36);
> +
> + if (vdd < 1650 || vdd > 3600)
> + return -EINVAL;
> +
> + if (vdd >= 1650 && vdd <= 1950)
> + return ilog2(MMC_VDD_165_195);
> +
> + /* base 2000 mV, step 100 mV, bit's base 8 */
> + bit = (vdd - 2000) / 100 + 8;
> + if (bit > max_bit)
> + return max_bit;
> + return bit;
> +}
> +
> +static int vddrange_to_ocrmask(int vdd_min, int vdd_max, unsigned int *mask)
> +{
> + if (vdd_max < vdd_min)
> + return -EINVAL;
> +
> + vdd_max = vdd_to_bitnum(vdd_max);
> + if (vdd_max < 0)
> + return -EINVAL;
> +
> + vdd_min = vdd_to_bitnum(vdd_min);
> + if (vdd_min < 0)
> + return -EINVAL;
> +
> + /* fill the mask, from max bit to min bit */
> + while (vdd_max >= vdd_min)
> + *mask |= 1 << vdd_max--;
> + return 0;
> +}
> +
> +struct of_mmc_spi {
> + int wp_gpio;
> + int cd_gpio;
> + struct mmc_spi_platform_data mmc_pdata;
> +};
> +
> +static struct of_mmc_spi *to_of_mmc_spi(struct device *dev)
> +{
> + return container_of(dev->platform_data, struct of_mmc_spi, mmc_pdata);
> +}
> +
> +static int mmc_get_ro(struct device *dev)
> +{
> + struct of_mmc_spi *oms = to_of_mmc_spi(dev);
> +
> + return gpio_get_value(oms->wp_gpio);
> +}
> +
> +static int mmc_get_cd(struct device *dev)
> +{
> + struct of_mmc_spi *oms = to_of_mmc_spi(dev);
> +
> + return gpio_get_value(oms->cd_gpio);
> +}
> +
> +static int of_mmc_spi_add(struct device *dev)
> +{
> + int ret = -EINVAL;
> + struct device_node *np = dev->archdata.of_node;
> + struct of_mmc_spi *oms;
> + const u32 *voltage_range;
> + int size;
> +
> + if (!np || !of_device_is_compatible(np, "mmc-spi"))
> + return NOTIFY_DONE;
> +
> + oms = kzalloc(sizeof(*oms), GFP_KERNEL);
> + if (!oms)
> + return notifier_to_errno(-ENOMEM);
> +
> + /* We don't support interrupts yet, let's poll. */
> + oms->mmc_pdata.caps |= MMC_CAP_NEEDS_POLL;
> +
> + voltage_range = of_get_property(np, "voltage-range", &size);
> + if (!voltage_range || size < sizeof(*voltage_range) * 2) {
> + dev_err(dev, "OF: voltage-range unspecified\n");
> + goto err_ocr;
> + }
> +
> + ret = vddrange_to_ocrmask(voltage_range[0], voltage_range[1],
> + &oms->mmc_pdata.ocr_mask);
> + if (ret) {
> + dev_err(dev, "OF: specified voltage-range is invalid\n");
> + goto err_ocr;
> + }
> +
> + oms->wp_gpio = of_get_gpio(np, 0);
> + if (gpio_is_valid(oms->wp_gpio)) {
> + ret = gpio_request(oms->wp_gpio, dev->bus_id);
> + if (ret < 0)
> + goto err_wp_gpio;
> + oms->mmc_pdata.get_ro = &mmc_get_ro;
> + }
> +
> + oms->cd_gpio = of_get_gpio(np, 1);
> + if (gpio_is_valid(oms->cd_gpio)) {
> + ret = gpio_request(oms->cd_gpio, dev->bus_id);
> + if (ret < 0)
> + goto err_cd_gpio;
> + oms->mmc_pdata.get_cd = &mmc_get_cd;
> + }
> +
> + dev->platform_data = &oms->mmc_pdata;
> +
> + return NOTIFY_STOP;
> +
> +err_cd_gpio:
> + if (gpio_is_valid(oms->wp_gpio))
> + gpio_free(oms->wp_gpio);
> +err_wp_gpio:
> +err_ocr:
> + kfree(oms);
> + return notifier_to_errno(ret);
> +}
> +
> +static int of_mmc_spi_del(struct device *dev)
> +{
> + struct device_node *np = dev->archdata.of_node;
> + struct of_mmc_spi *oms;
> +
> + if (!np || !of_device_is_compatible(np, "mmc-spi") ||
> + !dev->platform_data)
> + return NOTIFY_DONE;
> +
> + oms = to_of_mmc_spi(dev);
> +
> + if (gpio_is_valid(oms->cd_gpio))
> + gpio_free(oms->cd_gpio);
> + if (gpio_is_valid(oms->wp_gpio))
> + gpio_free(oms->wp_gpio);
> +
> + kfree(oms);
> + return NOTIFY_STOP;
> +}
> +
> +static int of_mmc_spi_notify(struct notifier_block *nb, unsigned long action,
> + void *_dev)
> +{
> + struct device *dev = _dev;
> +
> + switch (action) {
> + case BUS_NOTIFY_ADD_DEVICE:
> + return of_mmc_spi_add(dev);
> + case BUS_NOTIFY_DEL_DEVICE:
> + return of_mmc_spi_del(dev);
> + };
> + return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block of_mmc_spi_notifier = {
> + .notifier_call = of_mmc_spi_notify,
> +};
> +
> +/*
> + * Should be called early enough, but after SPI core initializes. So, we
> + * use subsys_initcall (as in the SPI core), and link order guaranties
> + * that we'll be called at the right time.
> + */
Why does this need to be loaded at subsys_initcall time? We have the
equivalent code on i2c loading as a normal module.
When the spi bus driver code is processing the child SPI device nodes,
it should request_module() this driver as a module. I made a note to
fix that on Grant's SPI bus driver.
spi@f00 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "fsl,mpc5200b-spi","fsl,mpc5200-spi";
Triggers loading of Grant's SPI module via normal OF module mechanism
reg = <0xf00 0x20>;
interrupts = <0x2 0xd 0x0 0x2 0xe 0x0>;
interrupt-parent = <&mpc5200_pic>;
Grant's code loops through the child nodes
mmc-slot@0 {
compatible = "mmc-spi";
Finds this and does request_module("mmc-spi");
Then it registers the device
reg = <0>;
max-speed = <50000000>;
/* Unregulated slot. */
voltage-range = <3300 3300>;
/*gpios = <&sdcsr_pio 1 0 /* WP */
/* &sdcsr_pio 0 1>; /* nCD */
};
};
As part of this module's initialization it may need to request_module
generic mmc core module, but I haven't traced things out that far yet.
None of these parts should need to be compiled in, they should all be
capable of being loaded as a modules.
> +static int __init of_mmc_spi_init(void)
> +{
> + int ret;
> +
> + ret = bus_register_notifier(&spi_bus_type, &of_mmc_spi_notifier);
> + if (ret) {
> + pr_err("%s: unable to register notifier on the spi bus\n",
> + __func__);
> + return ret;
> + }
> +
> + return 0;
> +}
> +subsys_initcall(of_mmc_spi_init);
> +
> +MODULE_DESCRIPTION("OpenFirmware bindings for the MMC-over-SPI driver");
> +MODULE_AUTHOR("Anton Vorontsov <avorontsov@...mvista.com>");
> +MODULE_LICENSE("GPL");
> --
> 1.5.5.1
>
> --
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--
Jon Smirl
jonsmirl@...il.com
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