Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Francesco Dolcini <francesco.dolcini@toradex.com>
To:     Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
Cc:     philippe.schenker@toradex.com,
        Francesco Dolcini <francesco.dolcini@toradex.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH net-next v2] net: phy: micrel: ksz9131 led errata workaround
Date:   Thu,  7 Oct 2021 18:45:35 +0200
Message-Id: <20211007164535.657245-1-francesco.dolcini@toradex.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?f5iZyCSbx3Ie0NFQ8OATq8k6UxlspPIS0zydTNE/4aUR+IXEdCm8yR5Tvx4m?=
 =?us-ascii?Q?vMsyBSzPTmm9HEswrDllv51dm/XfzVM+aI1pAHxuE5D/Sw77K7IPbG0hu98L?=
 =?us-ascii?Q?95kg4SLaSB4SPF3ABmcZFjS9dltAOItE3BX77c5cAgyjHYCe/ads/ITH34r6?=
 =?us-ascii?Q?kFa/Ke21A2069YS0fIbFMYWoOr7twEbQxzW0Ivkpg/v+svq2RDKzVTS7gAs9?=
 =?us-ascii?Q?rIGSdDs6Ju8BDYar7u0Wja6SHWXPTwHPAV4RyOC3xN8WI6WwaDu6sC/HS9QI?=
 =?us-ascii?Q?NnXmv2KRc9q3vNldZENwiz802PCc/texGOERBzAvSpHxuJ/hnWy3dN84rBV2?=
 =?us-ascii?Q?/oN+3ae7R2lzk4Lxx/wp9cCgEQzdzKpiBBC0ip5mCohollwghFPUX7VIsDRd?=
 =?us-ascii?Q?mhNDoZDskxgbhwUfH3IDvMsNkDDiqfIIabDwGQMCYq8prysuI7TyfMdmWZx2?=
 =?us-ascii?Q?uembR/5K/41tbzpmT7U0UJyXKdJOEaxZBn9+HBcnJq4vMNe9LHNX1rVXqM3Z?=
 =?us-ascii?Q?BWTmkmxgAj/wHXnALUXsPr/SKgP3Nhp5EXEcMhhOIO3Uh4dJ+Do74oHhazbY?=
 =?us-ascii?Q?fZFZlS5Iv23cRo6eIrC3kUQI67EiEnBqhJH1YMcUvErLgFBsqj63eeCh89AH?=
 =?us-ascii?Q?RMqckN4/tPbXYsU8mv+iRTmnPDPqA5e71zfkBQNwDUQaPViY9Jtcxc06xtTm?=
 =?us-ascii?Q?OxebgkXcTF/TBbyWBTV8xyiGDQ7SFBpglEpbJD+MTS2/8hpNYfp/DxPl4Ltz?=
 =?us-ascii?Q?dvutwlv1dLx2Rd1RNv1aW4xqDXzUu3o5FVI6CnIC75apGcS4xNLvFmmiOHXI?=
 =?us-ascii?Q?I4cGmC/Ho/bvjRXZ098A7atYKbLl07la0LbbS9FdUwQ0SMpbL1zj5lQ1/Jmt?=
 =?us-ascii?Q?/p8WlL2Tpaj2f/eW425mB9vbvNa86wxmf66Z96lgUOsYQyfASmcaAo4+svDH?=
 =?us-ascii?Q?2grqgrScnH+ZClvG+1dmjDPUWdHVf1YoVuCk43DCHXrAp+9+Y+EqzAWZngSo?=
 =?us-ascii?Q?/y3ynvOPJI/rTlAc297YouY2hsHR1lj3POlFvVcWf/w7CzQwWP95sn1fyeR8?=
 =?us-ascii?Q?XfnyRN1Lw3UWbJGfPXj9vj2Brxjw3RMbKbBN/9xkNyPaMGmqYrRsP7YpcKTb?=
 =?us-ascii?Q?wySusCNY0wrLW41u4bTg4nY2YCnN8IUzPGIJys24lyjgzD0/EcsvZfZz9IPw?=
 =?us-ascii?Q?Oz9v7hnM5K4TY5MAkz5r1tOeV6Su77QDeaY0vSOhTAYKlzXaa7WbfoEsI2r9?=
 =?us-ascii?Q?WQqn/g0Ku2txrQP/Nhn+Y+k1U+5EJOwFOwIXIVBdtmhT2I+EMimWlquk65PN?=
 =?us-ascii?Q?nlnGLtgOTPhSCIXwHXIYUemX?=
X-OriginatorOrg: toradex.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 872313dc-17b4-4dd2-391a-08d989b1e7d1
X-MS-Exchange-CrossTenant-AuthSource: HE1PR0501MB2602.eurprd05.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Oct 2021 16:45:44.2410
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: d9995866-0d9b-4251-8315-093f062abab4
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: BOVqJfJ0pPdMSW8OJwsxr3wHYc2N77pM+gLBTyFfXYGUZeX62YJ0hRNcayYMbQRwGG9mpYVr5YSYSQc+INZ2W8vVK+9ocYSCL4NuWU+WW1U=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: HE1PR0501MB2172
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Micrel KSZ9131 PHY LED behavior is not correct when configured in
Individual Mode, LED1 (Activity LED) is in the ON state when there is
no-link.

Workaround this by setting bit 9 of register 0x1e after verifying that
the LED configuration is Individual Mode.

This issue is described in KSZ9131RNX Silicon Errata DS80000693B [*]
and according to that it will not be corrected in a future silicon
revision.

[*] https://ww1.microchip.com/downloads/en/DeviceDoc/KSZ9131RNX-Silicon-Errata-and-Data-Sheet-Clarification-80000863B.pdf

Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
---
Changes v1 => v2:
 1. corrected errata URL in commit message
 2. check phy_read_mmd return value
---
 drivers/net/phy/micrel.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index c330a5a9f665..b70f62efdbc3 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -1003,6 +1003,26 @@ static int ksz9131_config_rgmii_delay(struct phy_device *phydev)
 			      txcdll_val);
 }
 
+/* Silicon Errata DS80000693B
+ *
+ * When LEDs are configured in Individual Mode, LED1 is ON in a no-link
+ * condition. Workaround is to set register 0x1e, bit 9, this way LED1 behaves
+ * according to the datasheet (off if there is no link).
+ */
+static int ksz9131_led_errata(struct phy_device *phydev)
+{
+	int reg;
+
+	reg = phy_read_mmd(phydev, 2, 0);
+	if (reg < 0)
+		return reg;
+
+	if (!(reg & BIT(4)))
+		return 0;
+
+	return phy_set_bits(phydev, 0x1e, BIT(9));
+}
+
 static int ksz9131_config_init(struct phy_device *phydev)
 {
 	struct device_node *of_node;
@@ -1058,6 +1078,10 @@ static int ksz9131_config_init(struct phy_device *phydev)
 	if (ret < 0)
 		return ret;
 
+	ret = ksz9131_led_errata(phydev);
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }
 
-- 
2.25.1