[PATCH v6 0/3] ahci: enable ahci sata support on imx6q

[PATCH v6 0/3] ahci: enable ahci sata support on imx6q

[Richard Zhu]

v6: add imx6q specific ahci sata support
  Thanks for Shawn's comments.
  - Speicify the ahb clock in the sata related dts changes.
  - Move the initialization of the sata PHY clock of the private
  data to the probe function.
  - Remove the empty device release function.
  - In order to be more readable, rename the imx_dev/imx_ahci_pdev
  to be ahci_dev/ahci_pdev, and do some other changes, such as typo
  error, more readable name of the variable.
  - Tested on imx6q sd board.
  - 

v5: http://www.spinics.net/lists/linux-ide/msg45712.html
  - Fix the wrong referrence usage of the private data.
  - Use the private data to contain the poninter of the PHY
  signals adjustment window(gpr)
  - Tested on imx6q sd board.
  - 

v4: http://www.spinics.net/lists/linux-ide/msg45699.html
  Thanks for the review comments provided by Sascha, and Alexander.
  - Use the private data and keep a pointer to the PHY clock.
  - Don't use the global platform device variable, because that
  it would make the driver broken for mutiple instances.
  - Don't do the "writel" with assignment.
  - Other minor changes, such as print the error code when printing
  error message, use a u32 type to store readl results, and so on.

v3: http://www.spinics.net/lists/linux-ide/msg45688.html
  - Keep arch/arm and ahci_platform driver clean.
  - Add the sata_imx standalone driver contained all the
  specific setup
  - Add the release function, support the loadable module
  driver.
  - Tested on imx6q sd board.

v2: http://www.spinics.net/lists/linux-ide/msg45666.html 
 - Setup standalone imx ahci sata driver, because of
 the misalignments of the bits definition of the HBA register.
 - Replace the node by the label in the board dts.
 - 

v1: http://www.spinics.net/lists/linux-ide/msg45581.html
 - add imx6q specific ahci sata support to arch/arm/mach-imx/mach-imx6q.c

These patches is based on imx/dt branch of
"http://git.linaro.org/git-ro/people/shawnguo/linux-2.6.git"

[v6 1/3] ARM: dtsi: enable ahci sata on imx6q platforms
[v6 2/3] ARM: imx6q: update the sata bits definitions of gpr13
[v6 3/3] sata: imx: add ahci sata support on imx platforms

arch/arm/boot/dts/imx6q-sabreauto.dts       |    4 +
arch/arm/boot/dts/imx6q-sabrelite.dts       |    4 +
arch/arm/boot/dts/imx6q-sabresd.dts         |    4 +
arch/arm/boot/dts/imx6q.dtsi                |    9 +
drivers/ata/Kconfig                         |    9 +
drivers/ata/Makefile                        |    1 +
drivers/ata/sata_imx.c                      |  241 +++++++++++++++++++++++++++
include/linux/mfd/syscon/imx6q-iomuxc-gpr.h |  121 +++++++++----
8 files changed, 356 insertions(+), 37 deletions(-)

[v6 1/3] ARM: dtsi: enable ahci sata on imx6q platforms

[Sergei Shtylyov]

On 07/12/2013 01:41 PM, Richard Zhu wrote:

> From: Richard Zhu <r65037@freescale.com>

> Only imx6q has the ahci sata controller, enable
> it on imx6q platforms.

> Signed-off-by: Richard Zhu <r65037@freescale.com>
[...]

> diff --git a/arch/arm/boot/dts/imx6q.dtsi b/arch/arm/boot/dts/imx6q.dtsi
> index e7dd2c4..93b65d9 100644
> --- a/arch/arm/boot/dts/imx6q.dtsi
> +++ b/arch/arm/boot/dts/imx6q.dtsi
> @@ -424,6 +424,15 @@
>   			};
>   		};
>
> +		ahci: ahci at 02200000 {

    According to ePAPR [1] section 2.2.2, "the name of the node should 
be somewhat generic, reflecting the function of the device and not its
precise programming model. If appropriate, the name should be one of the 
following choices:
[...]
- sata;
[...]"

[1] http://www.power.org/resources/downloads/Power_ePAPR_APPROVED_v1.0.pdf

WBR, Sergei

[v6 1/3] ARM: dtsi: enable ahci sata on imx6q platforms

[Zhu Richard-R65037]

Hi Sergei:
Thanks for your comments.


Best Regards
Richard Zhu


-----Original Message-----
From: Sergei Shtylyov [mailto:sergei.shtylyov at cogentembedded.com] 
Sent: Saturday, July 13, 2013 4:41 AM
To: Richard Zhu
Cc: shawn.guo at linaro.org; linux-arm-kernel at lists.infradead.org; jgarzik at pobox.com; tj at kernel.org; rob.herring at calxeda.com; s.hauer at pengutronix.de; linux-ide at vger.kernel.org; Zhu Richard-R65037
Subject: Re: [v6 1/3] ARM: dtsi: enable ahci sata on imx6q platforms

On 07/12/2013 01:41 PM, Richard Zhu wrote:

> From: Richard Zhu <r65037@freescale.com>

> Only imx6q has the ahci sata controller, enable it on imx6q platforms.

> Signed-off-by: Richard Zhu <r65037@freescale.com>
[...]

> diff --git a/arch/arm/boot/dts/imx6q.dtsi 
> b/arch/arm/boot/dts/imx6q.dtsi index e7dd2c4..93b65d9 100644
> --- a/arch/arm/boot/dts/imx6q.dtsi
> +++ b/arch/arm/boot/dts/imx6q.dtsi
> @@ -424,6 +424,15 @@
>   			};
>   		};
>
> +		ahci: ahci at 02200000 {

    According to ePAPR [1] section 2.2.2, "the name of the node should be somewhat generic, reflecting the function of the device and not its precise programming model. If appropriate, the name should be one of the following choices:
[...]
- sata;
[...]"

[1] http://www.power.org/resources/downloads/Power_ePAPR_APPROVED_v1.0.pdf
[Richard] Ok, ahci would be replaced by sata.

WBR, Sergei

[v6 3/3] sata: imx: add ahci sata support on imx platforms

[Shawn Guo]

On Fri, Jul 12, 2013 at 05:41:18PM +0800, Richard Zhu wrote:
> From: Richard Zhu <r65037@freescale.com>
> 
> imx6q contains one Synopsys AHCI SATA controller,
> But it can't share ahci_platform driver with other
> controllers.
> Because there are some misalignments of the generic
> AHCI controller.
> The bits definitions of the HBA registers, the Vendor
> Specific registers, the AHCI PHY clock and the AHCI
> signals adjustment window(GPR13 register).
>  - CAP_SSS(bit20) of the HOST_CAP is writable, default
>  value is '0', should be configured to be '1'
>  - bit0 (only one AHCI SATA port on imx6q) of the
>  HOST_PORTS_IMPL should be set to be '1'.(default 0)
>  - One Vendor Specific register HOST_TIMER1MS(offset:0xe0)
>  should be configured regarding to the frequency of AHB
>  bus clock.
>  - Configurations of the AHCI PHY clock, and the signal
>  parameters of the GPR13
> 
> Setup its own ahci sata driver, contained the imx6q specific
> initialized codes, re-use the generic ahci_platform driver, and
> keep the generic ahci_platform driver clean as much as possible.
> 
> Signed-off-by: Richard Zhu <r65037@freescale.com>
> ---
>  drivers/ata/Kconfig    |    9 ++
>  drivers/ata/Makefile   |    1 +
>  drivers/ata/sata_imx.c |  241 ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 251 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/ata/sata_imx.c
> 
> diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
> index a5a3ebc..275dc2c 100644
> --- a/drivers/ata/Kconfig
> +++ b/drivers/ata/Kconfig
> @@ -97,6 +97,15 @@ config SATA_AHCI_PLATFORM
>  
>  	  If unsure, say N.
>  
> +config SATA_IMX
> +	tristate "Freescale i.MX AHCI SATA support"
> +	depends on SATA_AHCI_PLATFORM
> +	help
> +	  This option enables support for the Freescale i.MX 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 c04d0fd..04b1c6c 100644
> --- a/drivers/ata/Makefile
> +++ b/drivers/ata/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_SATA_INIC162X)	+= sata_inic162x.o
>  obj-$(CONFIG_SATA_SIL24)	+= sata_sil24.o
>  obj-$(CONFIG_SATA_DWC)		+= sata_dwc_460ex.o
>  obj-$(CONFIG_SATA_HIGHBANK)	+= sata_highbank.o libahci.o
> +obj-$(CONFIG_SATA_IMX)		+= sata_imx.o
>  
>  # SFF w/ custom DMA
>  obj-$(CONFIG_PDC_ADMA)		+= pdc_adma.o
> diff --git a/drivers/ata/sata_imx.c b/drivers/ata/sata_imx.c
> new file mode 100644
> index 0000000..fb13867
> --- /dev/null
> +++ b/drivers/ata/sata_imx.c
> @@ -0,0 +1,241 @@
> +/*
> + * Freescale IMX AHCI SATA platform driver
> + * Copyright 2013 Freescale Semiconductor, Inc.
> + *
> + * 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/regmap.h>
> +#include <linux/ahci_platform.h>
> +#include <linux/of_device.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
> +#include "ahci.h"
> +
> +enum {
> +	HOST_TIMER1MS = 0xe0, /* Timer 1-ms */
> +};
> +
> +struct imx_ahci_priv {
> +	struct platform_device *ahci_pdev;
> +	struct clk *sata_ref_clk;
> +	struct regmap *gpr;
> +};
> +
> +static int imx6q_sata_init(struct device *dev, void __iomem *mmio)
> +{
> +	int ret = 0;
> +	unsigned int reg_val;
> +	struct clk *ahb_clk;
> +	struct imx_ahci_priv *imxpriv = dev_get_drvdata(dev->parent);
> +
> +	imxpriv->gpr =
> +		syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
> +	if (IS_ERR(imxpriv->gpr)) {
> +		dev_err(dev, "failed to find fsl,imx6q-iomux-gpr regmap\n");
> +		return PTR_ERR(imxpriv->gpr);
> +	}
> +
> +	ret = clk_prepare_enable(imxpriv->sata_ref_clk);
> +	if (ret < 0) {
> +		dev_err(dev, "prepare-enable sata_ref clock err:%d\n", ret);
> +		return ret;
> +	}
> +
> +	/*
> +	 * set PHY Paremeters, two steps to configure the GPR13,
> +	 * one write for rest of parameters, mask of first write
> +	 * is 0x07fffffd, and the other one write for setting
> +	 * the mpll_clk_en.
> +	 */
> +	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_RX_EQ_VAL_MASK
> +			| IMX6Q_GPR13_SATA_RX_LOS_LVL_MASK
> +			| IMX6Q_GPR13_SATA_RX_DPLL_MODE_MASK
> +			| IMX6Q_GPR13_SATA_SPD_MODE_MASK
> +			| IMX6Q_GPR13_SATA_MPLL_SS_EN
> +			| IMX6Q_GPR13_SATA_TX_ATTEN_MASK
> +			| IMX6Q_GPR13_SATA_TX_BOOST_MASK
> +			| IMX6Q_GPR13_SATA_TX_LVL_MASK
> +			| IMX6Q_GPR13_SATA_TX_EDGE_RATE
> +			, IMX6Q_GPR13_SATA_RX_EQ_VAL_3_0_DB
> +			| IMX6Q_GPR13_SATA_RX_LOS_LVL_SATA2M
> +			| IMX6Q_GPR13_SATA_RX_DPLL_MODE_2P_4F
> +			| IMX6Q_GPR13_SATA_SPD_MODE_3P0G
> +			| IMX6Q_GPR13_SATA_MPLL_SS_EN
> +			| IMX6Q_GPR13_SATA_TX_ATTEN_9_16
> +			| IMX6Q_GPR13_SATA_TX_BOOST_3_33_DB
> +			| IMX6Q_GPR13_SATA_TX_LVL_1_025_V);
> +	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_MPLL_CLK_EN,
> +			IMX6Q_GPR13_SATA_MPLL_CLK_EN);
> +	usleep_range(100, 200);
> +
> +	/*
> +	 * Configure the HWINIT bits of the HOST_CAP and HOST_PORTS_IMPL,
> +	 * and IP vendor specific register HOST_TIMER1MS.
> +	 * Configure CAP_SSS (support stagered spin up).
> +	 * Implement the port0.
> +	 * Get the ahb clock rate, and configure the TIMER1MS register.
> +	 */
> +	reg_val = readl(mmio + HOST_CAP);
> +	if (!(reg_val & HOST_CAP_SSS)) {
> +		reg_val |= HOST_CAP_SSS;
> +		writel(reg_val, mmio + HOST_CAP);
> +	}
> +	reg_val = readl(mmio + HOST_PORTS_IMPL);
> +	if (!(reg_val & 0x1)) {
> +		reg_val |= 0x1;
> +		writel(reg_val, mmio + HOST_PORTS_IMPL);
> +	}
> +
> +	ahb_clk = devm_clk_get(dev, "ahb");

Can we move this devm_clk_get() call into .probe as well?

> +	if (IS_ERR(ahb_clk)) {
> +		dev_err(dev, "no ahb clock.\n");
> +		clk_disable_unprepare(imxpriv->sata_ref_clk);
> +		devm_clk_put(dev, imxpriv->sata_ref_clk);
> +		return PTR_ERR(ahb_clk);
> +	}
> +	reg_val = clk_get_rate(ahb_clk) / 1000;
> +	writel(reg_val, mmio + HOST_TIMER1MS);
> +	devm_clk_put(dev, ahb_clk);
> +
> +	return 0;
> +}
> +
> +static void imx6q_sata_exit(struct device *dev)
> +{
> +	struct imx_ahci_priv *imxpriv =  dev_get_drvdata(dev->parent);
> +
> +	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_MPLL_CLK_EN,
> +			!IMX6Q_GPR13_SATA_MPLL_CLK_EN);
> +	clk_disable_unprepare(imxpriv->sata_ref_clk);
> +}
> +
> +static struct ahci_platform_data imx6q_sata_pdata = {
> +	.init = imx6q_sata_init,
> +	.exit = imx6q_sata_exit,
> +};
> +
> +static const struct of_device_id imx_ahci_of_match[] = {
> +	{ .compatible = "fsl,imx6q-ahci", .data = &imx6q_sata_pdata},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, imx_ahci_of_match);
> +
> +static int imx_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 imx_ahci_priv *imxpriv;
> +	struct device *ahci_dev;
> +	struct platform_device *ahci_pdev;
> +	int ret;
> +
> +	imxpriv = devm_kzalloc(dev, sizeof(*imxpriv), GFP_KERNEL);
> +	if (!imxpriv) {
> +		dev_err(dev, "can't alloc ahci_host_priv\n");
> +		return -ENOMEM;
> +	}
> +
> +	ahci_pdev = platform_device_alloc("ahci", -1);
> +	if (!ahci_pdev)
> +		return -ENODEV;
> +
> +	ahci_dev = &ahci_pdev->dev;
> +	ahci_dev->parent = dev;
> +
> +	imxpriv->sata_ref_clk = devm_clk_get(dev, "sata_ref");
> +	if (IS_ERR(imxpriv->sata_ref_clk)) {
> +		dev_err(dev, "can't get sata_ref clock.\n");
> +		ret = PTR_ERR(imxpriv->sata_ref_clk);
> +		goto err_pdev_put;
> +	}
> +
> +	imxpriv->ahci_pdev = ahci_pdev;
> +	platform_set_drvdata(pdev, imxpriv);
> +
> +	of_id = of_match_device(imx_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);

I do not think you need this.

> +		devm_clk_put(dev, imxpriv->sata_ref_clk);

The good thing about using devm_clk_get() above is you do not need to
explicitly call devm_clk_put() on either .remove or .probe failure.

> +err_pdev_put:
> +		platform_device_put(ahci_pdev);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int imx_ahci_remove(struct platform_device *pdev)
> +{
> +	struct imx_ahci_priv *imxpriv = platform_get_drvdata(pdev);
> +	struct platform_device *ahci_pdev = imxpriv->ahci_pdev;
> +
> +	platform_device_unregister(ahci_pdev);
> +	platform_set_drvdata(pdev, NULL);

Ditto, you do not need to do this.

Shawn

> +	return 0;
> +}
> +
> +static struct platform_driver imx_ahci_driver = {
> +	.probe = imx_ahci_probe,
> +	.remove = imx_ahci_remove,
> +	.driver = {
> +		.name = "sata-imx",
> +		.owner = THIS_MODULE,
> +		.of_match_table = imx_ahci_of_match,
> +	},
> +};
> +module_platform_driver(imx_ahci_driver);
> +
> +MODULE_DESCRIPTION("Freescale i.MX AHCI SATA platform driver");
> +MODULE_AUTHOR("Richard Zhu <Hong-Xing.Zhu@freescale.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("sata:imx");
> -- 
> 1.7.5.4
> 

[v6 3/3] sata: imx: add ahci sata support on imx platforms

[Zhu Richard-R65037]

Hi Shawn:
Thanks a lot for your great help on the patch-review.

Best Regards
Richard Zhu


-----Original Message-----
From: Shawn Guo [mailto:shawn.guo at linaro.org] 
Sent: Monday, July 15, 2013 10:03 AM
To: Richard Zhu
Cc: linux-arm-kernel at lists.infradead.org; jgarzik at pobox.com; tj at kernel.org; rob.herring at calxeda.com; s.hauer at pengutronix.de; linux-ide at vger.kernel.org; Zhu Richard-R65037
Subject: Re: [v6 3/3] sata: imx: add ahci sata support on imx platforms

On Fri, Jul 12, 2013 at 05:41:18PM +0800, Richard Zhu wrote:
> From: Richard Zhu <r65037@freescale.com>
> 
> imx6q contains one Synopsys AHCI SATA controller, But it can't share 
> ahci_platform driver with other controllers.
> Because there are some misalignments of the generic AHCI controller.
> The bits definitions of the HBA registers, the Vendor Specific 
> registers, the AHCI PHY clock and the AHCI signals adjustment 
> window(GPR13 register).
>  - CAP_SSS(bit20) of the HOST_CAP is writable, default  value is '0', 
> should be configured to be '1'
>  - bit0 (only one AHCI SATA port on imx6q) of the  HOST_PORTS_IMPL 
> should be set to be '1'.(default 0)
>  - One Vendor Specific register HOST_TIMER1MS(offset:0xe0)  should be 
> configured regarding to the frequency of AHB  bus clock.
>  - Configurations of the AHCI PHY clock, and the signal  parameters of 
> the GPR13
> 
> Setup its own ahci sata driver, contained the imx6q specific 
> initialized codes, re-use the generic ahci_platform driver, and keep 
> the generic ahci_platform driver clean as much as possible.
> 
> Signed-off-by: Richard Zhu <r65037@freescale.com>
> ---
>  drivers/ata/Kconfig    |    9 ++
>  drivers/ata/Makefile   |    1 +
>  drivers/ata/sata_imx.c |  241 
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 251 insertions(+), 0 deletions(-)  create mode 
> 100644 drivers/ata/sata_imx.c
> 
> diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig index 
> a5a3ebc..275dc2c 100644
> --- a/drivers/ata/Kconfig
> +++ b/drivers/ata/Kconfig
> @@ -97,6 +97,15 @@ config SATA_AHCI_PLATFORM
>  
>  	  If unsure, say N.
>  
> +config SATA_IMX
> +	tristate "Freescale i.MX AHCI SATA support"
> +	depends on SATA_AHCI_PLATFORM
> +	help
> +	  This option enables support for the Freescale i.MX 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 
> c04d0fd..04b1c6c 100644
> --- a/drivers/ata/Makefile
> +++ b/drivers/ata/Makefile
> @@ -10,6 +10,7 @@ obj-$(CONFIG_SATA_INIC162X)	+= sata_inic162x.o
>  obj-$(CONFIG_SATA_SIL24)	+= sata_sil24.o
>  obj-$(CONFIG_SATA_DWC)		+= sata_dwc_460ex.o
>  obj-$(CONFIG_SATA_HIGHBANK)	+= sata_highbank.o libahci.o
> +obj-$(CONFIG_SATA_IMX)		+= sata_imx.o
>  
>  # SFF w/ custom DMA
>  obj-$(CONFIG_PDC_ADMA)		+= pdc_adma.o
> diff --git a/drivers/ata/sata_imx.c b/drivers/ata/sata_imx.c new file 
> mode 100644 index 0000000..fb13867
> --- /dev/null
> +++ b/drivers/ata/sata_imx.c
> @@ -0,0 +1,241 @@
> +/*
> + * Freescale IMX AHCI SATA platform driver
> + * Copyright 2013 Freescale Semiconductor, Inc.
> + *
> + * 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/regmap.h>
> +#include <linux/ahci_platform.h>
> +#include <linux/of_device.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
> +#include "ahci.h"
> +
> +enum {
> +	HOST_TIMER1MS = 0xe0, /* Timer 1-ms */ };
> +
> +struct imx_ahci_priv {
> +	struct platform_device *ahci_pdev;
> +	struct clk *sata_ref_clk;
> +	struct regmap *gpr;
> +};
> +
> +static int imx6q_sata_init(struct device *dev, void __iomem *mmio) {
> +	int ret = 0;
> +	unsigned int reg_val;
> +	struct clk *ahb_clk;
> +	struct imx_ahci_priv *imxpriv = dev_get_drvdata(dev->parent);
> +
> +	imxpriv->gpr =
> +		syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
> +	if (IS_ERR(imxpriv->gpr)) {
> +		dev_err(dev, "failed to find fsl,imx6q-iomux-gpr regmap\n");
> +		return PTR_ERR(imxpriv->gpr);
> +	}
> +
> +	ret = clk_prepare_enable(imxpriv->sata_ref_clk);
> +	if (ret < 0) {
> +		dev_err(dev, "prepare-enable sata_ref clock err:%d\n", ret);
> +		return ret;
> +	}
> +
> +	/*
> +	 * set PHY Paremeters, two steps to configure the GPR13,
> +	 * one write for rest of parameters, mask of first write
> +	 * is 0x07fffffd, and the other one write for setting
> +	 * the mpll_clk_en.
> +	 */
> +	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_RX_EQ_VAL_MASK
> +			| IMX6Q_GPR13_SATA_RX_LOS_LVL_MASK
> +			| IMX6Q_GPR13_SATA_RX_DPLL_MODE_MASK
> +			| IMX6Q_GPR13_SATA_SPD_MODE_MASK
> +			| IMX6Q_GPR13_SATA_MPLL_SS_EN
> +			| IMX6Q_GPR13_SATA_TX_ATTEN_MASK
> +			| IMX6Q_GPR13_SATA_TX_BOOST_MASK
> +			| IMX6Q_GPR13_SATA_TX_LVL_MASK
> +			| IMX6Q_GPR13_SATA_TX_EDGE_RATE
> +			, IMX6Q_GPR13_SATA_RX_EQ_VAL_3_0_DB
> +			| IMX6Q_GPR13_SATA_RX_LOS_LVL_SATA2M
> +			| IMX6Q_GPR13_SATA_RX_DPLL_MODE_2P_4F
> +			| IMX6Q_GPR13_SATA_SPD_MODE_3P0G
> +			| IMX6Q_GPR13_SATA_MPLL_SS_EN
> +			| IMX6Q_GPR13_SATA_TX_ATTEN_9_16
> +			| IMX6Q_GPR13_SATA_TX_BOOST_3_33_DB
> +			| IMX6Q_GPR13_SATA_TX_LVL_1_025_V);
> +	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_MPLL_CLK_EN,
> +			IMX6Q_GPR13_SATA_MPLL_CLK_EN);
> +	usleep_range(100, 200);
> +
> +	/*
> +	 * Configure the HWINIT bits of the HOST_CAP and HOST_PORTS_IMPL,
> +	 * and IP vendor specific register HOST_TIMER1MS.
> +	 * Configure CAP_SSS (support stagered spin up).
> +	 * Implement the port0.
> +	 * Get the ahb clock rate, and configure the TIMER1MS register.
> +	 */
> +	reg_val = readl(mmio + HOST_CAP);
> +	if (!(reg_val & HOST_CAP_SSS)) {
> +		reg_val |= HOST_CAP_SSS;
> +		writel(reg_val, mmio + HOST_CAP);
> +	}
> +	reg_val = readl(mmio + HOST_PORTS_IMPL);
> +	if (!(reg_val & 0x1)) {
> +		reg_val |= 0x1;
> +		writel(reg_val, mmio + HOST_PORTS_IMPL);
> +	}
> +
> +	ahb_clk = devm_clk_get(dev, "ahb");

Can we move this devm_clk_get() call into .probe as well?
[Ok] it would be moved to .probe.

> +	if (IS_ERR(ahb_clk)) {
> +		dev_err(dev, "no ahb clock.\n");
> +		clk_disable_unprepare(imxpriv->sata_ref_clk);
> +		devm_clk_put(dev, imxpriv->sata_ref_clk);
> +		return PTR_ERR(ahb_clk);
> +	}
> +	reg_val = clk_get_rate(ahb_clk) / 1000;
> +	writel(reg_val, mmio + HOST_TIMER1MS);
> +	devm_clk_put(dev, ahb_clk);
> +
> +	return 0;
> +}
> +
> +static void imx6q_sata_exit(struct device *dev) {
> +	struct imx_ahci_priv *imxpriv =  dev_get_drvdata(dev->parent);
> +
> +	regmap_update_bits(imxpriv->gpr, 0x34, IMX6Q_GPR13_SATA_MPLL_CLK_EN,
> +			!IMX6Q_GPR13_SATA_MPLL_CLK_EN);
> +	clk_disable_unprepare(imxpriv->sata_ref_clk);
> +}
> +
> +static struct ahci_platform_data imx6q_sata_pdata = {
> +	.init = imx6q_sata_init,
> +	.exit = imx6q_sata_exit,
> +};
> +
> +static const struct of_device_id imx_ahci_of_match[] = {
> +	{ .compatible = "fsl,imx6q-ahci", .data = &imx6q_sata_pdata},
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, imx_ahci_of_match);
> +
> +static int imx_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 imx_ahci_priv *imxpriv;
> +	struct device *ahci_dev;
> +	struct platform_device *ahci_pdev;
> +	int ret;
> +
> +	imxpriv = devm_kzalloc(dev, sizeof(*imxpriv), GFP_KERNEL);
> +	if (!imxpriv) {
> +		dev_err(dev, "can't alloc ahci_host_priv\n");
> +		return -ENOMEM;
> +	}
> +
> +	ahci_pdev = platform_device_alloc("ahci", -1);
> +	if (!ahci_pdev)
> +		return -ENODEV;
> +
> +	ahci_dev = &ahci_pdev->dev;
> +	ahci_dev->parent = dev;
> +
> +	imxpriv->sata_ref_clk = devm_clk_get(dev, "sata_ref");
> +	if (IS_ERR(imxpriv->sata_ref_clk)) {
> +		dev_err(dev, "can't get sata_ref clock.\n");
> +		ret = PTR_ERR(imxpriv->sata_ref_clk);
> +		goto err_pdev_put;
> +	}
> +
> +	imxpriv->ahci_pdev = ahci_pdev;
> +	platform_set_drvdata(pdev, imxpriv);
> +
> +	of_id = of_match_device(imx_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);

I do not think you need this.
[Richard] ok, they would be removed.

> +		devm_clk_put(dev, imxpriv->sata_ref_clk);

The good thing about using devm_clk_get() above is you do not need to explicitly call devm_clk_put() on either .remove or .probe failure.
[Richard] ok, they would be removed.

> +err_pdev_put:
> +		platform_device_put(ahci_pdev);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int imx_ahci_remove(struct platform_device *pdev) {
> +	struct imx_ahci_priv *imxpriv = platform_get_drvdata(pdev);
> +	struct platform_device *ahci_pdev = imxpriv->ahci_pdev;
> +
> +	platform_device_unregister(ahci_pdev);
> +	platform_set_drvdata(pdev, NULL);

Ditto, you do not need to do this.
[Richard] ok, they would be removed. 

Shawn

> +	return 0;
> +}
> +
> +static struct platform_driver imx_ahci_driver = {
> +	.probe = imx_ahci_probe,
> +	.remove = imx_ahci_remove,
> +	.driver = {
> +		.name = "sata-imx",
> +		.owner = THIS_MODULE,
> +		.of_match_table = imx_ahci_of_match,
> +	},
> +};
> +module_platform_driver(imx_ahci_driver);
> +
> +MODULE_DESCRIPTION("Freescale i.MX AHCI SATA platform driver"); 
> +MODULE_AUTHOR("Richard Zhu <Hong-Xing.Zhu@freescale.com>"); 
> +MODULE_LICENSE("GPL"); MODULE_ALIAS("sata:imx");
> --
> 1.7.5.4
>