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Commit 2c06b9a2 authored by Naina Mehta's avatar Naina Mehta
Browse files

nvmem: qfprom-sys: Add driver to export cell value 



Add qfprom-sys driver to export the nvmem cell values as sysfs attrs to
enable user space access.

Change-Id: Ic1770054fe2a1b87cf56859aafba03f7340fe273
Signed-off-by: default avatarNaina Mehta <nainmeht@codeaurora.org>
parent 75a9b99e

drivers/soc/qcom/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -337,6 +337,16 @@ config QCOM_QMI_HELPERS 


source "drivers/soc/qcom/memshare/Kconfig"



config QCOM_QFPROM_SYS

	tristate "Qualcomm Technologies, Inc. QFPROM_SYS driver "

	depends on QCOM_QFPROM

	help

	  Qualcomm Technologies, Inc. QFPROM_SYS driver. The QFPROM SYS driver

	  provides access to the child nodes of QFPROM to user space. The cell

	  values are exported as sysfs entries.



	  Say y here to enable QFPROM SYS support.



config QCOM_RMTFS_MEM

	tristate "Qualcomm Remote Filesystem memory driver"

	depends on ARCH_QCOM

drivers/soc/qcom/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -96,3 +96,4 @@ obj-$(CONFIG_ICNSS2) += icnss2/ 
obj-$(CONFIG_QTI_HW_MEMLAT_SCMI_CLIENT)	+= memlat_scmi.o

obj-$(CONFIG_QTI_HW_MEMLAT) += rimps_memlat.o

obj-$(CONFIG_QTI_HW_MEMLAT_LOG)	+= rimps_log.o

obj-$(CONFIG_QCOM_QFPROM_SYS) += qfprom-sys.o

drivers/soc/qcom/qfprom-sys.c

0 → 100644
+154 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only



#include <linux/device.h>

#include <linux/module.h>

#include <linux/mod_devicetable.h>

#include <linux/io.h>

#include <linux/nvmem-consumer.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/slab.h>

#include <linux/sysfs.h>



struct qfprom_sys {

	int cell_count;

	struct nvmem_cell **cells;

	struct bin_attribute **attrs;

};



static ssize_t qfprom_sys_cell_read(struct file *filp, struct kobject *kobj,

				struct bin_attribute *attr,

				char *buf, loff_t pos, size_t count)

{

	struct nvmem_cell *cell;

	size_t len;

	u8 *data;



	cell = attr->private;

	if (!cell)

		return -EINVAL;



	data = nvmem_cell_read(cell, &len);

	if (IS_ERR(data))

		return -EINVAL;



	len = min(len, count);

	memcpy(buf, data, len);

	kfree(data);

	return len;

}



static int qfprom_sys_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct qfprom_sys *priv;

	struct nvmem_cell *cell;

	int cell_count;

	int i, ret;

	const char **cells;



	cell_count = of_property_count_strings(dev->of_node, "nvmem-cell-names");

	if (cell_count <= 0)

		return -EINVAL;



	priv = devm_kzalloc(dev, sizeof(struct qfprom_sys), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;



	priv->cells = devm_kzalloc(dev,

				cell_count * sizeof(struct nvmem_cell *),

				GFP_KERNEL);

	if (!priv->cells)

		return -ENOMEM;



	cells = devm_kzalloc(dev, cell_count * sizeof(char *), GFP_KERNEL);

	if (!cells)

		return -ENOMEM;



	priv->attrs = devm_kzalloc(dev,

			cell_count * sizeof(struct bin_attribute *),

			GFP_KERNEL);

	if (!priv->attrs)

		return -ENOMEM;



	ret = of_property_read_string_array(dev->of_node, "nvmem-cell-names",

						cells, cell_count);



	for (i = 0; i < cell_count; i++) {

		cell = nvmem_cell_get(dev, cells[i]);

		if (IS_ERR_OR_NULL(cell)) {

			ret = PTR_ERR(cell);

			dev_err(dev, "cell corresponding to %s not found\n",

					cells[i]);

			goto remove_cells;

		}



		priv->attrs[i] = devm_kzalloc(dev, sizeof(struct bin_attribute),

						GFP_KERNEL);

		if (!priv->attrs[i]) {

			ret = -ENOMEM;

			nvmem_cell_put(cell);

			goto remove_cells;

		}



		priv->cells[i] = cell;

		sysfs_bin_attr_init(priv->attrs[i]);

		priv->attrs[i]->attr.name = cells[i];

		priv->attrs[i]->attr.mode = 0444;

		priv->attrs[i]->private = cell;

		priv->attrs[i]->size = 4;

		priv->attrs[i]->read = qfprom_sys_cell_read;

		ret = sysfs_create_bin_file(&dev->kobj, priv->attrs[i]);

		if (ret) {

			dev_err(dev, "cell corresponding to %s\n", cells[i]);

			nvmem_cell_put(cell);

			goto remove_cells;

		}

	}



	priv->cell_count = cell_count;

	dev->platform_data = priv;

	return 0;



remove_cells:

	for (; i > 0; i--) {

		sysfs_remove_bin_file(&dev->kobj, priv->attrs[i-1]);

		nvmem_cell_put(priv->cells[i-1]);

	}

	priv->cell_count = 0;

	return ret;

}



static int qfprom_sys_remove(struct platform_device *pdev)

{

	struct qfprom_sys *priv;

	int i;



	priv = dev_get_platdata(&pdev->dev);

	for (i = 0; i < priv->cell_count; i++) {

		nvmem_cell_put(priv->cells[i]);

		sysfs_remove_bin_file(&pdev->dev.kobj, priv->attrs[i]);

	}



	return 0;

}



static const struct of_device_id qfprom_sys_of_match[] = {

	{ .compatible = "qcom,qfprom-sys",},

	{},

};



MODULE_DEVICE_TABLE(of, qfprom_sys_of_match);



static struct platform_driver qfprom_sys_driver = {

	.probe = qfprom_sys_probe,

	.remove = qfprom_sys_remove,

	.driver = {

		.name = "qcom,qfprom-sys",

		.of_match_table = qfprom_sys_of_match,

	},

};



module_platform_driver(qfprom_sys_driver);

MODULE_DESCRIPTION("Qualcomm Technologies, Inc. QFPROM_SYS driver");

MODULE_LICENSE("GPL v2");