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From: Andrew Lunn <andrew@lunn.ch>
To: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org,
	peter@korsgaard.com, palmer@sifive.com,
	linux-kernel@vger.kernel.org, robh+dt@kernel.org,
	linux-i2c@vger.kernel.org, paul.walmsley@sifive.com,
	linux-riscv@lists.infradead.org
Subject: Re: [PATCH v3 3/3] i2c-ocores: sifive: add polling mode workaround for FU540-C000 SoC
Date: Thu, 16 May 2019 15:07:20 +0200	[thread overview]
Message-ID: <20190516130720.GE14298@lunn.ch> (raw)
In-Reply-To: <1557983320-14461-4-git-send-email-sagar.kadam@sifive.com>

On Thu, May 16, 2019 at 10:38:40AM +0530, Sagar Shrikant Kadam wrote:
> The i2c-ocore driver already has a polling mode interface.But it needs
> a workaround for FU540 Chipset on HiFive unleashed board (RevA00).
> There is an erratum in FU540 chip that prevents interrupt driven i2c
> transfers from working, and also the I2C controller's interrupt bit
> cannot be cleared if set, due to this the existing i2c polling mode
> interface added in mainline earlier doesn't work, and CPU stall's
> infinitely, when-ever i2c transfer is initiated.
> 
> Ref:previous polling mode support in mainline
> 
> 	commit 69c8c0c0efa8 ("i2c: ocores: add polling interface")
> 
> The workaround / fix under OCORES_FLAG_BROKEN_IRQ is particularly for
> FU540-COOO SoC.
> 
> Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
> ---
>  drivers/i2c/busses/i2c-ocores.c | 34 ++++++++++++++++++++++++++++------
>  1 file changed, 28 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
> index aee1d86..00ee45c 100644
> --- a/drivers/i2c/busses/i2c-ocores.c
> +++ b/drivers/i2c/busses/i2c-ocores.c
> @@ -27,6 +27,7 @@
>  #include <linux/jiffies.h>
>  
>  #define OCORES_FLAG_POLL BIT(0)
> +#define OCORES_FLAG_BROKEN_IRQ BIT(2) /* Broken IRQ in HiFive Unleashed */

Hi Sigar

BIT(1). Don't leave a gap.

	Andrew

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  parent reply	other threads:[~2019-05-16 13:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-16  5:08 [PATCH v3 0/3] Extend dt bindings to support I2C on sifive devices and a fix broken IRQ in polling mode Sagar Shrikant Kadam
2019-05-16  5:08 ` [PATCH v3 1/3] dt-bindings: i2c: extend existing opencore bindings Sagar Shrikant Kadam
2019-05-16  5:08 ` [PATCH v3 2/3] i2c-ocore: sifive: add support for i2c device on FU540-c000 SoC Sagar Shrikant Kadam
2019-05-16  5:08 ` [PATCH v3 3/3] i2c-ocores: sifive: add polling mode workaround for FU540-C000 SoC Sagar Shrikant Kadam
2019-05-16 12:31   ` Andrew Lunn
2019-05-16 12:54     ` Sagar Kadam
2019-05-16 13:02       ` Andrew Lunn
2019-05-16 13:07   ` Andrew Lunn [this message]
2019-05-20  4:20     ` Sagar Kadam

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