[PATCH] [RFC v3] OF: OpenFirmware bindings for the mmc_spi driver
Anton Vorontsov
avorontsov at ru.mvista.com
Fri Jun 6 02:16:24 EST 2008
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 Withdrawn by Pierre Ossman.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 Withdrawn by OF people.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 at ru.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 at 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 at ru.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.
+ */
+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 at ru.mvista.com>");
+MODULE_LICENSE("GPL");
--
1.5.5.1
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