nvmem: qfprom: Add Qualcomm QFPROM support.

This patch adds QFPROM support driver which is used by other drivers
like thermal sensor and cpufreq.

On MSM parts there are some efuses (called qfprom) these fuses store
things like calibration data, speed bins.. etc. Drivers like cpufreq,
thermal sensors would read out this data for configuring the driver.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/Kconfig

@@ -11,3 +11,18 @@ menuconfig NVMEM
 	  will be called nvmem_core.
 
 	  If unsure, say no.
+
+if NVMEM
+
+config QCOM_QFPROM
+	tristate "QCOM QFPROM Support"
+	depends on ARCH_QCOM || COMPILE_TEST
+	select REGMAP_MMIO
+	help
+	  Say y here to enable QFPROM support. The QFPROM provides access
+	  functions for QFPROM data to rest of the drivers via nvmem interface.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called nvmem_qfprom.
+
+endif

drivers/nvmem/Makefile

@@ -4,3 +4,7 @@
 
 obj-$(CONFIG_NVMEM)		+= nvmem_core.o
 nvmem_core-y			:= core.o
+
+# Devices
+obj-$(CONFIG_QCOM_QFPROM)	+= nvmem_qfprom.o
+nvmem_qfprom-y			:= qfprom.o

drivers/nvmem/qfprom.c

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 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/device.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+static struct regmap_config qfprom_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 8,
+	.reg_stride = 1,
+};
+
+static struct nvmem_config econfig = {
+	.name = "qfprom",
+	.owner = THIS_MODULE,
+};
+
+static int qfprom_remove(struct platform_device *pdev)
+{
+	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
+
+	return nvmem_unregister(nvmem);
+}
+
+static int qfprom_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	struct nvmem_device *nvmem;
+	struct regmap *regmap;
+	void __iomem *base;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	qfprom_regmap_config.max_register = resource_size(res) - 1;
+
+	regmap = devm_regmap_init_mmio(dev, base, &qfprom_regmap_config);
+	if (IS_ERR(regmap)) {
+		dev_err(dev, "regmap init failed\n");
+		return PTR_ERR(regmap);
+	}
+	econfig.dev = dev;
+	nvmem = nvmem_register(&econfig);
+	if (IS_ERR(nvmem))
+		return PTR_ERR(nvmem);
+
+	platform_set_drvdata(pdev, nvmem);
+
+	return 0;
+}
+
+static const struct of_device_id qfprom_of_match[] = {
+	{ .compatible = "qcom,qfprom",},
+	{/* sentinel */},
+};
+MODULE_DEVICE_TABLE(of, qfprom_of_match);
+
+static struct platform_driver qfprom_driver = {
+	.probe = qfprom_probe,
+	.remove = qfprom_remove,
+	.driver = {
+		.name = "qcom,qfprom",
+		.of_match_table = qfprom_of_match,
+	},
+};
+module_platform_driver(qfprom_driver);
+MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org>");
+MODULE_DESCRIPTION("Qualcomm QFPROM driver");
+MODULE_LICENSE("GPL v2");