From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1brJuz-0000Qb-2k for barebox@lists.infradead.org; Tue, 04 Oct 2016 07:13:38 +0000 Date: Tue, 4 Oct 2016 09:13:14 +0200 From: Sascha Hauer Message-ID: <20161004071314.e7ptvxiqo33pdt6a@pengutronix.de> References: <1475505657-898-1-git-send-email-andrew.smirnov@gmail.com> <1475505657-898-14-git-send-email-andrew.smirnov@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1475505657-898-14-git-send-email-andrew.smirnov@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH 13/20] i.MX: Add 'lpuart' serial driver To: Andrey Smirnov Cc: barebox@lists.infradead.org On Mon, Oct 03, 2016 at 07:40:50AM -0700, Andrey Smirnov wrote: > Add 'lpuart' serial driver, based on analogous driver from U-Boot > > Signed-off-by: Andrey Smirnov > --- > drivers/serial/Kconfig | 4 + > drivers/serial/Makefile | 1 + > drivers/serial/serial_lpuart.c | 217 +++++++++++++++++++++++++++++++++++++++++ > include/serial/lpuart.h | 28 ++++-- > 4 files changed, 244 insertions(+), 6 deletions(-) > create mode 100644 drivers/serial/serial_lpuart.c > > diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig > index 146bf1e..02e869a 100644 > --- a/drivers/serial/Kconfig > +++ b/drivers/serial/Kconfig > @@ -137,4 +137,8 @@ config DRIVER_SERIAL_DIGIC > bool "Canon DIGIC serial driver" > depends on ARCH_DIGIC > > +config DRIVER_SERIAL_LPUART > + depends on ARCH_IMX > + bool "LPUART serial driver" > + > endmenu > diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile > index 189e777..7d1bae1 100644 > --- a/drivers/serial/Makefile > +++ b/drivers/serial/Makefile > @@ -20,3 +20,4 @@ obj-$(CONFIG_DRIVER_SERIAL_AUART) += serial_auart.o > obj-$(CONFIG_DRIVER_SERIAL_CADENCE) += serial_cadence.o > obj-$(CONFIG_DRIVER_SERIAL_EFI_STDIO) += efi-stdio.o > obj-$(CONFIG_DRIVER_SERIAL_DIGIC) += serial_digic.o > +obj-$(CONFIG_DRIVER_SERIAL_LPUART) += serial_lpuart.o > diff --git a/drivers/serial/serial_lpuart.c b/drivers/serial/serial_lpuart.c > new file mode 100644 > index 0000000..52fb6d3 > --- /dev/null > +++ b/drivers/serial/serial_lpuart.c > @@ -0,0 +1,217 @@ > +/* > + * Copyright (c) 2016 Zodiac Inflight Innovation > + * Author: Andrey Smirnov > + * > + * Based on analogous driver from U-Boot > + * > + * See file CREDITS for list of people who contributed to this > + * project. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 > + * as published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct lpuart { > + struct console_device cdev; > + int baudrate; > + int dte_mode; > + struct notifier_block notify; > + struct resource *io; > + void __iomem *base; > + struct clk *clk; > +}; > + > +static struct lpuart *cdev_to_lpuart(struct console_device *cdev) > +{ > + return container_of(cdev, struct lpuart, cdev); > +} > + > +static struct lpuart *nb_to_lpuart(struct notifier_block *nb) > +{ > + return container_of(nb, struct lpuart, notify); > +} > + > +static void lpuart_enable(struct lpuart *lpuart, bool on) > +{ > + u8 ctrl; > + > + ctrl = readb(lpuart->base + UARTCR2); > + if (on) > + ctrl |= UARTCR2_TE | UARTCR2_RE; > + else > + ctrl &= ~(UARTCR2_TE | UARTCR2_RE); > + writeb(ctrl, lpuart->base + UARTCR2); > +} > + > +static int lpuart_serial_setbaudrate(struct console_device *cdev, > + int baudrate) > +{ > + struct lpuart *lpuart = cdev_to_lpuart(cdev); > + > + lpuart_enable(lpuart, false); > + > + lpuart_setbrg(lpuart->base, > + clk_get_rate(lpuart->clk), > + baudrate); > + > + lpuart_enable(lpuart, true); > + > + lpuart->baudrate = baudrate; > + > + return 0; > +} > + > +static int lpuart_serial_getc(struct console_device *cdev) > +{ > + bool ready; > + struct lpuart *lpuart = cdev_to_lpuart(cdev); > + > + do { > + const u8 sr1 = readb(lpuart->base + UARTSR1); > + ready = !!(sr1 & (UARTSR1_OR | UARTSR1_RDRF)); > + } while (!ready); > + > + return readb(lpuart->base + UARTDR); > +} > + > +static void lpuart_serial_putc(struct console_device *cdev, char c) > +{ > + lpuart_putc(cdev_to_lpuart(cdev)->base, c); > +} > + > +/* Test whether a character is in the RX buffer */ > +static int lpuart_serial_tstc(struct console_device *cdev) > +{ > + return !!readb(cdev_to_lpuart(cdev)->base + UARTRCFIFO); > +} > + > +static void lpuart_serial_flush(struct console_device *cdev) > +{ > + bool tx_empty; > + struct lpuart *lpuart = cdev_to_lpuart(cdev); > + > + do { > + const u8 sr1 = readb(lpuart->base + UARTSR1); > + tx_empty = !!(sr1 & UARTSR1_TDRE); > + } while (!tx_empty); > +} > + > +static int lpuart_clocksource_clock_change(struct notifier_block *nb, > + unsigned long event, void *data) > +{ > + struct lpuart *lpuart = nb_to_lpuart(nb); > + > + return lpuart_serial_setbaudrate(&lpuart->cdev, lpuart->baudrate); > +} This doesn't make sense in this form. I introduced this code in the i.MX uart driver since I had the need to change PLL rates while the uart is active. When this happens I had to adjust the dividers for the new uart base clock. The code above doesn't react to base clock changes though, it takes the old rate stored in lpuart->baudrate. If you don't have to adjust PLL rates while the uart is active then I suggest that you just remove this code. > @@ -225,25 +225,35 @@ static inline void lpuart_setbrg(void __iomem *base, > unsigned int refclock, > unsigned int baudrate) > { > + unsigned int bfra; > u16 sbr; > + > sbr = (u16) (refclock / (16 * baudrate)); > > writeb(sbr >> 8, base + UARTBDH); > writeb(sbr & 0xff, base + UARTBDL); > + > + bfra = DIV_ROUND_UP(2 * refclock, baudrate) - 32 * sbr; > + bfra &= UARTCR4_BRFA_MASK; > + writeb(bfra, base + UARTCR4); > } > > -static inline void lpuart_setup(void __iomem *base, > - unsigned int refclock) > +static inline void lpuart_setup_with_fifo(void __iomem *base, > + unsigned int refclock, > + unsigned int twfifo) > { > - > /* Disable UART */ > writeb(0, base + UARTCR2); > writeb(0, base + UARTMODEM); > writeb(0, base + UARTCR1); > > - /* Disable FIFOs */ > - writeb(0, base + UARTPFIFO); > - writeb(0, base + UARTTWFIFO); > + if (twfifo) { > + writeb(UARTPFIFO_TXFE | UARTPFIFO_RXFE, base + UARTPFIFO); > + writeb((u8)twfifo, base + UARTTWFIFO); > + } else { > + writeb(0, base + UARTPFIFO); > + writeb(0, base + UARTTWFIFO); > + } > writeb(1, base + UARTRWFIFO); > writeb(UARTCFIFO_RXFLUSH | UARTCFIFO_TXFLUSH, base + UARTCFIFO); > > @@ -252,6 +262,12 @@ static inline void lpuart_setup(void __iomem *base, > writeb(UARTCR2_TE | UARTCR2_RE, base + UARTCR2); > } > > +static inline void lpuart_setup(void __iomem *base, > + unsigned int refclock) > +{ > + lpuart_setup_with_fifo(base, refclock, 0x00); > +} > + > static inline void lpuart_putc(void __iomem *base, int c) > { > if (!(readb(base + UARTCR2) & UARTCR2_TE)) This was introduced earlier with this series. No need to change it, just create it correctly in the first place. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox