I was able to test the patch [1] exclusion mechanism without access to actual hardware - by giving it a dummy regmap. See patch below.
Test cases (all via sysfs): 1. verify requested pwm cannot be requested as gpio 2. verify requested gpio cannot be requested as pwm 3. verify pwm "all LEDs" cannot be used if pwms/gpios in use 4. verify pwms/gpios cannot be requested if pwm "all LEDs" in use All test cases ok. Obviously, I could not test multi-threaded correctness. [1] https://lkml.org/lkml/2019/6/4/1039 --- drivers/pwm/pwm-pca9685.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c index 259fd58812ae..c059da5f86f4 100644 --- a/drivers/pwm/pwm-pca9685.c +++ b/drivers/pwm/pwm-pca9685.c @@ -83,6 +83,7 @@ struct pca9685 { struct regmap *regmap; int duty_ns; int period_ns; + u8 regs[PCA9685_NUMREGS]; #if IS_ENABLED(CONFIG_GPIOLIB) struct mutex lock; struct gpio_chip gpio; @@ -446,11 +447,31 @@ static const struct pwm_ops pca9685_pwm_ops = { .owner = THIS_MODULE, }; +static int read_reg_dummy(void *context, unsigned int reg, + unsigned int *val) +{ + struct pca9685 *pca = context; + + *val = pca->regs[reg]; + return 0; +} + +static int write_reg_dummy(void *context, unsigned int reg, + unsigned int val) +{ + struct pca9685 *pca = context; + + pca->regs[reg] = val; + return 0; +} + static const struct regmap_config pca9685_regmap_i2c_config = { .reg_bits = 8, .val_bits = 8, .max_register = PCA9685_NUMREGS, .cache_type = REGCACHE_NONE, + .reg_read = read_reg_dummy, + .reg_write = write_reg_dummy, }; static int pca9685_pwm_probe(struct i2c_client *client, @@ -464,7 +485,8 @@ static int pca9685_pwm_probe(struct i2c_client *client, if (!pca) return -ENOMEM; - pca->regmap = devm_regmap_init_i2c(client, &pca9685_regmap_i2c_config); + pca->regmap = devm_regmap_init(&client->dev, NULL, pca, + &pca9685_regmap_i2c_config); if (IS_ERR(pca->regmap)) { ret = PTR_ERR(pca->regmap); dev_err(&client->dev, "Failed to initialize register map: %d\n", -- 2.17.1
