Subject: [PATCH 1/3] ahci: exynos: add ahci sata support on Exynos platform

From: [email-masked] (Kishon Vijay Abraham I)
Date: Tue, 1 Oct 2013 18:06:03 +0530

On Tuesday 01 October 2013 12:03 PM, Yuvaraj Kumar C D wrote:
> Exynos5250 contains one Synopsys AHCI SATA controller.The avalaible
> ahci_platform driver is not sufficient to handle the AHCI PHY and PHY
> clock related initialization.
> 
> This patch adds exynos specific ahci sata driver,contained the exynos
> specific initialized codes, re-use the generic ahci_platform driver, and
> keep the generic ahci_platform driver clean as much as possible.
> 
> This patch depends on the below patch
> 	[1].drivers: phy: add generic PHY framework
> 		by Kishon Vijay Abraham I<[email-masked]>
> 
> Signed-off-by: Yuvaraj Kumar C D <[email-masked]>
> ---
>  drivers/ata/Kconfig       |    9 ++
>  drivers/ata/Makefile      |    1 +
>  drivers/ata/ahci_exynos.c |  226 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 236 insertions(+)
>  create mode 100644 drivers/ata/ahci_exynos.c
> 
> diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
> index 4e73772..99b2392 100644
> --- a/drivers/ata/Kconfig
> +++ b/drivers/ata/Kconfig
> @@ -106,6 +106,15 @@ config AHCI_IMX
>  
>  	  If unsure, say N.
>  
> +config AHCI_EXYNOS
> +	tristate "Samsung Exynos AHCI SATA support"
> +	depends on SATA_AHCI_PLATFORM

Can we select GENERIC_PHY here?
> +	help
> +	  This option enables support for the Samsung's Exynos SoC's
> +	  onboard AHCI SATA.
> +
> +	  If unsure, say N.
> +
>  config SATA_FSL
>  	tristate "Freescale 3.0Gbps SATA support"
>  	depends on FSL_SOC
> diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
> index 46518c6..0e1f420f 100644
> --- a/drivers/ata/Makefile
> +++ b/drivers/ata/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_SATA_SIL24)	+= sata_sil24.o
>  obj-$(CONFIG_SATA_DWC)		+= sata_dwc_460ex.o
>  obj-$(CONFIG_SATA_HIGHBANK)	+= sata_highbank.o libahci.o
>  obj-$(CONFIG_AHCI_IMX)		+= ahci_imx.o
> +obj-$(CONFIG_AHCI_EXYNOS)	+= ahci_exynos.o
>  
>  # SFF w/ custom DMA
>  obj-$(CONFIG_PDC_ADMA)		+= pdc_adma.o
> diff --git a/drivers/ata/ahci_exynos.c b/drivers/ata/ahci_exynos.c
> new file mode 100644
> index 0000000..7f0af00
> --- /dev/null
> +++ b/drivers/ata/ahci_exynos.c
> @@ -0,0 +1,226 @@
> +/*
> + * Samsung AHCI SATA platform driver
> + * Copyright 2013 Samsung Electronics Co., Ltd.
> + *
> + * based on the AHCI SATA platform driver by Jeff Garzik and Anton Vorontsov
> + *
> + * 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/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/i2c.h>
> +#include <linux/io.h>
> +#include <linux/ahci_platform.h>
> +#include <linux/of_device.h>
> +#include <linux/phy/phy.h>
> +#include "ahci.h"
> +
> +#define MHZ             (1000 * 1000)
> +
> +struct exynos_ahci_priv {
> +	struct platform_device *ahci_pdev;
> +	struct clk *sclk;
> +	unsigned int freq;
> +	struct phy *phy;
> +};
> +
> +static int exynos_sata_init(struct device *dev, void __iomem *mmio)
> +{
> +	struct exynos_ahci_priv *priv = dev_get_drvdata(dev->parent);
> +	int ret;
> +
> +	priv->phy = devm_phy_get(dev , "sata-phy");
                                    ^^
                             spurious space here

phy_get should be called from probe.
> +	if (IS_ERR(priv->phy))
> +		return PTR_ERR(priv->phy);
> +
> +	ret = phy_init(priv->phy);
> +	if (ret < 0) {
> +			dev_err(dev, "failed to init SATA PHY\n");
single tab is sufficient here and below.
> +			return ret;
> +	}
> +
> +	ret = clk_prepare_enable(priv->sclk);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to enable source clk\n");
> +		return ret;
> +	}
> +
> +	ret = clk_set_rate(priv->sclk, priv->freq * MHZ);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to set clk frequency\n");
> +		clk_disable_unprepare(priv->sclk);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void exynos_sata_exit(struct device *dev)
> +{
> +	struct exynos_ahci_priv *priv = dev_get_drvdata(dev->parent);
> +	if (!IS_ERR(priv->sclk))

This error check is not needed. You fail probe if you dont get clock anyways.
> +		clk_disable_unprepare(priv->sclk);
> +}
> +
> +static int exynos_sata_suspend(struct device *dev)
> +{
> +	struct exynos_ahci_priv *priv = dev_get_drvdata(dev->parent);
> +
> +	if (!IS_ERR(priv->sclk))
ditto..
> +		clk_disable_unprepare(priv->sclk);
> +	phy_power_off(priv->phy);
> +	return 0;
> +}
> +
> +static int exynos_sata_resume(struct device *dev)
> +{
> +	struct exynos_ahci_priv *priv = dev_get_drvdata(dev->parent);
> +	phy_power_on(priv->phy);
> +	exynos_sata_init(dev, NULL);
> +	return 0;
> +}
> +
> +static struct ahci_platform_data exynos_sata_pdata = {
> +	.init = exynos_sata_init,

Why is exynos_sata_init given as callback and also in exynos_sata_resume?
> +	.exit = exynos_sata_exit,
> +	.suspend = exynos_sata_suspend,
> +	.resume = exynos_sata_resume,

Can't we use this in runtime_suspend/runtime_resume or suspend/resume pm ops?
> +};
> +
> +static const struct of_device_id exynos_ahci_of_match[] = {
> +	{ .compatible = "samsung,exynos5250-sata-ahci",
> +		.data = &exynos_sata_pdata},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, exynos_ahci_of_match);
> +
> +static int exynos_sata_parse_dt(struct device_node *np,
> +				struct exynos_ahci_priv *priv)
> +{
> +	if (!np)
> +		return -EINVAL;
> +	return of_property_read_u32(np, "samsung,sata-freq",
> +						&priv->freq);
> +}
> +
> +static int exynos_ahci_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct resource *mem, *irq, res[2];
> +	const struct of_device_id *of_id;
> +	const struct ahci_platform_data *pdata = NULL;
> +	struct exynos_ahci_priv *priv;
> +	struct device *ahci_dev;
> +	struct platform_device *ahci_pdev;
> +	int ret;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv) {
> +		dev_err(dev, "can't alloc ahci_host_priv\n");

error message not needed. kzalloc will give a dump if it fails.
> +		return -ENOMEM;
> +	}
> +
> +	ahci_pdev = platform_device_alloc("ahci", -1);

Should be using PLATFORM_DEVID_AUTO unless it is absolutely necessary.
> +	if (!ahci_pdev)
> +		return -ENODEV;
> +
> +	ahci_dev = &ahci_pdev->dev;
> +	ahci_dev->parent = dev;
> +
> +	ret = exynos_sata_parse_dt(dev->of_node, priv);
> +	if (ret < 0) {
> +			dev_err(dev, "failed to parse device tree\n");
> +			goto err_out;
> +	}
> +
> +	priv->sclk = devm_clk_get(dev, "sclk_sata");
> +	if (IS_ERR(priv->sclk)) {
> +		dev_err(dev, "failed to get sclk_sata\n");
> +		ret = PTR_ERR(priv->sclk);
> +		goto err_out;
> +	}
> +	priv->ahci_pdev = ahci_pdev;
> +	platform_set_drvdata(pdev, priv);
> +
> +	of_id = of_match_device(exynos_ahci_of_match, dev);
> +	if (of_id) {
> +		pdata = of_id->data;
> +	} else {
> +		ret = -EINVAL;
> +		goto err_out;
> +	}
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> +	if (!mem || !irq) {
> +		dev_err(dev, "no mmio/irq resource\n");
> +		ret = -ENOMEM;
> +		goto err_out;
> +	}
> +
> +	res[0] = *mem;
> +	res[1] = *irq;
> +
> +	ahci_dev->coherent_dma_mask = DMA_BIT_MASK(32);
> +	ahci_dev->dma_mask = &ahci_dev->coherent_dma_mask;
> +	ahci_dev->of_node = dev->of_node;
> +
> +	ret = platform_device_add_resources(ahci_pdev, res, 2);
> +	if (ret)
> +		goto err_out;
> +
> +	ret = platform_device_add_data(ahci_pdev, pdata, sizeof(*pdata));
> +	if (ret)
> +		goto err_out;
> +
> +	ret = platform_device_add(ahci_pdev);
> +	if (ret) {
> +
> +
> +err_out:
> +		platform_set_drvdata(pdev, NULL);
> +		platform_device_put(ahci_pdev);
> +		return ret;
Move this to the end of this function and then goto err_out for better readability.

> +	}
> +
> +	return 0;
> +}
> +
> +static int exynos_ahci_remove(struct platform_device *pdev)
> +{
> +	struct exynos_ahci_priv *priv = platform_get_drvdata(pdev);
> +	struct platform_device *ahci_pdev = priv->ahci_pdev;
> +
> +	platform_device_unregister(ahci_pdev);
> +	platform_set_drvdata(pdev, NULL);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver exynos_ahci_driver = {
> +	.probe = exynos_ahci_probe,
> +	.remove = exynos_ahci_remove,
> +	.driver = {
> +		.name = "sata-exynos",
> +		.owner = THIS_MODULE,
> +		.of_match_table = exynos_ahci_of_match,
> +	},
> +};
> +module_platform_driver(exynos_ahci_driver);
> +
> +MODULE_DESCRIPTION("Samsung Exynos AHCI SATA platform driver");
> +MODULE_AUTHOR("Yuvaraj C D <[email-masked]>");
> +MODULE_LICENSE("GPL");

GPL v2?

Thanks
Kishon