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Subject[PATCH 1/3] usb: phy-generic: Add GPIO based ChipSelect
Date
usb: phy-generic: Add GPIO based ChipSelect

The ULPI ISP1504 uses the CHIP_SELECT_N (low active) pin to active the
chip. This patch add support for GPIO based ChipSelect almost the same
way implemented for the Reset feature.

Sample DT configuration:
pinctrl_usbphy2: usbphy-2 {
fsl,pins = <
/* chip select and reset gpio output */
MX27_PAD_PC_CD1_B__GPIO6_20 0x0
MX27_PAD_PC_CD2_B__GPIO6_19 0x0
>;
};

&usbphy2 {
cs-gpios = <&gpio6 20 1>;
reset-gpios = <&gpio6 19 1>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_usbphy2>;
};

Signed-off-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
---
drivers/usb/phy/phy-generic.c | 31 +++++++++++++++++++++++++++++++
drivers/usb/phy/phy-generic.h | 2 ++
2 files changed, 33 insertions(+)

diff --git a/drivers/usb/phy/phy-generic.c b/drivers/usb/phy/phy-generic.c
index fce3a9e..ff4d68c 100644
--- a/drivers/usb/phy/phy-generic.c
+++ b/drivers/usb/phy/phy-generic.c
@@ -181,6 +181,24 @@ int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_gen_xceiv *nop,
return -EPROBE_DEFER;
}

+ if(gpio_is_valid(nop->gpio_chipselect)) {
+ unsigned long gpio_flags;
+ dev_dbg(dev, "Requesting Chipselect GPIO %d\n",
+ nop->gpio_chipselect);
+ if (nop->cs_active_low)
+ gpio_flags = GPIOF_OUT_INIT_LOW;
+ else
+ gpio_flags = GPIOF_OUT_INIT_HIGH;
+
+ err = devm_gpio_request_one(dev, nop->gpio_chipselect,
+ gpio_flags, dev_name(dev));
+ if (err) {
+ dev_err(dev, "Error requesting Chipselect GPIO %d err=%d\n",
+ nop->gpio_chipselect, err);
+ return err;
+ }
+ }
+
if (gpio_is_valid(nop->gpio_reset)) {
unsigned long gpio_flags;

@@ -231,27 +249,40 @@ static int usb_phy_gen_xceiv_probe(struct platform_device *pdev)
return -ENOMEM;

nop->reset_active_low = true; /* default behaviour */
+ nop->cs_active_low = true;

if (dev->of_node) {
struct device_node *node = dev->of_node;
enum of_gpio_flags flags;
+ enum of_gpio_flags csflags;

if (of_property_read_u32(node, "clock-frequency", &clk_rate))
clk_rate = 0;

needs_vcc = of_property_read_bool(node, "vcc-supply");
+
nop->gpio_reset = of_get_named_gpio_flags(node, "reset-gpios",
0, &flags);
+
if (nop->gpio_reset == -EPROBE_DEFER)
return -EPROBE_DEFER;

nop->reset_active_low = flags & OF_GPIO_ACTIVE_LOW;

+ nop->gpio_chipselect = of_get_named_gpio_flags(node, "cs-gpios",
+ 0, &csflags);
+ if (gpio_is_valid(nop->gpio_chipselect))
+ nop->cs_active_low = csflags & OF_GPIO_ACTIVE_LOW;
+
} else if (pdata) {
type = pdata->type;
clk_rate = pdata->clk_rate;
needs_vcc = pdata->needs_vcc;
nop->gpio_reset = pdata->gpio_reset;
+ nop->gpio_chipselect = pdata->gpio_chipselect;
+ } else {
+ nop->gpio_reset = -1;
+ nop->gpio_chipselect = -1;
}

err = usb_phy_gen_create_phy(dev, nop, type, clk_rate, needs_vcc);
diff --git a/drivers/usb/phy/phy-generic.h b/drivers/usb/phy/phy-generic.h
index d2a220d..97eafc2 100644
--- a/drivers/usb/phy/phy-generic.h
+++ b/drivers/usb/phy/phy-generic.h
@@ -7,7 +7,9 @@ struct usb_phy_gen_xceiv {
struct clk *clk;
struct regulator *vcc;
int gpio_reset;
+ int gpio_chipselect;
bool reset_active_low;
+ bool cs_active_low;
};

int usb_gen_phy_init(struct usb_phy *phy);
--
1.7.10.4


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