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Fri, 3 Jan 2020 09:49:09 +0000 From: To: , , , CC: , , , , , , Subject: [PATCH v2 3/6] i2c: at91: Send bus clear command if SCL is down Thread-Topic: [PATCH v2 3/6] i2c: at91: Send bus clear command if SCL is down Thread-Index: AQHVwhsKlTodLDZUaUCcsTrXKcjnqA== Date: Fri, 3 Jan 2020 09:49:07 +0000 Message-ID: <20200103094821.13185-4-codrin.ciubotariu@microchip.com> References: <20200103094821.13185-1-codrin.ciubotariu@microchip.com> In-Reply-To: <20200103094821.13185-1-codrin.ciubotariu@microchip.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [188.25.143.200] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 48c1ff0e-8d07-407a-ed5b-08d790322df9 x-ms-traffictypediagnostic: BY5PR11MB4322: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8882; x-forefront-prvs: 0271483E06 x-forefront-antispam-report: SFV:NSPM; SFS:(10009020)(366004)(376002)(136003)(39860400002)(396003)(346002)(189003)(199004)(36756003)(478600001)(4326008)(6512007)(6486002)(110136005)(54906003)(316002)(5660300002)(107886003)(186003)(66946007)(66446008)(64756008)(66476007)(66556008)(8676002)(86362001)(6506007)(1076003)(8936002)(76116006)(26005)(81166006)(2906002)(91956017)(71200400001)(81156014)(2616005); DIR:OUT; SFP:1101; SCL:1; SRVR:BY5PR11MB4322; H:BY5PR11MB4497.namprd11.prod.outlook.com; FPR:; SPF:None; LANG:en; PTR:InfoNoRecords; MX:1; A:1; received-spf: None (protection.outlook.com: microchip.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: kIkWpXULEM56jowsxou1tLZTHDNAcKwFEQDpCyv5Wn1qS12iUIcojprBSeREBhDSZmc+mh9GlhYPCxDPdR8M8JuwmoVVR8PuzMKaZd5bjkmIzObpfnLegtPmO2c+73Z84k8qPVsTZgnZj1c+eA8YjDkfoqCboojuhi706ngs8HRPItGZE2pjLcOdVuCVEgnhUVqkcdH0+jzH864v/Le3Pj5PwrbGVzALFx9gAKCb4BqTa07mju15r+dyd/DnvwaW4waOJszWdeTbdMp1oPh9nO7hhICb+9a6C5slS4+7iskCCpOlzzQteyDps86Jpe/F8m5inCw07IpwPOvco2h2VgoDRQhR7lelTeelzX//r4S4BUkaKFTe9hxKCUBFzSgD9DQVDyt5WRO+xhgQFQEdOAzis+HsPxxj9mSJjEjbfwsZYPAkLBHikFkKjqyV8Joz MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 48c1ff0e-8d07-407a-ed5b-08d790322df9 X-MS-Exchange-CrossTenant-originalarrivaltime: 03 Jan 2020 09:49:07.8119 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 3f4057f3-b418-4d4e-ba84-d55b4e897d88 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: ZF+hHykKyiPM5al98LRpBzLgIumCVJEa1YdgXfcVEnkdgCh61srtj7XO19CtQOjl2ij1B2b/dk6cTLwgYR1Nq1yH10Ov9WXrD7BYe1BUhHQ= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR11MB4322 Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org After a transfer timeout, some faulty I2C slave devices might hold down the SCL pin. We can generate a bus clear command, hoping that the slave might release the pins. Signed-off-by: Codrin Ciubotariu --- Changes in v2: - use CLEAR command only if SDA is down; update patch subject to reflect this; - CLEAR command is no longer used for sama5d2, only sam9x60; drivers/i2c/busses/i2c-at91-core.c | 9 ++++++++ drivers/i2c/busses/i2c-at91-master.c | 32 +++++++++++++++++++++++----- drivers/i2c/busses/i2c-at91.h | 7 +++++- 3 files changed, 42 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c index e13af4874976..128eafc05adb 100644 --- a/drivers/i2c/busses/i2c-at91-core.c +++ b/drivers/i2c/busses/i2c-at91-core.c @@ -71,6 +71,7 @@ static struct at91_twi_pdata at91rm9200_config = { .has_dig_filtr = false, .has_adv_dig_filtr = false, .has_ana_filtr = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata at91sam9261_config = { @@ -82,6 +83,7 @@ static struct at91_twi_pdata at91sam9261_config = { .has_dig_filtr = false, .has_adv_dig_filtr = false, .has_ana_filtr = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata at91sam9260_config = { @@ -93,6 +95,7 @@ static struct at91_twi_pdata at91sam9260_config = { .has_dig_filtr = false, .has_adv_dig_filtr = false, .has_ana_filtr = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata at91sam9g20_config = { @@ -104,6 +107,7 @@ static struct at91_twi_pdata at91sam9g20_config = { .has_dig_filtr = false, .has_adv_dig_filtr = false, .has_ana_filtr = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata at91sam9g10_config = { @@ -115,6 +119,7 @@ static struct at91_twi_pdata at91sam9g10_config = { .has_dig_filtr = false, .has_adv_dig_filtr = false, .has_ana_filtr = false, + .has_clear_cmd = false, }; static const struct platform_device_id at91_twi_devtypes[] = { @@ -148,6 +153,7 @@ static struct at91_twi_pdata at91sam9x5_config = { .has_dig_filtr = false, .has_adv_dig_filtr = false, .has_ana_filtr = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata sama5d4_config = { @@ -159,6 +165,7 @@ static struct at91_twi_pdata sama5d4_config = { .has_dig_filtr = true, .has_adv_dig_filtr = false, .has_ana_filtr = false, + .has_clear_cmd = false, }; static struct at91_twi_pdata sama5d2_config = { @@ -170,6 +177,7 @@ static struct at91_twi_pdata sama5d2_config = { .has_dig_filtr = true, .has_adv_dig_filtr = true, .has_ana_filtr = true, + .has_clear_cmd = false, /* due to errata, CLEAR cmd is not working */ }; static struct at91_twi_pdata sam9x60_config = { @@ -181,6 +189,7 @@ static struct at91_twi_pdata sam9x60_config = { .has_dig_filtr = true, .has_adv_dig_filtr = true, .has_ana_filtr = true, + .has_clear_cmd = true, }; static const struct of_device_id atmel_twi_dt_ids[] = { diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c index c55e8ff35201..8c4f20317847 100644 --- a/drivers/i2c/busses/i2c-at91-master.c +++ b/drivers/i2c/busses/i2c-at91-master.c @@ -480,7 +480,7 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) unsigned long time_left; bool has_unre_flag = dev->pdata->has_unre_flag; bool has_alt_cmd = dev->pdata->has_alt_cmd; - struct i2c_bus_recovery_info *rinfo = &dev->rinfo; + bool has_clear_cmd = dev->pdata->has_clear_cmd; /* * WARNING: the TXCOMP bit in the Status Register is NOT a clear on @@ -641,10 +641,32 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) AT91_TWI_THRCLR | AT91_TWI_LOCKCLR); } - if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) { - dev_dbg(dev->dev, - "SDA is down; clear bus using gpio\n"); - i2c_recover_bus(&dev->adapter); + /* + * some faulty I2C slave devices might hold SDA down; + * we can send a bus clear command, hoping that the pins will be + * released + */ + if (has_clear_cmd) { + if (!(dev->transfer_status & AT91_TWI_SDA)) { + dev_dbg(dev->dev, + "SDA is down; sending bus clear command\n"); + if (dev->use_alt_cmd) { + unsigned int acr; + + acr = at91_twi_read(dev, AT91_TWI_ACR); + acr &= ~AT91_TWI_ACR_DATAL_MASK; + at91_twi_write(dev, AT91_TWI_ACR, acr); + } + at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_CLEAR); + } + } else { + struct i2c_bus_recovery_info *rinfo = &dev->rinfo; + + if (rinfo->get_sda && !(rinfo->get_sda(&dev->adapter))) { + dev_dbg(dev->dev, + "SDA is down; clear bus using gpio\n"); + i2c_recover_bus(&dev->adapter); + } } return ret; diff --git a/drivers/i2c/busses/i2c-at91.h b/drivers/i2c/busses/i2c-at91.h index eb335b71e775..80f77d523346 100644 --- a/drivers/i2c/busses/i2c-at91.h +++ b/drivers/i2c/busses/i2c-at91.h @@ -36,6 +36,7 @@ #define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */ #define AT91_TWI_QUICK BIT(6) /* SMBus quick command */ #define AT91_TWI_SWRST BIT(7) /* Software Reset */ +#define AT91_TWI_CLEAR BIT(15) /* Bus clear command */ #define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */ #define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */ #define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */ @@ -69,6 +70,8 @@ #define AT91_TWI_NACK BIT(8) /* Not Acknowledged */ #define AT91_TWI_EOSACC BIT(11) /* End Of Slave Access */ #define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */ +#define AT91_TWI_SCL BIT(24) /* TWI SCL status */ +#define AT91_TWI_SDA BIT(25) /* TWI SDA status */ #define AT91_TWI_INT_MASK \ (AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \ @@ -81,7 +84,8 @@ #define AT91_TWI_THR 0x0034 /* Transmit Holding Register */ #define AT91_TWI_ACR 0x0040 /* Alternative Command Register */ -#define AT91_TWI_ACR_DATAL(len) ((len) & 0xff) +#define AT91_TWI_ACR_DATAL_MASK GENMASK(15, 0) +#define AT91_TWI_ACR_DATAL(len) ((len) & AT91_TWI_ACR_DATAL_MASK) #define AT91_TWI_ACR_DIR BIT(8) #define AT91_TWI_FILTR 0x0044 @@ -118,6 +122,7 @@ struct at91_twi_pdata { bool has_dig_filtr; bool has_adv_dig_filtr; bool has_ana_filtr; + bool has_clear_cmd; struct at_dma_slave dma_slave; };