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From: Arseny Solokha <asolokha@kb.kras.ru>
To: Wolfram Sang <wsa@the-dreams.de>,
	linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Valentin Longchamp <valentin.longchamp@keymile.com>,
	Arseny Solokha <asolokha@kb.kras.ru>
Subject: [PATCH 3/4] i2c: mpc: fix PORDEVSR2 mask for MPC8533/44
Date: Fri, 10 Nov 2017 14:50:14 +0700	[thread overview]
Message-ID: <20171110075015.23906-4-asolokha@kb.kras.ru> (raw)
In-Reply-To: <20171110075015.23906-1-asolokha@kb.kras.ru>

According to the reference manuals for the corresponding SoCs, SEC
frequency ratio configuration is indicated by bit 26 of the POR Device
Status Register 2. Consequently, SEC_CFG bit should be tested by mask 0x20,
not 0x80. Testing the wrong bit leads to selection of wrong I2C clock
prescaler on those SoCs.

Signed-off-by: Arseny Solokha <asolokha@kb.kras.ru>
---
 drivers/i2c/busses/i2c-mpc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
index f47916466b82..8d60db0080f6 100644
--- a/drivers/i2c/busses/i2c-mpc.c
+++ b/drivers/i2c/busses/i2c-mpc.c
@@ -332,14 +332,18 @@ static u32 mpc_i2c_get_sec_cfg_8xxx(void)
 		if (prop) {
 			/*
 			 * Map and check POR Device Status Register 2
-			 * (PORDEVSR2) at 0xE0014
+			 * (PORDEVSR2) at 0xE0014. Note than while MPC8533
+			 * and MPC8544 indicate SEC frequency ratio
+			 * configuration as bit 26 in PORDEVSR2, other MPC8xxx
+			 * parts may store it differently or may not have it
+			 * at all.
 			 */
 			reg = ioremap(get_immrbase() + *prop + 0x14, 0x4);
 			if (!reg)
 				printk(KERN_ERR
 				       "Error: couldn't map PORDEVSR2\n");
 			else
-				val = in_be32(reg) & 0x00000080; /* sec-cfg */
+				val = in_be32(reg) & 0x00000020; /* sec-cfg */
 			iounmap(reg);
 		}
 	}
-- 
2.15.0

  parent reply	other threads:[~2017-11-10  7:50 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-10  7:50 [PATCH 0/4] i2c: mpc: Clean up clock selection Arseny Solokha
2017-11-10  7:50 ` [PATCH 1/4] i2c: mpc: get MPC8xxx I2C clock prescaler before using it in calculations Arseny Solokha
2017-11-10  7:50 ` [PATCH 2/4] i2c: mpc: unify obtaining the MPC8533/44 I2C clock prescaler w/ MPC8xxx Arseny Solokha
2017-11-10  7:50 ` Arseny Solokha [this message]
2017-11-10  7:50 ` [PATCH 4/4] i2c: mpc: always determine I2C clock prescaler at runtime Arseny Solokha
2017-12-07 10:19 ` [PATCH RESEND 0/4] i2c: mpc: Clean up clock selection Arseny Solokha
2017-12-07 10:20   ` [PATCH RESEND 1/4] i2c: mpc: get MPC8xxx I2C clock prescaler before using it in calculations Arseny Solokha
2017-12-30 18:18     ` [RESEND, " Wolfram Sang
2018-01-15 18:21       ` Wolfram Sang
2017-12-07 10:20   ` [PATCH RESEND 2/4] i2c: mpc: unify obtaining the MPC8533/44 I2C clock prescaler w/ MPC8xxx Arseny Solokha
2017-12-30 18:19     ` [RESEND, " Wolfram Sang
2018-01-15 18:21     ` Wolfram Sang
2017-12-07 10:20   ` [PATCH RESEND 3/4] i2c: mpc: fix PORDEVSR2 mask for MPC8533/44 Arseny Solokha
2017-12-30 18:11     ` [RESEND,3/4] " Wolfram Sang
2018-01-15 18:22     ` Wolfram Sang
2017-12-07 10:20   ` [PATCH RESEND 4/4] i2c: mpc: always determine I2C clock prescaler at runtime Arseny Solokha
2017-12-30 18:14     ` [RESEND, " Wolfram Sang
2018-01-10 11:36       ` Arseny Solokha
2018-01-10 11:36       ` [PATCH v2 " Arseny Solokha
2018-01-15 18:22         ` Wolfram Sang

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