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    Subject[PATCH 05/10] i2c/muxes: Juniper's PTXPMB CPLD I2C multiplexer
    Date
    From: Guenter Roeck <groeck@juniper.net>

    Introduce Juniper's PTX PMB CPLD I2C multiplexer driver.

    Signed-off-by: Debjit Ghosh <dghosh@juniper.net>
    Signed-off-by: Georgi Vlaev <gvlaev@juniper.net>
    Signed-off-by: Guenter Roeck <groeck@juniper.net>
    Signed-off-by: JawaharBalaji Thirumalaisamy <jawaharb@juniper.net>
    Signed-off-by: Rajat Jain <rajatjain@juniper.net>
    [Ported from Juniper kernel]
    Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
    ---
    drivers/i2c/muxes/Kconfig | 11 ++
    drivers/i2c/muxes/Makefile | 1 +
    drivers/i2c/muxes/i2c-mux-ptxpmb.c | 299 +++++++++++++++++++++++++++++++++++++
    3 files changed, 311 insertions(+)
    create mode 100644 drivers/i2c/muxes/i2c-mux-ptxpmb.c

    diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
    index e280c8e..f45a9cb 100644
    --- a/drivers/i2c/muxes/Kconfig
    +++ b/drivers/i2c/muxes/Kconfig
    @@ -61,6 +61,17 @@ config I2C_MUX_PINCTRL
    This driver can also be built as a module. If so, the module will be
    called pinctrl-i2cmux.

    +config I2C_MUX_PTXPMB
    + tristate "Juniper PTX PMB CPLD I2C multiplexer"
    + depends on MFD_JUNIPER_CPLD
    + default y if MFD_JUNIPER_CPLD
    + help
    + Select this to enable the Juniper PTX PMB CPLD I2C multiplexer driver
    + on the relevant Juniper platforms.
    +
    + This driver can also be built as a module. If so, the module
    + will be called i2c-mux-ptxpmb-cpld.
    +
    config I2C_MUX_REG
    tristate "Register-based I2C multiplexer"
    help
    diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
    index 7c267c2..78d8cba 100644
    --- a/drivers/i2c/muxes/Makefile
    +++ b/drivers/i2c/muxes/Makefile
    @@ -9,6 +9,7 @@ obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o
    obj-$(CONFIG_I2C_MUX_PCA9541) += i2c-mux-pca9541.o
    obj-$(CONFIG_I2C_MUX_PCA954x) += i2c-mux-pca954x.o
    obj-$(CONFIG_I2C_MUX_PINCTRL) += i2c-mux-pinctrl.o
    +obj-$(CONFIG_I2C_MUX_PTXPMB) += i2c-mux-ptxpmb.o
    obj-$(CONFIG_I2C_MUX_REG) += i2c-mux-reg.o

    ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
    diff --git a/drivers/i2c/muxes/i2c-mux-ptxpmb.c b/drivers/i2c/muxes/i2c-mux-ptxpmb.c
    new file mode 100644
    index 0000000..e8c7aee
    --- /dev/null
    +++ b/drivers/i2c/muxes/i2c-mux-ptxpmb.c
    @@ -0,0 +1,299 @@
    +/*
    + * PTX PMB CPLD I2C multiplexer
    + *
    + * Copyright (c) 2012, Juniper Networks. All rights reserved.
    + *
    + * This program is free software; you can redistribute it and/or modify it
    + * under the terms and conditions of the GNU General Public License,
    + * version 2, as published by the Free Software Foundation.
    + *
    + * This program is distributed in the hope 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.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program. If not, see <http://www.gnu.org/licenses/>.
    + */
    +
    +#include <linux/delay.h>
    +#include <linux/i2c.h>
    +#include <linux/i2c-mux.h>
    +#include <linux/init.h>
    +#include <linux/module.h>
    +#include <linux/platform_device.h>
    +#include <linux/slab.h>
    +#include <linux/mfd/ptxpmb_cpld.h>
    +#include <linux/io.h>
    +#include <linux/of_device.h>
    +
    +struct i2c_mux_ptxpmb {
    + struct device *dev;
    + struct ptxpmb_mux_data *pdata;
    + struct pmb_boot_cpld __iomem *cpld;
    + struct i2c_adapter *parent;
    + int bus_count;
    + struct i2c_mux_core *muxc;
    +};
    +
    +static const struct of_device_id i2c_mux_ptxpmb_of_match[] = {
    + { .compatible = "jnx,i2c-mux-ptxpmb-cpld",
    + .data = (void *)CPLD_TYPE_PTXPMB },
    + { .compatible = "jnx,i2c-mux-ngpmb-bcpld",
    + .data = (void *)CPLD_TYPE_NGPMB },
    + { },
    +};
    +MODULE_DEVICE_TABLE(of, i2c_mux_ptxpmb_of_match);
    +
    +#define I2C_GRP_FORCE_EN 0x80
    +
    +static int i2c_mux_ptxpmb_select(struct i2c_mux_core *muxc, u32 chan)
    +{
    + struct i2c_mux_ptxpmb *mux = i2c_mux_priv(muxc);
    + struct ptxpmb_mux_data *pdata = mux->pdata;
    + u8 group, enable, val;
    +
    + switch (pdata->cpld_type) {
    + case CPLD_TYPE_PTXPMB:
    + group = chan % pdata->num_channels;
    + enable = 1 << (chan / pdata->num_channels);
    + /*
    + * Writing into the enable register does not have an effect on
    + * FPC with P2020. It is necessary for FPC with P5020/P5040.
    + * The uKernel for SPMB uses undocumented CPLD registers to set
    + * group enable values (i2c_group_sel_force and
    + * i2c_group_en_force at offset 0x33 and 0x34). Bit 7 in
    + * i2c_group_sel_force must be set for this to work.
    + * i2c_group_en_force is active-low. This applies to SPMB with
    + * P2020; behavior with P5020/P5040 is unknown at this time.
    + */
    + if (pdata->use_force) {
    + iowrite8(group | I2C_GRP_FORCE_EN,
    + &mux->cpld->i2c_group_sel_force);
    + iowrite8(~enable, &mux->cpld->i2c_group_en_force);
    + } else {
    + iowrite8(group, &mux->cpld->i2c_group_sel);
    + ioread8(&mux->cpld->i2c_group_sel);
    + iowrite8(enable, &mux->cpld->i2c_group_en);
    + ioread8(&mux->cpld->i2c_group_en);
    + }
    + break;
    + case CPLD_TYPE_NGPMB:
    + val = ioread8(&mux->cpld->gpio_2);
    + val &= ~NGPMB_I2C_GRP_SEL_MASK;
    + val |= (chan << NGPMB_I2C_GRP_SEL_LSB) & NGPMB_I2C_GRP_SEL_MASK;
    + iowrite8(val, &mux->cpld->gpio_2);
    + break;
    + }
    + udelay(50);
    +
    + return 0;
    +}
    +
    +static int i2c_mux_ptxpmb_deselect(struct i2c_mux_core *muxc, u32 chan)
    +{
    + struct i2c_mux_ptxpmb *mux = i2c_mux_priv(muxc);
    + u8 val;
    +
    + switch (mux->pdata->cpld_type) {
    + case CPLD_TYPE_PTXPMB:
    + /*
    + * Restore defaults. Note that setting i2c_group_en does not
    + * have an effect on FPC with P2020, but is necessary for FPC
    + * with P5020/P5040.
    + */
    + if (mux->pdata->use_force) {
    + iowrite8(0 | I2C_GRP_FORCE_EN,
    + &mux->cpld->i2c_group_sel_force);
    + iowrite8(0xff, &mux->cpld->i2c_group_en_force);
    + } else {
    + iowrite8(0, &mux->cpld->i2c_group_sel);
    + ioread8(&mux->cpld->i2c_group_sel);
    + iowrite8(0, &mux->cpld->i2c_group_en);
    + ioread8(&mux->cpld->i2c_group_en);
    + }
    + break;
    + case CPLD_TYPE_NGPMB:
    + /* Use the (unconnected) channel 3 to deselct */
    + val = ioread8(&mux->cpld->gpio_2);
    + val &= ~NGPMB_I2C_GRP_SEL_MASK;
    + val |= (3 << NGPMB_I2C_GRP_SEL_LSB) & NGPMB_I2C_GRP_SEL_MASK;
    + iowrite8(val, &mux->cpld->gpio_2);
    + break;
    + }
    + return 0;
    +}
    +
    +#ifdef CONFIG_OF
    +static int i2c_mux_ptxpmb_parse_dt(struct i2c_mux_ptxpmb *mux,
    + struct device *dev)
    +{
    + struct device_node *np = dev->of_node;
    + int ret;
    + struct device_node *adapter_np;
    + struct i2c_adapter *adapter;
    + const struct of_device_id *match;
    +
    + if (!np)
    + return 0;
    +
    + mux->pdata = devm_kzalloc(dev, sizeof(*mux->pdata), GFP_KERNEL);
    + if (!mux->pdata)
    + return -ENOMEM;
    +
    + match = of_match_device(i2c_mux_ptxpmb_of_match, dev);
    + if (match)
    + mux->pdata->cpld_type = (int)(unsigned long)match->data;
    +
    + ret = of_property_read_u32(np, "num-enable", &mux->pdata->num_enable);
    + if (ret) {
    + dev_err(dev, "num-enable missing\n");
    + return -ENODEV;
    + }
    +
    + ret = of_property_read_u32(np, "num-channels",
    + &mux->pdata->num_channels);
    + if (ret)
    + mux->pdata->num_channels = 8;
    +
    + ret = of_property_read_u32(np, "base-bus-num",
    + &mux->pdata->base_bus_num);
    + if (ret)
    + mux->pdata->base_bus_num = 0;
    +
    + if (of_find_property(np, "use-force", NULL))
    + mux->pdata->use_force = true;
    +
    + adapter_np = of_parse_phandle(np, "i2c-parent", 0);
    + if (!adapter_np) {
    + dev_err(dev, "Cannot parse i2c-parent\n");
    + return -ENODEV;
    + }
    + adapter = of_find_i2c_adapter_by_node(adapter_np);
    + if (!adapter) {
    + dev_err(dev, "Cannot find parent bus\n");
    + return -ENODEV;
    + }
    + mux->pdata->parent_bus_num = i2c_adapter_id(adapter);
    + put_device(&adapter->dev);
    +
    + return 0;
    +}
    +#else
    +static inline int i2c_mux_ptxpmb_parse_dt(struct i2c_mux_ptxpmb *mux,
    + struct device *dev)
    +{
    + return 0;
    +}
    +#endif
    +
    +static int i2c_mux_ptxpmb_probe(struct platform_device *pdev)
    +{
    + struct i2c_mux_ptxpmb *mux;
    + struct i2c_mux_core *muxc;
    + int i, ret;
    + struct resource *res;
    + struct device *dev = &pdev->dev;
    +
    + mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
    + if (!mux)
    + return -ENOMEM;
    +
    + platform_set_drvdata(pdev, mux);
    +
    + mux->dev = dev;
    +
    + mux->pdata = dev->platform_data;
    + if (!mux->pdata) {
    + ret = i2c_mux_ptxpmb_parse_dt(mux, dev);
    + if (ret < 0)
    + return ret;
    + }
    + if (!mux->pdata) {
    + dev_err(dev, "No platform / devicetree data\n");
    + return -ENODEV;
    + }
    +
    + if (mux->pdata->num_enable <= 0 || mux->pdata->num_enable > 8 ||
    + mux->pdata->num_channels <= 0 || mux->pdata->num_channels > 8) {
    + dev_err(dev, "Invalid platform data\n");
    + return -EINVAL;
    + }
    +
    + mux->bus_count = mux->pdata->num_enable * mux->pdata->num_channels;
    +
    + mux->parent = i2c_get_adapter(mux->pdata->parent_bus_num);
    + if (!mux->parent) {
    + dev_err(dev, "Parent adapter (%d) not found\n",
    + mux->pdata->parent_bus_num);
    + return -ENODEV;
    + }
    +
    + muxc = i2c_mux_alloc(mux->parent, dev, mux->bus_count, 0, 0,
    + i2c_mux_ptxpmb_select, i2c_mux_ptxpmb_deselect);
    + if (!muxc) {
    + ret = -ENOMEM;
    + goto err;
    + }
    + muxc->priv = mux;
    + mux->muxc = muxc;
    +
    + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    + if (!res) {
    + dev_err(dev, "No memory resource\n");
    + ret = -ENODEV;
    + goto err;
    + }
    +
    + mux->cpld = devm_ioremap_nocache(dev, res->start, resource_size(res));
    + if (!mux->cpld) {
    + ret = -ENOMEM;
    + goto err;
    + }
    +
    + for (i = 0; i < mux->bus_count; i++) {
    + u32 bus = mux->pdata->base_bus_num ?
    + mux->pdata->base_bus_num + i : 0;
    +
    + ret = i2c_mux_add_adapter(muxc, bus, i, 0);
    + if (ret) {
    + dev_err(dev, "Failed to add adapter %d\n", i);
    + goto err_del_adapter;
    + }
    + }
    +
    + return 0;
    +
    +err_del_adapter:
    + i2c_mux_del_adapters(mux->muxc);
    +err:
    + i2c_put_adapter(mux->parent);
    + return ret;
    +}
    +
    +static int i2c_mux_ptxpmb_remove(struct platform_device *pdev)
    +{
    + struct i2c_mux_ptxpmb *mux = platform_get_drvdata(pdev);
    +
    + i2c_mux_del_adapters(mux->muxc);
    + i2c_put_adapter(mux->parent);
    +
    + return 0;
    +}
    +
    +static struct platform_driver i2c_mux_ptxpmb_driver = {
    + .driver = {
    + .name = "i2c-mux-ptxpmb-cpld",
    + .owner = THIS_MODULE,
    + .of_match_table = i2c_mux_ptxpmb_of_match,
    + },
    + .probe = i2c_mux_ptxpmb_probe,
    + .remove = i2c_mux_ptxpmb_remove,
    +};
    +
    +module_platform_driver(i2c_mux_ptxpmb_driver);
    +
    +MODULE_DESCRIPTION("ptxpmb CPLD I2C multiplexer driver");
    +MODULE_AUTHOR("Guenter Roeck <groeck@juniper.net>");
    +MODULE_LICENSE("GPL v2");
    +MODULE_ALIAS("platform:i2c-mux-ptxpmb-cpld");
    --
    1.9.1
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