linux-kernel - RE: [PATCH v1 tty-next 2/2] 8250: microchip: pci1xxxx: Add power management functions to pci1xxxx's quad-uart driver.

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Date:   Fri, 2 Sep 2022 02:20:18 +0000
From:   <Kumaravel.Thiagarajan@...rochip.com>
To:     <ilpo.jarvinen@...ux.intel.com>
CC:     <gregkh@...uxfoundation.org>, <jirislaby@...nel.org>,
        <andy.shevchenko@...il.com>, <u.kleine-koenig@...gutronix.de>,
        <johan@...nel.org>, <wander@...hat.com>,
        <etremblay@...tech-controls.com>, <macro@...am.me.uk>,
        <geert+renesas@...der.be>, <jk@...abs.org>,
        <phil.edworthy@...esas.com>, <lukas@...ner.de>,
        <linux-kernel@...r.kernel.org>, <linux-serial@...r.kernel.org>,
        <UNGLinuxDriver@...rochip.com>
Subject: RE: [PATCH v1 tty-next 2/2] 8250: microchip: pci1xxxx: Add power
 management functions to pci1xxxx's  quad-uart driver.

> -----Original Message-----
> From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
> Sent: Wednesday, August 31, 2022 3:24 PM
> To: Kumaravel Thiagarajan - I21417 <Kumaravel.Thiagarajan@...rochip.com>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>; Jiri Slaby
> <jirislaby@...nel.org>; andy.shevchenko@...il.com; u.kleine-
> koenig@...gutronix.de; johan@...nel.org; wander@...hat.com;
> etremblay@...tech-controls.com; macro@...am.me.uk;
> geert+renesas@...der.be; jk@...abs.org; phil.edworthy@...esas.com;
> Lukas Wunner <lukas@...ner.de>; LKML <linux-kernel@...r.kernel.org>;
> linux-serial <linux-serial@...r.kernel.org>; UNGLinuxDriver
> <UNGLinuxDriver@...rochip.com>
> Subject: Re: [PATCH v1 tty-next 2/2] 8250: microchip: pci1xxxx: Add power
> management functions to pci1xxxx's quad-uart driver.
> 
> 
> On Tue, 30 Aug 2022, Kumaravel Thiagarajan wrote:
> 
> > pci1xxxx's quad-uart function has the capability to wake up the host
> > from suspend state. Enable wakeup before entering into suspend and
> > disable wakeup upon resume.
> >
> > Signed-off-by: Kumaravel Thiagarajan
> > <kumaravel.thiagarajan@...rochip.com>
> > ---
> >  drivers/tty/serial/8250/8250_pci1xxxx.c | 122
> > ++++++++++++++++++++++++
> >  1 file changed, 122 insertions(+)
> >
> > diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c
> > b/drivers/tty/serial/8250/8250_pci1xxxx.c
> > index 56852ae0585e..38c2a6a9e5d5 100644
> > --- a/drivers/tty/serial/8250/8250_pci1xxxx.c
> > +++ b/drivers/tty/serial/8250/8250_pci1xxxx.c
> > @@ -70,6 +70,7 @@
> >
> >  #define UART_PCI_CTRL_REG            0x80
> >  #define UART_PCI_CTRL_SET_MULTIPLE_MSI       BIT(4)
> > +#define UART_PCI_CTRL_D3_CLK_ENABLE  BIT(0)
> 
> Reorder.
I have ordered this like - Register offset followed by individual bits from MSB to LSB.
Should I reorder this based on some other criteria?

> 
> > +static char pci1xxxx_port_suspend(int line)
> 
> Why char???
I will modify this to bool.

> 
> > +{
> > +     struct uart_8250_port *up = serial8250_get_port(line);
> > +     struct uart_port *port = &up->port;
> > +     unsigned long flags;
> > +     u8 wakeup_mask;
> > +     char ret = 0;
> > +
> > +     if (port->suspended == 0 && port->dev) {
> > +             wakeup_mask = readb(up->port.membase +
> > + UART_WAKE_MASK_REG);
> > +
> > +             spin_lock_irqsave(&port->lock, flags);
> > +             port->mctrl &= ~TIOCM_OUT2;
> > +             port->ops->set_mctrl(port, port->mctrl);
> > +             spin_unlock_irqrestore(&port->lock, flags);
> > +
> > +             if ((wakeup_mask & UART_WAKE_SRCS) != UART_WAKE_SRCS)
> > +                     ret = 0x01;
> > +             else
> > +                     ret = 0x00;
> 
> Is it a bool or should you name these it with a #define?
bool is the correct data type. I will fix this.

> 
> > +     }
> > +
> > +     writeb(UART_WAKE_SRCS, port->membase + UART_WAKE_REG);
> > +
> > +     return ret;
> > +}
> > +
> > +void pci1xxxx_port_resume(int line)
> > +{
> > +     struct uart_8250_port *up = serial8250_get_port(line);
> > +     struct uart_port *port = &up->port;
> > +     unsigned long flags;
> > +
> > +     writeb(UART_WAKE_SRCS, port->membase + UART_WAKE_REG);
> > +
> > +     if (port->suspended == 0) {
> > +             spin_lock_irqsave(&port->lock, flags);
> > +             port->mctrl |= TIOCM_OUT2;
> > +             port->ops->set_mctrl(port, port->mctrl);
> > +             spin_unlock_irqrestore(&port->lock, flags);
> > +     }
> > +}
> > +
> > +static int pci1xxxx_suspend(struct device *dev) {
> > +     struct pci1xxxx_8250 *priv = dev_get_drvdata(dev);
> > +     struct pci_dev *pcidev = to_pci_dev(dev);
> > +     unsigned int data;
> > +     void __iomem *p;
> > +     char wakeup = 0;
> > +     int i;
> > +
> > +     for (i = 0; i < priv->nr; i++) {
> > +             if (priv->line[i] >= 0) {
> > +                     serial8250_suspend_port(priv->line[i]);
> > +                     wakeup |= pci1xxxx_port_suspend(priv->line[i]);
> > +             }
> > +     }
> > +
> > +     p = pci_ioremap_bar(pcidev, 0);
> > +     if (!p) {
> > +             dev_err(dev, "remapping of bar 0 memory failed");
> > +             return -ENOMEM;
> > +     }
> > +
> > +     data = readl(p + UART_RESET_REG);
> > +     writel(data | UART_RESET_D3_RESET_DISABLE, p + UART_RESET_REG);
> > +
> > +     if (wakeup)
> 
> It looks you'd want bool instead of char here.
Yes. I will modify this to bool.

Thank You.

Regards,
Kumaravel