On Sat, Aug 20, 2016 at 02:06:29PM +0200, Johan Hovold wrote:
> [ +CC: Karl and Konstantin ]
>
> On Fri, Jul 22, 2016 at 11:33:15AM +0100, Martyn Welch wrote:
> > This patch adds support for the GPIO found on the CP2105. Unlike the GPIO
> > provided by some of the other devices supported by the cp210x driver, the
> > GPIO on the CP2015 is muxed on pins otherwise used for serial control
> > lines. The GPIO have been configured in 2 separate banks as the choice to
> > configure the pins for GPIO is made separately for pins shared with each
> > of the 2 serial ports this device provides, though the choice is made for
> > all pins associated with that port in one go. The choice of whether to use
> > the pins for GPIO or serial is made by adding configuration to a one-time
> > programable PROM in the chip and can not be changed at runtime. The device
> > defaults to GPIO.
> >
> > This device supports either push-pull or open-drain modes, it doesn't
> > provide an explicit input mode, though the state of the GPIO can be read
> > when used in open-drain mode. Like with pin use, the mode is configured in
> > the one-time programable PROM and can't be changed at runtime.
> >
> > Signed-off-by: Martyn Welch <martyn.welch@xxxxxxxxxxxxxxx>
> > Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > ---
> >
> > V2: - Doesn't break build when gpiolib isn't selected.
> >
> > V3: - Tracking GPIO state so pins no longer get their state changed should
> > the pin be in open-drain mode and be pulled down externally whilst
> > another pin is set.
> > - Reworked buffers and moved to byte accesses to remove the
> > questionable buffer size logic and byte swapping.
> > - Added error reporting.
> > - Removed incorrect/pointless comments.
> > - Renamed tmp variable to make use clearer.
> >
> > V4: - Fixed memory leak in cp210x_gpio_get error path.
> >
> > V5: - Determining shared GPIO based on device type.
> > - Reordered vendor specific values by value.
> > - Use interface device for gpio messages.
> > - Remove unnecessary empty lines.
> > - Using kzalloc rather than kcalloc.
> > - Added locking to port_priv->output_state.
> > - Added dummy cp2105_shared_gpio_init for !CONFIG_GPIOLIB.
> > - Removed unnecessary masking on u8.
> > - Added support for use of GPIO pin as RS485 traffic indication or
> > activity LEDs.
> > - Use correct dev for GPIO device.
> > - Set can_sleep.
> > - Roll in initial configuration state support.
> > - Print error message & continue if GPIO fails.
> > - Simplified ifdef'ing.
>
> My apologies for the extreme delay for v5 review.
>
Sorry for the delayed response too.
> > drivers/usb/serial/cp210x.c | 351 +++++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 348 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> > index 4d6a5c6..b3153b8 100644
> > --- a/drivers/usb/serial/cp210x.c
> > +++ b/drivers/usb/serial/cp210x.c
> > @@ -23,6 +23,9 @@
> > #include <linux/usb.h>
> > #include <linux/uaccess.h>
> > #include <linux/usb/serial.h>
> > +#include <linux/gpio/driver.h>
> > +#include <linux/bitops.h>
> > +#include <linux/mutex.h>
> >
> > #define DRIVER_DESC "Silicon Labs CP210x RS232 serial adaptor driver"
> >
> > @@ -44,10 +47,14 @@ static int cp210x_tiocmset(struct tty_struct *, unsigned int, unsigned int);
> > static int cp210x_tiocmset_port(struct usb_serial_port *port,
> > unsigned int, unsigned int);
> > static void cp210x_break_ctl(struct tty_struct *, int);
> > +static int cp210x_attach(struct usb_serial *);
> > +static void cp210x_release(struct usb_serial *);
> > static int cp210x_port_probe(struct usb_serial_port *);
> > static int cp210x_port_remove(struct usb_serial_port *);
> > static void cp210x_dtr_rts(struct usb_serial_port *p, int on);
> >
> > +#define CP210X_FEATURE_HAS_SHARED_GPIO BIT(0)
>
> This one is not currently used, so should be removed.
>
Agh, oops, missed that.
> > +
> > static const struct usb_device_id id_table[] = {
> > { USB_DEVICE(0x045B, 0x0053) }, /* Renesas RX610 RX-Stick */
> > { USB_DEVICE(0x0471, 0x066A) }, /* AKTAKOM ACE-1001 cable */
> > @@ -207,9 +214,20 @@ static const struct usb_device_id id_table[] = {
> >
> > MODULE_DEVICE_TABLE(usb, id_table);
> >
> > +struct cp210x_dev_private {
>
> Rename this cp210x_serial_private.
>
OK
> > + u8 partnum;
> > +};
> > +
> > struct cp210x_port_private {
> > __u8 bInterfaceNumber;
> > bool has_swapped_line_ctl;
> > +#ifdef CONFIG_GPIOLIB
> > + struct usb_serial *serial;
> > + struct gpio_chip gc;
> > + struct mutex output_lock;
> > + unsigned int output_state;
> > + unsigned int *gpio_map;
> > +#endif
>
> As mentioned in my comments to v4, these belong in the interface private
> data (i.e. private data of the parent device).
>
Ah, sorry.
> > };
> >
> > static struct usb_serial_driver cp210x_device = {
> > @@ -228,6 +246,8 @@ static struct usb_serial_driver cp210x_device = {
> > .tx_empty = cp210x_tx_empty,
> > .tiocmget = cp210x_tiocmget,
> > .tiocmset = cp210x_tiocmset,
> > + .attach = cp210x_attach,
> > + .release = cp210x_release,
> > .port_probe = cp210x_port_probe,
> > .port_remove = cp210x_port_remove,
> > .dtr_rts = cp210x_dtr_rts
> > @@ -270,6 +290,7 @@ static struct usb_serial_driver * const serial_drivers[] = {
> > #define CP210X_SET_CHARS 0x19
> > #define CP210X_GET_BAUDRATE 0x1D
> > #define CP210X_SET_BAUDRATE 0x1E
> > +#define CP210X_VENDOR_SPECIFIC 0xFF
> >
> > /* CP210X_IFC_ENABLE */
> > #define UART_ENABLE 0x0001
> > @@ -312,6 +333,30 @@ static struct usb_serial_driver * const serial_drivers[] = {
> > #define CONTROL_WRITE_DTR 0x0100
> > #define CONTROL_WRITE_RTS 0x0200
> >
> > +/* CP210X_VENDOR_SPECIFIC values */
> > +#define CP210X_READ_LATCH 0x00C2
> > +#define CP210X_GET_PARTNUM 0x370B
> > +#define CP210X_GET_PORTCONFIG 0x370C
> > +#define CP210X_GET_DEVICEMODE 0x3711
> > +#define CP210X_WRITE_LATCH 0x37E1
> > +
> > +/* Part number definitions */
> > +#define CP2101_PARTNUM 0x01
> > +#define CP2102_PARTNUM 0x02
> > +#define CP2103_PARTNUM 0x03
> > +#define CP2104_PARTNUM 0x04
> > +#define CP2105_PARTNUM 0x05
> > +#define CP2108_PARTNUM 0x08
>
> Please use a CP210X_ prefix, and rename these CP210X_PARTNUM_CP2101,
> etc.
>
OK
> > +
> > +/* CP2105 port configuration values */
> > +#define CP2105_SCI_GPIO0_TXLED_MODE 0x01
> > +#define CP2105_SCI_GPIO1_RXLED_MODE 0x02
> > +
> > +
>
> Remove one newline.
>
OK
> > +#define CP2105_ECI_GPIO0_TXLED_MODE 0x01
> > +#define CP2105_ECI_GPIO1_RXLED_MODE 0x02
> > +#define CP2105_ECI_GPIO1_RS485_MODE 0x04
>
> If all of these are bitmasks, you should use BIT(n).
>
I guess they are - will convert.
> Also move all of these vendor-specific defines last (i.e. above
> cp210x_read_reg_block).
>
OK
> > +
> > /* CP210X_GET_COMM_STATUS returns these 0x13 bytes */
> > struct cp210x_comm_status {
> > __le32 ulErrors;
> > @@ -1104,11 +1149,263 @@ static void cp210x_break_ctl(struct tty_struct *tty, int break_state)
> > cp210x_write_u16_reg(port, CP210X_SET_BREAK, state);
> > }
> >
> > +#ifdef CONFIG_GPIOLIB
> > +static int cp210x_gpio_direction_get(struct gpio_chip *gc, unsigned gpio)
> > +{
> > + return 0;
> > +}
> > +
> > +static int cp210x_gpio_get(struct gpio_chip *gc, unsigned gpio)
> > +{
> > + struct cp210x_port_private *port_priv =
> > + container_of(gc, struct cp210x_port_private, gc);
>
> Just use tabs for indentation here.
>
OK
> > + struct usb_serial *serial = port_priv->serial;
> > + u8 *buf;
> > + int result;
> > +
> > + buf = kzalloc(sizeof(*buf), GFP_KERNEL);
> > + if (!buf)
> > + return -ENOMEM;
> > +
> > + result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
> > + CP210X_VENDOR_SPECIFIC,
> > + REQTYPE_INTERFACE_TO_HOST, CP210X_READ_LATCH,
> > + port_priv->bInterfaceNumber, buf, 1,
> > + USB_CTRL_GET_TIMEOUT);
>
> Please consider adding generic helpers for these vendor requests as that
> would allow you to remove a lot of the buffer-management code.
>
> We could even consider using those to implement the current reg_block
> helpers later.
>
> > + if (result != 1) {
> > + dev_err(&serial->interface->dev,
> > + "failed to get gpio state: %d\n", result);
> > + result = 0;
> > + goto err;
> > + }
> > +
> > + result = (*buf >> port_priv->gpio_map[gpio]) & 0x1;
> > +
> > +err:
> > + kfree(buf);
> > +
> > + return result;
> > +}
> > +
> > +static void cp210x_gpio_set(struct gpio_chip *gc, unsigned gpio, int value)
> > +{
> > + struct cp210x_port_private *port_priv =
> > + container_of(gc, struct cp210x_port_private, gc);
> > + struct usb_serial *serial = port_priv->serial;
> > + int result;
> > + u8 *buf;
> > +
> > + buf = kzalloc(sizeof(*buf) * 2, GFP_KERNEL);
> > + if (!buf)
> > + return;
> > +
> > + mutex_lock(&port_priv->output_lock);
> > +
> > + if (value == 0)
> > + port_priv->output_state &= ~BIT(port_priv->gpio_map[gpio]);
> > + else
> > + port_priv->output_state |= BIT(port_priv->gpio_map[gpio]);
> > +
> > + mutex_unlock(&port_priv->output_lock);
> > +
> > + buf[1] = port_priv->output_state;
> > + buf[0] = 0xFF;
>
> You should consider using a struct for this message instead of a raw
> byte array. Perhaps the field names could be found in one of those
> SiLabs application notes.
>
I'll have a look, but I think they just used raw byte arrays from memory.
> > +
> > + result = usb_control_msg(serial->dev,
> > + usb_sndctrlpipe(serial->dev, 0),
> > + CP210X_VENDOR_SPECIFIC,
> > + REQTYPE_HOST_TO_INTERFACE, CP210X_WRITE_LATCH,
> > + port_priv->bInterfaceNumber, buf, 2,
> > + USB_CTRL_SET_TIMEOUT);
> > + if (result != 2) {
> > + dev_err(&serial->interface->dev,
> > + "failed to set gpio state: %d\n", result);
> > + }
> > +
> > + kfree(buf);
> > +}
> > +
> > +/*
> > + * This function is for configuring GPIO using shared pins, where other signals
> > + * are made unavailable by configuring the use of GPIO. This is believed to be
> > + * only applicable to the cp2105 at this point, the other devices supported by
> > + * 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.
> > + */
>
> Instead of exposing a varying number of gpios and hence varying chip
> offsets depending on current configuration, I think we should always
> register all gpios and instead (possibly) refuse requests for them in
> case the corresponding pin is currently not configured for gpio
> function.
>
> This way gpio base+offset will always map to the same physical pin.
>
> Judging from the various cp210x datasheets, this scheme will fit the
> other device types as well.
>
I'd like to hear Linus' take on that prior to making that change as I'd
prefer not to do it then have him NACK it. Linus?
> > +static int cp2105_shared_gpio_init(struct usb_serial_port *port)
> > +{
> > + struct usb_serial *serial = port->serial;
> > + struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
> > + u8 *mode;
> > + u8 *config;
> > + int result;
> > + int i;
> > +
> > + mode = kzalloc(sizeof(*mode) * 2, GFP_KERNEL);
> > + if (!mode)
> > + return -ENOMEM;
> > +
> > + config = kzalloc(sizeof(*config) * 15, GFP_KERNEL);
> > + if (!config) {
> > + result = -ENOMEM;
> > + goto err1;
> > + }
>
> Same as above, please use packed structs for these messages too instead
> of hard-coding sizes and offsets (cf. struct cp210x_comm_status).
>
> I think I saw some more structure to them in Karl's OTP scripts, and
> perhaps Konstantin can also provide some insight?
>
Ok, will take a look.
> > +
> > + result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
> > + CP210X_VENDOR_SPECIFIC, REQTYPE_DEVICE_TO_HOST,
> > + CP210X_GET_DEVICEMODE,
> > + port_priv->bInterfaceNumber, mode,
> > + 2, USB_CTRL_GET_TIMEOUT);
> > + if (result != 2) {
> > + dev_err(&port->dev, "failed to get device mode: %d\n", result);
> > + if (result > 0)
> > + result = -EPROTO;
> > +
> > + goto err2;
> > + }
> > +
> > + result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
> > + CP210X_VENDOR_SPECIFIC, REQTYPE_DEVICE_TO_HOST,
> > + CP210X_GET_PORTCONFIG,
> > + port_priv->bInterfaceNumber, config, 15,
> > + USB_CTRL_GET_TIMEOUT);
> > + if (result != 15) {
> > + dev_err(&port->dev, "failed to get port config: %d\n", result);
> > + if (result > 0)
> > + result = -EPROTO;
> > +
> > + goto err2;
> > + }
> > +
> > + /* 2 banks of GPIO - One for the pins taken from each serial port */
> > + if (port_priv->bInterfaceNumber == 0) {
> > + if (mode[0] == 0) {
> > + result = 0;
> > + goto err2;
> > + }
> > +
> > + port_priv->gc.label = "cp210x_eci";
> > + port_priv->gc.ngpio = 2;
> > + port_priv->gpio_map = kzalloc(sizeof(*port_priv->gpio_map) *
> > + port_priv->gc.ngpio,
> > + GFP_KERNEL);
>
> You must check for allocation failures.
>
> I don't think you'll need gpio_map at all if you always register all
> gpios.
>
> You may want a single bitmask to store which pins are configured for
> gpio-function, and use that in a new request() callback instead.
>
> Just use the same label for all cp210x gpiochips, there will never be
> more than one per interface anyway.
>
OK
> > +
> > + i = 0;
> > +
> > + if (config[13] & CP2105_ECI_GPIO0_TXLED_MODE) {
> > + port_priv->gc.ngpio -= 1;
> > + } else {
> > + port_priv->gpio_map[i] = 0;
> > + i++;
> > + }
> > +
> > + if (config[13] & (CP2105_ECI_GPIO1_RXLED_MODE |
> > + CP2105_ECI_GPIO1_RS485_MODE)) {
> > + port_priv->gc.ngpio -= 1;
> > + } else {
> > + port_priv->gpio_map[i] = 1;
> > + i++;
> > + }
> > +
> > + if (port_priv->gc.ngpio == 0) {
> > + result = 0;
> > + goto err2;
> > + }
> > + } else if (port_priv->bInterfaceNumber == 1) {
> > + if (mode[1] == 0) {
> > + result = 0;
> > + goto err2;
> > + }
> > +
> > + port_priv->gc.label = "cp210x_sci";
> > + port_priv->gc.ngpio = 3;
> > + port_priv->gpio_map = kzalloc(sizeof(*port_priv->gpio_map) *
> > + port_priv->gc.ngpio,
> > + GFP_KERNEL);
>
> Error handling missing here too.
>
OK
> > +
> > + i = 0;
> > +
> > + if (config[12] & CP2105_SCI_GPIO0_TXLED_MODE) {
> > + port_priv->gc.ngpio -= 1;
> > + } else {
> > + port_priv->gpio_map[i] = 0;
> > + i++;
> > + }
> > +
> > + if (config[12] & CP2105_SCI_GPIO1_RXLED_MODE) {
> > + port_priv->gc.ngpio -= 1;
> > + } else {
> > + port_priv->gpio_map[i] = 1;
> > + i++;
> > + }
> > +
> > + port_priv->gpio_map[i] = 2;
> > + } else {
> > + result = -ENODEV;
> > + goto err2;
> > + }
> > +
> > + port_priv->gc.get_direction = cp210x_gpio_direction_get;
> > + port_priv->gc.get = cp210x_gpio_get;
> > + port_priv->gc.set = cp210x_gpio_set;
> > + port_priv->gc.owner = THIS_MODULE;
> > + port_priv->gc.parent = &serial->interface->dev;
> > + port_priv->gc.base = -1;
> > + port_priv->gc.can_sleep = true;
> > +
> > + port_priv->serial = serial;
> > +
> > + /*
> > + * Need to track the state of the output pins, the read function
> > + * returns value seen on the pin, not the value being currently
> > + * driven.
> > + */
> > + if (port_priv->bInterfaceNumber == 0)
> > + port_priv->output_state = (config[4] >> 2) & 0x3;
> > + else
> > + port_priv->output_state = (config[5] >> 1) & 0x7;
> > +
> > + mutex_init(&port_priv->output_lock);
> > +
> > + result = gpiochip_add(&port_priv->gc);
> > +
> > +err2:
>
> Please rename these out_free_config...
>
OK
> > + kfree(config);
> > +err1:
>
> ...and out_free_mode, which is more descriptive.
>
OK
> > + kfree(mode);
> > +
> > + return result;
> > +}
> > +
> > +void cp210x_shared_gpio_remove(struct usb_serial_port *port)
> > +{
> > + struct cp210x_port_private *port_priv;
> > +
> > + port_priv = usb_get_serial_port_data(port);
> > +
> > + if (port_priv->gc.label)
> > + gpiochip_remove(&port_priv->gc);
>
> This can be done unconditionally after the changes suggested above.
>
> > +}
> > +
> > +#else
> > +
> > +static int cp2105_shared_gpio_init(struct usb_serial_port *port)
> > +{
> > + return 0;
> > +}
> > +
> > +void cp210x_shared_gpio_remove(struct usb_serial_port *port)
> > +{
> > + /* Nothing to do */
> > +}
> > +#endif
> > +
> > static int cp210x_port_probe(struct usb_serial_port *port)
> > {
> > struct usb_serial *serial = port->serial;
> > struct usb_host_interface *cur_altsetting;
> > struct cp210x_port_private *port_priv;
> > + struct cp210x_dev_private *dev_priv = usb_get_serial_data(serial);
> > int ret;
> >
> > port_priv = kzalloc(sizeof(*port_priv), GFP_KERNEL);
> > @@ -1121,12 +1418,22 @@ static int cp210x_port_probe(struct usb_serial_port *port)
> > usb_set_serial_port_data(port, port_priv);
> >
> > ret = cp210x_detect_swapped_line_ctl(port);
> > - if (ret) {
> > - kfree(port_priv);
> > - return ret;
> > + if (ret)
> > + goto err_ctl;
> > +
> > + if (dev_priv->partnum == CP2105_PARTNUM) {
> > + ret = cp2105_shared_gpio_init(port);
> > + if (ret < 0)
> > + dev_err(&port->dev,
> > + "GPIO initialisation failed, continuing without GPIO support\n");
> > }
>
> So move this to attach().
>
OK
> >
> > return 0;
> > +
> > +err_ctl:
> > + kfree(port_priv);
> > +
> > + return ret;
> > }
> >
> > static int cp210x_port_remove(struct usb_serial_port *port)
> > @@ -1134,11 +1441,49 @@ static int cp210x_port_remove(struct usb_serial_port *port)
> > struct cp210x_port_private *port_priv;
> >
> > port_priv = usb_get_serial_port_data(port);
> > +
> > + cp210x_shared_gpio_remove(port);
> > +
> > kfree(port_priv);
> >
> > return 0;
> > }
> >
> > +static int cp210x_attach(struct usb_serial *serial)
> > +{
> > + struct cp210x_dev_private *priv;
> > + int result;
> > +
> > + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > +
> > + result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
> > + CP210X_VENDOR_SPECIFIC, REQTYPE_DEVICE_TO_HOST,
> > + CP210X_GET_PARTNUM, 0, &priv->partnum, 1,
>
> Always use a dedicated DMA-able buffer for transfers like this one.
> Adding a couple of helper function for this as suggested above, would
> take care of that.
>
OK
> > + USB_CTRL_GET_TIMEOUT);
> > + if (result != 1) {
> > + dev_err(&serial->interface->dev, "failed to get model: %d\n",
> > + result);
> > + goto err;
> > + }
> > +
> > + usb_set_serial_data(serial, (void *)priv);
> > +
> > + return 0;
> > +err:
> > + kfree(priv);
> > +
> > + return result;
> > +}
> > +
> > +static void cp210x_release(struct usb_serial *serial)
> > +{
> > + struct cp210x_dev_private *priv = usb_get_serial_data(serial);
> > +
> > + kfree(priv);
> > +}
> > +
> > module_usb_serial_driver(serial_drivers, id_table);
> >
> > MODULE_DESCRIPTION(DRIVER_DESC);
>
> Thanks,
> Johan
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