[RFC PATCH 3/9] drm/i915/spi: add driver for on-die spi device

[Tomas Winkler]

Add the platform driver for i915 on-die spi device, exposed via mfd
framework.

Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler at intel.com>
---
 drivers/gpu/drm/i915/Kconfig             |   2 +
 drivers/gpu/drm/i915/Makefile            |   3 +
 drivers/gpu/drm/i915/spi/intel_spi_drv.c | 116 +++++++++++++++++++++++
 3 files changed, 121 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/spi/intel_spi_drv.c

diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
index abcaa8da45ac..13c870e5878e 100644
--- a/drivers/gpu/drm/i915/Kconfig
+++ b/drivers/gpu/drm/i915/Kconfig
@@ -27,6 +27,8 @@ config DRM_I915
 	select CEC_CORE if CEC_NOTIFIER
 	select VMAP_PFN
 	select MFD_CORE
+	select MTD
+	select MTD_PARTITIONED_MASTER
 	help
 	  Choose this option if you have a system that has "Intel Graphics
 	  Media Accelerator" or "HD Graphics" integrated graphics,
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 7fa9120feb8d..f209cd541eec 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -299,6 +299,9 @@ endif
 obj-$(CONFIG_DRM_I915) += i915.o
 obj-$(CONFIG_DRM_I915_GVT_KVMGT) += gvt/kvmgt.o
 
+obj-m += i915_spi.o
+i915_spi-y := spi/intel_spi_drv.o
+
 # header test
 
 # exclude some broken headers from the test coverage
diff --git a/drivers/gpu/drm/i915/spi/intel_spi_drv.c b/drivers/gpu/drm/i915/spi/intel_spi_drv.c
new file mode 100644
index 000000000000..23261f35b71f
--- /dev/null
+++ b/drivers/gpu/drm/i915/spi/intel_spi_drv.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright(c) 2019-2021, Intel Corporation. All rights reserved.
+ */
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/io.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <spi/intel_spi.h>
+
+struct i915_spi {
+	void __iomem *base;
+	size_t size;
+	unsigned int nregions;
+	struct {
+		const char *name;
+		u8 id;
+		u64 offset;
+		u64 size;
+	} regions[];
+};
+
+static int i915_spi_probe(struct platform_device *platdev)
+{
+	struct resource *bar;
+	struct device *device;
+	struct i915_spi *spi;
+	struct i915_spi_region *regions;
+	unsigned int nregions;
+	unsigned int i, n;
+	size_t size;
+	char *name;
+	size_t name_size;
+
+	device = &platdev->dev;
+
+	regions = dev_get_platdata(&platdev->dev);
+	if (!regions) {
+		dev_err(device, "no regions defined\n");
+		return -ENODEV;
+	}
+
+	/* count available regions */
+	for (nregions = 0, i = 0; i < I915_SPI_REGIONS; i++) {
+		if (regions[i].name)
+			nregions++;
+	}
+
+	if (!nregions) {
+		dev_err(device, "no regions defined\n");
+		return -ENODEV;
+	}
+
+	size = sizeof(*spi) + sizeof(spi->regions[0]) * nregions;
+	spi = devm_kzalloc(device, size, GFP_KERNEL);
+	if (!spi)
+		return -ENOMEM;
+
+	spi->nregions = nregions;
+	for (n = 0, i = 0; i < I915_SPI_REGIONS; i++) {
+		if (regions[i].name) {
+			name_size = strlen(dev_name(&platdev->dev)) +
+				    strlen(regions[i].name) + 2; /* for point */
+			name = devm_kzalloc(device, name_size, GFP_KERNEL);
+			if (!name)
+				continue;
+			snprintf(name, name_size, "%s.%s",
+				 dev_name(&platdev->dev), regions[i].name);
+			spi->regions[n].name = name;
+			spi->regions[n].id = i;
+			n++;
+		}
+	}
+
+	bar = platform_get_resource(platdev, IORESOURCE_MEM, 0);
+	if (!bar)
+		return -ENODEV;
+
+	spi->base = devm_ioremap_resource(device, bar);
+	if (IS_ERR(spi->base)) {
+		dev_err(device, "mmio not mapped\n");
+		return PTR_ERR(spi->base);
+	}
+
+	platform_set_drvdata(platdev, spi);
+
+	dev_dbg(device, "i915-spi is bound\n");
+
+	return 0;
+}
+
+static int i915_spi_remove(struct platform_device *platdev)
+{
+	platform_set_drvdata(platdev, NULL);
+
+	return 0;
+}
+
+MODULE_ALIAS("platform:i915-spi");
+static struct platform_driver i915_spi_driver = {
+	.probe  = i915_spi_probe,
+	.remove = i915_spi_remove,
+	.driver = {
+		.name = "i915-spi",
+	},
+};
+
+module_platform_driver(i915_spi_driver);
+
+MODULE_LICENSE("GPL and additional rights");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("Intel DGFX SPI driver");
-- 
2.26.2