mfd: intel_quark_i2c_gpio: Add Intel Quark X1000 I2C-GPIO MFD Driver

In Quark X1000, there's a single PCI device that provides both
an I2C controller and a GPIO controller. This MFD driver will
split the 2 devices for their respective drivers.

This patch is based on Josef Ahmad's initial work for Quark enabling.
Acked-by: Michael Turquette <mturquette@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Weike Chen <alvin.chen@intel.com>
Signed-off-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -283,6 +283,18 @@ config HTC_I2CPLD
 	  This device provides input and output GPIOs through an I2C
 	  interface to one or more sub-chips.
 
+config MFD_INTEL_QUARK_I2C_GPIO
+	tristate "Intel Quark MFD I2C GPIO"
+	depends on PCI
+	depends on X86
+	depends on COMMON_CLK
+	select MFD_CORE
+	help
+	  This MFD provides support for I2C and GPIO that exist only
+	  in a single PCI device. It splits the 2 IO devices to
+	  their respective IO driver.
+	  The GPIO exports a total amount of 8 interrupt-capable GPIOs.
+
 config LPC_ICH
 	tristate "Intel ICH LPC"
 	depends on PCI

drivers/mfd/Makefile

@@ -139,6 +139,7 @@ obj-$(CONFIG_AB8500_CORE)	+= ab8500-core.o ab8500-sysctrl.o
 obj-$(CONFIG_MFD_TIMBERDALE)    += timberdale.o
 obj-$(CONFIG_PMIC_ADP5520)	+= adp5520.o
 obj-$(CONFIG_MFD_KEMPLD)	+= kempld-core.o
+obj-$(CONFIG_MFD_INTEL_QUARK_I2C_GPIO)	+= intel_quark_i2c_gpio.o
 obj-$(CONFIG_LPC_SCH)		+= lpc_sch.o
 obj-$(CONFIG_LPC_ICH)		+= lpc_ich.o
 obj-$(CONFIG_MFD_RDC321X)	+= rdc321x-southbridge.o

drivers/mfd/intel_quark_i2c_gpio.c

+/*
+ * Intel Quark MFD PCI driver for I2C & GPIO
+ *
+ * Copyright(c) 2014 Intel Corporation.
+ *
+ * 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.
+ *
+ * Intel Quark PCI device for I2C and GPIO controller sharing the same
+ * PCI function. This PCI driver will split the 2 devices into their
+ * respective drivers.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/mfd/core.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/dmi.h>
+#include <linux/platform_data/gpio-dwapb.h>
+#include <linux/platform_data/i2c-designware.h>
+
+/* PCI BAR for register base address */
+#define MFD_I2C_BAR		0
+#define MFD_GPIO_BAR		1
+
+/* The base GPIO number under GPIOLIB framework */
+#define INTEL_QUARK_MFD_GPIO_BASE	8
+
+/* The default number of South-Cluster GPIO on Quark. */
+#define INTEL_QUARK_MFD_NGPIO		8
+
+/* The DesignWare GPIO ports on Quark. */
+#define INTEL_QUARK_GPIO_NPORTS	1
+
+#define INTEL_QUARK_IORES_MEM	0
+#define INTEL_QUARK_IORES_IRQ	1
+
+#define INTEL_QUARK_I2C_CONTROLLER_CLK "i2c_designware.0"
+
+/* The Quark I2C controller source clock */
+#define INTEL_QUARK_I2C_CLK_HZ	33000000
+
+#define INTEL_QUARK_I2C_NCLK	1
+
+struct intel_quark_mfd {
+	struct pci_dev		*pdev;
+	struct clk		*i2c_clk;
+	struct clk_lookup	*i2c_clk_lookup;
+};
+
+struct i2c_mode_info {
+	const char *name;
+	unsigned int i2c_scl_freq;
+};
+
+static const struct i2c_mode_info platform_i2c_mode_info[] = {
+	{
+		.name = "Galileo",
+		.i2c_scl_freq = 100000,
+	},
+	{
+		.name = "GalileoGen2",
+		.i2c_scl_freq = 400000,
+	},
+};
+
+static struct resource intel_quark_i2c_res[] = {
+	[INTEL_QUARK_IORES_MEM] = {
+		.flags = IORESOURCE_MEM,
+	},
+	[INTEL_QUARK_IORES_IRQ] = {
+		.flags = IORESOURCE_IRQ,
+	},
+};
+
+static struct resource intel_quark_gpio_res[] = {
+	[INTEL_QUARK_IORES_MEM] = {
+		.flags = IORESOURCE_MEM,
+	},
+};
+
+static struct mfd_cell intel_quark_mfd_cells[] = {
+	{
+		.id = MFD_I2C_BAR,
+		.name = "i2c_designware",
+		.num_resources = ARRAY_SIZE(intel_quark_i2c_res),
+		.resources = intel_quark_i2c_res,
+		.ignore_resource_conflicts = true,
+	},
+	{
+		.id = MFD_GPIO_BAR,
+		.name = "gpio-dwapb",
+		.num_resources = ARRAY_SIZE(intel_quark_gpio_res),
+		.resources = intel_quark_gpio_res,
+		.ignore_resource_conflicts = true,
+	},
+};
+
+static const struct pci_device_id intel_quark_mfd_ids[] = {
+	{ PCI_VDEVICE(INTEL, 0x0934), },
+	{},
+};
+MODULE_DEVICE_TABLE(pci, intel_quark_mfd_ids);
+
+static int intel_quark_register_i2c_clk(struct intel_quark_mfd *quark_mfd)
+{
+	struct pci_dev *pdev = quark_mfd->pdev;
+	struct clk_lookup *i2c_clk_lookup;
+	struct clk *i2c_clk;
+	int ret;
+
+	i2c_clk_lookup = devm_kcalloc(&pdev->dev, INTEL_QUARK_I2C_NCLK,
+				      sizeof(*i2c_clk_lookup), GFP_KERNEL);
+	if (!i2c_clk_lookup)
+		return -ENOMEM;
+
+	i2c_clk_lookup[0].dev_id = INTEL_QUARK_I2C_CONTROLLER_CLK;
+
+	i2c_clk = clk_register_fixed_rate(&pdev->dev,
+					  INTEL_QUARK_I2C_CONTROLLER_CLK, NULL,
+					  CLK_IS_ROOT, INTEL_QUARK_I2C_CLK_HZ);
+
+	quark_mfd->i2c_clk_lookup = i2c_clk_lookup;
+	quark_mfd->i2c_clk = i2c_clk;
+
+	ret = clk_register_clkdevs(i2c_clk, i2c_clk_lookup,
+				   INTEL_QUARK_I2C_NCLK);
+	if (ret)
+		dev_err(&pdev->dev, "Fixed clk register failed: %d\n", ret);
+
+	return ret;
+}
+
+static void intel_quark_unregister_i2c_clk(struct pci_dev *pdev)
+{
+	struct intel_quark_mfd *quark_mfd = dev_get_drvdata(&pdev->dev);
+
+	if (!quark_mfd->i2c_clk || !quark_mfd->i2c_clk_lookup)
+		return;
+
+	clkdev_drop(quark_mfd->i2c_clk_lookup);
+	clk_unregister(quark_mfd->i2c_clk);
+}
+
+static int intel_quark_i2c_setup(struct pci_dev *pdev, struct mfd_cell *cell)
+{
+	const char *board_name = dmi_get_system_info(DMI_BOARD_NAME);
+	struct dw_i2c_platform_data *pdata;
+	struct resource *res = (struct resource *)cell->resources;
+	struct device *dev = &pdev->dev;
+	unsigned int i;
+
+	res[INTEL_QUARK_IORES_MEM].start =
+		pci_resource_start(pdev, MFD_I2C_BAR);
+	res[INTEL_QUARK_IORES_MEM].end =
+		pci_resource_end(pdev, MFD_I2C_BAR);
+
+	res[INTEL_QUARK_IORES_IRQ].start = pdev->irq;
+	res[INTEL_QUARK_IORES_IRQ].end = pdev->irq;
+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	/* Fast mode by default */
+	pdata->i2c_scl_freq = 400000;
+
+	for (i = 0; i < ARRAY_SIZE(platform_i2c_mode_info); i++)
+		if (!strcmp(board_name, platform_i2c_mode_info[i].name))
+			pdata->i2c_scl_freq
+				= platform_i2c_mode_info[i].i2c_scl_freq;
+
+	cell->platform_data = pdata;
+	cell->pdata_size = sizeof(*pdata);
+
+	return 0;
+}
+
+static int intel_quark_gpio_setup(struct pci_dev *pdev, struct mfd_cell *cell)
+{
+	struct dwapb_platform_data *pdata;
+	struct resource *res = (struct resource *)cell->resources;
+	struct device *dev = &pdev->dev;
+
+	res[INTEL_QUARK_IORES_MEM].start =
+		pci_resource_start(pdev, MFD_GPIO_BAR);
+	res[INTEL_QUARK_IORES_MEM].end =
+		pci_resource_end(pdev, MFD_GPIO_BAR);
+
+	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return -ENOMEM;
+
+	/* For intel quark x1000, it has only one port: portA */
+	pdata->nports = INTEL_QUARK_GPIO_NPORTS;
+	pdata->properties = devm_kcalloc(dev, pdata->nports,
+					 sizeof(*pdata->properties),
+					 GFP_KERNEL);
+	if (!pdata->properties)
+		return -ENOMEM;
+
+	/* Set the properties for portA */
+	pdata->properties->node		= NULL;
+	pdata->properties->name		= "intel-quark-x1000-gpio-portA";
+	pdata->properties->idx		= 0;
+	pdata->properties->ngpio	= INTEL_QUARK_MFD_NGPIO;
+	pdata->properties->gpio_base	= INTEL_QUARK_MFD_GPIO_BASE;
+	pdata->properties->irq		= pdev->irq;
+	pdata->properties->irq_shared	= true;
+
+	cell->platform_data = pdata;
+	cell->pdata_size = sizeof(*pdata);
+
+	return 0;
+}
+
+static int intel_quark_mfd_probe(struct pci_dev *pdev,
+				 const struct pci_device_id *id)
+{
+	struct intel_quark_mfd *quark_mfd;
+	int ret;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return ret;
+
+	quark_mfd = devm_kzalloc(&pdev->dev, sizeof(*quark_mfd), GFP_KERNEL);
+	if (!quark_mfd)
+		return -ENOMEM;
+	quark_mfd->pdev = pdev;
+
+	ret = intel_quark_register_i2c_clk(quark_mfd);
+	if (ret)
+		return ret;
+
+	dev_set_drvdata(&pdev->dev, quark_mfd);
+
+	ret = intel_quark_i2c_setup(pdev, &intel_quark_mfd_cells[MFD_I2C_BAR]);
+	if (ret)
+		return ret;
+
+	ret = intel_quark_gpio_setup(pdev,
+				     &intel_quark_mfd_cells[MFD_GPIO_BAR]);
+	if (ret)
+		return ret;
+
+	return mfd_add_devices(&pdev->dev, 0, intel_quark_mfd_cells,
+			       ARRAY_SIZE(intel_quark_mfd_cells), NULL, 0,
+			       NULL);
+}
+
+static void intel_quark_mfd_remove(struct pci_dev *pdev)
+{
+	intel_quark_unregister_i2c_clk(pdev);
+	mfd_remove_devices(&pdev->dev);
+}
+
+static struct pci_driver intel_quark_mfd_driver = {
+	.name		= "intel_quark_mfd_i2c_gpio",
+	.id_table	= intel_quark_mfd_ids,
+	.probe		= intel_quark_mfd_probe,
+	.remove		= intel_quark_mfd_remove,
+};
+
+module_pci_driver(intel_quark_mfd_driver);
+
+MODULE_AUTHOR("Raymond Tan <raymond.tan@intel.com>");
+MODULE_DESCRIPTION("Intel Quark MFD PCI driver for I2C & GPIO");
+MODULE_LICENSE("GPL v2");