From: Aisheng Dong <aisheng.dong@nxp.com>
To: Clark Wang <xiaoning.wang@nxp.com>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>
Cc: "kernel@pengutronix.de" <kernel@pengutronix.de>,
"festevam@gmail.com" <festevam@gmail.com>,
dl-linux-imx <linux-imx@nxp.com>,
"sumit.semwal@linaro.org" <sumit.semwal@linaro.org>,
"christian.koenig@amd.com" <christian.koenig@amd.com>,
"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 09/11] i2c: imx-lpi2c: fix i2c timing issue
Date: Fri, 19 Mar 2021 05:15:14 +0000 [thread overview]
Message-ID: <AM6PR04MB49660A7D1AB880EFF530654680689@AM6PR04MB4966.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20210317065359.3109394-10-xiaoning.wang@nxp.com>
> From: Clark Wang <xiaoning.wang@nxp.com>
> Sent: Wednesday, March 17, 2021 2:54 PM
>
> The clkhi and clklo ratio was not very precise before that can make the time of
> START/STOP/HIGH LEVEL out of specification.
>
> Therefore, the calculation of these times has been modified in this patch.
> At the same time, the mode rate definition of i2c is corrected.
>
> Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
> Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
> ---
> drivers/i2c/busses/i2c-imx-lpi2c.c | 27 ++++++++++++++-------------
> 1 file changed, 14 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c
> b/drivers/i2c/busses/i2c-imx-lpi2c.c
> index 7216a393095d..5dbe85126f24 100644
> --- a/drivers/i2c/busses/i2c-imx-lpi2c.c
> +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
> @@ -73,17 +73,17 @@
> #define MCFGR1_IGNACK BIT(9)
> #define MRDR_RXEMPTY BIT(14)
>
> -#define I2C_CLK_RATIO 2
> +#define I2C_CLK_RATIO 24 / 59
Where is this ratio coming from?
Can you describe why use it in commit message?
Regards
Aisheng
> #define CHUNK_DATA 256
>
> #define I2C_PM_TIMEOUT 1000 /* ms */
>
> enum lpi2c_imx_mode {
> - STANDARD, /* 100+Kbps */
> - FAST, /* 400+Kbps */
> - FAST_PLUS, /* 1.0+Mbps */
> - HS, /* 3.4+Mbps */
> - ULTRA_FAST, /* 5.0+Mbps */
> + STANDARD, /* <=100Kbps */
> + FAST, /* <=400Kbps */
> + FAST_PLUS, /* <=1.0Mbps */
> + HS, /* <=3.4Mbps */
> + ULTRA_FAST, /* <=5.0Mbps */
> };
>
> enum lpi2c_imx_pincfg {
> @@ -156,13 +156,13 @@ static void lpi2c_imx_set_mode(struct
> lpi2c_imx_struct *lpi2c_imx)
> unsigned int bitrate = lpi2c_imx->bitrate;
> enum lpi2c_imx_mode mode;
>
> - if (bitrate < I2C_MAX_FAST_MODE_FREQ)
> + if (bitrate <= I2C_MAX_STANDARD_MODE_FREQ)
> mode = STANDARD;
> - else if (bitrate < I2C_MAX_FAST_MODE_PLUS_FREQ)
> + else if (bitrate <= I2C_MAX_FAST_MODE_FREQ)
> mode = FAST;
> - else if (bitrate < I2C_MAX_HIGH_SPEED_MODE_FREQ)
> + else if (bitrate <= I2C_MAX_FAST_MODE_PLUS_FREQ)
> mode = FAST_PLUS;
> - else if (bitrate < I2C_MAX_ULTRA_FAST_MODE_FREQ)
> + else if (bitrate <= I2C_MAX_HIGH_SPEED_MODE_FREQ)
> mode = HS;
> else
> mode = ULTRA_FAST;
> @@ -209,7 +209,8 @@ static void lpi2c_imx_stop(struct lpi2c_imx_struct
> *lpi2c_imx)
> } while (1);
> }
>
> -/* CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */
> +/* CLKLO = (1 - I2C_CLK_RATIO) * clk_cycle, SETHOLD = CLKHI, DATAVD =
> CLKHI/2
> + CLKHI = I2C_CLK_RATIO * clk_cycle */
> static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx) {
> u8 prescale, filt, sethold, clkhi, clklo, datavd; @@ -232,8 +233,8 @@
> static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
>
> for (prescale = 0; prescale <= 7; prescale++) {
> clk_cycle = clk_rate / ((1 << prescale) * lpi2c_imx->bitrate)
> - - 3 - (filt >> 1);
> - clkhi = (clk_cycle + I2C_CLK_RATIO) / (I2C_CLK_RATIO + 1);
> + - (2 + filt) / (1 << prescale);
> + clkhi = clk_cycle * I2C_CLK_RATIO;
> clklo = clk_cycle - clkhi;
> if (clklo < 64)
> break;
> --
> 2.25.1
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next prev parent reply other threads:[~2021-03-19 5:17 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-17 6:53 [PATCH 00/11] i2c: imx-lpi2c: New features and bug fixes Clark Wang
2021-03-17 6:53 ` [PATCH 01/11] i2c: imx-lpi2c: directly retrun ISR when detect a NACK Clark Wang
2021-03-19 4:25 ` Aisheng Dong
2021-03-17 6:53 ` [PATCH 02/11] i2c: imx-lpi2c: add runtime pm support Clark Wang
2021-03-19 4:40 ` Aisheng Dong
2021-03-19 5:33 ` Clark Wang
2021-03-19 6:16 ` Clark Wang
2021-03-19 8:00 ` Clark Wang
2021-03-19 10:26 ` Aisheng Dong
2021-03-17 6:53 ` [PATCH 03/11] i2c: imx-lpi2c: add ipg clk for lpi2c driver Clark Wang
2021-03-19 4:46 ` Aisheng Dong
2021-03-19 6:23 ` Clark Wang
2021-03-19 9:18 ` Aisheng Dong
2021-03-17 6:53 ` [PATCH 04/11] i2c: imx-lpi2c: manage irq resource request/release in runtime pm Clark Wang
2021-03-19 4:53 ` Aisheng Dong
2021-03-19 7:03 ` Clark Wang
2021-03-19 10:12 ` Aisheng Dong
2021-03-17 6:53 ` [PATCH 05/11] i2c: imx-lpi2c: add debug message when i2c peripheral clk doesn't work Clark Wang
2021-03-19 4:56 ` Aisheng Dong
2021-03-19 7:07 ` Clark Wang
2021-03-17 6:53 ` [PATCH 06/11] i2c: imx-lpi2c: improve i2c driver probe priority Clark Wang
2021-03-19 5:05 ` Aisheng Dong
2021-03-19 5:38 ` Wolfram Sang
2021-03-19 7:39 ` [EXT] " Clark Wang
2021-03-17 6:53 ` [PATCH 07/11] i2c: imx-lpi2c: increase PM timeout to avoid operate clk frequently Clark Wang
2021-03-19 5:10 ` Aisheng Dong
2021-03-17 6:53 ` [PATCH 08/11] i2c: imx-lpi2c: add bus recovery feature Clark Wang
2021-03-19 5:11 ` Aisheng Dong
2021-03-17 6:53 ` [PATCH 09/11] i2c: imx-lpi2c: fix i2c timing issue Clark Wang
2021-03-19 5:15 ` Aisheng Dong [this message]
2021-03-19 7:21 ` Clark Wang
2021-03-17 6:53 ` [PATCH 10/11] i2c: imx-lpi2c: fix type char overflow issue when calculating the clock cycle Clark Wang
2021-03-19 5:16 ` Aisheng Dong
2021-03-17 6:53 ` [PATCH 11/11] i2c: imx-lpi2c: add edma mode support Clark Wang
2021-03-19 5:28 ` Aisheng Dong
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