From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> The bcm2835 SOC contains 3 auxiliar devices (spi1, spi2 and uart1) that all are enabled via a shared register. To serialize access to this shared register this soc-driver is created that implements: bcm2835aux_enable(struct device *dev, const char *property); bcm2835aux_disable(struct device *dev, const char *property); Which will read the property from the device tree of the device and enable/disable that specific device as per device tree. First use of this api will be spi-bcm2835aux. Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> --- drivers/soc/Kconfig | 1 + drivers/soc/Makefile | 1 + drivers/soc/bcm/Kconfig | 11 +++ drivers/soc/bcm/Makefile | 1 + drivers/soc/bcm/bcm2835-aux.c | 154 +++++++++++++++++++++++++++++++++++ include/linux/soc/bcm/bcm2835-aux.h | 23 ++++++ 6 files changed, 191 insertions(+) create mode 100644 drivers/soc/bcm/Kconfig create mode 100644 drivers/soc/bcm/Makefile create mode 100644 drivers/soc/bcm/bcm2835-aux.c create mode 100644 include/linux/soc/bcm/bcm2835-aux.h diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig index 96ddecb..5506e39 100644 --- a/drivers/soc/Kconfig +++ b/drivers/soc/Kconfig @@ -1,5 +1,6 @@ menu "SOC (System On Chip) specific Drivers" +source "drivers/soc/bcm/Kconfig" source "drivers/soc/mediatek/Kconfig" source "drivers/soc/qcom/Kconfig" source "drivers/soc/sunxi/Kconfig" diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile index 7dc7c0d..c5744e1 100644 --- a/drivers/soc/Makefile +++ b/drivers/soc/Makefile @@ -2,6 +2,7 @@ # Makefile for the Linux Kernel SOC specific device drivers. # +obj-$(CONFIG_ARCH_BCM) += bcm/ obj-$(CONFIG_ARCH_MEDIATEK) += mediatek/ obj-$(CONFIG_ARCH_QCOM) += qcom/ obj-$(CONFIG_ARCH_SUNXI) += sunxi/ diff --git a/drivers/soc/bcm/Kconfig b/drivers/soc/bcm/Kconfig new file mode 100644 index 0000000..b0af34b3 --- /dev/null +++ b/drivers/soc/bcm/Kconfig @@ -0,0 +1,11 @@ +# +# Broadcom SoC drivers +# +config SOC_BCM2835_AUX + tristate "Broadcom BCM2835 aux" + depends on OF + depends on ARCH_BCM2835 || COMPILE_TEST + + help + Support to enable/disable the BCM2835 auxiliar + devices spi1, spi2, uart1 diff --git a/drivers/soc/bcm/Makefile b/drivers/soc/bcm/Makefile new file mode 100644 index 0000000..370a872 --- /dev/null +++ b/drivers/soc/bcm/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_SOC_BCM2835_AUX) += bcm2835-aux.o diff --git a/drivers/soc/bcm/bcm2835-aux.c b/drivers/soc/bcm/bcm2835-aux.c new file mode 100644 index 0000000..887508d --- /dev/null +++ b/drivers/soc/bcm/bcm2835-aux.c @@ -0,0 +1,154 @@ +/* + * bcm2835-aux + * + * Copyright (C) 2015 Martin Sperl + * + * Author: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> + * + * 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/device.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/soc/bcm/bcm2835-aux.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/spinlock.h> + +static DEFINE_SPINLOCK(bcm2835aux_lock); + +static struct platform_driver bcm2835aux_driver; + +static int bcm2835aux_dev_match(struct device *dev, void *data) +{ + struct device_node *dn = data; + + return (dev->of_node == dn) ? 1 : 0; +} + +static void *bcm2835aux_find_base(struct device *dev, const char *property) +{ + struct device *found = NULL; + struct device_node *np; + + /* get the phandle of the device */ + np = of_parse_phandle(dev->of_node, property, 0); + if (!np) { + dev_err(dev, "missing property %s\n", property); + return ERR_PTR(-ENODEV); + } + + /* now find the device it points to */ + found = driver_find_device(&bcm2835aux_driver.driver, NULL, + np, bcm2835aux_dev_match); + if (!found) { + dev_err(dev, "device for phandle of %s not found\n", + property); + return ERR_PTR(-ENODEV); + } + + /* now we got the device, so return the pointer */ + return dev_get_drvdata(found); +} + +static u32 bcm2835aux_find_mask(struct device *dev, const char *property) +{ + int err; + u32 mask; + + err = of_property_read_u32_index(dev->of_node, property, 1, &mask); + if (err) { + dev_err(dev, "missing argument to %s: %d\n", + property, err); + return 0; + } + + return mask; +} + +static int bcm2835aux_bitset(struct device *dev, const char *property, + bool set) +{ + u32 v, mask; + unsigned long flags; + void __iomem *base; + + /* find the device */ + base = bcm2835aux_find_base(dev, property); + if (IS_ERR(base)) + return PTR_ERR(base); + + /* and extract the mask */ + mask = bcm2835aux_find_mask(dev, property); + if (!mask) + return -ENOENT; + + spin_lock_irqsave(&bcm2835aux_lock, flags); + + v = readl(base); + if (set) + v |= mask; + else + v &= ~mask; + + writel(v, base); + + spin_unlock_irqrestore(&bcm2835aux_lock, flags); + + return 0; +} + +int bcm2835aux_enable(struct device *dev, const char *property) +{ + return bcm2835aux_bitset(dev, property, true); +} +EXPORT_SYMBOL_GPL(bcm2835aux_enable); + +int bcm2835aux_disable(struct device *dev, const char *property) +{ + return bcm2835aux_bitset(dev, property, false); +} +EXPORT_SYMBOL_GPL(bcm2835aux_disable); + +static int bcm2835aux_probe(struct platform_device *pdev) +{ + struct resource *res; + void __iomem *base; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENOENT; + + base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(base)) + return PTR_ERR(base); + + platform_set_drvdata(pdev, base); + + return 0; +} + +static const struct of_device_id bcm2835aux_match[] = { + { .compatible = "brcm,bcm2835-aux", }, + {} +}; +MODULE_DEVICE_TABLE(of, bcm2835aux_match); + +static struct platform_driver bcm2835aux_driver = { + .driver = { + .name = "bcm2835-aux", + .of_match_table = bcm2835aux_match, + }, + .probe = bcm2835aux_probe, +}; +module_platform_driver(bcm2835aux_driver); + +MODULE_DESCRIPTION("enable/disable driver for aux-spi1/spi2/uart1 on Broadcom BCM2835"); +MODULE_AUTHOR("Martin Sperl <kernel@xxxxxxxxxxxxxxxx>"); +MODULE_LICENSE("GPL v2"); diff --git a/include/linux/soc/bcm/bcm2835-aux.h b/include/linux/soc/bcm/bcm2835-aux.h new file mode 100644 index 0000000..17a64c6 --- /dev/null +++ b/include/linux/soc/bcm/bcm2835-aux.h @@ -0,0 +1,23 @@ +/* + * Copyright (C) 2015 Martin Sperl + * + * 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. + * + * 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 General Public License for more details. + */ + +#ifndef __BCM2835_AUX_H__ +#define __BCM2835_AUX_H__ + +struct device; + +int bcm2835aux_enable(struct device *dev, const char *property); +int bcm2835aux_disable(struct device *dev, const char *property); + +#endif -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html