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From: David Laight <david.laight.linux@gmail.com>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	Jarkko Nikula <jarkko.nikula@linux.intel.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>
Subject: Re: [PATCH v3 4/5] i3c: mipi-i3c-hci: use parity8 helper instead of open coding it
Date: Mon, 6 Jan 2025 13:06:53 +0000	[thread overview]
Message-ID: <20250106130653.7fe81eae@pumpkin> (raw)
In-Reply-To: <20250106092725.22869-5-wsa+renesas@sang-engineering.com>

On Mon,  6 Jan 2025 10:27:22 +0100
Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:

> The kernel has now a generic helper for getting parity with easier to
> understand semantics. Make use of it.

This need to explain that although the algorithm has changed the existing
code is wrong.

	David
 
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
> ---
>  drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 11 +----------
>  1 file changed, 1 insertion(+), 10 deletions(-)
> 
> diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> index 47b9b4d4ed3f..85c4916972e4 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> @@ -40,15 +40,6 @@
>  #define dat_w0_write(i, v)	writel(v, hci->DAT_regs + (i) * 8)
>  #define dat_w1_write(i, v)	writel(v, hci->DAT_regs + (i) * 8 + 4)
>  
> -static inline bool dynaddr_parity(unsigned int addr)
> -{
> -	addr |= 1 << 7;
> -	addr += addr >> 4;
> -	addr += addr >> 2;
> -	addr += addr >> 1;
> -	return (addr & 1);
> -}
> -
>  static int hci_dat_v1_init(struct i3c_hci *hci)
>  {
>  	unsigned int dat_idx;
> @@ -123,7 +114,7 @@ static void hci_dat_v1_set_dynamic_addr(struct i3c_hci *hci,
>  	dat_w0 = dat_w0_read(dat_idx);
>  	dat_w0 &= ~(DAT_0_DYNAMIC_ADDRESS | DAT_0_DYNADDR_PARITY);
>  	dat_w0 |= FIELD_PREP(DAT_0_DYNAMIC_ADDRESS, address) |
> -		  (dynaddr_parity(address) ? DAT_0_DYNADDR_PARITY : 0);
> +		  (parity8(address) ? 0 : DAT_0_DYNADDR_PARITY);
>  	dat_w0_write(dat_idx, dat_w0);
>  }
>  


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WARNING: multiple messages have this Message-ID (diff)
From: David Laight <david.laight.linux@gmail.com>
To: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	Jarkko Nikula <jarkko.nikula@linux.intel.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>
Subject: Re: [PATCH v3 4/5] i3c: mipi-i3c-hci: use parity8 helper instead of open coding it
Date: Mon, 6 Jan 2025 13:06:53 +0000	[thread overview]
Message-ID: <20250106130653.7fe81eae@pumpkin> (raw)
In-Reply-To: <20250106092725.22869-5-wsa+renesas@sang-engineering.com>

On Mon,  6 Jan 2025 10:27:22 +0100
Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:

> The kernel has now a generic helper for getting parity with easier to
> understand semantics. Make use of it.

This need to explain that although the algorithm has changed the existing
code is wrong.

	David
 
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
> ---
>  drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 11 +----------
>  1 file changed, 1 insertion(+), 10 deletions(-)
> 
> diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> index 47b9b4d4ed3f..85c4916972e4 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> @@ -40,15 +40,6 @@
>  #define dat_w0_write(i, v)	writel(v, hci->DAT_regs + (i) * 8)
>  #define dat_w1_write(i, v)	writel(v, hci->DAT_regs + (i) * 8 + 4)
>  
> -static inline bool dynaddr_parity(unsigned int addr)
> -{
> -	addr |= 1 << 7;
> -	addr += addr >> 4;
> -	addr += addr >> 2;
> -	addr += addr >> 1;
> -	return (addr & 1);
> -}
> -
>  static int hci_dat_v1_init(struct i3c_hci *hci)
>  {
>  	unsigned int dat_idx;
> @@ -123,7 +114,7 @@ static void hci_dat_v1_set_dynamic_addr(struct i3c_hci *hci,
>  	dat_w0 = dat_w0_read(dat_idx);
>  	dat_w0 &= ~(DAT_0_DYNAMIC_ADDRESS | DAT_0_DYNADDR_PARITY);
>  	dat_w0 |= FIELD_PREP(DAT_0_DYNAMIC_ADDRESS, address) |
> -		  (dynaddr_parity(address) ? DAT_0_DYNADDR_PARITY : 0);
> +		  (parity8(address) ? 0 : DAT_0_DYNADDR_PARITY);
>  	dat_w0_write(dat_idx, dat_w0);
>  }
>  


  reply	other threads:[~2025-01-10 11:19 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-06  9:27 [PATCH v3 0/5] i3c: introduce and use generic parity helper Wolfram Sang
2025-01-06  9:27 ` Wolfram Sang
2025-01-06  9:27 ` [PATCH v3 1/5] bitops: add generic parity calculation for u8 Wolfram Sang
2025-01-06  9:27   ` Wolfram Sang
2025-01-06  9:27 ` [PATCH v3 2/5] hwmon: (spd5118) Use generic parity calculation Wolfram Sang
2025-01-06  9:27   ` Wolfram Sang
2025-01-06  9:27 ` [PATCH v3 3/5] i3c: dw: use parity8 helper instead of open coding it Wolfram Sang
2025-01-06  9:27   ` Wolfram Sang
2025-01-06  9:27 ` [PATCH v3 4/5] i3c: mipi-i3c-hci: " Wolfram Sang
2025-01-06  9:27   ` Wolfram Sang
2025-01-06 13:06   ` David Laight [this message]
2025-01-06 13:06     ` David Laight
2025-01-06  9:27 ` [PATCH v3 5/5] i3c: cdns: " Wolfram Sang
2025-01-06  9:27   ` Wolfram Sang

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