Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757283Ab1FUSnI (ORCPT ); Tue, 21 Jun 2011 14:43:08 -0400 Received: from rs35.luxsci.com ([66.216.127.90]:35785 "EHLO rs35.luxsci.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756895Ab1FUSnG (ORCPT ); Tue, 21 Jun 2011 14:43:06 -0400 X-Greylist: delayed 580 seconds by postgrey-1.27 at vger.kernel.org; Tue, 21 Jun 2011 14:43:06 EDT Message-ID: <4E00E3D2.6050602@firmworks.com> Date: Tue, 21 Jun 2011 08:32:50 -1000 From: Mitch Bradley User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.17) Gecko/20110414 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: Shawn Guo CC: Grant Likely , patches@linaro.org, netdev@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, Jason Liu , linux-kernel@vger.kernel.org, Jeremy Kerr , Sascha Hauer , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/3] serial/imx: add device tree support References: <1308410354-21387-1-git-send-email-shawn.guo@linaro.org> <1308410354-21387-2-git-send-email-shawn.guo@linaro.org> <20110618161934.GH8195@ponder.secretlab.ca> <20110619073000.GA23171@S2100-06.ap.freescale.net> <20110621135558.GB9228@S2101-09.ap.freescale.net> In-Reply-To: <20110621135558.GB9228@S2101-09.ap.freescale.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5871 Lines: 188 I wonder if it makes sense to create a new device node "/linux-devices" to express a desired mapping from device nodes to /dev entries? The properties could be the names of device special files and the values the corresponding node phandles. On 6/21/2011 3:55 AM, Shawn Guo wrote: > Hi Grant, > > I just gave a try to use aliases node for identify the device index. > Please take a look and let me know if it's what you expect. > > On Sun, Jun 19, 2011 at 03:30:02PM +0800, Shawn Guo wrote: > [...] >>>> >>>> +#ifdef CONFIG_OF >>>> +static int serial_imx_probe_dt(struct imx_port *sport, >>>> + struct platform_device *pdev) >>>> +{ >>>> + struct device_node *node = pdev->dev.of_node; >>>> + const __be32 *line; >>>> + >>>> + if (!node) >>>> + return -ENODEV; >>>> + >>>> + line = of_get_property(node, "id", NULL); >>>> + if (!line) >>>> + return -ENODEV; >>>> + >>>> + sport->port.line = be32_to_cpup(line) - 1; >>> >>> Hmmm, I really would like to be rid of this. Instead, if uarts must >>> be enumerated, the driver should look for a /aliases/uart* property >>> that matches the of_node. Doing it that way is already established in >>> the OpenFirmware documentation, and it ensures there are no overlaps >>> in the global namespace. >>> >> >> I just gave one more try to avoid using 'aliases', and you gave a >> 'no' again. Now, I know how hard you are on this. Okay, I start >> thinking about your suggestion seriously :) >> >>> We do need some infrastructure to make that easier though. Would you >>> have time to help put that together? >>> >> Ok, I will give it a try. >> > > diff --git a/arch/arm/boot/dts/imx51-babbage.dts b/arch/arm/boot/dts/imx51-babbage.dts > index da0381a..f4a5c3c 100644 > --- a/arch/arm/boot/dts/imx51-babbage.dts > +++ b/arch/arm/boot/dts/imx51-babbage.dts > @@ -18,6 +18,12 @@ > compatible = "fsl,imx51-babbage", "fsl,imx51"; > interrupt-parent =<&tzic>; > > + aliases { > + serial0 =&uart0; > + serial1 =&uart1; > + serial2 =&uart2; > + }; > + > chosen { > bootargs = "console=ttymxc0,115200 root=/dev/mmcblk0p3 rootwait"; > }; > @@ -47,29 +53,29 @@ > reg =<0x70000000 0x40000>; > ranges; > > - uart@7000c000 { > + uart2: uart@7000c000 { > compatible = "fsl,imx51-uart", "fsl,imx21-uart"; > reg =<0x7000c000 0x4000>; > interrupts =<33>; > id =<3>; > - fsl,has-rts-cts; > + fsl,uart-has-rtscts; > }; > }; > > - uart@73fbc000 { > + uart0: uart@73fbc000 { > compatible = "fsl,imx51-uart", "fsl,imx21-uart"; > reg =<0x73fbc000 0x4000>; > interrupts =<31>; > id =<1>; > - fsl,has-rts-cts; > + fsl,uart-has-rtscts; > }; > > - uart@73fc0000 { > + uart1: uart@73fc0000 { > compatible = "fsl,imx51-uart", "fsl,imx21-uart"; > reg =<0x73fc0000 0x4000>; > interrupts =<32>; > id =<2>; > - fsl,has-rts-cts; > + fsl,uart-has-rtscts; > }; > }; > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index 632ebae..13df5d2 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -737,6 +737,37 @@ err0: > EXPORT_SYMBOL(of_parse_phandles_with_args); > > /** > + * of_get_device_index - Get device index by looking up "aliases" node > + * @np: Pointer to device node that asks for device index > + * @name: The device alias without index number > + * > + * Returns the device index if find it, else returns -ENODEV. > + */ > +int of_get_device_index(struct device_node *np, const char *alias) > +{ > + struct device_node *aliases = of_find_node_by_name(NULL, "aliases"); > + struct property *prop; > + char name[32]; > + int index = 0; > + > + if (!aliases) > + return -ENODEV; > + > + while (1) { > + snprintf(name, sizeof(name), "%s%d", alias, index); > + prop = of_find_property(aliases, name, NULL); > + if (!prop) > + return -ENODEV; > + if (np == of_find_node_by_path(prop->value)) > + break; > + index++; > + } > + > + return index; > +} > +EXPORT_SYMBOL(of_get_device_index); > + > +/** > * prom_add_property - Add a property to a node > */ > int prom_add_property(struct device_node *np, struct property *prop) > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c > index da436e0..852668f 100644 > --- a/drivers/tty/serial/imx.c > +++ b/drivers/tty/serial/imx.c > @@ -1271,18 +1271,18 @@ static int serial_imx_probe_dt(struct imx_port *sport, > struct device_node *node = pdev->dev.of_node; > const struct of_device_id *of_id = > of_match_device(imx_uart_dt_ids,&pdev->dev); > - const __be32 *line; > + int line; > > if (!node) > return -ENODEV; > > - line = of_get_property(node, "id", NULL); > - if (!line) > + line = of_get_device_index(node, "serial"); > + if (IS_ERR_VALUE(line)) > return -ENODEV; > > - sport->port.line = be32_to_cpup(line) - 1; > + sport->port.line = line; > > - if (of_get_property(node, "fsl,has-rts-cts", NULL)) > + if (of_get_property(node, "fsl,uart-has-rtscts", NULL)) > sport->have_rtscts = 1; > > if (of_get_property(node, "fsl,irda-mode", NULL)) > diff --git a/include/linux/of.h b/include/linux/of.h > index bfc0ed1..3153752 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -213,6 +213,8 @@ extern int of_parse_phandles_with_args(struct device_node *np, > const char *list_name, const char *cells_name, int index, > struct device_node **out_node, const void **out_args); > > +extern int of_get_device_index(struct device_node *np, const char *alias); > + > extern int of_machine_is_compatible(const char *compat); > > extern int prom_add_property(struct device_node* np, struct property* prop); > -- 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/