Date:	Wed, 29 Apr 2015 09:23:50 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org,
	Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	Jarkko Nikula <jarkko.nikula@...ux.intel.com>
Subject: Re: [PATCH v1 3/3] mfd: Add support for Intel Sunrisepoint LPSS
 devices

On Tue, 31 Mar 2015, Andy Shevchenko wrote:
> The new coming Intel platforms such as Skylake will contain Sunrisepoint PCH.

Can you use the same naming conventions as the Skylake's predecessors?

Currently lpc_ich and lpc_sch exist.

> The main difference to the previous platforms is that the LPSS devices are
> compound devices where usually main (SPI, HSUART, or I2C) and DMA IPs are
> present.
> 
> This patch brings the driver for such devices found on Sunrisepoint PCH.
> 
> Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  drivers/mfd/Kconfig           |  24 ++
>  drivers/mfd/Makefile          |   3 +
>  drivers/mfd/intel-lpss-acpi.c |  84 +++++++
>  drivers/mfd/intel-lpss-pci.c  | 106 +++++++++
>  drivers/mfd/intel-lpss.c      | 523 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/mfd/intel-lpss.h      |  62 +++++

Can you move this to include/?

>  6 files changed, 802 insertions(+)
>  create mode 100644 drivers/mfd/intel-lpss-acpi.c
>  create mode 100644 drivers/mfd/intel-lpss-pci.c
>  create mode 100644 drivers/mfd/intel-lpss.c
>  create mode 100644 drivers/mfd/intel-lpss.h
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index d5ad04d..b1a6778 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -325,6 +325,30 @@ config INTEL_SOC_PMIC
>  	  thermal, charger and related power management functions
>  	  on these systems.
>  
> +config MFD_INTEL_LPSS
> +	tristate "Intel Low Power Subsystem support"
> +	depends on X86
> +	select COMMON_CLK
> +	select MFD_CORE
> +	help
> +	  This driver provides necessary plumbing for Intel Low Power
> +	  Subsystem (LPSS) devices such as I2C, SPI and HS-UART starting
> +	  from Intel Sunrisepoint (Intel Skylake PCH) and newer chipsets.
> +
> +config MFD_INTEL_LPSS_ACPI
> +	tristate "Intel Low Power Subsystem support in ACPI mode"
> +	depends on MFD_INTEL_LPSS && ACPI
> +	help
> +	  This driver support Intel Low Power Subsystem devices in ACPI
> +	  mode.
> +
> +config MFD_INTEL_LPSS_PCI
> +	tristate "Intel Low Power Subsystem support in PCI mode"
> +	depends on MFD_INTEL_LPSS && PCI
> +	help
> +	  This driver support Intel Low Power Subsystem devices in PCI
> +	  mode.
> +
>  config MFD_INTEL_MSIC
>  	bool "Intel MSIC"
>  	depends on INTEL_SCU_IPC
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 0e5cfeb..cdf29b9 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -161,6 +161,9 @@ obj-$(CONFIG_TPS65911_COMPARATOR)	+= tps65911-comparator.o
>  obj-$(CONFIG_MFD_TPS65090)	+= tps65090.o
>  obj-$(CONFIG_MFD_AAT2870_CORE)	+= aat2870-core.o
>  obj-$(CONFIG_MFD_ATMEL_HLCDC)	+= atmel-hlcdc.o
> +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-$(CONFIG_MFD_PALMAS)	+= palmas.o
>  obj-$(CONFIG_MFD_VIPERBOARD)    += viperboard.o
> diff --git a/drivers/mfd/intel-lpss-acpi.c b/drivers/mfd/intel-lpss-acpi.c
> new file mode 100644
> index 0000000..0d92d73
> --- /dev/null
> +++ b/drivers/mfd/intel-lpss-acpi.c
> @@ -0,0 +1,84 @@
> +/*
> + * Intel LPSS ACPI support.
> + *
> + * Copyright (C) 2015, Intel Corporation
> + *
> + * Authors: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> + *          Mika Westerberg <mika.westerberg@...ux.intel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/ioport.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pm.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/platform_device.h>
> +
> +#include "intel-lpss.h"
> +
> +static const struct intel_lpss_platform_info spt_info = {
> +	.clk_rate = 120000000,
> +};
> +
> +static const struct acpi_device_id intel_lpss_acpi_ids[] = {
> +	/* SPT */
> +	{ "INT3446", (kernel_ulong_t)&spt_info },
> +	{ "INT3447", (kernel_ulong_t)&spt_info },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(acpi, intel_lpss_acpi_ids);
> +
> +static int intel_lpss_acpi_probe(struct platform_device *pdev)
> +{
> +	struct intel_lpss_platform_info *info;
> +	const struct acpi_device_id *id;
> +
> +	id = acpi_match_device(intel_lpss_acpi_ids, &pdev->dev);
> +	if (!id)
> +		return -ENODEV;
> +
> +	info = devm_kmemdup(&pdev->dev, (void *)id->driver_data, sizeof(*info),
> +			    GFP_KERNEL);
> +	if (!info)
> +		return -ENOMEM;
> +
> +	info->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	info->irq = platform_get_irq(pdev, 0);
> +
> +	pm_runtime_set_active(&pdev->dev);
> +	pm_runtime_enable(&pdev->dev);
> +
> +	return intel_lpss_probe(&pdev->dev, info);
> +}
> +
> +static int intel_lpss_acpi_remove(struct platform_device *pdev)
> +{
> +	intel_lpss_remove(&pdev->dev);
> +	pm_runtime_disable(&pdev->dev);
> +
> +	return 0;
> +}
> +
> +static INTEL_LPSS_PM_OPS(intel_lpss_acpi_pm_ops);
> +
> +static struct platform_driver intel_lpss_acpi_driver = {
> +	.probe = intel_lpss_acpi_probe,
> +	.remove = intel_lpss_acpi_remove,
> +	.driver = {
> +		.name = "intel-lpss",
> +		.acpi_match_table = intel_lpss_acpi_ids,
> +		.pm = &intel_lpss_acpi_pm_ops,
> +	},
> +};
> +
> +module_platform_driver(intel_lpss_acpi_driver);
> +
> +MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@...ux.intel.com>");
> +MODULE_AUTHOR("Mika Westerberg <mika.westerberg@...ux.intel.com>");
> +MODULE_DESCRIPTION("Intel LPSS ACPI driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/mfd/intel-lpss-pci.c b/drivers/mfd/intel-lpss-pci.c
> new file mode 100644
> index 0000000..fd8d25d
> --- /dev/null
> +++ b/drivers/mfd/intel-lpss-pci.c
> @@ -0,0 +1,106 @@
> +/*
> + * Intel LPSS PCI support.
> + *
> + * Copyright (C) 2015, Intel Corporation
> + *
> + * Authors: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> + *          Mika Westerberg <mika.westerberg@...ux.intel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/ioport.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/pm.h>
> +#include <linux/pm_runtime.h>
> +
> +#include "intel-lpss.h"
> +
> +static int intel_lpss_pci_probe(struct pci_dev *pdev,
> +				const struct pci_device_id *id)
> +{
> +	struct intel_lpss_platform_info *info;
> +	int ret;
> +
> +	ret = pcim_enable_device(pdev);
> +	if (ret)
> +		return ret;
> +
> +	info = devm_kmemdup(&pdev->dev, (void *)id->driver_data, sizeof(*info),
> +			    GFP_KERNEL);
> +	if (!info)
> +		return -ENOMEM;
> +
> +	info->mem = &pdev->resource[0];
> +	info->irq = pdev->irq;
> +
> +	ret = intel_lpss_probe(&pdev->dev, info);
> +	if (ret)
> +		return ret;
> +
> +	pm_runtime_put(&pdev->dev);
> +	return 0;
> +}
> +
> +static void intel_lpss_pci_remove(struct pci_dev *pdev)
> +{
> +	pm_runtime_get_sync(&pdev->dev);
> +	intel_lpss_remove(&pdev->dev);
> +}
> +
> +static INTEL_LPSS_PM_OPS(intel_lpss_pci_pm_ops);
> +
> +static const struct intel_lpss_platform_info spt_info = {
> +	.clk_rate = 120000000,
> +};
> +
> +static const struct intel_lpss_platform_info spt_uart_info = {
> +	.clk_rate = 120000000,
> +	.clk_con_id = "baudclk",
> +};
> +
> +static const struct pci_device_id intel_lpss_pci_ids[] = {
> +	/* SPT-LP */
> +	{ PCI_VDEVICE(INTEL, 0x9d27), (kernel_ulong_t)&spt_uart_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d28), (kernel_ulong_t)&spt_uart_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d29), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d2a), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d60), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d61), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d62), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d63), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d64), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d65), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0x9d66), (kernel_ulong_t)&spt_uart_info },
> +	/* SPT-H */
> +	{ PCI_VDEVICE(INTEL, 0xa127), (kernel_ulong_t)&spt_uart_info },
> +	{ PCI_VDEVICE(INTEL, 0xa128), (kernel_ulong_t)&spt_uart_info },
> +	{ PCI_VDEVICE(INTEL, 0xa129), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0xa12a), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0xa160), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0xa161), (kernel_ulong_t)&spt_info },
> +	{ PCI_VDEVICE(INTEL, 0xa166), (kernel_ulong_t)&spt_uart_info },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(pci, intel_lpss_pci_ids);
> +
> +static struct pci_driver intel_lpss_pci_driver = {
> +	.name = "intel-lpss",
> +	.id_table = intel_lpss_pci_ids,
> +	.probe = intel_lpss_pci_probe,
> +	.remove = intel_lpss_pci_remove,
> +	.driver = {
> +		.pm = &intel_lpss_pci_pm_ops,
> +	},
> +};
> +
> +module_pci_driver(intel_lpss_pci_driver);
> +
> +MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@...ux.intel.com>");
> +MODULE_AUTHOR("Mika Westerberg <mika.westerberg@...ux.intel.com>");
> +MODULE_DESCRIPTION("Intel LPSS PCI driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/mfd/intel-lpss.c b/drivers/mfd/intel-lpss.c
> new file mode 100644
> index 0000000..78d1921
> --- /dev/null
> +++ b/drivers/mfd/intel-lpss.c
> @@ -0,0 +1,523 @@
> +/*
> + * Intel Sunrisepoint LPSS core support.
> + *
> + * Copyright (C) 2015, Intel Corporation
> + *
> + * Authors: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> + *          Mika Westerberg <mika.westerberg@...ux.intel.com>
> + *          Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> + *          Jarkko Nikula <jarkko.nikula@...ux.intel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk-provider.h>
> +#include <linux/debugfs.h>
> +#include <linux/idr.h>
> +#include <linux/ioport.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mfd/core.h>
> +#include <linux/platform_data/dma-dw.h>
> +#include <linux/pm_qos.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/seq_file.h>
> +
> +#include "intel-lpss.h"
> +
> +#define LPSS_DEV_OFFSET		0x000
> +#define LPSS_DEV_SIZE		0x200
> +#define LPSS_PRIV_OFFSET	0x200
> +#define LPSS_PRIV_SIZE		0x100
> +#define LPSS_IDMA_OFFSET	0x800
> +#define LPSS_IDMA_SIZE		0x800
> +
> +/* Offsets from lpss->priv */
> +#define LPSS_PRIV_RESETS		0x04
> +#define LPSS_PRIV_RESETS_FUNC		BIT(2)
> +#define LPSS_PRIV_RESETS_IDMA		0x3
> +
> +#define LPSS_PRIV_ACTIVELTR		0x10
> +#define LPSS_PRIV_IDLELTR		0x14
> +
> +#define LPSS_PRIV_LTR_REQ		BIT(15)
> +#define LPSS_PRIV_LTR_SCALE_MASK	0xc00
> +#define LPSS_PRIV_LTR_SCALE_1US		0x800
> +#define LPSS_PRIV_LTR_SCALE_32US	0xc00
> +#define LPSS_PRIV_LTR_VALUE_MASK	0x3ff
> +
> +#define LPSS_PRIV_CLK_GATE		0x38
> +#define LPSS_PRIV_CLK_GATE_IP_SHIFT	0
> +#define LPSS_PRIV_CLK_GATE_IDMA_SHIFT	2
> +#define LPSS_PRIV_CLK_GATE_EN_MASK	0x2 /* Dynamic gating disabled */
> +
> +#define LPSS_PRIV_CAPS			0xfc
> +#define LPSS_PRIV_CAPS_NO_IDMA		BIT(8)
> +#define LPSS_PRIV_CAPS_TYPE_SHIFT	4
> +#define LPSS_PRIV_CAPS_TYPE_MASK	(0xf << LPSS_PRIV_CAPS_TYPE_SHIFT)
> +
> +/* This matches the type field in CAPS register */
> +enum intel_lpss_dev_type {
> +	LPSS_DEV_I2C = 0,
> +	LPSS_DEV_UART,
> +	LPSS_DEV_SPI,
> +};
> +
> +struct intel_lpss {
> +	const struct intel_lpss_platform_info *info;
> +	enum intel_lpss_dev_type type;
> +	struct clk *clk;
> +	struct clk_lookup **clocks;
> +	unsigned int ndevs;
> +	const struct mfd_cell *devs;
> +	struct device *dev;
> +	void __iomem *priv;
> +	int devid;
> +	u32 caps;
> +	u32 active_ltr;
> +	u32 idle_ltr;
> +	struct dentry *debugfs;
> +};
> +
> +static const struct dw_dma_platform_data intel_lpss_idma_pdata = {
> +	.type = DW_DMAC_TYPE_INTEL,
> +	.nr_channels = 2,
> +	.is_private = true,
> +	.block_size = 0x1ffff,
> +	.nr_masters = 1,
> +	.data_width = {2},

.data_width = { 2 },

> +};
> +
> +static const struct resource intel_lpss_dev_resources[] = {
> +	DEFINE_RES_MEM_NAMED(LPSS_DEV_OFFSET, LPSS_DEV_SIZE, "lpss_dev"),
> +	DEFINE_RES_MEM_NAMED(LPSS_PRIV_OFFSET, LPSS_PRIV_SIZE, "lpss_priv"),
> +	DEFINE_RES_IRQ(0),
> +};

Why has this been called 'dev' and 'priv'?  Neither of which are
particularlly helpful address names and I can't find them in the
datasheet.  Why not 'base' and 'extended', or something?

> +static const struct resource intel_lpss_idma_resources[] = {
> +	DEFINE_RES_MEM(LPSS_IDMA_OFFSET, LPSS_IDMA_SIZE),
> +	DEFINE_RES_IRQ(0),
> +};
> +
> +/*
> + * Cells needs to be ordered so that the iDMA is created first. This is
> + * because we need to be sure the DMA is available when the host controller
> + * driver is probed.
> + */
> +static const struct mfd_cell intel_lpss_i2c_devs[] = {
> +	{
> +		.name = "dw_dmac",
> +		.num_resources = ARRAY_SIZE(intel_lpss_idma_resources),
> +		.resources = intel_lpss_idma_resources,
> +		.platform_data = (void *)&intel_lpss_idma_pdata,
> +		.pdata_size = sizeof(intel_lpss_idma_pdata),
> +	},
> +	{
> +		.name = "i2c_designware",
> +		.num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
> +		.resources = intel_lpss_dev_resources,
> +	},
> +};
> +
> +static const struct mfd_cell intel_lpss_uart_devs[] = {
> +	{
> +		.name = "dw_dmac",
> +		.num_resources = ARRAY_SIZE(intel_lpss_idma_resources),
> +		.resources = intel_lpss_idma_resources,
> +		.platform_data = (void *)&intel_lpss_idma_pdata,
> +		.pdata_size = sizeof(intel_lpss_idma_pdata),
> +	},
> +	{
> +		.name = "dw-apb-uart",
> +		.num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
> +		.resources = intel_lpss_dev_resources,
> +	},
> +};
> +
> +static const struct mfd_cell intel_lpss_spi_devs[] = {
> +	{
> +		.name = "dw_dmac",
> +		.num_resources = ARRAY_SIZE(intel_lpss_idma_resources),
> +		.resources = intel_lpss_idma_resources,
> +		.platform_data = (void *)&intel_lpss_idma_pdata,
> +		.pdata_size = sizeof(intel_lpss_idma_pdata),
> +	},
> +	{
> +		.name = "pxa2xx-spi",
> +		.num_resources = ARRAY_SIZE(intel_lpss_dev_resources),
> +		.resources = intel_lpss_dev_resources,
> +	},
> +};
> +
> +static DEFINE_IDA(intel_lpss_devid_ida);

What's wrong with using PLATFORM_DEVID_AUTO?

> +static struct dentry *intel_lpss_debugfs;
> +
> +static void intel_lpss_cache_ltr(struct intel_lpss *lpss)
> +{
> +	lpss->active_ltr = readl(lpss->priv + LPSS_PRIV_ACTIVELTR);
> +	lpss->idle_ltr = readl(lpss->priv + LPSS_PRIV_IDLELTR);
> +}
> +
> +static int intel_lpss_debugfs_add(struct intel_lpss *lpss)
> +{
> +	struct dentry *dir;
> +
> +	dir = debugfs_create_dir(dev_name(lpss->dev), intel_lpss_debugfs);
> +	if (IS_ERR(dir))
> +		return PTR_ERR(dir);
> +
> +	/* Cache the values into lpss structure */
> +	intel_lpss_cache_ltr(lpss);
> +
> +	debugfs_create_x32("capabilities", S_IRUGO, dir, &lpss->caps);
> +	debugfs_create_x32("active_ltr", S_IRUGO, dir, &lpss->active_ltr);
> +	debugfs_create_x32("idle_ltr", S_IRUGO, dir, &lpss->idle_ltr);
> +
> +	lpss->debugfs = dir;
> +	return 0;
> +}
> +
> +static void intel_lpss_debugfs_remove(struct intel_lpss *lpss)
> +{
> +	debugfs_remove_recursive(lpss->debugfs);
> +}

A comment here explaining what you're doing below wouldn't go amiss.

> +static void intel_lpss_ltr_set(struct device *dev, s32 val)
> +{
> +	struct intel_lpss *lpss = dev_get_drvdata(dev);
> +	u32 ltr;
> +
> +	ltr = readl(lpss->priv + LPSS_PRIV_ACTIVELTR);
> +
> +	if (val == PM_QOS_LATENCY_ANY || val < 0) {
> +		ltr &= ~LPSS_PRIV_LTR_REQ;
> +	} else {
> +		ltr |= LPSS_PRIV_LTR_REQ;
> +		ltr &= ~LPSS_PRIV_LTR_SCALE_MASK;
> +		ltr &= ~LPSS_PRIV_LTR_VALUE_MASK;
> +
> +		if (val > LPSS_PRIV_LTR_VALUE_MASK)
> +			ltr |= LPSS_PRIV_LTR_SCALE_32US | val >> 5;
> +		else
> +			ltr |= LPSS_PRIV_LTR_SCALE_1US | val;
> +	}
> +
> +	if (ltr == lpss->active_ltr)
> +		return;
> +
> +	writel(ltr, lpss->priv + LPSS_PRIV_ACTIVELTR);
> +	writel(ltr, lpss->priv + LPSS_PRIV_IDLELTR);
> +
> +	/* Cache the values into lpss structure */
> +	intel_lpss_cache_ltr(lpss);
> +}
> +
> +static void intel_lpss_ltr_add(struct intel_lpss *lpss)
> +{
> +	lpss->dev->power.set_latency_tolerance = intel_lpss_ltr_set;
> +	dev_pm_qos_expose_latency_tolerance(lpss->dev);
> +}
> +
> +static void intel_lpss_ltr_remove(struct intel_lpss *lpss)
> +{
> +	dev_pm_qos_hide_latency_tolerance(lpss->dev);
> +	lpss->dev->power.set_latency_tolerance = NULL;
> +}
> +
> +static int intel_lpss_assign_devs(struct intel_lpss *lpss)
> +{
> +	unsigned int type;
> +
> +	type = lpss->caps & LPSS_PRIV_CAPS_TYPE_MASK;
> +	type >>= LPSS_PRIV_CAPS_TYPE_SHIFT;
> +
> +	switch (type) {
> +	case LPSS_DEV_I2C:
> +		lpss->devs = intel_lpss_i2c_devs;
> +		break;
> +	case LPSS_DEV_UART:
> +		lpss->devs = intel_lpss_uart_devs;
> +		break;
> +	case LPSS_DEV_SPI:
> +		lpss->devs = intel_lpss_spi_devs;
> +		break;
> +	default:
> +		return -ENODEV;
> +	}
> +
> +	lpss->type = type;
> +
> +	return 0;
> +}
> +
> +static bool intel_lpss_has_idma(const struct intel_lpss *lpss)
> +{
> +	return (lpss->caps & LPSS_PRIV_CAPS_NO_IDMA) == 0;
> +}
> +
> +static void intel_lpss_reset(const struct intel_lpss *lpss)

Not very descriptive function name.  'de|assert'?

> +{
> +	u32 value = LPSS_PRIV_RESETS_FUNC | LPSS_PRIV_RESETS_IDMA;
> +
> +	/* Bring out the device from reset */
> +	writel(value, lpss->priv + LPSS_PRIV_RESETS);
> +}

All of this clock stuff below need s Clock Ack.

> +static void intel_lpss_unregister_clock_tree(struct clk *clk)
> +{
> +	struct clk *parent;
> +
> +	while (clk) {
> +		parent = clk_get_parent(clk);
> +		clk_unregister(clk);
> +		clk = parent;
> +	}
> +}
> +
> +static int intel_lpss_register_clock_divider(struct intel_lpss *lpss,
> +					     const char *devname,
> +					     struct clk **clk)
> +{
> +	char name[32];
> +	struct clk *tmp = *clk;
> +
> +	snprintf(name, sizeof(name), "%s-enable", devname);
> +	tmp = clk_register_gate(NULL, name, __clk_get_name(tmp), 0,
> +				lpss->priv, 0, 0, NULL);
> +	if (IS_ERR(tmp))
> +		return PTR_ERR(tmp);
> +
> +	snprintf(name, sizeof(name), "%s-div", devname);
> +	tmp = clk_register_fractional_divider(NULL, name, __clk_get_name(tmp),
> +					      0, lpss->priv, 1, 15, 16, 15, 0,
> +					      NULL);
> +	if (IS_ERR(tmp))
> +		return PTR_ERR(tmp);
> +	*clk = tmp;
> +
> +	snprintf(name, sizeof(name), "%s-update", devname);
> +	tmp = clk_register_gate(NULL, name, __clk_get_name(tmp),
> +				CLK_SET_RATE_PARENT, lpss->priv, 31, 0, NULL);
> +	if (IS_ERR(tmp))
> +		return PTR_ERR(tmp);
> +	*clk = tmp;
> +
> +	return 0;
> +}
> +
> +static int intel_lpss_register_clock(struct intel_lpss *lpss)
> +{
> +	const struct mfd_cell *devs = lpss->devs;
> +	struct clk_lookup **clocks;
> +	struct clk *clk, *root;
> +	char devname[24];
> +	int ret = -ENOMEM;
> +
> +	if (!lpss->info->clk_rate)
> +		return 0;
> +
> +	clocks = devm_kcalloc(lpss->dev, lpss->ndevs, sizeof(*clocks),
> +			      GFP_KERNEL);
> +	if (!clocks)
> +		return -ENOMEM;
> +
> +	/* Root clock */
> +	root = clk_register_fixed_rate(NULL, dev_name(lpss->dev), NULL,
> +				       CLK_IS_ROOT, lpss->info->clk_rate);
> +	if (IS_ERR(root))
> +		return PTR_ERR(root);
> +
> +	clk = root;
> +
> +	snprintf(devname, sizeof(devname), "%s.%d", devs[1].name, lpss->devid);
> +
> +	/*
> +	 * Support for clock divider only if it has some preset value.
> +	 * Otherwise we assume that the divider is not used.
> +	 */
> +	if (lpss->type != LPSS_DEV_I2C) {
> +		ret = intel_lpss_register_clock_divider(lpss, devname, &clk);
> +		if (ret)
> +			goto err_clk_register;
> +	}
> +
> +	/* Clock for the host controller */
> +	clocks[0] = clk_register_clkdev(clk, lpss->info->clk_con_id, "%s",
> +					devname);
> +	if (IS_ERR(clocks[0]))
> +		goto err_clk_register;
> +
> +	/*
> +	 * If the slice has integrated DMA block create clock for that as
> +	 * well now.
> +	 */
> +	if (lpss->ndevs > 1) {
> +		clocks[1] = clk_register_clkdev(root, "hclk", "%s.%d",
> +						devs[0].name, lpss->devid);
> +		if (IS_ERR(clocks[1]))
> +			goto err_hclk_register;
> +	}
> +
> +	lpss->clocks = clocks;
> +	lpss->clk = clk;
> +
> +	return 0;
> +
> +err_hclk_register:
> +	clkdev_drop(clocks[0]);
> +
> +err_clk_register:
> +	intel_lpss_unregister_clock_tree(clk);
> +
> +	return ret;
> +}
> +
> +static void intel_lpss_unregister_clock(struct intel_lpss *lpss)
> +{
> +	unsigned int i;
> +
> +	if (IS_ERR_OR_NULL(lpss->clk))
> +		return;
> +
> +	for (i = 0; i < lpss->ndevs; i++)
> +		clkdev_drop(lpss->clocks[i]);
> +
> +	intel_lpss_unregister_clock_tree(lpss->clk);
> +}
> +
> +int intel_lpss_probe(struct device *dev,
> +		     const struct intel_lpss_platform_info *info)
> +{
> +	const struct mfd_cell *devs;
> +	struct intel_lpss *lpss;
> +	struct resource priv;
> +	int ret;
> +
> +	if (!info || !info->mem || info->irq <= 0)
> +		return -EINVAL;
> +
> +	lpss = devm_kzalloc(dev, sizeof(*lpss), GFP_KERNEL);
> +	if (!lpss)
> +		return -ENOMEM;
> +
> +	memset(&priv, 0, sizeof(priv));
> +	priv.start = info->mem->start + LPSS_PRIV_OFFSET;
> +	priv.end = priv.start + LPSS_PRIV_SIZE - 1;
> +	priv.flags = IORESOURCE_MEM;
> +
> +	lpss->priv = devm_ioremap_resource(dev, &priv);
> +	if (!lpss->priv)
> +		return -ENOMEM;
> +
> +	intel_lpss_reset(lpss);
> +
> +	lpss->info = info;
> +	lpss->dev = dev;
> +	lpss->caps = readl(lpss->priv + LPSS_PRIV_CAPS);
> +	lpss->ndevs = intel_lpss_has_idma(lpss) ? 2 : 1;

This is fragile.

I'd prefer you dynamically allocate resources here, instead of
statically up the top then 'jumping' over the ones you don't need.

> +	dev_set_drvdata(dev, lpss);
> +
> +	ret = intel_lpss_assign_devs(lpss);
> +	if (ret < 0)
> +		return ret;

Is ret allowed to be >0?  If not just 'if (ret)'.

> +	lpss->devid = ida_simple_get(&intel_lpss_devid_ida, 0, 0, GFP_KERNEL);
> +	if (lpss->devid < 0)
> +		return lpss->devid;

PLATFORM_DEVID_AUTO does this for you.

> +	ret = intel_lpss_register_clock(lpss);
> +	if (ret < 0)
> +		goto err_clk_register;
> +
> +	intel_lpss_ltr_add(lpss);

Add what, to what?  What is 'ltr'?

> +	ret = intel_lpss_debugfs_add(lpss);
> +	if (ret)
> +		dev_warn(lpss->dev, "Failed to create debugfs entries\n");
> +
> +	devs = intel_lpss_has_idma(lpss) ? lpss->devs : lpss->devs + 1;

*cringe*

> +	ret = mfd_add_devices(dev, lpss->devid, devs, lpss->ndevs,
> +			      info->mem, info->irq, NULL);
> +	if (ret < 0)
> +		goto err_remove_ltr;
> +
> +	return 0;
> +
> +err_remove_ltr:
> +	intel_lpss_debugfs_remove(lpss);
> +	intel_lpss_ltr_remove(lpss);
> +
> +err_clk_register:
> +	ida_simple_remove(&intel_lpss_devid_ida, lpss->devid);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(intel_lpss_probe);
> +
> +void intel_lpss_remove(struct device *dev)
> +{
> +	struct intel_lpss *lpss = dev_get_drvdata(dev);
> +
> +	mfd_remove_devices(dev);
> +	intel_lpss_debugfs_remove(lpss);
> +	intel_lpss_ltr_remove(lpss);
> +	intel_lpss_unregister_clock(lpss);
> +	ida_simple_remove(&intel_lpss_devid_ida, lpss->devid);
> +}
> +EXPORT_SYMBOL_GPL(intel_lpss_remove);
> +
> +static int resume_lpss_device(struct device *dev, void *data)
> +{
> +	pm_runtime_resume(dev);
> +	return 0;
> +}
> +
> +int intel_lpss_prepare(struct device *dev)
> +{
> +	/*
> +	 * Resume both child devices before entering system sleep. This
> +	 * ensures that they are in proper state before they get suspended.
> +	 */
> +	device_for_each_child(dev, NULL, resume_lpss_device);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(intel_lpss_prepare);
> +
> +int intel_lpss_suspend(struct device *dev)
> +{
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(intel_lpss_suspend);
> +
> +int intel_lpss_resume(struct device *dev)
> +{
> +	struct intel_lpss *lpss = dev_get_drvdata(dev);
> +	intel_lpss_reset(lpss);
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(intel_lpss_resume);
> +
> +static int __init intel_lpss_init(void)
> +{
> +	intel_lpss_debugfs = debugfs_create_dir("intel_lpss", NULL);
> +	return 0;
> +}
> +module_init(intel_lpss_init);
> +
> +static void __exit intel_lpss_exit(void)
> +{
> +	debugfs_remove(intel_lpss_debugfs);
> +}
> +module_exit(intel_lpss_exit);
> +
> +MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@...ux.intel.com>");
> +MODULE_AUTHOR("Mika Westerberg <mika.westerberg@...ux.intel.com>");
> +MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@...ux.intel.com>");
> +MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@...ux.intel.com>");
> +MODULE_DESCRIPTION("Intel LPSS core driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/mfd/intel-lpss.h b/drivers/mfd/intel-lpss.h
> new file mode 100644
> index 0000000..f28cb28
> --- /dev/null
> +++ b/drivers/mfd/intel-lpss.h
> @@ -0,0 +1,62 @@
> +/*
> + * Intel LPSS core support.
> + *
> + * Copyright (C) 2015, Intel Corporation
> + *
> + * Authors: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> + *          Mika Westerberg <mika.westerberg@...ux.intel.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef __MFD_INTEL_LPSS_H
> +#define __MFD_INTEL_LPSS_H
> +
> +struct device;
> +struct resource;
> +
> +struct intel_lpss_platform_info {
> +	struct resource *mem;
> +	int irq;
> +	unsigned long clk_rate;
> +	const char *clk_con_id;
> +};
> +
> +int intel_lpss_probe(struct device *dev,
> +		     const struct intel_lpss_platform_info *info);
> +void intel_lpss_remove(struct device *dev);
> +
> +#ifdef CONFIG_PM
> +int intel_lpss_prepare(struct device *dev);
> +int intel_lpss_suspend(struct device *dev);
> +int intel_lpss_resume(struct device *dev);

Why are you exporting these?

> +#ifdef CONFIG_PM_SLEEP
> +#define INTEL_LPSS_SLEEP_PM_OPS			\
> +	.prepare = intel_lpss_prepare,		\
> +	.suspend = intel_lpss_suspend,		\
> +	.resume = intel_lpss_resume,		\
> +	.freeze = intel_lpss_suspend,		\
> +	.thaw = intel_lpss_resume,		\
> +	.poweroff = intel_lpss_suspend,		\
> +	.restore = intel_lpss_resume,
> +#endif

SET_SYSTEM_SLEEP_PM_OPS?

> +#define INTEL_LPSS_RUNTIME_PM_OPS		\
> +	.runtime_suspend = intel_lpss_suspend,	\
> +	.runtime_resume = intel_lpss_resume,

SET_RUNTIME_PM_OPS

> +#else /* !CONFIG_PM */
> +#define INTEL_LPSS_SLEEP_PM_OPS
> +#define INTEL_LPSS_RUNTIME_PM_OPS
> +#endif /* CONFIG_PM */
> +
> +#define INTEL_LPSS_PM_OPS(name)			\
> +const struct dev_pm_ops name = {		\
> +	INTEL_LPSS_SLEEP_PM_OPS			\
> +	INTEL_LPSS_RUNTIME_PM_OPS		\
> +}

Why is this in the header?

> +#endif /* __MFD_INTEL_LPSS_H */

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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