[PATCH] mmc: sdhci-pxav3: dt: Support "power-gpios" property

[PATCH] mmc: sdhci-pxav3: dt: Support "power-gpios" property

[Chris Ball]

Tested on OLPC XO-4/MMP3, where the card power for two of the
controllers is a sideband GPIO.  The third cell in the power-gpios
property controls whether the GPIO is active high/active low.

(Also, pass host_caps2 through from platdata to the mmc host.)

Signed-off-by: Chris Ball <cjb@laptop.org>
---
This patch depends on "mmc: slot-gpio: Add support for power gpios"

 drivers/mmc/host/sdhci-pxav3.c          | 25 +++++++++++++++++++++++++
 include/linux/platform_data/pxa_sdhci.h |  2 ++
 2 files changed, 27 insertions(+)

diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
index 8a9b367..0bdb326 100644
--- a/drivers/mmc/host/sdhci-pxav3.c
+++ b/drivers/mmc/host/sdhci-pxav3.c
@@ -24,12 +24,14 @@
 #include <linux/gpio.h>
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
+#include <linux/mmc/slot-gpio.h>
 #include <linux/platform_data/pxa_sdhci.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 
 #include "sdhci.h"
 #include "sdhci-pltfm.h"
@@ -182,6 +184,7 @@ static struct sdhci_pxa_platdata *pxav3_get_mmc_pdata(struct device *dev)
 	struct device_node *np = dev->of_node;
 	u32 bus_width;
 	u32 clk_delay_cycles;
+	enum of_gpio_flags gpio_flags;
 
 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
@@ -204,6 +207,10 @@ static struct sdhci_pxa_platdata *pxav3_get_mmc_pdata(struct device *dev)
 	if (of_find_property(np, "wp-inverted", NULL))
 		pdata->quirks |= SDHCI_QUIRK_INVERTED_WRITE_PROTECT;
 
+	pdata->power_gpio = of_get_named_gpio_flags(np, "power-gpios", 0, &gpio_flags);
+	if (gpio_flags != OF_GPIO_ACTIVE_LOW)
+		pdata->host_caps2 |= MMC_CAP2_PWR_ACTIVE_HIGH;
+
 	return pdata;
 }
 #else
@@ -272,8 +279,19 @@ static int __devinit sdhci_pxav3_probe(struct platform_device *pdev)
 			host->quirks |= pdata->quirks;
 		if (pdata->host_caps)
 			host->mmc->caps |= pdata->host_caps;
+		if (pdata->host_caps2)
+			host->mmc->caps2 |= pdata->host_caps2;
 		if (pdata->pm_caps)
 			host->mmc->pm_caps |= pdata->pm_caps;
+
+		if (gpio_is_valid(pdata->power_gpio)) {
+			ret = mmc_gpio_request_pwr(host->mmc, pdata->power_gpio);
+			if (ret) {
+				dev_err(mmc_dev(host->mmc),
+					"failed to allocate power gpio\n");
+				goto err_power_req;
+			}
+		}
 	}
 
 	host->ops = &pxav3_sdhci_ops;
@@ -291,6 +309,8 @@ static int __devinit sdhci_pxav3_probe(struct platform_device *pdev)
 err_add_host:
 	clk_disable_unprepare(clk);
 	clk_put(clk);
+	mmc_gpio_free_pwr(host->mmc);
+err_power_req:
 err_clk_get:
 	sdhci_pltfm_free(pdev);
 	kfree(pxa);
@@ -300,6 +320,7 @@ err_clk_get:
 static int __devexit sdhci_pxav3_remove(struct platform_device *pdev)
 {
 	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_pxa_platdata *pdata = pdev->dev.platform_data;
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct sdhci_pxa *pxa = pltfm_host->priv;
 
@@ -307,6 +328,10 @@ static int __devexit sdhci_pxav3_remove(struct platform_device *pdev)
 
 	clk_disable_unprepare(pltfm_host->clk);
 	clk_put(pltfm_host->clk);
+
+	if (gpio_is_valid(pdata->power_gpio))
+		mmc_gpio_free_pwr(host->mmc);
+
 	sdhci_pltfm_free(pdev);
 	kfree(pxa);
 
diff --git a/include/linux/platform_data/pxa_sdhci.h b/include/linux/platform_data/pxa_sdhci.h
index 51ad099..e08ffc2 100644
--- a/include/linux/platform_data/pxa_sdhci.h
+++ b/include/linux/platform_data/pxa_sdhci.h
@@ -47,8 +47,10 @@ struct sdhci_pxa_platdata {
 	bool		clk_delay_enable;
 	unsigned int	ext_cd_gpio;
 	bool		ext_cd_gpio_invert;
+	unsigned int	power_gpio;
 	unsigned int	max_speed;
 	unsigned int	host_caps;
+	unsigned int	host_caps2;
 	unsigned int	quirks;
 	unsigned int	pm_caps;
 };
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

Re: [PATCH] mmc: sdhci-pxav3: dt: Support "power-gpios" property

[zhangfei gao]

On Sun, Sep 9, 2012 at 11:06 AM, Chris Ball <cjb@laptop.org> wrote:
> Tested on OLPC XO-4/MMP3, where the card power for two of the
> controllers is a sideband GPIO.  The third cell in the power-gpios
> property controls whether the GPIO is active high/active low.
>
> (Also, pass host_caps2 through from platdata to the mmc host.)
>
> Signed-off-by: Chris Ball <cjb@laptop.org>
> ---
> This patch depends on "mmc: slot-gpio: Add support for power gpios"
>
>  drivers/mmc/host/sdhci-pxav3.c          | 25 +++++++++++++++++++++++++
>  include/linux/platform_data/pxa_sdhci.h |  2 ++
>  2 files changed, 27 insertions(+)

Thanks Chris.
One questions is could we simply use fixed voltage regulator to control gpio?
And register this gpio as vmmc.

Thanks

Re: [PATCH] mmc: sdhci-pxav3: dt: Support "power-gpios" property

[Haojian Zhuang]

On Tue, Sep 11, 2012 at 1:00 PM, zhangfei gao <zhangfei.gao@gmail.com> wrote:
> On Sun, Sep 9, 2012 at 11:06 AM, Chris Ball <cjb@laptop.org> wrote:
>> Tested on OLPC XO-4/MMP3, where the card power for two of the
>> controllers is a sideband GPIO.  The third cell in the power-gpios
>> property controls whether the GPIO is active high/active low.
>>
>> (Also, pass host_caps2 through from platdata to the mmc host.)
>>
>> Signed-off-by: Chris Ball <cjb@laptop.org>
>> ---
>> This patch depends on "mmc: slot-gpio: Add support for power gpios"
>>
>>  drivers/mmc/host/sdhci-pxav3.c          | 25 +++++++++++++++++++++++++
>>  include/linux/platform_data/pxa_sdhci.h |  2 ++
>>  2 files changed, 27 insertions(+)
>
> Thanks Chris.
> One questions is could we simply use fixed voltage regulator to control gpio?
> And register this gpio as vmmc.
>
> Thanks

Hi Chris,

As my understanding, the buck/LDO supplies power to MMC slot with 2.8V. We
can call it as regulator A. GPIO pin is used to control this power
supply to MMC
slot. We can call it as regulator B (fixed regulator).

I think that we can linked these two regulators as cascade. Since we
won't change
voltage as regulator A. This link won't bring us any issue. So we only need to
control regulator B in mmc driver. How do you think about this idea?

Regards
Haojian