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Date: Thu, 18 Feb 2016 08:36:17 -0600
From: Rob Herring <robh@...nel.org>
To: Raveendra Padasalagi <raveendra.padasalagi@...adcom.com>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Russell King <linux@....linux.org.uk>,
Arnd Bergmann <arnd@...db.de>, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-input@...r.kernel.org,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>,
Jonathan Richardson <jonathar@...adcom.com>,
Jon Mason <jonmason@...adcom.com>,
Florian Fainelli <f.fainelli@...il.com>,
Anup Patel <anup.patel@...adcom.com>,
Ray Jui <rjui@...adcom.com>,
Scott Branden <sbranden@...adcom.com>,
linux-kernel@...r.kernel.org, bcm-kernel-feedback-list@...adcom.com
Subject: Re: [PATCH v2 1/3] input: cygnus-update touchscreen dt node document
On Wed, Feb 17, 2016 at 03:13:44PM +0530, Raveendra Padasalagi wrote:
> In Cygnus SOC touch screen controller registers are shared
> with ADC and flex timer. Using readl/writel could lead to
> race condition. So touch screen driver is enhanced to support
>
> 1. If touchscreen register's are not shared. Register access
> is handled through readl/writel if "brcm,iproc-touchscreen"
> compatible is provided in touchscreen dt node. This will help
> for future SOC's if comes with dedicated touchscreen IP register's.
>
> 2. If touchscreen register's are shared with other IP's, register
> access is handled through syscon framework API's to take care of
> mutually exclusive access. This feature can be enabled by selecting
> "brcm,iproc-touchscreen-syscon" compatible string in the touchscreen
> dt node.
>
> Hence touchscreen dt node bindings document is updated to take care
> of above changes in the touchscreen driver.
>
> Signed-off-by: Raveendra Padasalagi <raveendra.padasalagi@...adcom.com>
> Reviewed-by: Ray Jui <ray.jui@...adcom.com>
> Reviewed-by: Scott Branden <scott.branden@...adcom.com>
> ---
> .../input/touchscreen/brcm,iproc-touchscreen.txt | 57 +++++++++++++++++++---
> 1 file changed, 51 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/brcm,iproc-touchscreen.txt b/Documentation/devicetree/bindings/input/touchscreen/brcm,iproc-touchscreen.txt
> index 34e3382..f530c25 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/brcm,iproc-touchscreen.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/brcm,iproc-touchscreen.txt
> @@ -1,12 +1,30 @@
> * Broadcom's IPROC Touchscreen Controller
>
> Required properties:
> -- compatible: must be "brcm,iproc-touchscreen"
> -- reg: physical base address of the controller and length of memory mapped
> - region.
> +- compatible: should be one of
> + "brcm,iproc-touchscreen"
> + "brcm,iproc-touchscreen-syscon"
More specific and this is not how you do syscon. Either the block is or
isn't. You can't have it both ways.
> +- ts_syscon: if "brcm,iproc-touchscreen-syscon" compatible string
> + is selected then "ts_syscon" is mandatory or else not required.
> + The "ts_syscon" is handler of syscon node defining physical base
> + address of the controller and length of memory mapped region.
> + If this property is selected please make sure MFD_SYSCON config
> + is enabled in the defconfig file.
> +- reg: if "brcm,iproc-touchscreen" compatible string is selected
> + then "reg" property is mandatory or else not required.
> + The "reg" should be physical base address of the controller and
> + length of memory mapped region.
I thought every chip to date is a syscon. Add reg support when you
actually need it.
> - clocks: The clock provided by the SOC to driver the tsc
> - clock-name: name for the clock
> - interrupts: The touchscreen controller's interrupt
> +- address-cells: Specify the number of u32 entries needed in child nodes.
> + Should set to 1. This property is mandatory when
> + "brcm,iproc-touchscreen-syscon" compatible string is selected
> + or else not required.
> +- size-cells: Specify number of u32 entries needed to specify child nodes size
> + in reg property. Should set to 1.This property is mandatory when
> + "brcm,iproc-touchscreen-syscon" compatible string is selected or
> + else not required.
>
> Optional properties:
> - scanning_period: Time between scans. Each step is 1024 us. Valid 1-256.
> @@ -53,13 +71,40 @@ Optional properties:
> - touchscreen-inverted-x: X axis is inverted (boolean)
> - touchscreen-inverted-y: Y axis is inverted (boolean)
>
> -Example:
> +Example 1: An example of touchscreen node with "brcm,iproc-touchscreen-syscon"
> + compatible string.
> +
> + ts_adc_syscon: ts_adc_syscon@...80a6000 {
> + compatible = "syscon";
> + reg = <0x180a6000 0xc30>;
> + };
>
> touchscreen: tsc@...80A6000 {
Drop the '0x' and the node name should be touchscreen, not tsc.
> - compatible = "brcm,iproc-touchscreen";
> + compatible = "brcm,iproc-touchscreen-syscon";
> #address-cells = <1>;
> #size-cells = <1>;
> - reg = <0x180A6000 0x40>;
> + ts_syscon = <&ts_adc_syscon>;
> + clocks = <&adc_clk>;
> + clock-names = "tsc_clk";
> + interrupts = <GIC_SPI 164 IRQ_TYPE_LEVEL_HIGH>;
> +
> + scanning_period = <5>;
> + debounce_timeout = <40>;
> + settling_timeout = <7>;
> + touch_timeout = <10>;
> + average_data = <5>;
> + fifo_threshold = <1>;
New properties?
> + /* Touchscreen is rotated 180 degrees. */
> + touchscreen-inverted-x;
> + touchscreen-inverted-y;
> + };
> +
> +Example 2: An example of touchscreen node with "brcm,iproc-touchscreen"
> + compatible string.
> +
> + touchscreen: tsc@...80A6000 {
> + compatible = "brcm,iproc-touchscreen";
> + reg = <0x180a6000 0x40>;
> clocks = <&adc_clk>;
> clock-names = "tsc_clk";
> interrupts = <GIC_SPI 164 IRQ_TYPE_LEVEL_HIGH>;
> --
> 1.9.1
>
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