From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eddie James Subject: [PATCH v2 5/6] drivers/i2c: Add bus recovery for FSI algorithm Date: Mon, 10 Jul 2017 13:38:01 -0500 Message-ID: <1499711882-12918-6-git-send-email-eajames@linux.vnet.ibm.com> References: <1499711882-12918-1-git-send-email-eajames@linux.vnet.ibm.com> Return-path: In-Reply-To: <1499711882-12918-1-git-send-email-eajames@linux.vnet.ibm.com> Sender: linux-i2c-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, wsa@the-dreams.de, robh+dt@kernel.org, gregkh@linuxfoundation.org, jk@ozlabs.org, joel@jms.id.au, andrew@aj.id.au, eajames@linux.vnet.ibm.com, cbostic@linux.vnet.ibm.com, "Edward A. James" List-Id: devicetree@vger.kernel.org From: "Edward A. James" Bus recovery should reset the engine and force clock the bus 9 times to recover most situations. Signed-off-by: Edward A. James --- drivers/i2c/busses/i2c-fsi.c | 75 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 insertions(+) diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c index 1c7fcae..2739535 100644 --- a/drivers/i2c/busses/i2c-fsi.c +++ b/drivers/i2c/busses/i2c-fsi.c @@ -468,6 +468,80 @@ static u32 fsi_i2c_functionality(struct i2c_adapter *adap) return I2C_FUNC_I2C | I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_10BIT_ADDR; } +static int fsi_i2c_low_level_recover_bus(struct fsi_i2c_master *i2c) +{ + int i, rc; + u32 mode, dummy = 0; + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return rc; + + mode |= I2C_MODE_DIAG; + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return rc; + + for (i = 0; i < 9; ++i) { + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); + if (rc) + return rc; + } + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SDA, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SDA, &dummy); + if (rc) + return rc; + + mode &= ~I2C_MODE_DIAG; + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); + + return rc; +} + +static int fsi_i2c_recover_bus(struct i2c_adapter *adap) +{ + int rc; + u32 dummy = 0; + struct fsi_i2c_port *port = adap->algo_data; + struct fsi_i2c_master *i2c = port->master; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_dev_init(i2c); + if (rc) + return rc; + + rc = fsi_i2c_low_level_recover_bus(i2c); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy); + + return rc; +} + +static struct i2c_bus_recovery_info fsi_i2c_bus_recovery_info = { + .recover_bus = fsi_i2c_recover_bus, +}; + static const struct i2c_algorithm fsi_i2c_algorithm = { .master_xfer = fsi_i2c_xfer, .functionality = fsi_i2c_functionality, @@ -507,6 +581,7 @@ static int fsi_i2c_probe(struct device *dev) port->adapter.dev.of_node = np; port->adapter.dev.parent = dev; port->adapter.algo = &fsi_i2c_algorithm; + port->adapter.bus_recovery_info = &fsi_i2c_bus_recovery_info; port->adapter.algo_data = port; snprintf(port->adapter.name, sizeof(port->adapter.name), -- 1.8.3.1