This patch adds GPIO support for CP2102N devices.
It introduces new generic code to support emulating separate
input and outputs directions even though these devices
only know output modes (open-drain and pushpull). Existing
GPIO support for CP2105 has been migrated over to the new
code structure.
Only limitation is that for the QFN28 variant, only 4 out of
7 GPIOs are supported. This is because the config array
locations of the last 3 pins are not documented, and reverse
engineering revealed offsets that conflicted with other
documented functions. Hence we'll play it safe instead
until somebody clears this up further.
Signed-off-by: Karoly Pados <pados@xxxxxxxx>
---
Patch changelog:
v1: Initial implementation.
v2: Incorporate Johan's feedback, most importantly generalize
new code and unify with CP2105.
v3 (by Johan): Apply stylistic and minor bug fixes.
v4: Corrected commit message. No code changes.
drivers/usb/serial/cp210x.c | 245 ++++++++++++++++++++++++++++++------
1 file changed, 209 insertions(+), 36 deletions(-)
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 4a118eb13590..b9bc80700be7 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -224,9 +224,10 @@ MODULE_DEVICE_TABLE(usb, id_table);
struct cp210x_serial_private {
#ifdef CONFIG_GPIOLIB
struct gpio_chip gc;
- u8 config;
- u8 gpio_mode;
bool gpio_registered;
+ u8 gpio_pushpull;
+ u8 gpio_altfunc;
+ u8 gpio_input;
#endif
u8 partnum;
speed_t max_speed;
@@ -343,6 +344,7 @@ static struct usb_serial_driver * const serial_drivers[] = {
#define CONTROL_WRITE_RTS 0x0200
/* CP210X_VENDOR_SPECIFIC values */
+#define CP210X_READ_2NCONFIG 0x000E
#define CP210X_READ_LATCH 0x00C2
#define CP210X_GET_PARTNUM 0x370B
#define CP210X_GET_PORTCONFIG 0x370C
@@ -452,6 +454,12 @@ struct cp210x_config {
#define CP2105_GPIO1_RXLED_MODE BIT(1)
#define CP2105_GPIO1_RS485_MODE BIT(2)
+/* CP2102N configuration array indices */
+#define CP210X_2NCONFIG_CONFIG_VERSION_IDX 2
+#define CP210X_2NCONFIG_GPIO_MODE_IDX 581
+#define CP210X_2NCONFIG_GPIO_RSTLATCH_IDX 587
+#define CP210X_2NCONFIG_GPIO_CONTROL_IDX 600
+
/* CP210X_VENDOR_SPECIFIC, CP210X_WRITE_LATCH call writes these 0x2 bytes. */
struct cp210x_gpio_write {
u8 mask;
@@ -1313,17 +1321,8 @@ static int cp210x_gpio_request(struct gpio_chip *gc, unsigned int offset)
struct usb_serial *serial = gpiochip_get_data(gc);
struct cp210x_serial_private *priv = usb_get_serial_data(serial);
- switch (offset) {
- case 0:
- if (priv->config & CP2105_GPIO0_TXLED_MODE)
- return -ENODEV;
- break;
- case 1:
- if (priv->config & (CP2105_GPIO1_RXLED_MODE |
- CP2105_GPIO1_RS485_MODE))
- return -ENODEV;
- break;
- }
+ if (priv->gpio_altfunc & BIT(offset))
+ return -ENODEV;
return 0;
}
@@ -1331,10 +1330,15 @@ static int cp210x_gpio_request(struct gpio_chip *gc, unsigned int offset)
static int cp210x_gpio_get(struct gpio_chip *gc, unsigned int gpio)
{
struct usb_serial *serial = gpiochip_get_data(gc);
+ struct cp210x_serial_private *priv = usb_get_serial_data(serial);
+ u8 req_type = REQTYPE_DEVICE_TO_HOST;
int result;
u8 buf;
- result = cp210x_read_vendor_block(serial, REQTYPE_INTERFACE_TO_HOST,
+ if (priv->partnum == CP210X_PARTNUM_CP2105)
+ req_type = REQTYPE_INTERFACE_TO_HOST;
+
+ result = cp210x_read_vendor_block(serial, req_type,
CP210X_READ_LATCH, &buf, sizeof(buf));
if (result < 0)
return result;
@@ -1345,7 +1349,9 @@ static int cp210x_gpio_get(struct gpio_chip *gc, unsigned int gpio)
static void cp210x_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
{
struct usb_serial *serial = gpiochip_get_data(gc);
+ struct cp210x_serial_private *priv = usb_get_serial_data(serial);
struct cp210x_gpio_write buf;
+ int result;
if (value == 1)
buf.state = BIT(gpio);
@@ -1354,25 +1360,68 @@ static void cp210x_gpio_set(struct gpio_chip *gc, unsigned int gpio, int value)
buf.mask = BIT(gpio);
- cp210x_write_vendor_block(serial, REQTYPE_HOST_TO_INTERFACE,
- CP210X_WRITE_LATCH, &buf, sizeof(buf));
+ if (priv->partnum == CP210X_PARTNUM_CP2105) {
+ result = cp210x_write_vendor_block(serial,
+ REQTYPE_HOST_TO_INTERFACE,
+ CP210X_WRITE_LATCH, &buf,
+ sizeof(buf));
+ } else {
+ u16 wIndex = buf.state << 8 | buf.mask;
+
+ result = usb_control_msg(serial->dev,
+ usb_sndctrlpipe(serial->dev, 0),
+ CP210X_VENDOR_SPECIFIC,
+ REQTYPE_HOST_TO_DEVICE,
+ CP210X_WRITE_LATCH,
+ wIndex,
+ NULL, 0, USB_CTRL_SET_TIMEOUT);
+ }
+
+ if (result < 0) {
+ dev_err(&serial->interface->dev, "failed to set GPIO value: %d\n",
+ result);
+ }
}
static int cp210x_gpio_direction_get(struct gpio_chip *gc, unsigned int gpio)
{
- /* Hardware does not support an input mode */
- return 0;
+ struct usb_serial *serial = gpiochip_get_data(gc);
+ struct cp210x_serial_private *priv = usb_get_serial_data(serial);
+
+ return priv->gpio_input & BIT(gpio);
}
static int cp210x_gpio_direction_input(struct gpio_chip *gc, unsigned int gpio)
{
- /* Hardware does not support an input mode */
- return -ENOTSUPP;
+ struct usb_serial *serial = gpiochip_get_data(gc);
+ struct cp210x_serial_private *priv = usb_get_serial_data(serial);
+
+ if (priv->partnum == CP210X_PARTNUM_CP2105) {
+ /* hardware does not support an input mode */
+ return -ENOTSUPP;
+ }
+
+ /* push-pull pins cannot be changed to be inputs */
+ if (priv->gpio_pushpull & BIT(gpio))
+ return -EINVAL;
+
+ /* make sure to release pin if it is being driven low */
+ cp210x_gpio_set(gc, gpio, 1);
+
+ priv->gpio_input |= BIT(gpio);
+
+ return 0;
}
static int cp210x_gpio_direction_output(struct gpio_chip *gc, unsigned int gpio,
int value)
{
+ struct usb_serial *serial = gpiochip_get_data(gc);
+ struct cp210x_serial_private *priv = usb_get_serial_data(serial);
+
+ priv->gpio_input &= ~BIT(gpio);
+ cp210x_gpio_set(gc, gpio, value);
+
return 0;
}
@@ -1385,11 +1434,11 @@ static int cp210x_gpio_set_config(struct gpio_chip *gc, unsigned int gpio,
/* Succeed only if in correct mode (this can't be set at runtime) */
if ((param == PIN_CONFIG_DRIVE_PUSH_PULL) &&
- (priv->gpio_mode & BIT(gpio)))
+ (priv->gpio_pushpull & BIT(gpio)))
return 0;
if ((param == PIN_CONFIG_DRIVE_OPEN_DRAIN) &&
- !(priv->gpio_mode & BIT(gpio)))
+ !(priv->gpio_pushpull & BIT(gpio)))
return 0;
return -ENOTSUPP;
@@ -1402,12 +1451,13 @@ static int cp210x_gpio_set_config(struct gpio_chip *gc, unsigned int gpio,
* this driver that provide GPIO do so in a way that does not impact other
* signals and are thus expected to have very different initialisation.
*/
-static int cp2105_shared_gpio_init(struct usb_serial *serial)
+static int cp2105_gpioconf_init(struct usb_serial *serial)
{
struct cp210x_serial_private *priv = usb_get_serial_data(serial);
struct cp210x_pin_mode mode;
struct cp210x_config config;
u8 intf_num = cp210x_interface_num(serial);
+ u8 iface_config;
int result;
result = cp210x_read_vendor_block(serial, REQTYPE_DEVICE_TO_HOST,
@@ -1424,20 +1474,26 @@ static int cp2105_shared_gpio_init(struct usb_serial *serial)
/* 2 banks of GPIO - One for the pins taken from each serial port */
if (intf_num == 0) {
- if (mode.eci == CP210X_PIN_MODE_MODEM)
+ if (mode.eci == CP210X_PIN_MODE_MODEM) {
+ /* mark all GPIOs of this interface as reserved */
+ priv->gpio_altfunc = 0xff;
return 0;
+ }
- priv->config = config.eci_cfg;
- priv->gpio_mode = (u8)((le16_to_cpu(config.gpio_mode) &
+ iface_config = config.eci_cfg;
+ priv->gpio_pushpull = (u8)((le16_to_cpu(config.gpio_mode) &
CP210X_ECI_GPIO_MODE_MASK) >>
CP210X_ECI_GPIO_MODE_OFFSET);
priv->gc.ngpio = 2;
} else if (intf_num == 1) {
- if (mode.sci == CP210X_PIN_MODE_MODEM)
+ if (mode.sci == CP210X_PIN_MODE_MODEM) {
+ /* mark all GPIOs of this interface as reserved */
+ priv->gpio_altfunc = 0xff;
return 0;
+ }
- priv->config = config.sci_cfg;
- priv->gpio_mode = (u8)((le16_to_cpu(config.gpio_mode) &
+ iface_config = config.sci_cfg;
+ priv->gpio_pushpull = (u8)((le16_to_cpu(config.gpio_mode) &
CP210X_SCI_GPIO_MODE_MASK) >>
CP210X_SCI_GPIO_MODE_OFFSET);
priv->gc.ngpio = 3;
@@ -1445,6 +1501,125 @@ static int cp2105_shared_gpio_init(struct usb_serial *serial)
return -ENODEV;
}
+ /* mark all pins which are not in GPIO mode */
+ if (iface_config & CP2105_GPIO0_TXLED_MODE) /* GPIO 0 */
+ priv->gpio_altfunc |= BIT(0);
+ if (iface_config & (CP2105_GPIO1_RXLED_MODE | /* GPIO 1 */
+ CP2105_GPIO1_RS485_MODE))
+ priv->gpio_altfunc |= BIT(1);
+
+ /* driver implementation for CP2105 only supports outputs */
+ priv->gpio_input = 0;
+
+ return 0;
+}
+
+static int cp2102n_gpioconf_init(struct usb_serial *serial)
+{
+ struct cp210x_serial_private *priv = usb_get_serial_data(serial);
+ const u16 config_size = 0x02a6;
+ u8 gpio_rst_latch;
+ u8 config_version;
+ u8 gpio_pushpull;
+ u8 *config_buf;
+ u8 gpio_latch;
+ u8 gpio_ctrl;
+ int result;
+ u8 i;
+
+ /*
+ * Retrieve device configuration from the device.
+ * The array received contains all customization settings done at the
+ * factory/manufacturer. Format of the array is documented at the
+ * time of writing at:
+ * https://www.silabs.com/community/interface/knowledge-base.entry.html/2017/03/31/cp2102n_setconfig-xsfa
+ */
+ config_buf = kmalloc(config_size, GFP_KERNEL);
+ if (!config_buf)
+ return -ENOMEM;
+
+ result = cp210x_read_vendor_block(serial,
+ REQTYPE_DEVICE_TO_HOST,
+ CP210X_READ_2NCONFIG,
+ config_buf,
+ config_size);
+ if (result < 0) {
+ kfree(config_buf);
+ return result;
+ }
+
+ config_version = config_buf[CP210X_2NCONFIG_CONFIG_VERSION_IDX];
+ gpio_pushpull = config_buf[CP210X_2NCONFIG_GPIO_MODE_IDX];
+ gpio_ctrl = config_buf[CP210X_2NCONFIG_GPIO_CONTROL_IDX];
+ gpio_rst_latch = config_buf[CP210X_2NCONFIG_GPIO_RSTLATCH_IDX];
+
+ kfree(config_buf);
+
+ /* Make sure this is a config format we understand. */
+ if (config_version != 0x01)
+ return -ENOTSUPP;
+
+ /*
+ * We only support 4 GPIOs even on the QFN28 package, because
+ * config locations of GPIOs 4-6 determined using reverse
+ * engineering revealed conflicting offsets with other
+ * documented functions. So we'll just play it safe for now.
+ */
+ priv->gc.ngpio = 4;
+
+ /*
+ * Get default pin states after reset. Needed so we can determine
+ * the direction of an open-drain pin.
+ */
+ gpio_latch = (gpio_rst_latch >> 3) & 0x0f;
+
+ /* 0 indicates open-drain mode, 1 is push-pull */
+ priv->gpio_pushpull = (gpio_pushpull >> 3) & 0x0f;
+
+ /* 0 indicates GPIO mode, 1 is alternate function */
+ priv->gpio_altfunc = (gpio_ctrl >> 2) & 0x0f;
+
+ /*
+ * The CP2102N does not strictly has input and output pin modes,
+ * it only knows open-drain and push-pull modes which is set at
+ * factory. An open-drain pin can function both as an
+ * input or an output. We emulate input mode for open-drain pins
+ * by making sure they are not driven low, and we do not allow
+ * push-pull pins to be set as an input.
+ */
+ for (i = 0; i < priv->gc.ngpio; ++i) {
+ /*
+ * Set direction to "input" iff pin is open-drain and reset
+ * value is 1.
+ */
+ if (!(priv->gpio_pushpull & BIT(i)) && (gpio_latch & BIT(i)))
+ priv->gpio_input |= BIT(i);
+ }
+
+ return 0;
+}
+
+static int cp210x_gpio_init(struct usb_serial *serial)
+{
+ struct cp210x_serial_private *priv = usb_get_serial_data(serial);
+ int result;
+
+ switch (priv->partnum) {
+ case CP210X_PARTNUM_CP2105:
+ result = cp2105_gpioconf_init(serial);
+ break;
+ case CP210X_PARTNUM_CP2102N_QFN28:
+ case CP210X_PARTNUM_CP2102N_QFN24:
+ case CP210X_PARTNUM_CP2102N_QFN20:
+ result = cp2102n_gpioconf_init(serial);
+ break;
+ default:
+ return 0;
+ }
+
+ if (result < 0)
+ return result;
+
priv->gc.label = "cp210x";
priv->gc.request = cp210x_gpio_request;
priv->gc.get_direction = cp210x_gpio_direction_get;
@@ -1477,7 +1652,7 @@ static void cp210x_gpio_remove(struct usb_serial *serial)
#else
-static int cp2105_shared_gpio_init(struct usb_serial *serial)
+static int cp210x_gpio_init(struct usb_serial *serial)
{
return 0;
}
@@ -1588,12 +1763,10 @@ static int cp210x_attach(struct usb_serial *serial)
cp210x_init_max_speed(serial);
- if (priv->partnum == CP210X_PARTNUM_CP2105) {
- result = cp2105_shared_gpio_init(serial);
- if (result < 0) {
- dev_err(&serial->interface->dev,
- "GPIO initialisation failed, continuing without GPIO support\n");
- }
+ result = cp210x_gpio_init(serial);
+ if (result < 0) {
+ dev_err(&serial->interface->dev, "GPIO initialisation failed: %d\n",
+ result);
}
return 0;
--
2.18.0
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