mfd: intel-peci-client: Add PECI client MFD driver

This commit adds PECI client MFD driver.

OpenBMC-Staging-Count: 2
Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>

3 files changed, 165 insertions, 0 deletions

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 76f9909cf396..9af5730ad7ba 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -605,6 +605,20 @@ config MFD_INTEL_MSIC
 	  Passage) chip. This chip embeds audio, battery, GPIO, etc.
 	  devices used in Intel Medfield platforms.
 
+config MFD_INTEL_PECI_CLIENT
+	bool "Intel PECI client"
+	depends on (PECI || COMPILE_TEST)
+	select MFD_CORE
+	help
+	  If you say yes to this option, support will be included for the
+	  Intel PECI (Platform Environment Control Interface) client. PECI is a
+	  one-wire bus interface that provides a communication channel from PECI
+	  clients in Intel processors and chipset components to external
+	  monitoring or control devices.
+
+	  Additional drivers must be enabled in order to use the functionality
+	  of the device.
+
 config MFD_IPAQ_MICRO
 	bool "Atmel Micro ASIC (iPAQ h3100/h3600/h3700) Support"
 	depends on SA1100_H3100 || SA1100_H3600
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 12980a4ad460..b8c1da8e748b 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -204,6 +204,7 @@ obj-$(CONFIG_MFD_INTEL_LPSS)	+= intel-lpss.o
 obj-$(CONFIG_MFD_INTEL_LPSS_PCI)	+= intel-lpss-pci.o
 obj-$(CONFIG_MFD_INTEL_LPSS_ACPI)	+= intel-lpss-acpi.o
 obj-$(CONFIG_MFD_INTEL_MSIC)	+= intel_msic.o
+obj-$(CONFIG_MFD_INTEL_PECI_CLIENT)	+= intel-peci-client.o
 obj-$(CONFIG_MFD_PALMAS)	+= palmas.o
 obj-$(CONFIG_MFD_VIPERBOARD)    += viperboard.o
 obj-$(CONFIG_MFD_RC5T583)	+= rc5t583.o rc5t583-irq.o
diff --git a/drivers/mfd/intel-peci-client.c b/drivers/mfd/intel-peci-client.c
new file mode 100644
index 000000000000..d53e4f1078ac
--- /dev/null
+++ b/drivers/mfd/intel-peci-client.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Intel Corporation
+
+#include <linux/bitfield.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/intel-peci-client.h>
+#include <linux/module.h>
+#include <linux/peci.h>
+#include <linux/of_device.h>
+
+#define CPU_ID_MODEL_MASK      GENMASK(7, 4)
+#define CPU_ID_FAMILY_MASK     GENMASK(11, 8)
+#define CPU_ID_EXT_MODEL_MASK  GENMASK(19, 16)
+#define CPU_ID_EXT_FAMILY_MASK GENMASK(27, 20)
+
+#define LOWER_NIBBLE_MASK      GENMASK(3, 0)
+#define UPPER_NIBBLE_MASK      GENMASK(7, 4)
+#define LOWER_BYTE_MASK        GENMASK(7, 0)
+#define UPPER_BYTE_MASK        GENMASK(16, 8)
+
+enum cpu_gens {
+	CPU_GEN_HSX = 0, /* Haswell Xeon */
+	CPU_GEN_BRX,     /* Broadwell Xeon */
+	CPU_GEN_SKX,     /* Skylake Xeon */
+};
+
+static struct mfd_cell peci_functions[] = {
+	{ .name = "peci-cputemp", },
+	{ .name = "peci-dimmtemp", },
+	/* TODO: Add additional PECI sideband functions into here */
+};
+
+static const struct cpu_gen_info cpu_gen_info_table[] = {
+	[CPU_GEN_HSX] = {
+		.family        = 6, /* Family code */
+		.model         = INTEL_FAM6_HASWELL_X,
+		.core_max      = CORE_MAX_ON_HSX,
+		.chan_rank_max = CHAN_RANK_MAX_ON_HSX,
+		.dimm_idx_max  = DIMM_IDX_MAX_ON_HSX },
+	[CPU_GEN_BRX] = {
+		.family        = 6, /* Family code */
+		.model         = INTEL_FAM6_BROADWELL_X,
+		.core_max      = CORE_MAX_ON_BDX,
+		.chan_rank_max = CHAN_RANK_MAX_ON_BDX,
+		.dimm_idx_max  = DIMM_IDX_MAX_ON_BDX },
+	[CPU_GEN_SKX] = {
+		.family        = 6, /* Family code */
+		.model         = INTEL_FAM6_SKYLAKE_X,
+		.core_max      = CORE_MAX_ON_SKX,
+		.chan_rank_max = CHAN_RANK_MAX_ON_SKX,
+		.dimm_idx_max  = DIMM_IDX_MAX_ON_SKX },
+};
+
+static int peci_client_get_cpu_gen_info(struct peci_client_manager *priv)
+{
+	u32 cpu_id;
+	u16 family;
+	u8 model;
+	int rc;
+	int i;
+
+	rc = peci_get_cpu_id(priv->client->adapter, priv->client->addr,
+			     &cpu_id);
+	if (rc)
+		return rc;
+
+	family = FIELD_PREP(LOWER_BYTE_MASK,
+			    FIELD_GET(CPU_ID_FAMILY_MASK, cpu_id)) |
+		 FIELD_PREP(UPPER_BYTE_MASK,
+			    FIELD_GET(CPU_ID_EXT_FAMILY_MASK, cpu_id));
+	model = FIELD_PREP(LOWER_NIBBLE_MASK,
+			   FIELD_GET(CPU_ID_MODEL_MASK, cpu_id)) |
+		FIELD_PREP(UPPER_NIBBLE_MASK,
+			   FIELD_GET(CPU_ID_EXT_MODEL_MASK, cpu_id));
+
+	for (i = 0; i < ARRAY_SIZE(cpu_gen_info_table); i++) {
+		const struct cpu_gen_info *cpu_info = &cpu_gen_info_table[i];
+
+		if (family == cpu_info->family && model == cpu_info->model) {
+			priv->gen_info = cpu_info;
+			break;
+		}
+	}
+
+	if (!priv->gen_info) {
+		dev_err(priv->dev, "Can't support this CPU: 0x%x\n", cpu_id);
+		rc = -ENODEV;
+	}
+
+	return rc;
+}
+
+static int peci_client_probe(struct peci_client *client)
+{
+	struct device *dev = &client->dev;
+	struct peci_client_manager *priv;
+	uint cpu_no;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, priv);
+	priv->client = client;
+	priv->dev = dev;
+	cpu_no = client->addr - PECI_BASE_ADDR;
+
+	ret = peci_client_get_cpu_gen_info(priv);
+	if (ret)
+		return ret;
+
+	ret = devm_mfd_add_devices(priv->dev, cpu_no, peci_functions,
+				   ARRAY_SIZE(peci_functions), NULL, 0, NULL);
+	if (ret < 0) {
+		dev_err(priv->dev, "Failed to register child devices: %d\n",
+			ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id peci_client_of_table[] = {
+	{ .compatible = "intel,peci-client" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, peci_client_of_table);
+#endif
+
+static const struct peci_device_id peci_client_ids[] = {
+	{ .name = "peci-client" },
+	{ }
+};
+MODULE_DEVICE_TABLE(peci, peci_client_ids);
+
+static struct peci_driver peci_client_driver = {
+	.probe    = peci_client_probe,
+	.id_table = peci_client_ids,
+	.driver   = {
+		.name           = "peci-client",
+		.of_match_table = of_match_ptr(peci_client_of_table),
+	},
+};
+module_peci_driver(peci_client_driver);
+
+MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>");
+MODULE_DESCRIPTION("PECI client driver");
+MODULE_LICENSE("GPL v2");