diff options
| author | Evan Nimmo <evan.nimmo@alliedtelesis.co.nz> | 2020-09-09 08:32:47 +1200 |
|---|---|---|
| committer | Wolfram Sang <wsa@kernel.org> | 2020-09-09 10:22:40 +0200 |
| commit | 0a355aeb24081e4538d4d424cd189f16c0bbd983 (patch) | |
| tree | 1b60d8759866b80c55351986b16f9b6ad9695d98 /drivers | |
| parent | 0065ec0054be8da664ac0830bb887dd7574ed251 (diff) | |
i2c: algo: pca: Reapply i2c bus settings after reset
If something goes wrong (such as the SCL being stuck low) then we need
to reset the PCA chip. The issue with this is that on reset we lose all
config settings and the chip ends up in a disabled state which results
in a lock up/high CPU usage. We need to re-apply any configuration that
had previously been set and re-enable the chip.
Signed-off-by: Evan Nimmo <evan.nimmo@alliedtelesis.co.nz>
Reviewed-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/i2c/algos/i2c-algo-pca.c | 35 |
1 files changed, 23 insertions, 12 deletions
diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c index 710fbef9a9c2..384af88e58ad 100644 --- a/drivers/i2c/algos/i2c-algo-pca.c +++ b/drivers/i2c/algos/i2c-algo-pca.c @@ -41,8 +41,22 @@ static void pca_reset(struct i2c_algo_pca_data *adap) pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET); pca_outw(adap, I2C_PCA_IND, 0xA5); pca_outw(adap, I2C_PCA_IND, 0x5A); + + /* + * After a reset we need to re-apply any configuration + * (calculated in pca_init) to get the bus in a working state. + */ + pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IMODE); + pca_outw(adap, I2C_PCA_IND, adap->bus_settings.mode); + pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLL); + pca_outw(adap, I2C_PCA_IND, adap->bus_settings.tlow); + pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLH); + pca_outw(adap, I2C_PCA_IND, adap->bus_settings.thi); + + pca_set_con(adap, I2C_PCA_CON_ENSIO); } else { adap->reset_chip(adap->data); + pca_set_con(adap, I2C_PCA_CON_ENSIO | adap->bus_settings.clock_freq); } } @@ -423,13 +437,14 @@ static int pca_init(struct i2c_adapter *adap) " Use the nominal frequency.\n", adap->name); } - pca_reset(pca_data); - clock = pca_clock(pca_data); printk(KERN_INFO "%s: Clock frequency is %dkHz\n", adap->name, freqs[clock]); - pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock); + /* Store settings as these will be needed when the PCA chip is reset */ + pca_data->bus_settings.clock_freq = clock; + + pca_reset(pca_data); } else { int clock; int mode; @@ -496,19 +511,15 @@ static int pca_init(struct i2c_adapter *adap) thi = tlow * min_thi / min_tlow; } + /* Store settings as these will be needed when the PCA chip is reset */ + pca_data->bus_settings.mode = mode; + pca_data->bus_settings.tlow = tlow; + pca_data->bus_settings.thi = thi; + pca_reset(pca_data); printk(KERN_INFO "%s: Clock frequency is %dHz\n", adap->name, clock * 100); - - pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE); - pca_outw(pca_data, I2C_PCA_IND, mode); - pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL); - pca_outw(pca_data, I2C_PCA_IND, tlow); - pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH); - pca_outw(pca_data, I2C_PCA_IND, thi); - - pca_set_con(pca_data, I2C_PCA_CON_ENSIO); } udelay(500); /* 500 us for oscillator to stabilise */ |