Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752927Ab1BQHs4 (ORCPT ); Thu, 17 Feb 2011 02:48:56 -0500 Received: from symlink.to.noone.org ([85.10.207.172]:52896 "EHLO sym.noone.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752670Ab1BQHsv (ORCPT ); Thu, 17 Feb 2011 02:48:51 -0500 Date: Thu, 17 Feb 2011 08:48:46 +0100 From: Tobias Klauser To: Thomas Chou Cc: nios2-dev@sopc.et.ntust.edu.tw, Greg Kroah-Hartman , linux-serial@vger.kernel.org, Grant Likely , devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [Nios2-dev] [PATHV v2] tty: serial: altera_uart: Add devicetree support Message-ID: <20110217074846.GG4076@distanz.ch> References: <1297872732-10207-1-git-send-email-tklauser@distanz.ch> <4D5C86C1.8070404@wytron.com.tw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D5C86C1.8070404@wytron.com.tw> X-Editor: Vi IMproved 7.1 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5576 Lines: 177 Hi Thomas, Thanks a lot for your comments. On 2011-02-17 at 03:24:01 +0100, Thomas Chou wrote: > On 02/17/2011 12:12 AM, Tobias Klauser wrote: >> With the recent switch of the (currently still out-of-tree) Nios2 Linux >> port to devicetree we want to be able to retreive the resources and >> properties from dts. >> >> The old method to retreive resources and properties from platform data >> is still supported. >> >> Cc: Grant Likely >> Signed-off-by: Tobias Klauser >> --- >> Thanks to Grant Likely for the review. >> >> changes in v2: >> - fall back to uartclk from platform data if the device tree property >> is not available. >> - Only include MODULE_DEVICE_TABLE if CONFIG_OF is set so we don't >> advertise device tree support if CONFIG_OF isn't active. >> - change vendor prefix in match table to be uppercase for consistency >> with documentation >> >> .../devicetree/bindings/serial/altera_uart.txt | 7 +++ >> drivers/tty/serial/altera_uart.c | 50 ++++++++++++++++++-- >> 2 files changed, 53 insertions(+), 4 deletions(-) >> create mode 100644 Documentation/devicetree/bindings/serial/altera_uart.txt >> >> diff --git a/Documentation/devicetree/bindings/serial/altera_uart.txt b/Documentation/devicetree/bindings/serial/altera_uart.txt >> new file mode 100644 >> index 0000000..71cae3f >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/serial/altera_uart.txt >> @@ -0,0 +1,7 @@ >> +Altera UART >> + >> +Required properties: >> +- compatible : should be "ALTR,uart-1.0" >> + >> +Optional properties: >> +- clock-frequency : frequency of the clock input to the UART >> diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c >> index 5e80977..4f0898c 100644 >> --- a/drivers/tty/serial/altera_uart.c >> +++ b/drivers/tty/serial/altera_uart.c >> @@ -24,6 +24,7 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> >> @@ -484,6 +485,29 @@ static struct uart_driver altera_uart_driver = { >> .cons = ALTERA_UART_CONSOLE, >> }; >> >> +#ifdef CONFIG_OF >> +static int altera_uart_get_of_uartclk(struct platform_device *pdev, >> + struct uart_port *port) >> +{ >> + int len; >> + const __be32 *clk; >> + >> + clk = of_get_property(pdev->dev.of_node, "clock-frequency",&len); >> + if (!clk || len< sizeof(__be32)) >> + return -ENODEV; >> + >> + port->uartclk = be32_to_cpup(clk); >> + >> + return 0; >> +} >> +#else >> +static int altera_uart_get_of_uartclk(struct platform_device *pdev, >> + struct uart_port *port) >> +{ >> + return -ENODEV; >> +} >> +#endif /* CONFIG_OF */ >> + >> static int __devinit altera_uart_probe(struct platform_device *pdev) >> { >> struct altera_uart_platform_uart *platp = pdev->dev.platform_data; >> @@ -491,6 +515,7 @@ static int __devinit altera_uart_probe(struct platform_device *pdev) >> struct resource *res_mem; >> struct resource *res_irq; >> int i = pdev->id; >> + int ret; >> >> /* -1 emphasizes that the platform must have one port, no .N suffix */ >> if (i == -1) >> @@ -515,6 +540,14 @@ static int __devinit altera_uart_probe(struct platform_device *pdev) >> else if (platp->irq) >> port->irq = platp->irq; >> >> + /* Try to get the uartclk from devicetree, fall back to platform data >> + * otherwise */ > > Please follow multi-line comment style. > > /* > * xxxx > * xxxx > */ I will fix this. >> + ret = altera_uart_get_of_uartclk(pdev, port); >> + if (ret&& platp) >> + port->uartclk = platp->uartclk; >> + else if (ret) >> + return ret; >> + > > Better reverse the priority, with platform data checked first. > > if (platp) > port->uartclk = platp->uartclk; > else { > ret = altera_uart_get_of_uartclk(pdev, port); > if (ret) > return ret; > } Do you have a specific reasoning for this? I thought it might make sense to do it in the same order as with the resources above, but I have no problem changing it to the way you suggest. > >> port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE); >> if (!port->membase) >> return -ENOMEM; >> @@ -527,7 +560,6 @@ static int __devinit altera_uart_probe(struct platform_device *pdev) >> port->line = i; >> port->type = PORT_ALTERA_UART; >> port->iotype = SERIAL_IO_MEM; >> - port->uartclk = platp->uartclk; >> port->ops =&altera_uart_ops; >> port->flags = UPF_BOOT_AUTOCONF; >> >> @@ -550,13 +582,23 @@ static int __devexit altera_uart_remove(struct platform_device *pdev) >> return 0; >> } >> >> +#ifdef CONFIG_OF >> +static struct of_device_id altera_uart_match[] = { >> + { .compatible = "ALTR,uart-1.0", }, >> + {}, >> +}; >> +MODULE_DEVICE_TABLE(of, altera_uart_match); >> +#else >> +#define altera_uart_match NULL >> +#endif /* CONFIG_OF */ >> + >> static struct platform_driver altera_uart_platform_driver = { >> .probe = altera_uart_probe, >> .remove = __devexit_p(altera_uart_remove), >> .driver = { >> - .name = DRV_NAME, >> - .owner = THIS_MODULE, >> - .pm = NULL, >> + .name = DRV_NAME, >> + .owner = THIS_MODULE, >> + .of_match_table = altera_uart_match, >> }, >> }; Cheers Tobias -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/