Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932084Ab1FUTOO (ORCPT ); Tue, 21 Jun 2011 15:14:14 -0400 Received: from mail-yi0-f46.google.com ([209.85.218.46]:46263 "EHLO mail-yi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757272Ab1FUTOL convert rfc822-to-8bit (ORCPT ); Tue, 21 Jun 2011 15:14:11 -0400 MIME-Version: 1.0 In-Reply-To: <20110621135558.GB9228@S2101-09.ap.freescale.net> 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> From: Grant Likely Date: Tue, 21 Jun 2011 13:13:50 -0600 X-Google-Sender-Auth: HFfMlT7mjPpU6vet3mNP3mgb0nY Message-ID: Subject: Re: [PATCH 1/3] serial/imx: add device tree support To: Shawn Guo Cc: 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, David Gibson Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8031 Lines: 227 On Tue, Jun 21, 2011 at 7:55 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. Thanks Shawn. This is definitely on track. Comments below... > > 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; > + ? ? ? }; > + Hmmm. David Gibson had tossed out an idea of automatically generating aliases from labels. It may be time to revisit that idea. David, perhaps using this format for a label should turn it into an alias (prefix label with an asterisk): *thealias: i2c@12340000 { /*...*/ }; .... although that approach gets *really* hairy when considering that different boards will want different enumeration. How would one override an automatic alias defined by an included .dts file? > ? ? ? ?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++; > + ? ? ? } Rather than parsing the alias strings everytime, it would probably be better to preprocess all the properties in the aliases node and create a lookup table of alias->node references that can be walked quickly and trivially. Also, when obtaining an enumeration for a device, you'll need to be careful about what number gets returned. If the node doesn't match a given alias, but aliases do exist for other devices of like type, then you need to be careful not to assign a number already assigned to another device via an alias (this of course assumes the driver supports dynamics enumeration, which many drivers will). It would be \> + > + ? ? ? 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; Personally, it an alias isn't present, then I'd dynamically assign a port id. > > - ? ? ? 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); > > -- > Regards, > Shawn > > -- Grant Likely, B.Sc., P.Eng. 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