soc: qcom: Add GSBI driver

The GSBI (General Serial Bus Interface) driver controls the overarching
configuration of the shared serial bus infrastructure on APQ8064, IPQ8064, and
earlier QCOM processors.  The GSBI supports UART, I2C, SPI, and UIM
functionality in various combinations.

Signed-off-by: Andy Gross <agross@codeaurora.org>
Signed-off-by: Kumar Gala <galak@codeaurora.org>
This commit is contained in:
Andy Gross 2014-04-24 11:31:21 -05:00 committed by Kumar Gala
parent 3a6e08218f
commit 5d144e36b7
5 changed files with 103 additions and 0 deletions

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menu "SOC (System On Chip) specific Drivers"
source "drivers/soc/qcom/Kconfig"
endmenu

5
drivers/soc/Makefile Normal file
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#
# Makefile for the Linux Kernel SOC specific device drivers.
#
obj-$(CONFIG_ARCH_QCOM) += qcom/

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drivers/soc/qcom/Kconfig Normal file
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#
# QCOM Soc drivers
#
config QCOM_GSBI
tristate "QCOM General Serial Bus Interface"
depends on ARCH_QCOM
help
Say y here to enable GSBI support. The GSBI provides control
functions for connecting the underlying serial UART, SPI, and I2C
devices to the output pins.

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obj-$(CONFIG_QCOM_GSBI) += qcom_gsbi.o

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/*
* Copyright (c) 2014, The Linux foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License rev 2 and
* only rev 2 as published by the free Software foundation.
*
* 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.
*/
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#define GSBI_CTRL_REG 0x0000
#define GSBI_PROTOCOL_SHIFT 4
static int gsbi_probe(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
struct resource *res;
void __iomem *base;
struct clk *hclk;
u32 mode, crci = 0;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(base))
return PTR_ERR(base);
if (of_property_read_u32(node, "qcom,mode", &mode)) {
dev_err(&pdev->dev, "missing mode configuration\n");
return -EINVAL;
}
/* not required, so default to 0 if not present */
of_property_read_u32(node, "qcom,crci", &crci);
dev_info(&pdev->dev, "GSBI port protocol: %d crci: %d\n", mode, crci);
hclk = devm_clk_get(&pdev->dev, "iface");
if (IS_ERR(hclk))
return PTR_ERR(hclk);
clk_prepare_enable(hclk);
writel_relaxed((mode << GSBI_PROTOCOL_SHIFT) | crci,
base + GSBI_CTRL_REG);
/* make sure the gsbi control write is not reordered */
wmb();
clk_disable_unprepare(hclk);
return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
}
static const struct of_device_id gsbi_dt_match[] = {
{ .compatible = "qcom,gsbi-v1.0.0", },
};
MODULE_DEVICE_TABLE(of, gsbi_dt_match);
static struct platform_driver gsbi_driver = {
.driver = {
.name = "gsbi",
.owner = THIS_MODULE,
.of_match_table = gsbi_dt_match,
},
.probe = gsbi_probe,
};
module_platform_driver(gsbi_driver);
MODULE_AUTHOR("Andy Gross <agross@codeaurora.org>");
MODULE_DESCRIPTION("QCOM GSBI driver");
MODULE_LICENSE("GPL v2");