You will need to talk through the options with your GP. The greater the changes needed at work, the more contact you are likely to have with your GP, who is also likely to be in contact with your employer, subject to your consent.
If your organisation offers a workplace occupational health (OH) service, your GP is likely to be in regular contact with them. But this should only be with your agreement. You are entitled to be kept fully informed at all stages of any discussions or communications between your GP and your employer.
Some GPs know more than others about employers' duties to make 'reasonable adjustments' and about good practice. Depending on your disability, there may be a lot to consider. 'Reasonable adjustments' is a very broad term, ranging from a few basic changes (e.g. your start time, days of work, responsibilities, etc.) to significant changes (e.g. providing disabled access).
You should also check our advice on dealing with doctors.
Expert charities may also be able to help you. There is also a confidential occupational health web resource – the government-funded Fit for Work service, which has an employee hub, and a free advice line.