Commit 1967d1e6 authored by Yong Cong Sin's avatar Yong Cong Sin Committed by Dan Kalowsky
Browse files

drivers: syscon: do not assume that a function isn't supported 



When a function pointer is `NULL`, it could be that the underlying
hardware doesn't support it, or it isn't implemented.

If a function isn't supported by the hardware, its driver should
return `-ENOTSUP`, the API layer should return `-ENOSYS` when a
function isn't implemented.

Signed-off-by: default avatarYong Cong Sin <yongcong.sin@gmail.com>
parent 9696765b

include/zephyr/drivers/syscon.h

+17 −9
Original line number Diff line number Diff line
@@ -71,7 +71,8 @@ __subsystem struct syscon_driver_api { 
 *

 * @param dev The device to get the register size for.

 * @param addr Where to write the base address.

 * @return 0 When addr was written to.

 * @return 0 When @a addr was written to.

 * @return -ENOSYS If the API or function isn't implemented.

 */

__syscall int syscon_get_base(const struct device *dev, uintptr_t *addr);
@@ -79,8 +80,8 @@ static inline int z_impl_syscon_get_base(const struct device *dev, uintptr_t *ad 
{

	const struct syscon_driver_api *api = (const struct syscon_driver_api *)dev->api;



	if (api == NULL) {

		return -ENOTSUP;

	if ((api == NULL) || (api->get_base == NULL)) {

		return -ENOSYS;

	}



	return api->get_base(dev, addr);
@@ -96,7 +97,8 @@ static inline int z_impl_syscon_get_base(const struct device *dev, uintptr_t *ad 
 * @param reg The register offset

 * @param val The returned value read from the syscon register

 *

 * @return 0 on success, negative on error

 * @return 0 on success.

 * @return -ENOSYS If the API or function isn't implemented.

 */

__syscall int syscon_read_reg(const struct device *dev, uint16_t reg, uint32_t *val);
@@ -104,8 +106,8 @@ static inline int z_impl_syscon_read_reg(const struct device *dev, uint16_t reg, 
{

	const struct syscon_driver_api *api = (const struct syscon_driver_api *)dev->api;



	if (api == NULL) {

		return -ENOTSUP;

	if ((api == NULL) || (api->read == NULL)) {

		return -ENOSYS;

	}



	return api->read(dev, reg, val);
@@ -121,7 +123,8 @@ static inline int z_impl_syscon_read_reg(const struct device *dev, uint16_t reg, 
 * @param reg The register offset

 * @param val The value to be written in the register

 *

 * @return 0 on success, negative on error

 * @return 0 on success.

 * @return -ENOSYS If the API or function isn't implemented.

 */

__syscall int syscon_write_reg(const struct device *dev, uint16_t reg, uint32_t val);
@@ -129,8 +132,8 @@ static inline int z_impl_syscon_write_reg(const struct device *dev, uint16_t reg 
{

	const struct syscon_driver_api *api = (const struct syscon_driver_api *)dev->api;



	if (api == NULL) {

		return -ENOTSUP;

	if ((api == NULL) || (api->write == NULL)) {

		return -ENOSYS;

	}



	return api->write(dev, reg, val);
@@ -142,6 +145,7 @@ static inline int z_impl_syscon_write_reg(const struct device *dev, uint16_t reg 
 * @param dev The device to get the register size for.

 * @param size Pointer to write the size to.

 * @return 0 for success.

 * @return -ENOSYS If the API or function isn't implemented.

 */

__syscall int syscon_get_size(const struct device *dev, size_t *size);
@@ -149,6 +153,10 @@ static inline int z_impl_syscon_get_size(const struct device *dev, size_t *size) 
{

	const struct syscon_driver_api *api = (const struct syscon_driver_api *)dev->api;



	if ((api == NULL) || (api->get_size == NULL)) {

		return -ENOSYS;

	}



	return api->get_size(dev, size);

}

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