Message-Id: <1475853451-22121-6-git-send-email-pantelis.antoniou@konsulko.com>
Date:   Fri,  7 Oct 2016 18:17:26 +0300
From:   Pantelis Antoniou <pantelis.antoniou@...sulko.com>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Alexandre Courbot <gnurou@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        Frank Rowand <frowand.list@...il.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Wim Van Sebroeck <wim@...ana.be>,
        Guenter Roeck <linux@...ck-us.net>,
        Peter Rosin <peda@...ntia.se>,
        Debjit Ghosh <dghosh@...iper.net>,
        Georgi Vlaev <gvlaev@...iper.net>,
        Guenter Roeck <groeck@...iper.net>,
        JawaharBalaji Thirumalaisamy <jawaharb@...iper.net>,
        Rajat Jain <rajatjain@...iper.net>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-gpio@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-mtd@...ts.infradead.org, linux-watchdog@...r.kernel.org
Subject: [PATCH 05/10] i2c/muxes: Juniper's PTXPMB CPLD I2C multiplexer

From: Guenter Roeck <groeck@...iper.net>

Introduce Juniper's PTX PMB CPLD I2C multiplexer driver.

Signed-off-by: Debjit Ghosh <dghosh@...iper.net>
Signed-off-by: Georgi Vlaev <gvlaev@...iper.net>
Signed-off-by: Guenter Roeck <groeck@...iper.net>
Signed-off-by: JawaharBalaji Thirumalaisamy <jawaharb@...iper.net>
Signed-off-by: Rajat Jain <rajatjain@...iper.net>
[Ported from Juniper kernel]
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@...sulko.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@...iper.net>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:i2c-mux-ptxpmb-cpld");
-- 
1.9.1

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