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Subject[PATCH V2 4/5] usb: serial: f81534: add H/W disable port support
Date
The F81532/534 can be disable port by manufacturer with
following H/W design.
1: Connect DCD/DSR/CTS/RI pin to ground.
2: Connect RX pin to ground.

In driver, we'll implements some detect method likes following:
1: Read MSR.
2: Turn MCR LOOP bit on, off and read LSR after delay with 60ms.
It'll contain BREAK status in LSR.

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
---
V2:
1: f81534_check_port_hw_disabled() change return type from int to bool.
2: Add help function f81534_set_phy_port_register() /
f81534_get_phy_port_register() for f81534_check_port_hw_disabled()
to read register without port.
3: Re-write f81534_calc_num_ports() & f81534_attach() to reduce the
f81534_check_port_hw_disabled() repeatedly called.

drivers/usb/serial/f81534.c | 160 +++++++++++++++++++++++++++-----------------
1 file changed, 99 insertions(+), 61 deletions(-)

diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
index 7f175f39a171..a4666171239a 100644
--- a/drivers/usb/serial/f81534.c
+++ b/drivers/usb/serial/f81534.c
@@ -307,6 +307,20 @@ static int f81534_set_mask_register(struct usb_serial *serial, u16 reg,
return f81534_set_register(serial, reg, tmp);
}

+static int f81534_set_phy_port_register(struct usb_serial *serial, int phy,
+ u16 reg, u8 data)
+{
+ return f81534_set_register(serial, reg + F81534_UART_OFFSET * phy,
+ data);
+}
+
+static int f81534_get_phy_port_register(struct usb_serial *serial, int phy,
+ u16 reg, u8 *data)
+{
+ return f81534_get_register(serial, reg + F81534_UART_OFFSET * phy,
+ data);
+}
+
static int f81534_set_port_register(struct usb_serial_port *port, u16 reg,
u8 data)
{
@@ -730,6 +744,70 @@ static int f81534_find_config_idx(struct usb_serial *serial, u8 *index)
}

/*
+ * The F81532/534 will not report serial port to USB serial subsystem when
+ * H/W DCD/DSR/CTS/RI/RX pin connected to ground.
+ *
+ * To detect RX pin status, we'll enable MCR interal loopback, disable it and
+ * delayed for 60ms. It connected to ground If LSR register report UART_LSR_BI.
+ */
+static bool f81534_check_port_hw_disabled(struct usb_serial *serial, int phy)
+{
+ int status;
+ u8 old_mcr;
+ u8 msr;
+ u8 lsr;
+ u8 msr_mask;
+
+ msr_mask = UART_MSR_DCD | UART_MSR_RI | UART_MSR_DSR | UART_MSR_CTS;
+
+ status = f81534_get_phy_port_register(serial, phy,
+ F81534_MODEM_STATUS_REG, &msr);
+ if (status)
+ return false;
+
+ if ((msr & msr_mask) != msr_mask)
+ return false;
+
+ status = f81534_set_phy_port_register(serial, phy,
+ F81534_FIFO_CONTROL_REG, UART_FCR_ENABLE_FIFO |
+ UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+ if (status)
+ return false;
+
+ status = f81534_get_phy_port_register(serial, phy,
+ F81534_MODEM_CONTROL_REG, &old_mcr);
+ if (status)
+ return false;
+
+ status = f81534_set_phy_port_register(serial, phy,
+ F81534_MODEM_CONTROL_REG, UART_MCR_LOOP);
+ if (status)
+ return false;
+
+ status = f81534_set_phy_port_register(serial, phy,
+ F81534_MODEM_CONTROL_REG, 0x0);
+ if (status)
+ return false;
+
+ msleep(60);
+
+ status = f81534_get_phy_port_register(serial, phy,
+ F81534_LINE_STATUS_REG, &lsr);
+ if (status)
+ return false;
+
+ status = f81534_set_phy_port_register(serial, phy,
+ F81534_MODEM_CONTROL_REG, old_mcr);
+ if (status)
+ return false;
+
+ if ((lsr & UART_LSR_BI) == UART_LSR_BI)
+ return true;
+
+ return false;
+}
+
+/*
* We had 2 generation of F81532/534 IC. All has an internal storage.
*
* 1st is pure USB-to-TTL RS232 IC and designed for 4 ports only, no any
@@ -750,11 +828,10 @@ static int f81534_find_config_idx(struct usb_serial *serial, u8 *index)
static int f81534_calc_num_ports(struct usb_serial *serial,
struct usb_serial_endpoints *epds)
{
+ struct f81534_serial_private *serial_priv;
struct device *dev = &serial->interface->dev;
int size_bulk_in = usb_endpoint_maxp(epds->bulk_in[0]);
int size_bulk_out = usb_endpoint_maxp(epds->bulk_out[0]);
- u8 setting[F81534_CUSTOM_DATA_SIZE];
- u8 setting_idx;
u8 num_port = 0;
int status;
size_t i;
@@ -765,8 +842,15 @@ static int f81534_calc_num_ports(struct usb_serial *serial,
return -ENODEV;
}

+ serial_priv = devm_kzalloc(&serial->interface->dev,
+ sizeof(*serial_priv), GFP_KERNEL);
+ if (!serial_priv)
+ return -ENOMEM;
+
+ usb_set_serial_data(serial, serial_priv);
+
/* Check had custom setting */
- status = f81534_find_config_idx(serial, &setting_idx);
+ status = f81534_find_config_idx(serial, &serial_priv->setting_idx);
if (status) {
dev_err(&serial->interface->dev, "%s: find idx failed: %d\n",
__func__, status);
@@ -777,11 +861,12 @@ static int f81534_calc_num_ports(struct usb_serial *serial,
* We'll read custom data only when data available, otherwise we'll
* read default value instead.
*/
- if (setting_idx != F81534_CUSTOM_NO_CUSTOM_DATA) {
+ if (serial_priv->setting_idx != F81534_CUSTOM_NO_CUSTOM_DATA) {
status = f81534_read_flash(serial,
F81534_CUSTOM_ADDRESS_START +
F81534_CONF_OFFSET,
- sizeof(setting), setting);
+ sizeof(serial_priv->conf_data),
+ serial_priv->conf_data);
if (status) {
dev_err(&serial->interface->dev,
"%s: get custom data failed: %d\n",
@@ -791,13 +876,13 @@ static int f81534_calc_num_ports(struct usb_serial *serial,

dev_dbg(&serial->interface->dev,
"%s: read config from block: %d\n", __func__,
- setting_idx);
+ serial_priv->setting_idx);
} else {
/* Read default board setting */
status = f81534_read_flash(serial,
- F81534_DEF_CONF_ADDRESS_START, F81534_NUM_PORT,
- setting);
-
+ F81534_DEF_CONF_ADDRESS_START,
+ sizeof(serial_priv->conf_data),
+ serial_priv->conf_data);
if (status) {
dev_err(&serial->interface->dev,
"%s: read failed: %d\n", __func__,
@@ -811,7 +896,10 @@ static int f81534_calc_num_ports(struct usb_serial *serial,

/* New style, find all possible ports */
for (i = 0; i < F81534_NUM_PORT; ++i) {
- if (setting[i] & F81534_PORT_UNAVAILABLE)
+ if (f81534_check_port_hw_disabled(serial, i))
+ serial_priv->conf_data[i] |= F81534_PORT_UNAVAILABLE;
+
+ if (serial_priv->conf_data[i] & F81534_PORT_UNAVAILABLE)
continue;

++num_port;
@@ -1228,61 +1316,11 @@ static int f81534_attach(struct usb_serial *serial)
{
struct f81534_serial_private *serial_priv;
int index = 0;
- int status;
int i;

- serial_priv = devm_kzalloc(&serial->interface->dev,
- sizeof(*serial_priv), GFP_KERNEL);
- if (!serial_priv)
- return -ENOMEM;
-
- usb_set_serial_data(serial, serial_priv);
-
+ serial_priv = usb_get_serial_data(serial);
mutex_init(&serial_priv->urb_mutex);

- /* Check had custom setting */
- status = f81534_find_config_idx(serial, &serial_priv->setting_idx);
- if (status) {
- dev_err(&serial->interface->dev, "%s: find idx failed: %d\n",
- __func__, status);
- return status;
- }
-
- /*
- * We'll read custom data only when data available, otherwise we'll
- * read default value instead.
- */
- if (serial_priv->setting_idx == F81534_CUSTOM_NO_CUSTOM_DATA) {
- /*
- * The default configuration layout:
- * byte 0/1/2/3: uart setting
- */
- status = f81534_read_flash(serial,
- F81534_DEF_CONF_ADDRESS_START,
- F81534_DEF_CONF_SIZE,
- serial_priv->conf_data);
- if (status) {
- dev_err(&serial->interface->dev,
- "%s: read reserve data failed: %d\n",
- __func__, status);
- return status;
- }
- } else {
- /* Only read 8 bytes for mode & GPIO */
- status = f81534_read_flash(serial,
- F81534_CUSTOM_ADDRESS_START +
- F81534_CONF_OFFSET,
- sizeof(serial_priv->conf_data),
- serial_priv->conf_data);
- if (status) {
- dev_err(&serial->interface->dev,
- "%s: idx: %d get data failed: %d\n",
- __func__, serial_priv->setting_idx,
- status);
- return status;
- }
- }
-
/* Assign phy-to-logic mapping */
for (i = 0; i < F81534_NUM_PORT; ++i) {
if (serial_priv->conf_data[i] & F81534_PORT_UNAVAILABLE)
--
2.7.4
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