Add auxiliary driver for intel discrete graphics
on-die spi device.

CC: Rodrigo Vivi <rodrigo.v...@intel.com>
Signed-off-by: Tomas Winkler <tomas.wink...@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demar...@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usys...@intel.com>
---
 drivers/spi/Kconfig        |  11 +++
 drivers/spi/Makefile       |   1 +
 drivers/spi/spi-intel-dg.c | 146 +++++++++++++++++++++++++++++++++++++
 3 files changed, 158 insertions(+)
 create mode 100644 drivers/spi/spi-intel-dg.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index ddae0fde798e..d84896e6e7a0 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -507,6 +507,17 @@ config SPI_INTEL_PLATFORM
          To compile this driver as a module, choose M here: the module
          will be called spi-intel-platform.
 
+config SPI_INTEL_DG
+       tristate "Intel Discrete Graphic SPI flash driver"
+       depends on AUXILIARY_BUS || COMPILE_TEST
+       depends on MTD
+       help
+         This enables support for Intel Discrete Graphic SPI
+         auxiliary device.
+
+         To compile this driver as a module, choose M here: the module
+         will be called spi-intel-dg.
+
 config SPI_JCORE
        tristate "J-Core SPI Master"
        depends on OF && (SUPERH || COMPILE_TEST)
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 4ff8d725ba5e..e158761d6844 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_SPI_INGENIC)             += spi-ingenic.o
 obj-$(CONFIG_SPI_INTEL)                        += spi-intel.o
 obj-$(CONFIG_SPI_INTEL_PCI)            += spi-intel-pci.o
 obj-$(CONFIG_SPI_INTEL_PLATFORM)       += spi-intel-platform.o
+obj-$(CONFIG_SPI_INTEL_DG)             += spi-intel-dg.o
 obj-$(CONFIG_SPI_LANTIQ_SSC)           += spi-lantiq-ssc.o
 obj-$(CONFIG_SPI_JCORE)                        += spi-jcore.o
 obj-$(CONFIG_SPI_LJCA)                 += spi-ljca.o
diff --git a/drivers/spi/spi-intel-dg.c b/drivers/spi/spi-intel-dg.c
new file mode 100644
index 000000000000..8dc5448fc901
--- /dev/null
+++ b/drivers/spi/spi-intel-dg.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(c) 2019-2024, Intel Corporation. All rights reserved.
+ */
+
+#include <linux/device.h>
+#include <linux/intel_dg_spi_aux.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+struct intel_dg_spi {
+       struct kref refcnt;
+       void __iomem *base;
+       size_t size;
+       unsigned int nregions;
+       struct {
+               const char *name;
+               u8 id;
+               u64 offset;
+               u64 size;
+       } regions[];
+};
+
+static void intel_dg_spi_release(struct kref *kref)
+{
+       struct intel_dg_spi *spi = container_of(kref, struct intel_dg_spi, 
refcnt);
+       int i;
+
+       pr_debug("freeing spi memory\n");
+       for (i = 0; i < spi->nregions; i++)
+               kfree(spi->regions[i].name);
+       kfree(spi);
+}
+
+static int intel_dg_spi_probe(struct auxiliary_device *aux_dev,
+                         const struct auxiliary_device_id *aux_dev_id)
+{
+       struct intel_dg_spi_dev *ispi = 
auxiliary_dev_to_intel_dg_spi_dev(aux_dev);
+       struct device *device;
+       struct intel_dg_spi *spi;
+       unsigned int nregions;
+       unsigned int i, n;
+       size_t size;
+       char *name;
+       size_t name_size;
+       int ret;
+
+       device = &aux_dev->dev;
+
+       /* count available regions */
+       for (nregions = 0, i = 0; i < INTEL_DG_SPI_REGIONS; i++) {
+               if (ispi->regions[i].name)
+                       nregions++;
+       }
+
+       if (!nregions) {
+               dev_err(device, "no regions defined\n");
+               return -ENODEV;
+       }
+
+       size = sizeof(*spi) + sizeof(spi->regions[0]) * nregions;
+       spi = kzalloc(size, GFP_KERNEL);
+       if (!spi)
+               return -ENOMEM;
+
+       kref_init(&spi->refcnt);
+
+       spi->nregions = nregions;
+       for (n = 0, i = 0; i < INTEL_DG_SPI_REGIONS; i++) {
+               if (ispi->regions[i].name) {
+                       name_size = strlen(dev_name(&aux_dev->dev)) +
+                                   strlen(ispi->regions[i].name) + 2; /* for 
point */
+                       name = kzalloc(name_size, GFP_KERNEL);
+                       if (!name)
+                               continue;
+                       snprintf(name, name_size, "%s.%s",
+                                dev_name(&aux_dev->dev), 
ispi->regions[i].name);
+                       spi->regions[n].name = name;
+                       spi->regions[n].id = i;
+                       n++;
+               }
+       }
+
+       spi->base = devm_ioremap_resource(device, &ispi->bar);
+       if (IS_ERR(spi->base)) {
+               dev_err(device, "mmio not mapped\n");
+               ret = PTR_ERR(spi->base);
+               goto err;
+       }
+
+       dev_set_drvdata(&aux_dev->dev, spi);
+
+       dev_dbg(device, "bound\n");
+
+       return 0;
+
+err:
+       kref_put(&spi->refcnt, intel_dg_spi_release);
+       return ret;
+}
+
+static void intel_dg_spi_remove(struct auxiliary_device *aux_dev)
+{
+       struct intel_dg_spi *spi = dev_get_drvdata(&aux_dev->dev);
+
+       if (!spi)
+               return;
+
+       dev_set_drvdata(&aux_dev->dev, NULL);
+
+       kref_put(&spi->refcnt, intel_dg_spi_release);
+}
+
+static const struct auxiliary_device_id intel_dg_spi_id_table[] = {
+       {
+               .name = "i915.spi",
+       },
+       {
+               .name = "xe.spi",
+       },
+       {
+               /* sentinel */
+       }
+};
+MODULE_DEVICE_TABLE(auxiliary, intel_dg_spi_id_table);
+
+static struct auxiliary_driver intel_dg_spi_driver = {
+       .probe  = intel_dg_spi_probe,
+       .remove = intel_dg_spi_remove,
+       .driver = {
+               /* auxiliary_driver_register() sets .name to be the modname */
+       },
+       .id_table = intel_dg_spi_id_table
+};
+
+module_auxiliary_driver(intel_dg_spi_driver);
+
+MODULE_ALIAS("auxiliary:i915.spi");
+MODULE_ALIAS("auxiliary:xe.spi");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("Intel DGFX SPI driver");
-- 
2.34.1

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