mfd: ocelot: Add support for the vsc7512 chip via spi (f3e89362) · Commits · EulixOS / Software / Kernel

MAINTAINERS

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		@@ -14745,6 +14745,7 @@ OCELOT EXTERNAL SWITCH CONTROL
		M: Colin Foster <colin.foster@in-advantage.com>
		S: Supported
		F: Documentation/devicetree/bindings/mfd/mscc,ocelot.yaml
		F: drivers/mfd/ocelot*
		F: include/linux/mfd/ocelot.h

		OCXL (Open Coherent Accelerator Processor Interface OpenCAPI) DRIVER

drivers/mfd/Kconfig

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		@@ -963,6 +963,27 @@ config MFD_MENF21BMC
		This driver can also be built as a module. If so the module
		will be called menf21bmc.

		config MFD_OCELOT
		tristate "Microsemi Ocelot External Control Support"
		depends on SPI_MASTER
		select MFD_CORE
		select REGMAP_SPI
		help
		Ocelot is a family of networking chips that support multiple ethernet
		and fibre interfaces. In addition to networking, they contain several
		other functions, including pinctrl, MDIO, and communication with
		external chips. While some chips have an internal processor capable of
		running an OS, others don't. All chips can be controlled externally
		through different interfaces, including SPI, I2C, and PCIe.

		Say yes here to add support for Ocelot chips (VSC7511, VSC7512,
		VSC7513, VSC7514) controlled externally.

		To compile this driver as a module, choose M here: the module will be
		called ocelot-soc.

		If unsure, say N.

		config EZX_PCAP
		bool "Motorola EZXPCAP Support"
		depends on SPI_MASTER

drivers/mfd/Makefile

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		@@ -120,6 +120,9 @@ obj-$(CONFIG_MFD_MC13XXX_I2C) += mc13xxx-i2c.o

		obj-$(CONFIG_MFD_CORE) += mfd-core.o

		ocelot-soc-objs := ocelot-core.o ocelot-spi.o
		obj-$(CONFIG_MFD_OCELOT) += ocelot-soc.o

		obj-$(CONFIG_EZX_PCAP) += ezx-pcap.o
		obj-$(CONFIG_MFD_CPCAP) += motorola-cpcap.o

drivers/mfd/ocelot-core.c

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		// SPDX-License-Identifier: (GPL-2.0 OR MIT)
		/*
		* Core driver for the Ocelot chip family.
		*
		* The VSC7511, 7512, 7513, and 7514 can be controlled internally via an
		* on-chip MIPS processor, or externally via SPI, I2C, PCIe. This core driver is
		* intended to be the bus-agnostic glue between, for example, the SPI bus and
		* the child devices.
		*
		* Copyright 2021-2022 Innovative Advantage Inc.
		*
		* Author: Colin Foster <colin.foster@in-advantage.com>
		*/

		#include <linux/bits.h>
		#include <linux/device.h>
		#include <linux/export.h>
		#include <linux/iopoll.h>
		#include <linux/ioport.h>
		#include <linux/kernel.h>
		#include <linux/mfd/core.h>
		#include <linux/mfd/ocelot.h>
		#include <linux/module.h>
		#include <linux/regmap.h>
		#include <linux/types.h>

		#include <soc/mscc/ocelot.h>

		#include "ocelot.h"

		#define REG_GCB_SOFT_RST 0x0008

		#define BIT_SOFT_CHIP_RST BIT(0)

		#define VSC7512_MIIM0_RES_START 0x7107009c
		#define VSC7512_MIIM1_RES_START 0x710700c0
		#define VSC7512_MIIM_RES_SIZE 0x024

		#define VSC7512_PHY_RES_START 0x710700f0
		#define VSC7512_PHY_RES_SIZE 0x004

		#define VSC7512_GPIO_RES_START 0x71070034
		#define VSC7512_GPIO_RES_SIZE 0x06c

		#define VSC7512_SIO_CTRL_RES_START 0x710700f8
		#define VSC7512_SIO_CTRL_RES_SIZE 0x100

		#define VSC7512_GCB_RST_SLEEP_US 100
		#define VSC7512_GCB_RST_TIMEOUT_US 100000

		static int ocelot_gcb_chip_rst_status(struct ocelot_ddata *ddata)
		{
		int val, err;

		err = regmap_read(ddata->gcb_regmap, REG_GCB_SOFT_RST, &val);
		if (err)
		return err;

		return val;
		}

		int ocelot_chip_reset(struct device *dev)
		{
		struct ocelot_ddata *ddata = dev_get_drvdata(dev);
		int ret, val;

		/*
		* Reset the entire chip here to put it into a completely known state.
		* Other drivers may want to reset their own subsystems. The register
		* self-clears, so one write is all that is needed and wait for it to
		* clear.
		*/
		ret = regmap_write(ddata->gcb_regmap, REG_GCB_SOFT_RST, BIT_SOFT_CHIP_RST);
		if (ret)
		return ret;

		return readx_poll_timeout(ocelot_gcb_chip_rst_status, ddata, val, !val,
		VSC7512_GCB_RST_SLEEP_US, VSC7512_GCB_RST_TIMEOUT_US);
		}
		EXPORT_SYMBOL_NS(ocelot_chip_reset, MFD_OCELOT);

		static const struct resource vsc7512_miim0_resources[] = {
		DEFINE_RES_REG_NAMED(VSC7512_MIIM0_RES_START, VSC7512_MIIM_RES_SIZE, "gcb_miim0"),
		DEFINE_RES_REG_NAMED(VSC7512_PHY_RES_START, VSC7512_PHY_RES_SIZE, "gcb_phy"),
		};

		static const struct resource vsc7512_miim1_resources[] = {
		DEFINE_RES_REG_NAMED(VSC7512_MIIM1_RES_START, VSC7512_MIIM_RES_SIZE, "gcb_miim1"),
		};

		static const struct resource vsc7512_pinctrl_resources[] = {
		DEFINE_RES_REG_NAMED(VSC7512_GPIO_RES_START, VSC7512_GPIO_RES_SIZE, "gcb_gpio"),
		};

		static const struct resource vsc7512_sgpio_resources[] = {
		DEFINE_RES_REG_NAMED(VSC7512_SIO_CTRL_RES_START, VSC7512_SIO_CTRL_RES_SIZE, "gcb_sio"),
		};

		static const struct mfd_cell vsc7512_devs[] = {
		{
		.name = "ocelot-pinctrl",
		.of_compatible = "mscc,ocelot-pinctrl",
		.num_resources = ARRAY_SIZE(vsc7512_pinctrl_resources),
		.resources = vsc7512_pinctrl_resources,
		}, {
		.name = "ocelot-sgpio",
		.of_compatible = "mscc,ocelot-sgpio",
		.num_resources = ARRAY_SIZE(vsc7512_sgpio_resources),
		.resources = vsc7512_sgpio_resources,
		}, {
		.name = "ocelot-miim0",
		.of_compatible = "mscc,ocelot-miim",
		.of_reg = VSC7512_MIIM0_RES_START,
		.use_of_reg = true,
		.num_resources = ARRAY_SIZE(vsc7512_miim0_resources),
		.resources = vsc7512_miim0_resources,
		}, {
		.name = "ocelot-miim1",
		.of_compatible = "mscc,ocelot-miim",
		.of_reg = VSC7512_MIIM1_RES_START,
		.use_of_reg = true,
		.num_resources = ARRAY_SIZE(vsc7512_miim1_resources),
		.resources = vsc7512_miim1_resources,
		},
		};

		static void ocelot_core_try_add_regmap(struct device *dev,
		const struct resource *res)
		{
		if (dev_get_regmap(dev, res->name))
		return;

		ocelot_spi_init_regmap(dev, res);
		}

		static void ocelot_core_try_add_regmaps(struct device *dev,
		const struct mfd_cell *cell)
		{
		int i;

		for (i = 0; i < cell->num_resources; i++)
		ocelot_core_try_add_regmap(dev, &cell->resources[i]);
		}

		int ocelot_core_init(struct device *dev)
		{
		int i, ndevs;

		ndevs = ARRAY_SIZE(vsc7512_devs);

		for (i = 0; i < ndevs; i++)
		ocelot_core_try_add_regmaps(dev, &vsc7512_devs[i]);

		return devm_mfd_add_devices(dev, PLATFORM_DEVID_AUTO, vsc7512_devs, ndevs, NULL, 0, NULL);
		}
		EXPORT_SYMBOL_NS(ocelot_core_init, MFD_OCELOT);

		MODULE_DESCRIPTION("Externally Controlled Ocelot Chip Driver");
		MODULE_AUTHOR("Colin Foster <colin.foster@in-advantage.com>");
		MODULE_LICENSE("GPL");
		MODULE_IMPORT_NS(MFD_OCELOT_SPI);

drivers/mfd/ocelot-spi.c

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		// SPDX-License-Identifier: (GPL-2.0 OR MIT)
		/*
		* SPI core driver for the Ocelot chip family.
		*
		* This driver will handle everything necessary to allow for communication over
		* SPI to the VSC7511, VSC7512, VSC7513 and VSC7514 chips. The main functions
		* are to prepare the chip's SPI interface for a specific bus speed, and a host
		* processor's endianness. This will create and distribute regmaps for any
		* children.
		*
		* Copyright 2021-2022 Innovative Advantage Inc.
		*
		* Author: Colin Foster <colin.foster@in-advantage.com>
		*/

		#include <linux/device.h>
		#include <linux/err.h>
		#include <linux/errno.h>
		#include <linux/export.h>
		#include <linux/ioport.h>
		#include <linux/mod_devicetable.h>
		#include <linux/module.h>
		#include <linux/regmap.h>
		#include <linux/spi/spi.h>
		#include <linux/types.h>
		#include <linux/units.h>

		#include "ocelot.h"

		#define REG_DEV_CPUORG_IF_CTRL 0x0000
		#define REG_DEV_CPUORG_IF_CFGSTAT 0x0004

		#define CFGSTAT_IF_NUM_VCORE (0 << 24)
		#define CFGSTAT_IF_NUM_VRAP (1 << 24)
		#define CFGSTAT_IF_NUM_SI (2 << 24)
		#define CFGSTAT_IF_NUM_MIIM (3 << 24)

		#define VSC7512_DEVCPU_ORG_RES_START 0x71000000
		#define VSC7512_DEVCPU_ORG_RES_SIZE 0x38

		#define VSC7512_CHIP_REGS_RES_START 0x71070000
		#define VSC7512_CHIP_REGS_RES_SIZE 0x14

		static const struct resource vsc7512_dev_cpuorg_resource =
		DEFINE_RES_REG_NAMED(VSC7512_DEVCPU_ORG_RES_START,
		VSC7512_DEVCPU_ORG_RES_SIZE,
		"devcpu_org");

		static const struct resource vsc7512_gcb_resource =
		DEFINE_RES_REG_NAMED(VSC7512_CHIP_REGS_RES_START,
		VSC7512_CHIP_REGS_RES_SIZE,
		"devcpu_gcb_chip_regs");

		static int ocelot_spi_initialize(struct device *dev)
		{
		struct ocelot_ddata *ddata = dev_get_drvdata(dev);
		u32 val, check;
		int err;

		val = OCELOT_SPI_BYTE_ORDER;

		/*
		* The SPI address must be big-endian, but we want the payload to match
		* our CPU. These are two bits (0 and 1) but they're repeated such that
		* the write from any configuration will be valid. The four
		* configurations are:
		*
		* 0b00: little-endian, MSB first
		* \| 111111 \| 22221111 \| 33222222 \|
		* \| 76543210 \| 54321098 \| 32109876 \| 10987654 \|
		*
		* 0b01: big-endian, MSB first
		* \| 33222222 \| 22221111 \| 111111 \| \|
		* \| 10987654 \| 32109876 \| 54321098 \| 76543210 \|
		*
		* 0b10: little-endian, LSB first
		* \| 111111 \| 11112222 \| 22222233 \|
		* \| 01234567 \| 89012345 \| 67890123 \| 45678901 \|
		*
		* 0b11: big-endian, LSB first
		* \| 22222233 \| 11112222 \| 111111 \| \|
		* \| 45678901 \| 67890123 \| 89012345 \| 01234567 \|
		*/
		err = regmap_write(ddata->cpuorg_regmap, REG_DEV_CPUORG_IF_CTRL, val);
		if (err)
		return err;

		/*
		* Apply the number of padding bytes between a read request and the data
		* payload. Some registers have access times of up to 1us, so if the
		* first payload bit is shifted out too quickly, the read will fail.
		*/
		val = ddata->spi_padding_bytes;
		err = regmap_write(ddata->cpuorg_regmap, REG_DEV_CPUORG_IF_CFGSTAT, val);
		if (err)
		return err;

		/*
		* After we write the interface configuration, read it back here. This
		* will verify several different things. The first is that the number of
		* padding bytes actually got written correctly. These are found in bits
		* 0:3.
		*
		* The second is that bit 16 is cleared. Bit 16 is IF_CFGSTAT:IF_STAT,
		* and will be set if the register access is too fast. This would be in
		* the condition that the number of padding bytes is insufficient for
		* the SPI bus frequency.
		*
		* The last check is for bits 31:24, which define the interface by which
		* the registers are being accessed. Since we're accessing them via the
		* serial interface, it must return IF_NUM_SI.
		*/
		check = val \| CFGSTAT_IF_NUM_SI;

		err = regmap_read(ddata->cpuorg_regmap, REG_DEV_CPUORG_IF_CFGSTAT, &val);
		if (err)
		return err;

		if (check != val)
		return -ENODEV;

		return 0;
		}

		static const struct regmap_config ocelot_spi_regmap_config = {
		.reg_bits = 24,
		.reg_stride = 4,
		.reg_downshift = 2,
		.val_bits = 32,

		.write_flag_mask = 0x80,

		.use_single_write = true,
		.can_multi_write = false,

		.reg_format_endian = REGMAP_ENDIAN_BIG,
		.val_format_endian = REGMAP_ENDIAN_NATIVE,
		};

		static int ocelot_spi_regmap_bus_read(void context, const void reg, size_t reg_size,
		void *val, size_t val_size)
		{
		struct spi_transfer xfers[3] = {0};
		struct device *dev = context;
		struct ocelot_ddata *ddata;
		struct spi_device *spi;
		struct spi_message msg;
		unsigned int index = 0;

		ddata = dev_get_drvdata(dev);
		spi = to_spi_device(dev);

		xfers[index].tx_buf = reg;
		xfers[index].len = reg_size;
		index++;

		if (ddata->spi_padding_bytes) {
		xfers[index].len = ddata->spi_padding_bytes;
		xfers[index].tx_buf = ddata->dummy_buf;
		xfers[index].dummy_data = 1;
		index++;
		}

		xfers[index].rx_buf = val;
		xfers[index].len = val_size;
		index++;

		spi_message_init_with_transfers(&msg, xfers, index);

		return spi_sync(spi, &msg);
		}

		static int ocelot_spi_regmap_bus_write(void context, const void data, size_t count)
		{
		struct device *dev = context;
		struct spi_device *spi = to_spi_device(dev);

		return spi_write(spi, data, count);
		}

		static const struct regmap_bus ocelot_spi_regmap_bus = {
		.write = ocelot_spi_regmap_bus_write,
		.read = ocelot_spi_regmap_bus_read,
		};

		struct regmap ocelot_spi_init_regmap(struct device dev, const struct resource *res)
		{
		struct regmap_config regmap_config;

		memcpy(&regmap_config, &ocelot_spi_regmap_config, sizeof(regmap_config));

		regmap_config.name = res->name;
		regmap_config.max_register = resource_size(res) - 1;
		regmap_config.reg_base = res->start;

		return devm_regmap_init(dev, &ocelot_spi_regmap_bus, dev, &regmap_config);
		}
		EXPORT_SYMBOL_NS(ocelot_spi_init_regmap, MFD_OCELOT_SPI);

		static int ocelot_spi_probe(struct spi_device *spi)
		{
		struct device *dev = &spi->dev;
		struct ocelot_ddata *ddata;
		struct regmap *r;
		int err;

		ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
		if (!ddata)
		return -ENOMEM;

		spi_set_drvdata(spi, ddata);

		if (spi->max_speed_hz <= 500000) {
		ddata->spi_padding_bytes = 0;
		} else {
		/*
		* Calculation taken from the manual for IF_CFGSTAT:IF_CFG.
		* Register access time is 1us, so we need to configure and send
		* out enough padding bytes between the read request and data
		* transmission that lasts at least 1 microsecond.
		*/
		ddata->spi_padding_bytes = 1 + (spi->max_speed_hz / HZ_PER_MHZ + 2) / 8;

		ddata->dummy_buf = devm_kzalloc(dev, ddata->spi_padding_bytes, GFP_KERNEL);
		if (!ddata->dummy_buf)
		return -ENOMEM;
		}

		spi->bits_per_word = 8;

		err = spi_setup(spi);
		if (err)
		return dev_err_probe(&spi->dev, err, "Error performing SPI setup\n");

		r = ocelot_spi_init_regmap(dev, &vsc7512_dev_cpuorg_resource);
		if (IS_ERR(r))
		return PTR_ERR(r);

		ddata->cpuorg_regmap = r;

		r = ocelot_spi_init_regmap(dev, &vsc7512_gcb_resource);
		if (IS_ERR(r))
		return PTR_ERR(r);

		ddata->gcb_regmap = r;

		/*
		* The chip must be set up for SPI before it gets initialized and reset.
		* This must be done before calling init, and after a chip reset is
		* performed.
		*/
		err = ocelot_spi_initialize(dev);
		if (err)
		return dev_err_probe(dev, err, "Error initializing SPI bus\n");

		err = ocelot_chip_reset(dev);
		if (err)
		return dev_err_probe(dev, err, "Error resetting device\n");

		/*
		* A chip reset will clear the SPI configuration, so it needs to be done
		* again before we can access any registers.
		*/
		err = ocelot_spi_initialize(dev);
		if (err)
		return dev_err_probe(dev, err, "Error initializing SPI bus after reset\n");

		err = ocelot_core_init(dev);
		if (err)
		return dev_err_probe(dev, err, "Error initializing Ocelot core\n");

		return 0;
		}

		static const struct spi_device_id ocelot_spi_ids[] = {
		{ "vsc7512", 0 },
		{ }
		};

		static const struct of_device_id ocelot_spi_of_match[] = {
		{ .compatible = "mscc,vsc7512" },
		{ }
		};
		MODULE_DEVICE_TABLE(of, ocelot_spi_of_match);

		static struct spi_driver ocelot_spi_driver = {
		.driver = {
		.name = "ocelot-soc",
		.of_match_table = ocelot_spi_of_match,
		},
		.id_table = ocelot_spi_ids,
		.probe = ocelot_spi_probe,
		};
		module_spi_driver(ocelot_spi_driver);

		MODULE_DESCRIPTION("SPI Controlled Ocelot Chip Driver");
		MODULE_AUTHOR("Colin Foster <colin.foster@in-advantage.com>");
		MODULE_LICENSE("Dual MIT/GPL");
		MODULE_IMPORT_NS(MFD_OCELOT);